Orders of magnitude (length)

The following are examples of orders of magnitude for different lengths.

Objects of sizes in different order of magnitude (at inconsistent intervals)

Graphical overview of sizes

Overview

Scale	Range (m)		Unit	Example items
	≥	<
Subatomic	–	0	–	Gravitational singularity
	10−36	10−33	ℓP	Fixed value (not a range). Quantum foam, string
	10−18	10−15	am	Proton, neutron, pion
Atomic to cellular	10−15	10−12	fm	Atomic nucleus
	10−12	10−9	pm	Wavelength of gamma rays and X-rays, hydrogen atom
	10−9	10−6	nm	DNA helix, virus, wavelength of optical spectrum, transistors used in CPUs
Cellular to human	10−6	10−3	μm	Bacterium, fog water droplet, human hair's diameter[note 1]
	10−3	1	mm	Mosquito, golf ball, domestic cat, violin, football
Human to astronomical	1	103	m	Piano, human, automobile, sperm whale, football field, Eiffel Tower
	103	106	km	Mount Everest, length of Panama Canal and Trans-Siberian Railway, larger asteroid
Astronomical	106	109	Mm	The Moon, Earth, one light-second
	109	1012	Gm	Sun, one light-minute, Earth's orbit
	1012	1015	Tm	Orbits of outer planets, Solar System
	1015	1018	Pm	A light-year, the distance to Proxima Centauri
	1018	1021	Em	Galactic arm
	1021	1024	Zm	Milky Way, distance to Andromeda Galaxy
	1024	1027	Ym	Huge-LQG, Hercules–Corona Borealis Great Wall, Observable universe

Detailed list

To help compare different orders of magnitude, the following list describes various lengths between ${\displaystyle 1.6\times 10^{-35}}$ metres and ${\displaystyle 10^{10^{10^{122}}}}$metres.

Subatomic scale

Factor (m)	Multiple	Value	Item
0	0	0	Singularity
10−35	1 Planck length	0.0000162 qm	Planck length; typical scale of hypothetical loop quantum gravity or size of a hypothetical string and of branes; according to string theory, lengths smaller than this do not make any physical sense.[1] Quantum foam is thought to exist at this scale.
10−24	1 yoctometre (ym)	142 ym	Effective cross section radius of 1 MeV neutrinos[2]
10−21	1 zeptometre (zm)		Preons, hypothetical particles proposed as subcomponents of quarks and leptons; the upper bound for the width of a cosmic string in string theory
		7 zm	Effective cross section radius of high-energy neutrinos[3]
		310 zm	De Broglie wavelength of protons at the Large Hadron Collider (4 TeV as of 2012[update])
10−18	1 attometre (am)		Upper limit for the size of quarks and electrons
			Sensitivity of the LIGO detector for gravitational waves[4]
			Upper bound of the typical size range for "fundamental strings"[1]
10−17	10 am		Range of the weak force
10−16	100 am	850 am	Approximate proton radius[5]

Atomic to cellular scale

Factor (m)	Multiple	Value	Item
10−15	1 femtometre (fm, fermi)	1 fm	Approximate limit of the gluon-mediated color force between quarks[6][7]
		1.5 fm	Effective cross section radius of an 11 MeV proton[8]
		2.81794 fm	Classical electron radius[9]
		3 fm	Approximate limit of the meson-mediated nuclear binding force[6][7]
		750 to 822.25 fm	Longest wavelength of gamma rays
10−12	1 picometre (pm)	1.75 to 15 fm	Diameter range of the atomic nucleus[1][10]
		1 pm	Distance between atomic nuclei in a white dwarf
		2.4 pm	Compton wavelength of electron
		5 pm	Wavelength of shortest X-rays
10−11	10 pm	28 pm	Radius of helium atom
		53 pm	Bohr radius (radius of a hydrogen atom)
10−10	100 pm	100 pm	1 ångström (also covalent radius of sulfur atom[11])
		154 pm	Length of a typical covalent bond (C–C)
		280 pm	Average size of the water molecule (actual lengths may vary)
		500 pm	Width of protein α helix
10−9	1 nanometre (nm)	1 nm	Diameter of a carbon nanotube[12] Diameter of smallest transistor gate (as of 2016)[13]
		2 nm	Diameter of the DNA helix[14]
		2.5 nm	Smallest microprocessor transistor gate oxide thickness (as of January 2007[update])[citation needed]
		3.4 nm	Length of a DNA turn (10 bp)[15]
		6–10 nm	Thickness of cell membrane
10−8	10 nm	10 nm	Upper range of thickness of cell wall in Gram-negative bacteria[16]
		10 nm	As of 2016[update], the 10 nanometre was the smallest semiconductor device fabrication node[17]
		40 nm	Extreme ultraviolet wavelength
		50 nm	Flying height of the head of a hard disk[18]
10−7	100 nm	121.6 nm	Wavelength of the Lyman-alpha line[19]
		120 nm	Typical diameter of the human immunodeficiency virus (HIV)[20]
		400–700 nm	Approximate wavelength range of visible light[21]

Cellular to human scale

Factor (m)	Multiple	Value	Item
10−6	1 micrometre (μm) (also called 1 micron)	1–4 μm	Typical length of a bacterium[22]
		4 μm	Typical diameter of spider silk[23]
		7 μm	Typical size of a red blood cell[24]
10−5	10 μm	10 μm	Typical size of a fog, mist, or cloud water droplet
		10 μm	Width of transistors in the Intel 4004, the world's first commercial microprocessor
		12 μm	Width of acrylic fiber
		17-181 μm	Width range of human hair[25]
10−4	100 μm	340 μm	Size of a pixel on a 17-inch monitor with a resolution of 1024×768
		560 μm	Thickness of the central area of a human cornea[26]
		750 μm	Maximum diameter of Thiomargarita namibiensis, the second largest bacterium ever discovered
10−3	1 millimetre (mm)	~5 mm	Length of an average flea is 1–10 mm (usually <5 mm)[27]
		2.54 mm	One-tenth inch; distance between pins in DIP (dual-inline-package) electronic components
		5.70 mm	Diameter of the projectile in 5.56×45mm NATO ammunition
10−2	1 centimetre (cm)	20 mm	Approximate width of an adult human finger
		54 mm × 86 mm	Dimensions of a credit card, according to the ISO/IEC 7810 ID-1 standard
		73–75 mm	Diameter of a baseball, according to Major League Baseball guidelines[28]
10−1	1 decimetre (dm)	120 mm	Diameter of a compact disc
		660 mm	Length of the longest pine cones, produced by the sugar pine[29]
		900 mm	Average length of a rapier, a fencing sword[30]

Human to astronomical scale

Planets of the Solar System to scale

Factor (m)	Multiple	Value	Item
1 (100)	1 metre (m)	1 m (exactly)	Since 2019, defined as the length of the path travelled by light in a vacuum during a time interval of 1/299,792,458 of a second, where the second is defined by a hyperfine transition frequency of caesium.
		2.72 m	Height of Robert Wadlow, tallest-known human.[31]
		8.38 m	Length of a London bus (AEC Routemaster)
101	1 decametre (dam)	33 m	Length of the longest-known blue whale[32]
		52 m	Height of the Niagara Falls[33]
		93.47 m	Height of the Statue of Liberty
102	1 hectometre (hm)	105 m	Length of a typical football field
		137 m (147 m)	Height (present and original) of the Great Pyramid of Giza
		300 m	Height of the Eiffel Tower, one of the famous monuments of Paris
		979 m	Height of the Salto Angel, the world's highest free-falling waterfall (Venezuela)
103	1 kilometre (km)	2.3 km	Length of the Three Gorges Dam, the largest dam in the world[34][35]
		3.1 km	Narrowest width of the Strait of Messina, separating Italy and Sicily
		8.848 km	Height of Mount Everest, the highest mountain on Earth
104	10 km	10.9 km	Depth of the Challenger Deep in the Mariana Trench, the deepest-known point on Earth's surface
		27 km	Circumference of the Large Hadron Collider, as of May 2010[update] the largest and highest energy particle accelerator
		42.195 km	Length of a marathon
105	100 km	100 km	The distance the IAU considers to be the limit to space, called the Karman line
		163 km	Length of the Suez Canal, connecting the Mediterranean Sea to the Red Sea
		491 km	Length of the Pyrenees, the mountain range separating Spain and France
		974.6 km	Greatest diameter of the dwarf planet Ceres.[36]
106	1 megametre (Mm)	2.38 Mm	Diameter of dwarf planet Pluto, formerly the smallest planet category[note 2] in the Solar System
		3.48 Mm	Diameter of the Moon
		5.2 Mm	Typical distance covered by the winner of the 24 Hours of Le Mans automobile endurance race
		6.259 Mm	Length of the Great Wall of China
		6.371 Mm	Average radius of Earth
		6.378 Mm	Equatorial radius of Earth
		6.6 Mm	Approximate length of the two longest rivers, the Nile and the Amazon
		7.821 Mm	Length of the Trans-Canada Highway
		9.288 Mm	Length of the Trans-Siberian Railway, longest in the world

Astronomical scale

Factor (m)	Multiple	Value	Item
107	10 Mm	12.756 Mm	Equatorial diameter of Earth
		20.004 Mm	Length of a meridian on Earth (distance between Earth's poles along the surface)[37]
		40.075 Mm	Length of Earth's equator
108	100 Mm	142.984 Mm	Diameter of Jupiter
		299.792 Mm	Distance traveled by light in vacuum in one second (a light-second, exactly 299,792,458 m by definition of the speed of light)
		384.4 Mm	Moon's orbital distance from Earth
109	1 gigametre (Gm)	1.39 Gm	Diameter of the Sun
		5.15 Gm	Greatest mileage ever recorded by a car (3.2 million miles by a 1966 Volvo P-1800S)[38]
1010	10 Gm	18 Gm	Approximately one light-minute
1011	100 Gm	150 Gm	1 astronomical unit (au); mean distance between Earth and Sun
1012	1 terametre (Tm)	1.3 Tm	Optical diameter of Betelgeuse
		1.4 Tm	Orbital distance of Saturn from Sun
		2 Tm	Estimated optical diameter of VY Canis Majoris, one of the largest-known stars
		5.9 Tm	Orbital distance of Pluto from the Sun
		~ 7.5 Tm	Outer boundary of the Kuiper belt
1013	10 Tm		Diameter of the Solar System as a whole[1]
		16.09 Tm	Total length of DNA molecules in all cells of an adult human body[39]
		21.49 Tm	Distance of the Voyager 1 spacecraft from Sun (as of Oct 2018[update]), the farthest man-made object so far[40]
		62.03 Tm	Estimated radius of the event horizon of the supermassive black hole in NGC 4889, the largest-known black hole to date
1014	100 Tm	180 Tm	Size of the debris disk around the star 51 Pegasi[41]
1015	1 petametre (Pm)	~7.5 Pm	Supposed outer boundary of the Oort cloud (~ 50,000 au)
		9.461 Pm	Distance traveled by light in vacuum in one year; at its current speed, Voyager 1 would need 17,500 years to travel this distance
1016	10 Pm	30.857 Pm	1 parsec
		39.9 Pm	Distance to nearest star (Proxima Centauri)
		41.3 Pm	As of March 2013, distance to nearest discovered extrasolar planet (Alpha Centauri Bc)
1017	100 Pm	193 Pm	As of October 2010, distance to nearest discovered extrasolar planet with potential to support life as presently defined by science (Gliese 581 d)
		615 Pm	Approximate radius of humanity's radio bubble, caused by high-power TV broadcasts leaking through the atmosphere into outer space
1018	1 exametre (Em)	1.9 Em	Distance to nearby solar twin (HIP 56948), a star with properties virtually identical to the Sun[42]
1019	10 Em	9.46 Em	Average thickness of Milky Way Galaxy[43] (1,000 to 3,000 ly by 21 cm observations[44])
1020	100 Em	113.5 Em	Thickness of Milky Way Galaxy's gaseous disk[45]
1021	1 zettametre (Zm)
		1.54 Zm	Distance to SN 1987A, the most recent naked eye supernova
		1.62 Zm	Distance to the Large Magellanic Cloud (a dwarf galaxy orbiting the Milky Way)
		1.66 Zm	Distance to the Small Magellanic Cloud (another dwarf galaxy orbiting the Milky Way)
		1.9 Zm	Diameter of galactic disk of Milky Way Galaxy[46][47][48][49]
		6.15 Zm	Diameter of the low surface brightness disc halo of the giant spiral galaxy Malin 1
1022	10 Zm	13.25 Zm	Radius of the diffuse stellar halo of IC 1101, one of the largest-known galaxies
		24 Zm	Distance to Andromeda Galaxy
		30.857 Zm	1 megaparsec
		50 Zm	Diameter of Local Group of galaxies
1023	100 Zm	300–600 Zm	Distance to Virgo cluster of galaxies
1024	1 yottametre (Ym)	2.19 Ym	Diameter of the Local Supercluster and the largest voids and filaments
		2.8 Ym	End of Greatness
		~5 Ym	Diameter of the Horologium Supercluster[50]
		9.461 Ym	Diameter of the Pisces–Cetus Supercluster Complex, the supercluster complex which includes Earth
1025	10 Ym	13 Ym	Length of the Sloan Great Wall, a giant wall of galaxies (galactic filament)[51]
		30.857 Ym	1 gigaparsec
		37.84 Ym	Length of the Huge-LQG, a group of 73 quasars
1026	100 Ym	95 Ym	Estimated light travel distance to certain quasars. Length of the Hercules–Corona Borealis Great Wall, a colossal wall of galaxies, the largest and the most massive structure in the observable universe as of 2014
		127 Ym	Estimated light travel distance to GN-z11, the most distant object ever observed
		870 Ym	Approximate diameter (comoving distance) of the visible universe[1]
1027	1 Rm	1.2 Rm	Lower bound of the (possibly infinite) radius of the universe, if it is a 3-sphere, according to one estimate using the WMAP data at 95% confidence[52] It equivalently implies that there are at minimum 21 particle horizon-sized volumes in the universe.
${\displaystyle 10^{10^{115}}}$[note 3]	${\displaystyle 10^{10^{115}}}$ m	${\displaystyle 10^{10^{115}}}$ m	According to the laws of probability, the distance one must travel until one encounters a volume of space identical to our observable universe with conditions identical to our own.[53][54]
${\displaystyle 10^{10^{10^{122}}}}$	${\displaystyle 10^{10^{10^{122}}}}$ m	${\displaystyle 10^{10^{10^{122}}}}$ m	Maximum size of universe after cosmological inflation, implied by one resolution of the No-Boundary Proposal[55]

1 quectometre and less

The quectometre (SI symbol: qm) is a unit of length in the metric system equal to 10⁻³⁰ metres. To help compare different orders of magnitude, this section lists lengths shorter than 10⁻³⁰ m (1 qm).

• 1.6 × 10⁻⁵ quectometres (1.6 × 10⁻³⁵ metres) – the Planck length (Measures of distance shorter than this do not make physical sense, according to current theories of physics.)
• 1 qm – 1 quectometre, the smallest named subdivision of the metre in the SI base unit of length, one nonillionth of a metre.^[56]

1 rontometre

The rontometre (SI symbol: rm) is a unit of length in the metric system equal to 10⁻²⁷ metres.

• 1 rm – 1 rontometre, a subdivision of the metre in the SI base unit of length, one octillionth of a metre.^[56]

10 rontometres

• 10 rm – the length of one side of a square whose area is one shed, a unit of target cross section used in nuclear physics

1 yoctometre

The yoctometre (SI symbol: ym) is a unit of length in the metric system equal to 10⁻²⁴ metres.

• 2 ym – the effective cross-section radius of 1 MeV neutrinos as measured by Clyde Cowan and Frederick Reines.^[57]

1 zeptometre

The zeptometre (SI symbol: zm) is a unit of length in the metric system equal to 10⁻²¹ metres. To help compare different orders of magnitude, this section lists lengths between 10⁻²¹ m and 10⁻²⁰ m (1 zm and 10 zm).

• 2 zm – the upper bound for the width of a cosmic string in string theory.^{[citation needed]}
• 2 zm – radius of effective cross section for a 20 GeV neutrino scattering off a nucleon^[3]
• 7 zm – radius of effective cross section for a 250^{[broken anchor]} GeV neutrino scattering off a nucleon^[3]

10 zeptometres

To help compare different orders of magnitude, this section lists lengths between 10⁻²⁰ m and 10⁻¹⁹ m (10 zm and 100 zm).

100 zeptometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁹ m and 10⁻¹⁸ m (100 zm and 1 am).

• 177 zm – de Broglie wavelength of protons at the Large Hadron Collider (7 TeV as of 2010)^{[citation needed]}

1 attometre

The attometre (SI symbol: am) is a unit of length in the metric system equal to 10⁻¹⁸ metres. To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁸ m and 10⁻¹⁷ m (1 am and 10 am).

• 1 am – sensitivity of the LIGO detector for gravitational waves^{[citation needed]}
• 1 am – upper limit for the size of quarks and electrons^{[citation needed]}

10 attometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁷ m and 10⁻¹⁶ m (10 am and 100 am).

• 10–100 am – range of the weak force^[58]
• 86 am – charge radius of a Bottom eta meson^[59]

100 attometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁶ m and 10⁻¹⁵ m (100 am and 1 fm).

• 831 am – approximate proton radius^[60][61]

1 femtometre (or 1 fermi)

The femtometre (SI symbol: fm) is a unit of length in the metric system equal to 10⁻¹⁵ metres. In particle physics, this unit is sometimes called a fermi, also with abbreviation "fm". To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁵ metres and 10⁻¹⁴ metres (1 femtometre and 10 fm).

• 1 fm – diameter of a neutron, approximate range-limit of the color force carried between quarks by gluons^[6][7]
• 1.5 fm – diameter of the scattering cross section of an 11 MeV proton with a target proton^[8]
• 1.75 fm – the effective charge diameter of a proton^[62]
• 2.81794 fm – classical electron radius^[63]
• 3 fm – approximate range-limit of the nuclear binding force mediated by mesons^[6][7]
• 7 fm – the radius of the effective scattering cross section for a gold nucleus scattering a 6^{[broken anchor]} MeV alpha particle over 140 degrees^[8]

10 femtometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹⁴ m and 10⁻¹³ m (10 fm and 100 fm).

• 1.75 to 15 fm – diameter range of the atomic nucleus^{[citation needed]}
• 10 fm – the length of one side of a square whose area is one barn (10⁻²⁸ m²), a unit of target cross section used in nuclear physics
• 30.8568 fm – 1 quectoparsec (10⁻³⁰ parsecs)

100 femtometres

To help compare different orders of magnitude, this section lists lengths between 10⁻¹³ m and 10⁻¹² m (100 fm and 1 pm).

• 570 fm – typical distance from the atomic nucleus of the two innermost electrons (electrons in the 1s shell) in the uranium atom, the heaviest naturally-occurring atom

1 picometre

The picometre (SI symbol: pm) is a unit of length in the metric system equal to 10⁻¹² metres (⁠1/1000000000000⁠ m = 0.000000000001 m). To help compare different orders of magnitude this section lists lengths between 10⁻¹² and 10⁻¹¹ m (1 pm and 10 pm).

• 1 pm – distance between atomic nuclei in a white dwarf^{[citation needed]}
• 1 pm – reference value of particle displacement in acoustics^[64]
• 2.4 pm – the Compton wavelength of an electron
• 5 pm – shorter X-ray wavelengths (approx.)

10 picometres

To help compare different orders of magnitude this section lists lengths between 10⁻¹¹ and 10⁻¹⁰ m (10 pm and 100 pm).

• 25 pm – approximate radius of a helium atom, the smallest neutral atom^[65][66]
• 30.8568 pm – 1 rontoparsec
• 50 pm – radius of a hydrogen atom
• 50 pm – bohr radius: approximate radius of a hydrogen atom
• ~50 pm – best resolution of a high-resolution transmission electron microscope
• 60 pm – radius of a carbon atom
• 93 pm – length of a diatomic carbon molecule
• 96 pm – H–O bond length in a water molecule

100 picometres

To help compare different orders of magnitude this section lists lengths between 10⁻¹⁰ and 10⁻⁹ m (100 pm and 1 nm; 1 Å and 10 Å).

• 100 pm – 1 ångström
• 100 pm – covalent radius of sulfur atom^[67]
• 120 pm – van der Waals radius of a neutral hydrogen atom^[68]
• 120 pm – radius of a gold atom
• 126 pm – covalent radius of ruthenium atom
• 135 pm – covalent radius of technetium atom
• 150 pm – length of a typical covalent bond (C–C)
• 153 pm – covalent radius of silver atom
• 155 pm – covalent radius of zirconium atom
• 175 pm – covalent radius of thulium atom
• 200 pm – highest resolution of a typical electron microscope^[69]
• 225 pm – covalent radius of caesium atom
• 280 pm – average size of the water molecule
• 298 pm – radius of a caesium atom, calculated to be the largest atomic radius
• 340 pm – thickness of single layer graphene
• 356.68 pm – width of diamond unit cell
• 403 pm – width of lithium fluoride unit cell
• 500 pm – Width of protein α helix
• 543 pm – silicon lattice spacing
• 560 pm – width of sodium chloride unit cell
• 700 pm – width of glucose molecule
• 700 pm – diameter of a buckyball^[70]
• 780 pm – mean width of quartz unit cell
• 820 pm – mean width of ice unit cell
• 900 pm – mean width of coesite unit cell

1 nanometre

The nanometre (SI symbol: nm) is a unit of length in the metric system equal to 10⁻⁹ metres (⁠1/1000000000⁠ m = 0.000000001 m). To help compare different orders of magnitude, this section lists lengths between 10⁻⁹ and 10⁻⁸ m (1 nm and 10 nm).

• 1 nm – diameter of a carbon nanotube
• 1 nm – roughly the length of a sucrose molecule, calculated by Albert Einstein
• 2.3 nm – length of a phospholipid
• 2.3 nm – smallest gate oxide thickness in microprocessors
• 3 nm – width of a DNA helix
• 3 nm – flying height of the head of a hard disk
• 3 nm – the average half-pitch of a memory cell manufactured circa 2022
• 3.4 nm – length of a DNA turn (10 bp)
• 3.8 nm – size of an albumin molecule
• 5 nm – size of the gate length of a 16 nm processor
• 5 nm – the average half-pitch of a memory cell manufactured circa 2019–2020
• 6 nm – length of a phospholipid bilayer
• 6–10 nm – thickness of cell membrane
• 6.8 nm – width of a haemoglobin molecule
• 7 nm – diameter of actin filaments
• 7 nm – the average half-pitch of a memory cell manufactured circa 2018
• 10 nm – thickness of cell wall in Gram-negative bacteria

10 nanometres

Comparison of sizes of semiconductor manufacturing process nodes with some microscopic objects and visible light wavelengths. At this scale, the width of a human hair is about 10 times that of the image.^[71]

To help compare different orders of magnitude this section lists lengths between 10⁻⁸ and 10⁻⁷ m (10 nm and 100 nm).

• 10 nm Shortest extreme ultraviolet wavelength or longest X-ray wavelength^[72]
• 10 nm – the average length of a nanowire
• 10 nm – lower size of tobacco smoke^[73]
• 10 nm – the average half-pitch of a memory cell manufactured circa 2016 –2017
• 13 nm – the length of the wavelength that is used for EUV lithography
• 14 nm – length of a porcine circovirus
• 14 nm – the average half-pitch of a memory cell manufactured circa 2013
• 15 nm – length of an antibody
• 18 nm – diameter of tobacco mosaic virus^[74] (Generally, viruses range in size from 20 nm to 450 nm.)^{[citation needed]}
• 20 nm – length of a nanobe, could be one of the smallest forms of life
• 20–80 nm – thickness of cell wall in Gram-positive bacteria^[75]
• 20 nm – thickness of bacterial flagellum^[76]
• 22 nm – the average half-pitch of a memory cell manufactured circa 2011–2012
• 22 nm – smallest feature size of production microprocessors in September 2009^[77]
• 25 nm – diameter of a microtubule
• 30 nm – lower size of cooking oil smoke
• 30.8568 nm – 1 yoctoparsec
• 32 nm – the average half-pitch of a memory cell manufactured circa 2009–2010
• 40 nm – extreme ultraviolet wavelength
• 45 nm – the average half-pitch of a memory cell manufactured circa 2007–2008
• 50 nm – upper size for airborne virus particles
• 50 nm – flying height of the head of a hard disk^[78]
• 65 nm – the average half-pitch of a memory cell manufactured circa 2005–2006
• 58 nm – height of a T7 bacteriophage
• 90 nm – human immunodeficiency virus (HIV) (generally, viruses range in size from 20 nm to 450 nm)
• 90 nm – the average half-pitch of a memory cell manufactured circa 2002–2003
• 100 nm – Length of a mesoporous silica nanoparticle

100 nanometres

Comparison of sizes of semiconductor manufacturing process nodes with some microscopic objects and visible light wavelengths. At this scale, the width of a human hair is about 10 times that of the image.^[79]

To help compare different orders of magnitude, this section lists lengths between 10⁻⁷ and 10⁻⁶ m (100 nm and 1 μm).

• 100 nm – greatest particle size that can fit through a surgical mask^[80]
• 100 nm – 90% of particles in wood smoke are smaller than this.^{[citation needed]}
• 120 nm – greatest particle size that can fit through a ULPA filter^[81]
• 120 nm – diameter of a human immunodeficiency virus (HIV)^[82]
• 120 nm – approximate diameter of SARS-CoV-2^[83]
• 125 nm – standard depth of pits on compact discs (width: 500 nm, length: 850 nm to 3.5 μm)
• 180 nm – typical length of the rabies virus
• 200 nm – typical size of a Mycoplasma bacterium, among the smallest bacteria
• 300 nm – greatest particle size that can fit through a HEPA (high efficiency particulate air) filter (N100 removes up to 99.97% at 300 nm, N95 removes up to 95% at 300 nm)^[84]
• 300–400 nm – near ultraviolet wavelength
• 400–420 nm – wavelength of violet light (see Color and Visible spectrum)
• 420–440 nm – wavelength of indigo light
• 440–500 nm – wavelength of blue light
• 500–520 nm – wavelength of cyan light
• 520–565 nm – wavelength of green light
• 565–590 nm – wavelength of yellow light
• 590–625 nm – wavelength of orange light
• 625–700 nm – wavelength of red light
• 700–1.4 μm – wavelength of near-infrared radiation

1 micrometre (or 1 micron)

The silk for a spider's web is 5–7 μm (0.00020–0.00028 in) wide.

The micrometre (SI symbol: μm) is a unit of length in the metric system equal to 10⁻⁶ metres (⁠1/1000000⁠ m = 0.000001 m). To help compare different orders of magnitude, this section lists some items with lengths between 10⁻⁶ and 10⁻⁵ m (between 1 and 10 micrometres, or μm).

• ~0.7–300 μm – wavelength of infrared radiation
• 1 μm – the side of a square of area 10⁻¹² m²
• 1 μm – edge of cube of volume 10⁻¹⁸ m³ (1 fL)
• 1–10 μm – diameter of a typical bacterium^{[citation needed]}
• 1 μm – length of a lysosome
• 1–2 μm – anthrax spore^[85]
• 2 μm – length of an average E. coli bacteria
• 3–4 μm – size of a typical yeast cell^[86]
• 5 μm – length of a typical human spermatozoon's head^[87]
• 6 μm – thickness of the tape in a 120-minute (C120) compact cassette^[88]
• 7 μm – diameter of the nucleus of a typical eukaryotic cell^{[citation needed]}
• about 7 μm – diameter of human red blood cells^[89]
• 3–8 μm – width of strand of spider web silk^[90]
• 5–10 μm – width of a chloroplast^[91]
• 8–11 μm – size of a ground-level fog or mist droplet^{[92][note 4]}
• 7–12 μm – the diameter of human white blood cells
• 8–10 μm – the diameter of human macrophages

10 micrometres

Fog particles are around 10–50 μm (0.00039–0.00197 in) long.

To help compare different orders of magnitude, this section lists lengths between 10⁻⁵ m and 10⁻⁴ m (10 μm and 100 μm).

• 10 μm – width of cotton fibre^[93]
• 10 μm – tolerance of a Lego brick^[94]
• 10 μm – transistor width of the Intel 4004, the world's first commercial microprocessor
• 10 μm – mean longest dimension of a human red blood cell^{[citation needed]}
• 5–20 μm – dust mite excreta^[95]
• 10.6 μm – wavelength of light emitted by a carbon dioxide laser
• 15 μm – width of silk fibre^{[citation needed]}
• 17 μm – minimum width of a strand of human hair^[25]
• 17.6 μm – one twip, a unit of length in typography
• 10 to 55 μm – width of wool fibre^[93]
• 25.4 μm – 1/1,000 inch, commonly referred to as 1 mil in the U.S. and 1 thou in the UK
• 30 μm – length of a human skin cell
• 30.8568 μm – 1 zeptoparsec
• 50 μm – typical length of Euglena gracilis, a flagellate protist^[96]
• 50 μm – typical length of a human liver cell, an average-sized body cell^{[citation needed]}
• 50 μm – length of a silt particle
• 60 μm – length of a sperm cell
• 78 μm — width of a pixel on the display of the iPhone 4, marketed as Retina Display^[97]
• 70 to 180 μm – thickness of paper

100 micrometres

A paramecium is around 300 μm (0.012 in) long.

To help compare different orders of magnitude, this section lists lengths between 10⁻⁴ m and 10⁻³ m (100 μm and 1 mm). The term myriometre (abbr. mom, equivalent to 100 micrometres; frequently confused with the myriametre, 10 kilometres)^[98] is deprecated; the decimal metric prefix myrio-^[99] is obsolete^{[100][101][102]} and was not included among the prefixes when the International System of Units was introduced in 1960.

• 100 μm – 1/10 of a millimetre
• 100 μm – 0.00394 inches
• 100 μm – smallest distance that can be seen with the naked eye
• 100 μm – average diameter of a strand of human hair^[25]
• 100 μm – thickness of a coat of paint
• 100 μm – length of a dust particle
• 120 μm – the geometric mean of the Planck length and the diameter of the observable universe: √8.8 × 10²⁶ m × 1.6 × 10⁻³⁵ m
• 120 μm – diameter of a human ovum
• 170 μm – length of the largest mammalian sperm cell (rat)^[103]
• 170 μm – length of the largest sperm cell in nature, belonging to the Drosophila bifurca fruit fly^[104][105]
• 181 μm – maximum width of a strand of human hair^[25]
• 100–400 μm – length of Demodex mites living in human hair follicles
• 175–200 μm – typical thickness of a solar cell.
• 200 μm – typical length of Paramecium caudatum, a ciliate protist
• 200 μm – nominal width of the smallest commonly available mechanical pencil lead (0.2 mm)
• 250–300 μm – length of a dust mite^[106]
• 340 μm – length of a pixel on a 17-inch monitor with a resolution of 1024×768
• 500 μm – typical length of Amoeba proteus, an amoeboid protist
• 500 μm – MEMS micro-engine^[107]
• 500 μm – average length of a grain of sand
• 500 μm – average length of a grain of salt
• 500 μm – average length of a grain of sugar
• 560 μm – thickness of the central area of a human cornea^[26]
• 750 μm – diameter of a Thiomargarita namibiensis, the largest bacteria known^[108]
• 760 μm – thickness of an identification card

1 millimetre

An average red ant is about 5 mm (0.20 in) long.

"1mm" redirects here. For the Perfume song, see Level3 (Perfume album). For the measure, see millimetre.

The millimetre (SI symbol: mm) is a unit of length in the metric system equal to 10⁻³ metres (⁠1/1000⁠ m = 0.001 m). To help compare different orders of magnitude, this section lists lengths between 10⁻³ m and 10⁻² m (1 mm and 1 cm).

• 1.0 mm – 1/1,000 of a metre
• 1.0 mm – 0.03937 inches or 5/127 (exactly)
• 1.0 mm – side of a square of area 1 mm²
• 1.0 mm – diameter of a pinhead
• 1.5 mm – average length of a flea^[27]
• 2.54 mm – distance between pins on old dual in-line package (DIP) electronic components
• 5 mm – length of an average red ant
• 5 mm – diameter of an average grain of rice
• 5.56×45mm NATO – standard ammunition size
• 6 mm – approximate width of a pencil
• 7 mm – length of a Paedophryne amauensis, the smallest-known vertebrate^[109]
• 7.1 mm – length of a sunflower seed
• 7.62×51mm NATO – common military ammunition size^[110]
• 8 mm – width of old-format home movie film
• 8 mm – length of a Paedocypris progenetica, the smallest-known fish^[111]

1 centimetre

An average human fingernail is 1 cm (0.39 in) wide

"10 mm" redirects here. For firearms cartridges, see 10 mm calibre.

The centimetre (SI symbol: cm) is a unit of length in the metric system equal to 10⁻² metres (⁠1/100⁠ m = 0.01 m). To help compare different orders of magnitude, this section lists lengths between 10⁻² m and 10⁻¹ m (1 cm and 1 dm).

• 1 cm – 10 millimetres
• 1 cm – 0.39 inches
• 1 cm – edge of a square of area 1 cm²
• 1 cm – edge of a cube of volume 1 mL
• 1 cm – length of a coffee bean
• 1 cm – approximate width of average fingernail
• 1.2 cm – length of a bee
• 1.2 cm – diameter of a die
• 1.5 cm – length of a very large mosquito
• 1.6 cm – length of a Jaragua Sphaero, a very small reptile
• 1.7 cm – length of a Thorius arboreus, the smallest salamander^[112]
• 2 cm – approximate width of an adult human finger
• 2.54 cm – 1 inch
• 3.08568 cm – 1 attoparsec
• 3.4 cm – length of a quail egg^[113]
• 3.5 cm – width of film commonly used in motion pictures and still photography
• 3.78 cm – amount of distance the Moon moves away from Earth each year^[114]
• 4.3 cm – minimum diameter of a golf ball^[115]
• 5 cm – usual diameter of a chicken egg
• 5 cm – height of a hummingbird, the smallest-known bird
• 5.08 cm – 2 inches,
• 5.5 × 5.5 × 5.5 cm – dimensions of a 3x3x3 Rubik's cube
• 6.1 cm – average height of an apple
• 7.3–7.5 cm – diameter of a baseball^[28]
• 8.6 cm × 5.4 cm – dimensions of a standard credit card (also called CR80)^[116][117]
• 9 cm – length of a speckled padloper, the smallest-known turtle

1 decimetre

"10cm" redirects here. For the band, see 10cm (band).

An adult human foot is about 28 cm (11 in) long.

The decimetre (SI symbol: dm) is a unit of length in the metric system equal to 10⁻¹ metres (⁠1/10⁠ m = 0.1 m). To help compare different orders of magnitude, this section lists lengths between 10 centimetres and 100 centimetres (10⁻¹ metre and 1 metre).

Conversions

10 centimetres (abbreviated to 10 cm) is equal to:

• 1 decimetre (dm), a term not in common use (1 L = 1 dm³.)
• 100 millimetres
• 3.9 inches
• a side of a square of area 0.01 m²
• the edge of a cube with a volume of 1×10⁻³ m³ (1 L)

Wavelengths

• 10 cm = 1.0 dm – wavelength of the highest UHF radio frequency, 3 GHz
• 12 cm = 1.2 dm – wavelength of the 2.45 GHz ISM radio band
• 21 cm = 2.1 dm – wavelength of the 1.4 GHz hydrogen emission line, a hyperfine transition of the hydrogen atom
• 100 cm = 10 dm – wavelength of the lowest UHF radio frequency, 300 MHz

Human-defined scales and structures

• 10.16 cm = 1.016 dm – 1 hand used in measuring height of horses (4 inches)
• 12 cm = 1.2 dm – diameter of a compact disc (CD) (= 120 mm)
• 15 cm = 1.5 dm – length of a Bic pen with cap on
• 22 cm = 2.2 dm – diameter of a typical association football (soccer ball)
• 30 cm = 3 dm – typical school-use ruler length (= 300 mm)
• 30.48 cm = 3.048 dm – 1 foot (measure)
• 60 cm = 6 dm – standard depth (front to back) of a domestic kitchen worktop in Europe (= 600 mm)
• 90 cm = 9 dm – average length of a rapier, a fencing sword^[30]
• 91.44 cm = 9.144 dm – one yard (measure)

Nature

• 10 cm = 1 dm – diameter of the human cervix upon entering the second stage of labour
• 11 cm = 1.1 dm – length of an average potato in the US
• 13 cm = 1.3 dm – body length of a Goliath birdeater
• 15 cm = 1.5 dm – approximate size of largest beetle species
• 19 cm = 1.9 dm – length of a banana
• 26.3 cm = 2.6 dm – length of average male human foot
• 29.98 cm = 2.998 dm – distance light in vacuum travels in one nanosecond
• 30 cm = 3.0 dm – maximum leg length of a Goliath birdeater
• 31 cm = 3.1 dm – wingspan of largest butterfly species Ornithoptera alexandrae
• 32 cm – length of the Goliath frog, the world's largest frog
• 46 cm = 4.6 dm – length of an average domestic cat
• 50 to 65 cm = 5–6.5 dm – a coati's tail
• 66 cm = 6.6 dm – length of the longest pine cones (produced by the sugar pine^[118])

Astronomical

• 84 cm = 8.4 dm – approximate diameter of 2008 TS26, a meteoroid

1 metre

"1m" redirects here. For other uses, see 1M.

Leonardo da Vinci drew the Vitruvian Man within a square of side 1.83 m (6 ft 0 in) and a circle about 1.2 m (3 ft 11 in) in radius.

To help compare different orders of magnitude, this section lists lengths between one metre and ten metres. Light, in vacuum, travels 1 metre in 1⁄299,792,458, or 3.3356409519815E-9 of a second.

Conversions

1 metre is:

• 10 decimetres
• 100 centimetres
• 1,000 millimetres
• 39.37 inches
• 3.28 feet
• 1.1 yards
• side of square with area 1 m²
• edge of cube with surface area 6 m² and volume 1 m³
• radius of circle with area π m²
• radius of sphere with surface area 4π m² and volume 4/3π m³

Human-defined scales and structures

• 1 m – approximate height of the top part of a doorknob on a door
• 1 m – diameter of a very large beach ball
• 1.29 m – length of the Cross Island Chapel, the smallest church in the world
• 1.4 m – length of a Peel P50, the world's smallest car
• 1.435 m – standard gauge of railway track used by about 60% of railways in the world = 4 ft 81⁄2 in
• 2.5 m – distance from the floor to the ceiling in an average residential house^[119]
• 2.7 m – length of the Starr Bumble Bee II, the smallest plane
• 2.77–3.44 m – wavelength of the broadcast radio FM band 87–108 MHz
• 3.05 m – the length of an old Mini
• 8 m – length of the Tsar Bomba, the largest bomb ever detonated
• 8.38 m – the length of a London Bus (AEC Routemaster)

Sports

• 2.44 m – height of an association football goal^[120]
• 2.45 m – highest high jump by a human (Javier Sotomayor)^[121]
• 3.05 m – (10 feet) height of the basket in basketball
• 8.95 m – longest long jump by a human (Mike Powell)^[122]

Nature

• 1 m – length of Rafflesia arnoldii, the largest flower in the world
• 1 m – height of Homo floresiensis (the "Hobbit")
• 1.15 m – a pizote (mammal)
• 1.5 m – height of an okapi
• 1.63 m – (5 feet 4 inches) (or 64 inches) – height of average U.S. female human as of 2002^[update] (source: U.S. Centers for Disease Control and Prevention (CDC))
• 1.75 m – (5 feet 8 inches) – height of average U.S. male human as of 2002^[update] (source: U.S. CDC as per female above)
• 2.4 m – wingspan of a mute swan
• 2.5 m – height of a sunflower
• 2.7 m – length of a leatherback sea turtle, the largest living turtle
• 2.72 m – (8 feet 11 inches) – tallest-known human (Robert Wadlow)^[31]
• 3 m – length of a giant Gippsland earthworm
• 3.63 m – the record wingspan for living birds (a wandering albatross)
• 3.7 m – leg span of a Japanese spider crab
• 3.7 m – length of a southern elephant seal, the largest living pinniped
• 5 m – length of an elephant
• 5.2 m – height of a giraffe^[123]
• 5.5 m – height of a Baluchitherium, the largest land mammal ever lived
• 6.5 m – wingspan of Argentavis, the largest flying bird known
• 6.7 m – length of a Microchaetus rappi
• 7.4 m – wingspan of Pelagornis, the bird with longest wingspan ever.^[124]
• 7.5 m – approximate length of the human gastrointestinal tract

Astronomical

• 3–6 m – approximate diameter of 2003 SQ222, a meteoroid
• 4.1 m – diameter of 2008 TC3, a small asteroid that flew into the Earth's atmosphere on 7 October 2008^[125]

1 decametre

A blue whale has been measured as 33 m (108 ft) long; this drawing compares its length to that of a human diver and a dolphin.

The decametre (SI symbol: dam) is a unit of length in the metric system equal to 10 metres (10¹ m). To help compare different orders of magnitude, this section lists lengths between 10 and 100 metres.

Conversions

10 metres (very rarely termed a decametre which is abbreviated as dam) is equal to:

• 10 metres
• 100 decimetres
• 1,000 centimetres
• 10,000 millimetres
• 10,000,000 micrometres (or rarely 10,000,000 microns)
• 32.8 feet
• 11 yards
• side of a square with area 100 m²

Human-defined scales and structures

• 10 metres – wavelength of the highest shortwave radio frequency, 30 MHz
• 10.2 metres – length of the Panzer VIII Maus, the world's largest tank
• 12 metres – height of the Newby-McMahon Building, the world's littlest skyscraper
• 23 metres – height of Luxor Obelisk, located in the Place de la Concorde, Paris, France
• 25 metres – wavelength of the broadcast radio shortwave band at 12 MHz
• 29 metres – height of the Savudrija Lighthouse
• 30 metres – height of Christ the Redeemer
• 31 metres – wavelength of the broadcast radio shortwave band at 9.7 MHz
• 32 metres – length of one arcsecond of latitude on the surface of the Earth
• 33.3 metres – height of the De Noord, the tallest windmill in the world
• 34 metres – height of the Split Point Lighthouse in Aireys Inlet, Victoria, Australia
• 40 metres – wingspan of the Mil Mi-26, the largest helicopter
• 40 metres – average depth beneath the seabed of the Channel tunnel
• 49 metres – wavelength of the broadcast radio shortwave band at 6.1 MHz
• 50 metres – length of a road train
• 50 metres – height of the Arc de Triomphe
• 55 metres – height of the Leaning Tower of Pisa
• 62 metres – wingspan of Concorde
• 62.5 metres – height of Pyramid of Djoser
• 64 metres – wingspan of a Boeing 747-400
• 69 metres – wingspan of an Antonov An-124 Ruslan
• 70 metres – length of the Bayeux Tapestry
• 70 metres – width of a typical association football field
• 73 metres – wingspan of a Airbus A380
• 73 metres – height of the Taj Mahal
• 77 metres – wingspan of a Boeing 747-8
• 88.4 metres – wingspan of an Antonov An-225 Mriya transport aircraft
• 93 metres – height of the Statue of Liberty (Liberty Enlightening the World)
• 96 metres – height of Big Ben
• 100 metres – wavelength of the lowest shortwave radio frequency, 3 MHz

Sports

• 11 metres – approximate width of a doubles tennis court
• 15 metres – width of a standard FIBA basketball court
• 15.24 metres – width of an NBA basketball court (50 feet)
• 18.44 metres – distance between the front of the pitcher's rubber and the rear point of home plate on a baseball field (60 feet, 6 inches)^[126]
• 20 metres – length of cricket pitch (22 yards)^[127]
• 27.43 metres – distance between bases on a baseball field (90 feet)
• 28 metres – length of a standard FIBA basketball court
• 28.65 metres – length of an NBA basketball court (94 feet)
• 49 metres – width of an American football field (531⁄3 yards)
• 59.436 metres – width of a Canadian football field (65 yards)
• 70 metres – typical width of an association football field
• 91 metres – length of an American football field (100 yards, measured between the goal lines)

Nature

• 10 metres – average length of human digestive tract^{[citation needed]}
• 12 metres – height of a saguaro cactus
• 12 metres – length of a whale shark, largest living fish
• 12 metres – wingspan of a Quetzalcoatlus, a pterosaur
• 12.8 metres – length of a Titanoboa, the largest snake to have ever lived
• 13 metres – length of a giant squid and colossal squid, the largest living invertebrates
• 15 metres – approximate distance the tropical circles of latitude are moving towards the equator and the polar circles are moving towards the poles each year due to a natural, gradual decrease in the Earth's axial tilt
• 16 metres – length of a sperm whale, the largest toothed whale
• 18 metres – height of a Sauroposeidon, the tallest-known dinosaur
• 20 metres – length of a Leedsichthys, the largest-known fish to have lived
• 21 metres – height of High Force waterfall in England
• 30.5 metres – length of the lion's mane jellyfish, the largest jellyfish in the world
• 33 metres – length of a blue whale,^[128] the largest animal on earth, living or extinct, in terms of mass
• 39 metres – length of a Supersaurus, the longest-known dinosaur and longest vertebrate^[129]
• 52 metres – height of Niagara Falls^[33]
• 55 metres – length of a bootlace worm, the longest-known animal^[130]
• 66 metres – highest possible sea level rise due to a complete melting of all ice on Earth
• 83 metres – height of a western hemlock
• 84 metres – height of General Sherman, the largest tree in the world

Astronomical

• 30 metres – diameter of 1998 KY26, a rapidly spinning meteoroid
• 30.8568 metres – 1 femtoparsec
• 32 metres – approximate diameter of 2008 HJ, a small meteoroid

1 hectometre

The Great Pyramid of Giza is 138.8 m (455 ft) high.

British driver location sign and location marker post on the M27 in Hampshire. The location marker posts are installed at 100-metre intervals.^[131]

The hectometre (SI symbol: hm) is a unit of length in the metric system equal to 100 metres (10² m). To compare different orders of magnitude this section lists lengths between 100 metres and 1,000 metres (1 kilometre).

Conversions

100 metres (sometimes termed a hectometre) is equal to:

• 328 feet
• one side of a 1 hectare square
• a fifth of a modern li, a Chinese unit of measurement
• the approximate distance travelled by light in 300 nanoseconds

Human-defined scales and structures

• 100 metres – wavelength of the highest medium wave radio frequency, 3 MHz
• 100 metres – spacing of location marker posts on British motorways
• 110 metres – height of the Saturn V
• 138.8 metres – height of the Great Pyramid of Giza (Pyramid of Cheops)
• 139 metres – height of the world's tallest roller coaster, Kingda Ka^[132]
• 157 metres – height of the Cologne Cathedral
• 162 metres – height of the Ulm Minster, the tallest church building in the world
• 165 metres – height of the Dushanbe Flagpole, the tallest flagpole from May 2011 to September 2014
• 169 metres – height of the Washington Monument
• 171 metres – height of the Jeddah Flagpole, the tallest flagpole from September 2014 to December 2021
• 182 metres – height of the Statue of Unity, the world's tallest statue
• 187 metres – shortest wavelength of the broadcast radio AM band, 1600 kHz
• 192 metres – height of the Gateway Arch
• 202 metres – height of the Cairo Flagpole, the tallest flagpole as of December 2021
• 202 metres – length of the Széchenyi Chain Bridge connecting Buda and Pest
• 220 metres – height of the Hoover Dam
• 245 metres – length of the LZ 129 Hindenburg
• 270 metres – length of the Titanic
• 318 metres – height of The New York Times Building
• 318.9 metres – height of the Chrysler Building
• 328 metres – height of Auckland's Sky Tower, the tallest free-standing structure in the Southern Hemisphere (1996–2022)
• 330 metres – height of the Eiffel Tower (including antenna)^[133]
• 336 metres – height of the world's tallest bridge as of October 2023, the Millau Viaduct
• 364.75 metres – length of the Icon of the Seas
• 390 metres – height of the Empire State Building
• 400–800 metres – approximate heights of the world's tallest skyscrapers from 1931 to 2010
• 458 metres – length of the Knock Nevis, the world's largest supertanker
• 553.33 metres – height of the CN Tower^[134]
• 555 metres – longest wavelength of the broadcast radio AM band, 540 kHz
• 630 metres – height of the KVLY-TV mast, second-tallest structure in the world
• 646 metres – height of the Warsaw radio mast, the world's tallest structure until its collapse in 1991
• 828 metres – height of Burj Khalifa, world's tallest structure on 17 January 2009^[135]
• 1,000 metres – wavelength of the lowest mediumwave radio frequency, 300 kHz

Sports

• 100 metres – the distance a very fast human can run in about 10 seconds
• 100.584 metres – length of a Canadian football field between the goal lines (110 yards)
• 91.5 metres – 137 metres – length of a soccer field^[120]
• 105 metres – length of football pitch (UEFA stadium categories 3 and 4)
• 105 metres – length of a typical football field
• 109.73 metres – total length of an American football field (120 yards, including the end zones)
• 110–150 metres – the width of an Australian football field
• 135–185 metres – the length of an Australian football field
• 137.16 metres – total length of a Canadian football field, including the end zones (150 yards)

Nature

• 115.5 metres – height of the world's tallest tree in 2007, the Hyperion sequoia^[136]
• 310 metres – maximum depth of Lake Geneva
• 340 metres – distance sound travels in air at sea level in one second; see Speed of sound
• 947 metres – height of the Tugela Falls, the highest waterfall in Africa
• 979 metres – height of the Angel Falls, the world's highest free-falling waterfall (Venezuela)

Astronomical

• 270 metres – length of 99942 Apophis
• 535 metres – length of 25143 Itokawa,^[137] a small asteroid visited by a spacecraft

1 kilometre

Mount Fuji is 3.776 kilometres (2.346 mi) high.

The kilometre (SI symbol: km) is a unit of length in the metric system equal to 1000 metres (10³ m). To help compare different orders of magnitude, this section lists lengths between 1 kilometre and 10 kilometres (10³ and 10⁴ metres).

Conversions

1 kilometre (unit symbol km) is equal to:

• 1,000 metres
• 0.621371 miles
• 1,093.61 yards
• 3,280.84 feet
• 39,370.1 inches
• 100,000 centimetres
• 1,000,000 millimetres
• Side of a square of area 1 km²
• Radius of a circle of area π km²

Human-defined scales and structures

• 1 km – wavelength of the highest long wave radio frequency, 300 kHz^[138]
• 4 km – width of Central Park
• 1.280 km – span of the Golden Gate Bridge (distance between towers)^[139]
• 1.609 km – 1 statute mile
• 1.852 km – 1 nautical mile, equal to 1 arcminute of latitude at the surface of the Earth^[140]
• 1.991 km – span of the Akashi Kaikyō Bridge^[141]
• 2.309 km – axial length of the Three Gorges Dam, the largest dam in the world^[34]
• 3.991 km – length of the Akashi Kaikyō Bridge, longest suspension bridge in the world as of December 2008^{[update][142]}
• 5.072 km – elevation of Tanggula Mountain Pass, below highest peak in the Tanggula Mountains, highest railway pass in the world as of August 2005^{[update][143]}
• 5.8 km – elevation of Cerro Aucanquilcha, highest road in the world, located in Chile^[144]
• 98 airports have paved runways from 4 km to 5.5 km in length.
• 8 km – length of Palm Jebel Ali, an artificial island built off the coast of Dubai
• 9.8 km – length of The World, an artificial archipelago that is also built off the coast of Dubai, whose islands resemble a world map

Nature

• 1.5 km – distance sound travels in water in one second

Geographical

See also: List of highest mountains on Earth

• 1.637 km – deepest dive of Lake Baikal in Russia, the world's largest freshwater lake^[145]
• 2.228 km – height of Mount Kosciuszko, highest point on mainland Australia^[146]
• Most of Manhattan is from 3 to 4 km wide.
• 3.776 km – height of Mount Fuji, highest peak in Japan
• 4.478 km – height of Matterhorn
• 4.509 km – height of Mount Wilhelm, highest peak in Papua New Guinea
• 4.810 km – height of Mont Blanc, highest peak in the Alps
• 4.884 km – height of Carstensz Pyramid, highest peak in Oceania^[147]
• 4.892 km – height of Mount Vinson, highest peak in Antarctica
• 5.610 km – height of Mount Damavand, highest peak in Iran
• 5.642 km – height of Mount Elbrus, highest peak in Europe
• 5.895 km – height of Mount Kilimanjaro, highest peak in Africa
• 6.081 km – height of Mount Logan, highest peak in Canada
• 6.190 km – height of Denali, highest peak in North America
• 6.959 km – height of Aconcagua, highest peak in South America
• 7.5 km – depth of Cayman Trench, deepest point in the Caribbean Sea
• 8.611 km – height of K2, second highest mountain on Earth
• 8.848 km – height of Mount Everest, highest peak on Earth, on the border between Nepal and China

Astronomical

• 1 km – diameter of 1620 Geographos
• 1 km – very approximate size of the smallest-known moons of Jupiter
• 1.4 km – diameter of Dactyl, the first confirmed asteroid moon
• 4.8 km – diameter of 5535 Annefrank, an inner belt asteroid
• 5 km – diameter of 3753 Cruithne
• 5 km – length of PSR B1257+12
• 8 km – diameter of Themisto, one of Jupiter's moons
• 8 km – diameter of the Vela Pulsar
• 8.6 km – diameter of Callirrhoe, also known as Jupiter XVII
• 9.737 km – length of PSR B1919+21

10 kilometres (1 myriametre)

The Strait of Gibraltar is 13 km (8.1 mi) wide.

To help compare different orders of magnitude, this section lists lengths between 10 and 100 kilometres (10⁴ to 10⁵ metres). The myriametre^[148] (sometimes also spelled myriometre; 10,000 metres) is a deprecated unit name; the decimal metric prefix myria-^[99] (sometimes also written as myrio-^{[149][150][151]}) is obsolete^{[100][101][102]} and was not included among the prefixes when the International System of Units was introduced in 1960.

Conversions

10 kilometres is equal to:

Distance marker on the Rhine: 36 (XXXVI) myriametres from Basel. The stated distance is 360 km (220 mi); the comma is the decimal separator in Germany.

• 10,000 metres
• About 6.2 miles
• 1 mil (the Scandinavian mile), now standardized as 10 km:
  • 1 mil, the unit of measure commonly used in Norway and Sweden^[152] used to be 11,295 m in Norway and 10,688 m in Sweden.
• farsang, unit of measure commonly used in Iran and Turkey^[153]

Sports

• 42.195 km – length of the marathon^[154]

Human-defined scales and structures

• 18 km – cruising altitude of Concorde
• 27 km – circumference of the Large Hadron Collider, as of May 2010^[update] the largest and highest energy particle accelerator
• 34.668 km – highest manned balloon flight (Malcolm D. Ross and Victor E. Prather on 4 May 1961)^[155]
• 38.422 km – length of the Second Lake Pontchartrain Causeway in Louisiana, US
• 39 km – undersea portion of the Channel tunnel
• 53.9 km – length of the Seikan Tunnel, as of October 2009^[update], the longest rail tunnel in the world^[156]
• 77 km – rough total length of the Panama Canal^[157]

Geographical

• 10 km – height of Mauna Kea in Hawaii, measured from its base on the ocean floor
• 11 km – deepest-known point of the ocean, Challenger Deep in the Mariana Trench
• 11 km – average height of the troposphere
• 14 km – width of the Strait of Gibraltar
• 21 km – length of Manhattan
• 22 km – narrowest width of the Cook Strait between New Zealand's main islands
• 23 km – depth of the largest earthquake ever recorded in the United Kingdom, in 1931 at the Dogger Bank of the North Sea
• 34 km – narrowest width of the English Channel at the Strait of Dover
• 50 km – approximate height of the stratosphere
• 90 km – width of the Bering Strait

Astronomical

• 10 km – diameter of the most massive neutron stars (3–5 solar masses)
• 13 km – mean diameter of Deimos, the smaller moon of Mars
• 20 km – diameter of the least massive neutron stars (1.44 solar masses)
• 20 km – diameter of Leda, one of Jupiter's moons
• 20 km – diameter of Pan, one of Saturn's moons
• 22 km – diameter of Phobos, the larger moon of Mars
• 27 km – height of Olympus Mons above the Mars reference level,^[158][159] the highest-known mountain of the Solar System
• 30.8568 km – 1 picoparsec
• 43 km – diameter difference of Earth's equatorial bulge
• 66 km – diameter of Naiad, the innermost of Neptune's moons

100 kilometres

The Suez Canal is 163 km (101 mi) long.

A length of 100 kilometres (about 62 miles), as a rough amount, is relatively common in measurements on Earth and for some astronomical objects. It is the altitude at which the FAI defines spaceflight to begin.

To help compare orders of magnitude, this section lists lengths between 100 and 1,000 kilometres (10⁵ and 10⁶ metres).

Conversions

A distance of 100 kilometres is equal to about 62 miles (or 62.13711922 miles).

Human-defined scales and structures

• 100 km – the Karman line: the internationally recognized boundary of outer space
• 105 km – distance from Giridih to Bokaro
• 109 km – length of High Speed 1 between London and the Channel Tunnel^[160]
• 130 km – range of a Scud-A missile
• 163 km – length of the Suez Canal
• 164 km – length of the Danyang–Kunshan Grand Bridge
• 213 km – length of Paris Métro
• 217 km – length of the Grand Union Canal
• 223 km – length of the Madrid Metro
• 300 km – range of a Scud-B missile
• 386 km – altitude of the International Space Station
• 408 km – length of the London Underground (active track)
• 460 km – distance from London to Paris
• 470 km – distance from Dublin to London as the crow flies
• 600 km – range of a Scud-C missile
• 600 km – height above ground of the Hubble Space Telescope
• 804.67 km – (500 miles) distance of the Indy 500 automobile race

Geographical

• 42 km – width of Singapore
• 75 km – width of Rhode Island
• 111 km – distance covered by one degree of latitude on Earth's surface
• 120 km – width of Brunei
• 180 km – distance between Mumbai and Nashik
• 200 km – width of Qatar
• 203 km – length of Sognefjorden, the third-largest fjord in the world
• 220 km – distance between Pune and Nashik
• 240 km – width of Rwanda
• 240 km – widest width of the English Channel
• 400 km – width of West Virginia
• 430 km – length of the Pyrenees
• 450 km – length of the Grand Canyon
• 500 km – widest width of Sweden from east to west
• 501 km – width of Uganda
• 550 km – distance from San Francisco to Los Angeles as the crow flies
• 560 km – distance of Bordeaux–Paris, formerly^[when?] the longest one-day professional cycling race^[161]
• 590 km – length of land boundary between Finland and Sweden
• 724 km – length of the Om River
• 800 km – width of Germany
• 871 km – distance from Sydney to Melbourne (along the Hume Highway)
• 897 km – length of the River Douro
• 900 km – distance from Berlin to Stockholm
• 956 km – distance from Washington, D.C., to Chicago, Illinois, as the crow flies
• 970 km – distance from Land's End to John o' Groats as the crow flies

Astronomical

• 100 km – the altitude at which the FAI defines spaceflight to begin
• 167 km – diameter of Amalthea, one of Jupiter's inner moons
• 200 km – width of Valles Marineris
• 220 km – diameter of Phoebe, the largest of Saturn's outer moons
• 300 km – the approximate distance travelled by light in one millisecond
• 340 km – diameter of Nereid, the third-largest moon of Neptune
• 350 km – lower bound of Low Earth orbit
• 420 km – diameter of Proteus, the second-largest moon of Neptune
• 468 km – diameter of the asteroid 4 Vesta
• 472 km – diameter of Miranda, one of Uranus's major moons
• 974.6 km – greatest diameter of 1 Ceres,^[36] the largest Solar System asteroid^{[note 2]}

1 megametre

Small planets, the Moon and dwarf planets in the Solar System have diameters from one to ten million metres. Top row: Mars (left), Mercury (right); bottom row: Moon (left), Pluto (center), and Haumea (right), to scale.

The megametre (SI symbol: Mm) is a unit of length in the metric system equal to 1000000 metres (10⁶ m). To help compare different orders of magnitude, this section lists lengths starting at 10⁶ m (1 Mm or 1,000 km).

Conversions

1 megametre is equal to:

• 1 E+6 m (one million metres)
• approximately 621.37 miles
• 1 E+12 μm (one trillion micrometres)
• Side of square with area 1,000,000 km²

Human-defined scales and structures

• 2.100 Mm – length of proposed Iran-Pakistan-India gas pipe
• 2.100 Mm – distance from Casablanca to Rome
• 2.288 Mm – length of the official Alaska Highway when it was built in the 1940s^[162]
• 3.069 Mm – length of Interstate 95 (from Houlton, Maine, to Miami, Florida)
• 3.846 Mm – length of U.S. Route 1 (from Fort Kent, Maine, to Key West, Florida)
• 5.000 Mm – width of the United States
• 5.007 Mm – estimated length of Interstate 90 (Seattle, Washington, to Boston, Massachusetts)
• 5.614 Mm – length of the Australian Dingo Fence^[163]
• 6.371 Mm – global-average Earth radius
• 6.4 Mm – length of the Great Wall of China
• 7.821 Mm – length of the Trans-Canada Highway, the world's longest national highway (from Victoria, British Columbia, to St. John's, Newfoundland)
• 8.836 Mm – road distance between Prudhoe Bay, Alaska, and Key West, Florida, the endpoints of the U.S. road network
• 8.852 Mm – aggregate length of the Great Wall of China, including trenches, hills and rivers^[164]
• 9.259 Mm – length of the Trans-Siberian railway^[165]

Sports

• The Munda Biddi Trail in Western Australia, Australia, is over 1,000 km long – the world's longest off-road cycle trail
• 1.200 Mm – the length of the Paris–Brest–Paris bicycling event
• Several endurance auto races are, or were, run for 1,000 km:
  • Bathurst 1000
  • 1000 km Brands Hatch
  • 1000 km Buenos Aires
  • 1000 km Donington
  • 1000 km Monza
  • 1000 km Nürburgring
  • 1000 km Silverstone
  • 1000 km Spa
  • 1000 km Suzuka
  • 1000 km Zeltweg

Geographical

• 1.010 Mm – distance from San Diego to El Paso as the crow flies
• 1.100 Mm – length of Italy
• 1.200 Mm – length of California
• 1.200 Mm – width of Texas
• 1.500 Mm – length of the Gobi Desert
• 1.600 Mm – length of the Namib, the oldest desert on Earth
• 2.000 Mm – distance from Beijing to Hong Kong as the crow flies
• 2.300 Mm – length of the Great Barrier Reef
• 2.800 Mm – narrowest width of Atlantic Ocean (Brazil-West Africa)
• 2.850 Mm – length of the Danube river
• 2.205 Mm – length of Sweden's total land boundaries
• 2.515 Mm – length of Norway's total land boundaries
• 3.690 Mm – length of the Volga river, longest in Europe
• 4.000 Mm – length of the Kalahari Desert
• 4.350 Mm – length of the Yellow River
• 4.600 Mm – width of the Mediterranean Sea
• 4.800 Mm – length of the Sahara
• 4.800 Mm – widest width of Atlantic Ocean (U.S.-Northern Africa)
• 5.100 Mm – distance from Dublin to New York as the crow flies
• 6.270 Mm – length of the Mississippi-Missouri River system
• 6.380 Mm – length of the Yangtze River
• 6.400 Mm – Length of the Amazon River
• 6.758 Mm – Length of the Nile system, longest on Earth
• 8.200 Mm – Approximate Distance from Dublin to San Francisco

Astronomical

• 1.000 Mm – estimated shortest axis of triaxial dwarf planet Haumea
• 1.186 Mm – diameter of Charon, the largest moon of Pluto
• 1.280 Mm – diameter of the trans-Neptunian object 50000 Quaoar
• 1.436 Mm – diameter of Iapetus, one of Saturn's major moons
• 1.578 Mm – diameter of Titania, the largest of Uranus's moons
• 1.960 Mm – estimated longest axis of Haumea
• 2.326 Mm – diameter of the dwarf planet Eris, the largest trans-Neptunian object found to date
• 2.376 Mm – diameter of Pluto
• 2.707 Mm – diameter of Triton, largest moon of Neptune
• 3.122 Mm – diameter of Europa, the smallest Galilean satellite of Jupiter
• 3.476 Mm – diameter of Earth's Moon
• 3.643 Mm – diameter of Io, a moon of Jupiter
• 4.821 Mm – diameter of Callisto, a moon of Jupiter
• 4.879 Mm – diameter of Mercury
• 5.150 Mm – diameter of Titan, the largest moon of Saturn
• 5.262 Mm – diameter of Jupiter's moon Ganymede, the largest moon in the Solar System
• 6.371 Mm – radius of Earth
• 6.792 Mm – diameter of Mars

10 megametres

Planets from Venus up to Uranus have diameters from ten to one hundred million metres. Top row: Uranus (left), Neptune (right); middle row: Earth (left), Sirius B (center), and Venus (right), to scale.

To help compare different orders of magnitude, this section lists lengths starting at 10⁷ metres (10 megametres or 10,000 kilometres).

Conversions

10 megametres (10 Mm) is

• 6,215 miles
• side of a square of area 100,000,000 square kilometres (km²)
• radius of a circle of area 314,159,265 km²

Human-defined scales and structures

• 11.085 Mm – length of the Kyiv-Vladivostok railway, a longer variant of the Trans-Siberian railway^[166]
• 13.300 Mm – length of roads rehabilitated and widened under the National Highway Development Project (launched in 1998) in India
• 39.000 Mm – length of the SEA-ME-WE 3 optical submarine telecommunications cable, joining 39 points between Norden, Germany, and Okinawa, Japan
• 67.000 Mm – total length of National Highways in India
• 80.000 Mm – 20,000 (metric, French) leagues (see Jules Verne, Twenty Thousand Leagues Under the Seas)

Geographical

• 10 Mm – approximate altitude of the outer boundary of the exosphere
• 10.001 Mm – length of the meridian arc from the North Pole to the Equator (the original definition of the metre was based on this length)
• 40.000 Mm – length of the Ring of Fire
• 60.000 Mm – total length of the mid-ocean ridges

Astronomical

• 12.000 Mm – diameter of Sirius B, a white dwarf^[167]
• 12.104 Mm – diameter of Venus
• 12.742 Mm – diameter of Earth
• 12.900 Mm – minimum distance of the meteoroid 2004 FU162 from the centre of Earth on 31 March 2004, closest on record
• 14.000 Mm – smallest diameter of Jupiter's Great Red Spot
• 19.000 Mm – separation between Pluto and Charon
• 30.8568 Mm – 1 nanoparsec
• 34.770 Mm – minimum distance of the asteroid 99942 Apophis on 13 April 2029 from the centre of Earth
• 35.786 Mm – altitude of geostationary orbit
• 40.005 Mm – polar circumference of the Earth
• 40.077 Mm – equatorial circumference of the Earth
• 49.528 Mm – diameter of Neptune
• 51.118 Mm – diameter of Uranus

100 megametres

The Earth-Moon orbit, Saturn, OGLE-TR-122b, Jupiter, and other objects, to scale. Click on image for detailed view and links to other length scales.

Scale model at megametres of the main Solar System bodies

To help compare different orders of magnitude, this section lists lengths starting at 10⁸ metres (100 megametres or 100,000 kilometres or 62,150 miles).

• 102 Mm – diameter of HD 149026 b, an unusually dense Jovian planet
• 115 Mm – width of Saturn's Rings
• 120 Mm – diameter of EBLM J0555-57Ab, the smallest-known star
• 120 Mm – diameter of Saturn
• 142 Mm – diameter of Jupiter, the largest planet in the Solar System
• 170 Mm – diameter of TRAPPIST-1, a star discovered to have seven planets around it
• 174 Mm – diameter of OGLE-TR-122b, one of the smallest known stars
• 180 Mm – average distance covered during life
• 215 Mm – diameter of Proxima Centauri, the nearest star to the Solar System
• 257 Mm – diameter of TrES-4, one of the largest exoplanets
• 260 Mm – diameter of the Barnard's Star
• 272 Mm – diameter of WASP-12b
• 299.792 Mm – one light-second; the distance light travels in vacuum in one second (see speed of light)
• 314 Mm – diameter of CT Cha b
• 384.4 Mm (238,855 mi) – average Earth–Moon distance^[168]
• 671 Mm – separation between Jupiter and Europa
• 696 Mm – radius of Sun
• 989 Mm – diameter of Epsilon Indi, one of the nearest stars to Earth

1 gigametre

13 things in the gigametre group

Upper part: Gamma Orionis, Algol B, the Sun (centre), and other objects to scale

; lower part: their darker mirror images (artist's interpretation).

The gigametre (SI symbol: Gm) is a unit of length in the metric system equal to 1000000000 metres (10⁹ m). To help compare different distances this section lists lengths starting at 10⁹ metres (1 gigametre (Gm) or 1 billion metres).

• 1.2 Gm – separation between Saturn and Titan
• 1.39 Gm – diameter of Sun^[169][170]
• 1.5 Gm – orbit from Earth of the James Webb Space Telescope
• 1.71 Gm – diameter of Alpha Centauri A, one of the closest stars.^[171]
• 2.19 Gm – closest approach of Comet Lexell to Earth, happened on 1 July 1770; closest comet approach on record
• 2.38 Gm – diameter of Sirius A, brightest naked eye star.^[172]
• 3 Gm – total length of "wiring" in the human brain^[173]
• 3.5 Gm – diameter of Vega^[174]
• 4.2 Gm – diameter of Algol B
• 4.3 Gm – circumference of Sun
• 5.0 Gm – closest approach of Comet Halley to Earth, happened on 10 April 837
• 5.0 Gm – (proposed) Size of the arms of the giant triangle shaped Michelson interferometer of the Laser Interferometer Space Antenna (LISA) planned to start observations sometime in the 2030s.
• 7.9 Gm – diameter of Gamma Orionis, a blue dwarf or blue giant
• 9.0 Gm – estimated diameter of the event horizon of Sagittarius A*, the supermassive black hole in the center of the Milky Way galaxy

10 gigametres

Rigel and Aldebaran (top left and right) compared to smaller stars, the Sun (very small dot in lower middle, with orbit of Mercury as yellow ellipse) and transparent sphere with radius of one light-minute

To help compare different distances this section lists lengths starting at 10¹⁰ metres (10 gigametres (Gm) or 10 million kilometres, or 0.07 astronomical units).

• 10.4 Gm – diameter of Spica, an oval-shaped blue giant star and a nearby supernova candidate.^[175]
• 12.6 Gm – diameter of Pollux, the closest red giant star to the Sun.^[176] It is a red clump star fusing helium into carbon at its core.^[177]
• 15 Gm – closest distance of Comet Hyakutake from Earth
• 18 Gm – one light-minute (see yellow sphere in right-hand diagram)
• 24 Gm – radius of a heliostationary orbit
• 30.8568 Gm – 1 microparsec
• 35 Gm – approximate diameter of Arcturus, a close red giant star.^[178] It is on the red giant branch, fusing hydrogen into helium in a shell surrounding an inert helium core.^[177]
• 46 Gm – perihelion distance of Mercury (yellow ellipse on the right)
• 55 Gm – 60,000-year perigee of Mars (last achieved on 27 August 2003)
• 58 Gm – average passing distance between Earth and Mars at the moment they overtake each other in their orbits
• 61 Gm – diameter of Aldebaran, a red giant branch star (large star on right)^[179]
• 70 Gm – aphelion distance of Mercury
• 76 Gm – Neso's apocentric distance; greatest distance of a natural satellite from its parent planet (Neptune)

100 gigametres

From largest to smallest: Jupiter's orbit, red supergiant star Betelgeuse, Mars' orbit, Earth's orbit, star R Doradus, and orbits of Venus, Mercury. Inside R Doradus's depiction are the blue supergiant star Rigel and red giant star Aldebaran. The faint yellow glow around the Sun represents one light-minute. Click image to see more details and links to their scales.

To help compare distances at different orders of magnitude this section lists lengths starting at 10¹¹ metres (100 gigametre or 100 million kilometres or 0.7 astronomical units).

• 103 Gm (0.69 au) – diameter of Rigel^[176]
• 109 Gm (0.7 au) – distance between Venus and the Sun
• 149.6 Gm (93.0 million mi; 1.0 au) – average distance between the Earth and the Sun – the original definition of the astronomical unit
• 199 Gm (1.3 au) – diameter of Rho Persei, an asymptotic giant branch star, fusing carbon into neon in a shell surrounding an inert core.^[180]
• 228 Gm (1.5 au) – distance between Mars and the Sun
• 248 Gm (1.7 au) – diameter of Enif, a small red supergiant star in the constellation Pegasus^[181]
• 280 Gm (1.9 au) – diameter of Deneb, a blue supergiant and the brightest star in the Cygnus constellation^[182]
• 511 Gm (3.4 au) – average diameter of Mira, a pulsating red giant and the progenitor of the Mira variables. It is an asymptotic giant branch star.^[183]
• 570 Gm (3.8 au) – length of the tail of Comet Hyakutake measured by Ulysses; the actual value could be much higher
• 590 Gm (3.9 au) – diameter of the Pistol Star, a blue hypergiant star^[184]
• 591 Gm (4.0 au) – minimum distance between the Earth and Jupiter
• 780 Gm (5.2 au) – distance between Jupiter and the Sun
• 785 Gm (5.25 au) – diameter of Rho Cassiopeiae, a rare yellow hypergiant star^[185]
• 947 Gm (6.4 au) – diameter of Antares A
• 965 Gm (6.4 au) – maximum distance between the Earth and Jupiter

1 terametre

Eight things in the terametre group

Comparison of size of the Kuiper belt (large faint torus) with the star VY Canis Majoris (within Saturn's orbit), Betelgeuse (inside Jupiter's orbit) and R Doradus (small central red sphere) together with the orbits of Neptune and Uranus, to scale. The yellow ellipses represent the orbits of each planet and the dwarf planet Pluto.

The terametre (SI symbol: Tm) is a unit of length in the metric system equal to 1000000000000 metres (10¹² m). To help compare different distances, this section lists lengths starting at 10¹² m (1 Tm or 1 billion km or 6.7 astronomical units).

• ≈1 Tm – 6.7 au – diameter of the red supergiant Betelgeuse based on multiple angular diameter estimates^[186]
• 1.032 Tm – 6.9 au – diameter of the blue hypergiant Eta Carinae (at optical depth 2/3)^[187]
• 1.079 Tm – 7.2 au – one light-hour
• 1.35 Tm – 9.04 au – estimated diameter of Mu Cephei, a red supergiant (possibly hypergiant) among the largest-known stars.^[188] Some estimates, however, go as high as 1.98 Tm (13.2 au).^[189]
• 1.4 Tm – 9.5 au – distance between Saturn and the Sun
• 1.47 Tm – 9.9 au – diameter of HR 5171 A, a yellow hypergiant star.^[190]
• 1.5 Tm – 10 au – estimated diameter of VV Cephei A, a red supergiant with a blue dwarf companion.^[191]
• 2 Tm – 13.2 au – estimated diameter of VY Canis Majoris, a red hypergiant that is among the largest-known stars^[192][193]
• 2.9 Tm – 19.4 au – distance between Uranus and the Sun
• 4.4 Tm – 29.4 au – perihelion distance of Pluto
• 4.5 Tm – 30.1 au – distance between Neptune and the Sun
• 4.5 Tm – 30.1 au – inner radius of the Kuiper belt
• 5.7 Tm – 38.1 au – perihelion distance of Eris
• 6.0 Tm – 40.5 au – distance from Earth at which the Pale Blue Dot photograph was taken.
• 7.3 Tm – 48.8 au – aphelion distance of Pluto
• 7.5 Tm – 50.1 au – outer radius of the Kuiper Belt

10 terametres

Sedna's orbit (left) is longer than 100 Tm, but other lengths are between 10 and 100 Tm: Comet Hale-Bopp's orbit (lower, faint orange); one light-day (yellow spherical shell with yellow Vernal point arrow as radius); the heliosphere's termination shock (blue shell); and other arrows show positions of Voyager 1 (red) and Pioneer 10 (green). Click on image for larger view and links to other scales.

To help compare different distances this section lists lengths starting at 10¹³ m (10 Tm or 10 billion km or 67 astronomical units).

• 10 Tm – 67 AU – diameter of a hypothetical quasi-star
• 11.1 Tm – 74.2 AU – distance that Voyager 1 began detecting returning particles from termination shock
• 11.4 Tm – 76.2 AU – perihelion distance of 90377 Sedna
• 12.1 Tm – 70 to 90 AU – distance to termination shock (Voyager 1 crossed at 94 AU)
• 12.9 Tm – 86.3 AU – distance to 90377 Sedna in March 2014
• 13.2 Tm – 88.6 AU – distance to Pioneer 11 in March 2014
• 14.1 Tm – 94.3 AU – estimated radius of the Solar System
• 14.4 Tm – 96.4 AU – distance to Eris in March 2014 (now near its aphelion)
• 15.1 Tm – 101 AU – distance to heliosheath
• 16.5 Tm – 111 AU – distance to Pioneer 10 as of March 2014
• 16.6 Tm – 111.2 AU – distance to Voyager 2 as of May 2016
• 18 Tm – 123.5 AU – distance between the Sun to the farthest dwarf planet in the Solar System, the Farout 2018 VG18
• 20.0 Tm – 135 AU – distance to Voyager 1 as of May 2016
• 20.6 Tm – 138 AU – distance to Voyager 1 as of late February 2017
• 21.1 Tm – 141 AU – distance to Voyager 1 as of November 2017
• 25.9 Tm – 173 AU – one light-day
• 30.8568 Tm – 206.3 AU – 1 milliparsec
• 55.7 Tm – 371 AU – aphelion distance of the comet Hale-Bopp

100 terametres

The largest yellow sphere indicates one light month distance from the Sun. Click the image for larger view, more details and links to other scales.

To help compare different distances this section lists lengths starting at 10¹⁴ m (100 Tm or 100 billion km or 670 astronomical units).

• 140 Tm – 937 AU – aphelion distance of 90377 Sedna
• 172 Tm – 1150 AU – Schwarzschild diameter of H1821+643, one of the most massive black holes known
• 181 Tm – 1210 AU – one light-week
• 308.568 Tm – 2063 AU – 1 centiparsec
• 757 Tm – 5059 AU – radius of the Stingray Nebula^[194]
• 777 Tm – 5180 AU – one light-month

1 petametre

Largest circle with yellow arrow indicates one light-year from Sun; Cat's Eye Nebula on left and Barnard 68 in middle are depicted in front of Comet 1910 A1's orbit. Click image for larger view, details and links to other scales.

The petametre (SI symbol: Pm) is a unit of length in the metric system equal to 10¹⁵ metres. To help compare different distances this section lists lengths starting at 10¹⁵ m (1 Pm or 1 trillion km or 6685 astronomical units (AU) or 0.11 light-years).

• 1.0 Pm = 0.105702341 light-years
• 1.9 Pm ± 0.5 Pm = 12,000 AU = 0.2 light-year radius of Cat's Eye Nebula's inner core^[195][196]
• 3.08568 Pm = 20,626 AU = 1 deciparsec
• 4.7 Pm = 30,000 AU = half-light-year diameter of Bok globule Barnard 68^[197]
• 7.5 Pm – 50,000 AU – possible outer boundary of Oort cloud (other estimates are 75,000 to 125,000 or even 189,000 AU (1.18, 2, and 3 light-years, respectively))
• 9.5 Pm – 63,241.1 AU – one light-year, the distance traveled by light in one year
• 9.9 Pm – 66,000 AU – aphelion distance of the C/1999 F1 (Catalina)

10 petametres

Objects with size order of magnitude 1e16m: Ten light-years (94.6 Pm) radius circle with yellow Vernal Point arrow; Bubble Nebula (NGC 7635), left; Dumbbell Nebula (NGC 6853), right; one light-year shell lower right with the smaller Cat's Eye Nebula (NGC_6543) and Barnard 68 adjacent.

1e16m lengths: Ten light-years (94.6 Pm) yellow shell; Sirius below right; BL Ceti below left; Proxima and Alpha Centauri upper right; light-year shell with Comet 1910 A1's orbit inside top right

To help compare different distances this section lists lengths starting at 10¹⁶ m (10 Pm or 66,800 AU, 1.06 light-years).

• 15 Pm – 1.59 light-years – possible outer radius of Oort cloud
• 20 Pm – 2.11 light-years – maximum extent of influence of the Sun's gravitational field^{[citation needed]}
• 30.9 Pm – 3.26 light-years – 1 parsec
• 39.9 Pm – 4.22 light-years – distance to Proxima Centauri (nearest star to Sun)
• 81.3 Pm – 8.59 light-years – distance to Sirius
• 94.6 Pm – 1 light-decade

100 petametres

Lengths with order of magnitude 1e17m: yellow Vernal Point arrow traces hundred light-year radius circle with smaller ten light-year circle at right; globular cluster Messier 5 in background; 12 light-year radius Orion Nebula middle right; 50-light-year-wide view of the Carina Nebula bottom left; Pleiades cluster and Bubble nebula with similar diameters each around 10 light-years bottom right; grey arrows show distances from Sun to stars Aldebaran (65 light-years) and Vega (25 light-years)

To help compare different distances this section lists lengths between 10¹⁷ m (100 Pm or 11 light-years) and 10¹⁸ m (106 light-years).

• 110 Pm – 12 light-years – Distance to Tau Ceti
• 230 Pm – 24 light-years – Diameter of the Orion Nebula^[198][199]
• 240 Pm – 25 light-years – Distance to Vega
• 260 Pm – 27 light-years – Distance to Chara, a star approximately as bright as the Sun. Its faintness gives an idea how the Sun would appear when viewed from this distance.
• 308.568 Tm – 32.6 light-years – 1 dekaparsec
• 350 Pm – 37 light-years – distance to Arcturus
• 373.1 Pm – 39.44 light-years – distance to TRAPPIST-1, a star recently discovered to have 7 planets around it
• 400 Pm – 42 light-years – distance to Capella
• 620 Pm – 65 light-years – distance to Aldebaran
• 750 Pm – 79.36 light-years – distance to Regulus
• 900 Pm – 92.73 light-years – distance to Algol
• 946 Pm – 1 light-century

1 exametre

Lengths with order of magnitude 1e18m: thousand light-year radius circle with yellow arrow and 100 light-year circle at right with globular cluster Messier 5 within and Carina Nebula in front; globular cluster Omega Centauri to left of both; part of the 1,400-light-year-wide Tarantula Nebula fills the background

The exametre (SI symbol: Em) is a unit of length in the metric system equal to 10¹⁸ metres. To help compare different distances this section lists lengths between 10¹⁸ m (1 Em or 105.7 light-years) and 10¹⁹ m (10 Em or 1,057 light-years).

• 1.2 Em – 129 light-years – diameter of Messier 13 (a typical globular cluster)
• 1.6 Em – 172 ± 12.5 light-years – diameter of Omega Centauri (one of the largest-known globular clusters, perhaps containing over a million stars)^[200][201]
• 3.08568 Em – 326.1 light-years – 1 hectoparsec
• 3.1 Em – 310 light-years – distance to Canopus according to Hipparcos^[202]
• 3.9 Em – 410 light-years – distance to Betelgeuse according to Hipparcos^[203]
• 6.2 Em – 650 light-years – distance to the Helix Nebula, located in the constellation Aquarius^[204]
• 8.2 Em – 860 light-years – distance to Rigel according to Hipparcos^[202]
• 9.4 Em — 1 light-millennium – 1000 light-years

10 exametres

To help compare different orders of magnitude, this section lists distances starting at 10 Em (10¹⁹ m or 1,100 light-years).

• 10.6 Em – 1,120 light-years – distance to WASP-96b
• 13 Em – 1,300 light-years – distance to the Orion Nebula^[205]
• 14 Em – 1,500 light-years – approximate thickness of the plane of the Milky Way galaxy at the Sun's location
• 14.2 Em – 1,520 light-years – diameter of the NGC 604
• 30.8568 Em – 3,261.6 light-years – 1 kiloparsec
• 31 Em – 3,200 light-years – distance to Deneb according to Hipparcos
• 46 Em – 4,900 light-years – distance to OGLE-TR-56, the first extrasolar planet discovered using the transit method
• 47 Em – 5,000 light-years – distance to the Boomerang nebula, coldest place known (1 K)
• 53 Em – 5,600 light-years – distance to the globular cluster M4 and the extrasolar planet PSR B1620-26 b within it
• 61 Em – 6,500 light-years – distance to Perseus Spiral Arm (next spiral arm out in the Milky Way galaxy)
• 71 Em – 7,500 light-years – distance to Eta Carinae
• 94.6073 Em – 1 light-decamillennium = 10,000 light-years

100 exametres

To help compare different orders of magnitude, this section lists distances starting at 100 Em (10²⁰ m or 11,000 light-years).

• 150 Em – 16,000 light-years – diameter of the Small Magellanic Cloud, a dwarf galaxy orbiting the Milky Way
• 200 Em – 21,500 light-years – distance to OGLE-2005-BLG-390Lb
• 240 Em – 25,000 light-years – distance to the Canis Major Dwarf Galaxy
• 260 Em – 28,000 light-years – distance to the center of the Galaxy
• 400 Em – 48,000 light years – diameter of the Fireworks Galaxy
• 830 Em – 88,000 light-years – distance to the Sagittarius Dwarf Elliptical Galaxy
• 946 Em – 1 light-centum-millennium = 100,000 light-years

1 zettametre

The zettametre (SI symbol: Zm) is a unit of length in the metric system equal to 10²¹ metres.^[56] To help compare different orders of magnitude, this section lists distances starting at 1 Zm (10²¹ m or 110,000 light-years).

• 1.7 Zm – 179,000 light-years – distance to the Large Magellanic Cloud, largest satellite galaxy of the Milky Way
• <1.9 Zm – <200,000 light-years – revised estimated diameter of the disc of the Milky Way Galaxy. The size was previously thought to be half of this.
• 2.0 Zm – 210,000 light-years – distance to the Small Magellanic Cloud
• 2.8 Zm – 300,000 light-years – distance to the Intergalactic Wanderer, one of the most distant globular clusters of Milky Way
• 8.5 Zm – 900,000 light-years – distance to the Leo I Dwarf Galaxy, farthest-known Milky Way satellite galaxy

10 zettametres

To help compare different orders of magnitude, this section lists distances starting at 10 Zm (10²² m or 1.1 million light-years).

• 24 Zm – 2.5 million light-years – distance to the Andromeda Galaxy
• 30.8568 Zm – 3.2616 million light-years – 1 megaparsec
• 40 Zm – 4.2 million light-years – distance to the IC 10, a distant member of the Local Group of galaxies
• 49.2 Zm – 5.2 million light-years – width of the Local Group of galaxies
• 95 Zm – 10 million light-years – distance to the Sculptor Galaxy in the Sculptor Group of galaxies
• 95 Zm – 10 million light-years – distance to the Maffei 1, the nearest giant elliptical galaxy in the Maffei 1 Group

100 zettametres

To help compare different orders of magnitude, this section lists distances starting at 100 Zm (10²³ m or 11 million light-years).

• 140 Zm – 15 million light-years – distance to Centaurus A galaxy
• 250 Zm – 27 million light-years – distance to the Pinwheel Galaxy
• 280 Zm – 30 million light-years – distance to the Sombrero Galaxy
• 570 Zm – 60 million light-years – approximate distance to the Virgo cluster, nearest galaxy cluster
• 620 Zm – 65 million light-years – approximate distance to the Fornax cluster
• 800 Zm – 85 million light-years – approximate distance to the Eridanus cluster

1 yottametre

The yottametre (SI symbol: Ym) is a unit of length in the metric system equal to 10²⁴ metres.^[56]

To help compare different orders of magnitude, this section lists distances starting at 1 Ym (10²⁴ m or 105.702 million light-years).

• 1.2 Ym – 127 million light-years – distance to the closest observed gamma ray burst GRB 980425
• 1.3 Ym – 137 million light-years – distance to the Centaurus Cluster of galaxies, the nearest large supercluster
• 1.9 Ym – 201 million light-years – diameter of the Local Supercluster
• 2.17 Ym – 1 light-galactic-years – 230 million light-years
• 2.3 Ym – 225 to 250 million light-years – distance light travels in vacuum in one galactic year
• 2.8 Ym – 296 million light-years – distance to the Coma Cluster
• 3.15 Ym – 330 million light years – diameter of the Boötes Void
• 3.2 Ym – 338 million light-years – distance to Stephan's Quintet
• 4.7 Ym – 496 million light-years – length of the CfA2 Great Wall, one of the largest observed superstructures in the Universe
• 6.1 Ym – 645 million light-years – distance to the Shapley Supercluster
• 9.5 Ym – 996 million light-years – diameter of the Eridanus Supervoid

10 yottametres

The universe within one billion light-years of Earth

To help compare different orders of magnitude, this section lists distances starting at 10 Ym (10²⁵ m or 1.1 billion light-years). At this scale, expansion of the universe becomes significant. Distance of these objects are derived from their measured redshifts, which depends on the cosmological models used.

• 13 Ym – 1.37 billion light-years – length of the South Pole Wall
• 13 Ym – 1.38 billion light-years – length of the Sloan Great Wall
• 18 Ym – redshift 0.16 – 1.9 billion light-years – distance to the quasar 3C 273 (light travel distance)
• 30.8568 Ym – 3.2616 billion light-years – 1 gigaparsec
• 31.2204106 Ym − 3.3 billion light-years − length of The Giant Arc, a large cosmic structure discovered in 2021
• 33 Ym – 3.5 billion light-years – maximum distance of the 2dF Galaxy Redshift Survey (light travel distance)
• 37.8 Ym – 4 billion light-years – length of the Huge-LQG
• 75 Ym – redshift 0.95 – 8 billion light-years – approximate distance to the supernova SN 2002dd in the Hubble Deep Field North (light travel distance)
• 85 Ym – redshift 1.6 – 9 billion light-years – approximate distance to the gamma-ray burst GRB 990123 (light travel distance)
• 94.6 Ym – 10 billion light-years – approximate distance to quasar OQ172
• 94.6 Ym – 10 billion light-years – length of the Hercules–Corona Borealis Great Wall, one of the largest and most massive-known cosmic structures known

100 yottametres

To help compare different orders of magnitude, this section lists distances starting at 100 Ym (10²⁶ m or 11 billion light-years). At this scale, expansion of the universe becomes significant. Distance of these objects are derived from their measured redshifts, which depend on the cosmological models used.

• 124 Ym – redshift 7.54 – 13.1 billion light-years – light travel distance (LTD) to the quasar ULAS J1342+0928, the most distant-known quasar as of 2017
• 130 Ym – redshift 1,000 – 13.8 billion light-years – distance (LTD) to the source of the cosmic microwave background radiation; radius of the observable universe measured as a LTD
• 260 Ym – 27.4 billion light-years – diameter of the observable universe (double LTD)
• 440 Ym – 46 billion light-years – radius of the universe measured as a comoving distance
• 590 Ym – 62 billion light-years – cosmological event horizon: the largest comoving distance from which light will ever reach us (the observer) at any time in the future
• 886.48 Ym – 93.7 billion light-years – the diameter of the observable universe (twice the particle horizon); however, there might be unobserved distances that are even greater.

1 ronnametre

The ronnametre (SI symbol: Rm) is a unit of length in the metric system equal to 10²⁷ metres.^[56]

To help compare different orders of magnitude, this section lists distances starting at 1 Rm (10²⁷ m or 105.7 billion light-years). At this scale, expansion of the universe becomes significant. Distance of these objects are derived from their measured redshifts, which depend on the cosmological models used.

• >1 Rm – >105.7 billion light-years – size of universe beyond the cosmic light horizon, depending on its curvature; if the curvature is zero (i.e. the universe is spatially flat), the value can be infinite (see Shape of the universe) as previously mentioned.
• 2.764 Rm - 292.2 billion light-years – circumference of the observable universe, as it is in the shape of a sphere.
• ≈10^1010122 (10^12,000) light-years – the possible size of the universe after cosmological inflation.

See also

• List of examples of lengths
• Fermi problem
• Scale (analytical tool)
• Spatial scale
• The Scale of the Universe

Notes

1. The diameter of human hair ranges from 17 to 181 μm Ley, Brian (1999). Elert, Glenn (ed.). "Diameter of a human hair". The Physics Factbook. Retrieved 8 December 2018.
2. The exact category (asteroid, dwarf planet, or planet) to which particular Solar System objects belong, has been subject to some revision since the discovery of extrasolar planets and trans-Neptunian objects
3. 10¹¹⁵ is 1 followed by 115 zeroes, or a googol multiplied by a quadrillion. 10¹⁰¹¹⁵ is 1 followed by a quadrillion googol zeroes. 10^1010122 is 1 followed by 10¹⁰¹²² (a googolplex^{10 sextillion}) zeroes.
4. But not cloud or high-level fog droplets; droplet size increases with altitude. For a contradictory study indicating larger drop sizes even in ground fog, see Eldridge, Ralph G. (October 1961). "A Few Fog Drop-Size Distributions". Journal of Meteorology. 18 (5): 671–6. Bibcode:1961JAtS...18..671E. doi:10.1175/1520-0469(1961)018<0671:AFFDSD>2.0.CO;2.

References

1. Burgess, Cliff; Quevedo, Fernando (November 2007). "The Great Cosmic Roller-Coaster Ride". Scientific American. 297 (5): 55. Bibcode:2007SciAm.297e..52B. doi:10.1038/scientificamerican1107-52 (inactive 2 November 2024). PMID 17990824. Retrieved 1 May 2017.{{cite journal}}: CS1 maint: DOI inactive as of November 2024 (link)
2. Nave, Carl R. "Cowan and Reines Neutrino Experiment". HyperPhysics. Retrieved 4 December 2008. (6.3 × 10⁻⁴⁴ cm², which gives an effective radius of about 1.42 × 10⁻²² m)
3. Nave, Carl R. "Neutron Absorption Cross-sections". HyperPhysics. Retrieved 4 December 2008. (area for 20 GeV about 10 × 10⁻⁴² m² gives effective radius of about 2 × 10⁻²¹ m; for 250 GeV about 150 × 10⁻⁴² m² gives effective radius of about 7 × 10⁻²¹ m)
4. Abbott, B. P.; et al. (2016). "Observation of Gravitational Waves from a Binary Black Hole Merger". Physical Review Letters. 116 (6): 061102. arXiv:1602.03837. Bibcode:2016PhRvL.116f1102A. doi:10.1103/PhysRevLett.116.061102. PMID 26918975. S2CID 124959784. On 14 September 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10⁻²¹.
5. Pohl, R.; et al. (July 2010). "The size of the proton". Nature. 466 (7303): 213–6. Bibcode:2010Natur.466..213P. doi:10.1038/nature09250. PMID 20613837. S2CID 4424731.
6. Strassler, Matt (30 May 2013). "The strength of the known forces". profmattstrassler.com.
7. Kolena. "The four forces: The strong interaction". Astrophysics Dept website. Duke University.
8. Nave, Carl R. "Scattering cross section". Retrieved 10 February 2009. (diameter of the scattering cross section of an 11 MeV proton with a target proton)
9. "CODATA Value: classical electron radius". The NIST Reference on Constants, Units, and Uncertainty. NIST.
10. H. E. Smith. "The Scale of the Universe". UCSD. Retrieved 10 February 2009. ~10⁻¹³cm
11. Winter, Mark (2008). "WebElements Periodic Table of the Elements / Sulfur / Radii". Retrieved 6 December 2008.
12. Flahaut E, Bacsa R, Peigney A, Laurent C (June 2003). "Gram-scale CCVD synthesis of double-walled carbon nanotubes" (PDF). Chemical Communications. 12 (12): 1442–3. doi:10.1039/b301514a. PMID 12841282. S2CID 30627446.
13. "The world's smallest transistor is 1nm long, physics be damned". 6 October 2016.
14. Stewart, Robert. "Dr". Radiobiology Software. Archived from the original on 30 June 2010. Retrieved 20 May 2015.
15. Langevin, Dominique (2008). "Chapter 10: DNA-Surfactant/Lipid Complexes at Liquid Interfaces". In Dias, Rita S; Lindman, Bjorn (eds.). DNA Interactions with Polymers and Surfactants. Hoboken, NJ: John Wiley & Sons, Inc. p. 265. doi:10.1002/9780470286364.ch10. ISBN 978-0-470-25818-7. DNA has 20 elementary charges per helical turn over the corresponding length of 3.4nm
16. Mai-Prochnow, Anne (9 December 2016). "Gram positive and Gram negative bacteria differ in their sensitivity to cold plasma". Scientific Reports. 6. Nature: 38610. Bibcode:2016NatSR...638610M. doi:10.1038/srep38610. PMC 5146927. PMID 27934958.
17. F., Adnan (17 October 2016). "Samsung announces industry-first mass production of System-on-Chip with 10nm FinFET technology". SamMobile.
18. "Hard drive basics – Capacities, RPM speeds, interfaces, and mechanics". helpwithpcs.com. Retrieved 13 July 2016.
19. Cohn, J. University of California, Berkeley Lyman alpha systems and cosmology. Retrieved 21 February 2009.
20. Seth, S.D.; Seth, Vimlesh (2009). Textbook of Pharmacology (3rd ed.). Elsevier. p. X111. ISBN 978-81-312-1158-8.
21. Nave, Carl R (2016). "Color". HyperPhysics. Georgia State University.
22. "Size of bacteria". What are bacteria?. Retrieved 19 July 2016.
23. Ko, Frank K.; Kawabata, Sueo; Inoue, Mari; Niwa, Masako; Fossey, Stephen; Song, John W. "Engineering properties of spider silk" (PDF). web.mit.edu.
24. Doohan, Jim. "Blood cells". biosbcc.net. Archived from the original on 23 July 2016. Retrieved 19 July 2016.
25. According to The Physics Factbook, the diameter of human hair ranges from 17 to 181 μmLey, Brian (1999). "Width of a Human Hair". The Physics Factbook.
26. Liu Z, Huang AJ, Pflugfelder SC (July 1999). "Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system". The British Journal of Ophthalmology. 83 (7): 774–8. doi:10.1136/bjo.83.7.774. PMC 1723104. PMID 10381661.
27. Order Siphonaptera – Fleas – BugGuide.Net Accessed 29 April 2014
28. "Official Rules". MLB. Retrieved 30 September 2011.
29. Bohun B. Kinloch Jr; William H. Scheuner. "Pinus lambertiana". Archived from the original on 8 June 2011. Retrieved 19 January 2017.
30. "What is a rapier – Renaissance swords Rapiers". 2-Clicks Swords.
31. "Robert Wadlow: Tallest man ever". Guinness World Records.
32. "Animal Records". Smithsonian National Zoological Park. Archived from the original on 23 August 2004.
33. "Niagara Falls Geology Facts & Figures". Niagara Parks Commission. Archived from the original on 19 July 2011. Retrieved 29 June 2011.
34. "Three Gorges Dam". encyclopedia.com. Cengage Learning.
35. "Exploring Chinese History :: Special Reports :: The Three Gorges Dam Project". www.ibiblio.org.
36. Thomas PC, Parker JW, McFadden LA, Russell CT, Stern SA, Sykes MV, Young EF (September 2005). "Differentiation of the asteroid Ceres as revealed by its shape". Nature. 437 (7056): 224–6. Bibcode:2005Natur.437..224T. doi:10.1038/nature03938. PMID 16148926. S2CID 17758979.
37. Weintrit, Adam (2013). "So, What is Actually the Distance from the Equator to the Pole? – Overview of the Meridian Distance Approximations". TransNav, the International Journal on Marine Navigation and Safety of Sea Transportation. 7 (2): 259–272. doi:10.12716/1001.07.02.14. ISSN 2083-6473.
38. "Volvo owner Irv Gordon, who drove 3.2M miles in his P1800, has died". autoblog.com. 16 November 2018. Retrieved 23 January 2021.
39. Starr, Barry (2 February 2009). "A Long and Winding DNA". KQED. Retrieved 3 July 2024.
40. "Spacecraft escaping the Solar System". Heavens Above. Archived from the original on 7 October 2018. Retrieved 19 October 2018.
41. "Twin Keck telescopes probe dual dust disks". (e) Science News. 24 September 2009.
42. Shiga, David. "Sun's 'twin' an ideal hunting ground for alien life". New Scientist. Retrieved 3 October 2007.
43. Christian, Eric; Samar, Safi-Harb. "How large is the Milky Way?". Archived from the original on 2 February 1999. Retrieved 14 November 2008.
44. Duncan, Martin (2008). "16" (PDF). Physics 216 – Introduction to Astrophysics. Archived from the original (PDF) on 17 December 2008. Retrieved 14 November 2008.
45. "Milky Way fatter than first thought". The Sydney Morning Herald. Australian Associated Press. 20 February 2008. Archived from the original on 28 April 2008. Retrieved 14 November 2008.
46. M. López-Corredoira, C. Allende Prieto, F. Garzón, H. Wang, C. Liu and L. Deng (2018). "Disk stars in the Milky Way detected beyond 25 kpc from its center". Astronomy & Astrophysics. 612: L8. arXiv:1804.03064. Bibcode:2018A&A...612L...8L. doi:10.1051/0004-6361/201832880. S2CID 59933365.{{cite journal}}: CS1 maint: multiple names: authors list (link)
47. Freeman, David (25 May 2018). "The Milky Way galaxy may be much bigger than we thought" (Press release). CNBC.
48. Martialay, Mary L. (11 March 2015). "The Corrugated Galaxy—Milky Way May Be Much Larger Than Previously Estimated" (Press release). Rensselaer Polytechnic Institute. Archived from the original on 13 March 2015.
49. Hall, Shannon (4 May 2015). "Size of the Milky Way Upgraded, Solving Galaxy Puzzle". Space.com. Archived from the original on 7 June 2015. Retrieved 9 June 2015.
50. "The Horologium Supercluster". Atlas of the Universe.
51. Gott, J. Richard; Jurić, Mario; Schlegel, David; Hoyle, Fiona; Vogeley, Michael; Tegmark, Max; Bahcall, Neta; Brinkmann, Jon (2005). "A Map of the Universe". The Astrophysical Journal. 624 (2): 463. arXiv:astro-ph/0310571. Bibcode:2005ApJ...624..463G. doi:10.1086/428890. S2CID 9654355.
52. Scott, Douglas; Zibin, J.P. (2006). "How Many Universes Do There Need To Be?". International Journal of Modern Physics D. 15 (12): 2229–2233. arXiv:astro-ph/0605709. Bibcode:2006IJMPD..15.2229S. doi:10.1142/S0218271806009662. S2CID 119437678.
53. Tegmark, M. (2003). "Parallel universes. Not just a staple of science fiction, other universes are a direct implication of cosmological observations". Scientific American. 288 (5): 40–51. arXiv:astro-ph/0302131. Bibcode:2003SciAm.288e..40T. doi:10.1038/scientificamerican0503-40. PMID 12701329.
54. Tegmark M (May 2003). "Parallel universes. Not just a staple of science fiction, other universes are a direct implication of cosmological observations". Scientific American. 288 (5): 40–51. arXiv:astro-ph/0302131. Bibcode:2003SciAm.288e..40T. doi:10.1038/scientificamerican0503-40. PMID 12701329.
55. Page, Don N.; Allende Prieto, C.; Garzon, F.; Wang, H.; Liu, C.; Deng, L. (18 October 2006). "Susskind's challenge to the Hartle Hawking no-boundary proposal and possible resolutions". Journal of Cosmology and Astro-Particle Physics. 2007 (1): 004. arXiv:hep-th/0610199. Bibcode:2007JCAP...01..004P. doi:10.1088/1475-7516/2007/01/004. S2CID 17403084.
56. "SI Brochure: The International System of Units (SI)". International Committee for Weights and Measures. Organisation Intergouvernementale de la Convention du Mètre. Retrieved 11 October 2014.
57. Nave, Carl R. "Cowan and Reines Neutrino Experiment". Retrieved 4 December 2008. (6.3×10⁻⁴⁴ cm², which gives an effective radius of about 2×10⁻²³ m)
58. Christman, J. (2001). "The Weak Interaction" (PDF). Physnet. Michigan State University. Archived from the original (PDF) on 20 July 2011.
59. Raya, Khépani; Bedolla, Marco A.; Cobos-Martínez, J. J.; Bashir, Adnan (31 October 2017). "Heavy quarkonia in a contact interaction and an algebraic model: mass spectrum, decay constants, charge radii and elastic and transition form factors". Few-Body Systems. 59 (6): 16. arXiv:1711.00383. Bibcode:2018FBS....59..133R. doi:10.1007/s00601-018-1455-y. S2CID 254061694.
60. Castelvecchi, Davide (11 November 2019). "How Big Is the Proton? Particle-Size Puzzle Leaps Closer to Resolution". Scientific American. Retrieved 3 July 2024.
61. Pohl, Randolf; Antognini, Aldo; Nez, François; Amaro, Fernando D.; Biraben, François; Cardoso, João M. R.; Covita, Daniel S.; Dax, Andreas; Dhawan, Satish; Fernandes, Luis M. P.; Giesen, Adolf; Graf, Thomas; Hänsch, Theodor W.; Indelicato, Paul; Julien, Lucile; Kao, Cheng-Yang; Knowles, Paul; Le Bigot, Eric-Olivier; Liu, Yi-Wei; Lopes, José A. M.; Ludhova, Livia; Cristina M. B. Monteiro; Mulhauser, Françoise; Nebel, Tobias; Rabinowitz, Paul; et al. (8 July 2010). "The size of the proton". Nature. 466 (7303): 213–216. Bibcode:2010Natur.466..213P. doi:10.1038/nature09250. PMID 20613837. S2CID 4424731.
62. "proton rms charge radius". The NIST Reference on Constants, Units, and Uncertainty.
63. NIST. CODATA Value: classical electron radius. Retrieved 2009-02-10
64. ISO 1683:2015
65. Winter, Mark (2008). "WebElements Periodic Table of the Elements / Hydrogen / radii". Archived from the original on 18 December 2008. Retrieved 6 December 2008.
66. Winter, Mark (2008). "WebElements Periodic Table of the Elements / Helium / radii". Archived from the original on 19 December 2008. Retrieved 6 December 2008.
67. Winter, Mark (2008). "WebElements Periodic Table of the Elements / Sulfur / Radii". Archived from the original on 11 December 2008. Retrieved 6 December 2008.
68. Winter, Mark (2008). "WebElements Periodic Table of the Elements / Periodicity / Van der Waals radius / periodicity". Archived from the original on 19 December 2008. Retrieved 6 December 2008.
69. "Resolution of an Electron Microscope". Archived from the original on 16 March 2009. Retrieved 25 April 2009.
70. "Buckminsterfullerene: Molecule of the Month". www.chm.bris.ac.uk. Retrieved 21 April 2019.
71. Smith, Graham T. (2002). Industrial metrology. Springer. pp. 253. ISBN 978-1-85233-507-6.
72. Introduction to the Electromagnetic Spectrum and Spectroscopy
73. Annis, Patty J. October 1991. Kansas State University. Fine Particle POLLUTION. Figure 1. (tobacco smoke: 10 to 1000 nm; virus particles: 3 to 50 nm; bacteria: 30 to 30000 nm; cooking oil smoke: 30 to 30000 nm; wood smoke: 7 to 3000 nm)
74. Stryer, Lubert (1988). Biochemistry. San Francisco: W.H. Freeman. ISBN 978-0-7167-1843-7.
75. "Through the Microscope". www.microbiologytext.com. Archived from the original on 12 June 2016. Retrieved 21 May 2017.
76. Kojima S, Blair D (2004). "The bacterial flagellar motor: structure and function of a complex molecular machine". Int Rev Cytol. International Review of Cytology. 233: 93–134. doi:10.1016/S0074-7696(04)33003-2. ISBN 978-0-12-364637-8. PMID 15037363.
77. "Moore's Law Marches on at Intel". Physorg.com. Retrieved 1 September 2018.
78. "Hard drive basics – Capacities, RPM speeds, interfaces and mechanics". www.helpwithpcs.com.
79. Smith, Graham T. (2002). Industrial metrology. Springer. p. 253. ISBN 978-1-85233-507-6.
80. Eninger, Robert M.; Hogan, Christopher J.; Biswas, Pratim; Adhikari, Atin; Reponen, Tiina; Grinshpun, Sergey A. (2009). "Electrospray versus Nebulization for Aerosolization and Filter Testing with Bacteriophage Particles". Aerosol Science and Technology. 43 (4): 298–304. Bibcode:2009AerST..43..298E. doi:10.1080/02786820802626355. S2CID 93465533.
81. "Air Pollution [Control] Technology Fact Sheet" (PDF). United States Environmental Protection Agency. Retrieved 3 July 2024.
82. Seth (18 November 2009). Textbook Of Pharmacology. Elsevier India. ISBN 9788131211588 – via Google Books.
83. "New Coronavirus (SARS-CoV-2) and the Safety Margins of Plasma Protein Therapies – Plasma Protein Therapeutics Association (PPTA)". Archived from the original on 2 June 2020. Retrieved 30 May 2020.
84. "NIOSH Guide to the Selection and Use of Particulate Respirators". Centers for Disease Control and Prevention. 1996. Retrieved 3 July 2024.
85. Spencer RC (March 2003). "Bacillus anthracis". Journal of Clinical Pathology. 56 (3): 182–7. doi:10.1136/jcp.56.3.182. PMC 1769905. PMID 12610093.
86. Walker K, Skelton H, Smith K (November 2002). "Cutaneous lesions showing giant yeast forms of Blastomyces dermatitidis". Journal of Cutaneous Pathology. 29 (10): 616–8. doi:10.1034/j.1600-0560.2002.291009.x. PMID 12453301. S2CID 39904013.
87. Smith, D.J. (2009). "Human sperm accumulation near surfaces: a simulation study" (PDF). Journal of Fluid Mechanics. 621: 295. Bibcode:2009JFM...621..289S. doi:10.1017/S0022112008004953. S2CID 3942426. Archived from the original (PDF) on 6 November 2013. Retrieved 20 May 2012.
88. "NAC Audio Cassette Glossary – Cassetro". nactape.com. Retrieved 16 March 2018.
89. "Genes are real things :: DNA from the Beginning". www.dnaftb.org.
90. Ramel, Gordon. "Spider Silk". Archived from the original on 4 December 2008. Retrieved 4 December 2008. garden spider silk has a diameter of about 0.003 mm ... Dragline silk (about 0.00032 inch (0.008 mm) in Nephila)
91. Wise, R.R.; Hoober, J.K. (2007). The Structure and Function of Plastids. Springer. p. 14. ISBN 978-1-4020-6570-5.
92. Zak, J. Allen (April 1994). Drop Size Distributions and Related Properties of Fog for Five Locations Measured From Aircraft (PDF) (Report). Hampton, VA: NASA – Langley Research Center. 4585.
93. IST – Innovative Sintering Technologies Ltd. "Fibreshape applications". Retrieved 4 December 2008. Histogram of cotton thickness
94. "Company Profile, page 20" (PDF). The Lego Group. 2010. Archived from the original (PDF) on 9 December 2012.
95. Lippmann, Morton (2000). Environmental Toxicants: Human Exposures and Their Health Effects. John Wiley and Sons. p. 453. ISBN 978-0-471-29298-2. Retrieved 4 December 2008. 20 μm .. 5 μm
96. Rossi, Massimiliano (27 November 2017). "Kinematics of flagellar swimming in Euglena gracilis: Helical trajectories and flagellar shapes". Proceedings of the National Academy of Sciences of the United States of America. 114 (50): 13085–13090. Bibcode:2017PNAS..11413085R. doi:10.1073/pnas.1708064114. hdl:11384/84166. PMC 5740643. PMID 29180429.
97. "Apple – iPhone 4S – See everything clearly with the Retina display". Apple Inc. Official Website. Apple Inc. Retrieved 10 March 2012.
98. Gyllenbok, Jan (2018). Encyclopedia of Historical Metrology, Weights, and Measures. Birkhäuser. ISBN 9783319575988.
99. "La Loi Du 18 Germinal An 3 – Décision de tracer le mètre, unité fondamentale, sur une règle de platine. Nomenclature des "mesures républicaines". Reprise de la triangulation" (in French). histoire.du.metre.free.fr. Retrieved 12 October 2015.
100. Comité International des Poids et Mesures (1935), Procès-Verbaux des Séances (in French), vol. 17 (2 ed.), Paris, France: Gauthier-Villars, imprimeur-libraire du Bureau des Longitudes, de l'École Polytechnique, p. 76
101. Roberts, Richard W. (1 June 1975). Metric System of Weights and Measures – Guidelines for Use. US: Director of the National Bureau of Standards. Federal Register FR Doc.75-15798 (18 June 1975). Accordingly, the following units and terms listed in the table of metric units in section 2 of the act of 28 July 1866, that legalized the metric system of weights and measures in the United States, are no longer accepted for use in the United States: myriameter, stere, millier or tonneau, quintal, myriagram, kilo (for kilogram).
102. Judson, Lewis V. (1 October 1976) [1963]. "Appendix 7" (PDF). In Barbrow, Louis E. (ed.). Weights and Measures Standards of the United States, a brief history. Derived from a prior work by Louis A. Fisher (1905). US: US Department of Commerce, National Bureau of Standards. p. 33. LCCN 76-600055. NBS Special Publication 447; NIST SP 447; 003-003-01654-3. Archived from the original (PDF) on 4 March 2016. Retrieved 12 October 2015.
103. Lindemann, Charles. "Sperm Facts". Dr. Charles Lindmann's Lab. Oakland University.
104. Popiolek, Kim. "Dr. Charles Lindemann's Lab: Sperm Facts". Oakland University.
105. Santoso, Alex (17 June 2006). "World's Biggest Sperm Belongs to a Tiny Fly". Neatorama.
106. Lyon, William F. "House Dust Mites". Ohio State University Extension. HYG-2157-97. Archived from the original on 2 November 2001.
107. Rodgers, Steven. "Designing and Operating Electrostatically Driven Microengines" (PDF). Sandia National Laboratory. Retrieved 3 July 2024.
108. "CNN – Scientists discover biggest bacteria ever – April 15, 1999". www.cnn.com. Retrieved 20 May 2017.
109. "World's Smallest Frog Found—Fly-Size Beast Is Tiniest Vertebrate". 13 January 2017. Archived from the original on 13 January 2012. Retrieved 20 May 2017.
110. NATO Infantry Weapons Standardization, Per G. Arvidsson, ChairmanWeapons & Sensors Working GroupLand Capability Group 1 – Dismounted Soldier NATO Army Armaments Group Archived 1 December 2012 at the Wayback Machine Accessed 29 April 2014
111. "World's smallest vertebrate has a big secret". New Scientist. Retrieved 20 May 2017.
112. Lindstrom, Hannah. "The Smallest Salamander". Mongabay.com. Retrieved 20 May 2017.
113. "Comparing quail eggs". BackYard Chickens. Retrieved 20 May 2017.
114. "Why the Moon is getting further away from Earth". BBC News. 1 February 2011. Retrieved 5 November 2021.
115. "USGA: Guide to the Rules on Clubs and Balls". USGA. Retrieved 30 September 2011.
116. "CR80 Card Specification". CardLogix Corporation. Retrieved 3 July 2024.
117. "Credit Card Dimensions". Retrieved 30 September 2011.
118. Kinloch, Bohun B. Jr. & Scheuner, William H. "Pinus lambertiana". Archived from the original on 8 June 2011. Retrieved 1 May 2017.
119. "HTwins.net – The Scale of the Universe". htwins.net. Archived from the original on 29 November 2010. Retrieved 20 May 2017.
120. Laws of the Game (PDF), FIFA, 1 June 2017, archived from the original (PDF) on 13 November 2017, retrieved 21 March 2018
121. IAAF International Association of Athletics Federations – IAAF.org - Statistics - Top Lists, archived from the original on 16 January 2008, retrieved 9 April 2010
122. IAAF International Association of Athletics Federations – IAAF.org - Past Results, archived from the original on 4 June 2011, retrieved 9 April 2010
123. Dagg, A. I. (1971), Mammalian Species 5 (Giraffa camelopardalis ed.), pp. 1–8
124. "Fossil of 'largest flying bird' identified". BBC News. 7 July 2014. Retrieved 19 July 2022.
125. Plait, P. (6 October 2008). "Incoming!!!". Bad Astronomy. Archived from the original on 7 October 2008. Retrieved 8 October 2008.
126. "Rule 1.04 The Playing Field" (PDF). Official Baseball Rules. Major League Baseball. 25 January 2010. pp. 1–5. Archived (PDF) from the original on 27 April 2011. Retrieved 1 April 2011. See especially Diagram No. 1, page 3.
127. "Law 7 (The pitch)". Laws of Cricket. Marylebone Cricket Club. October 2010. Archived from the original on 14 May 2011. Retrieved 1 April 2011.
128. "Animal Records". Smithsonian National Zoological Park. Archived from the original on 28 March 2009. Retrieved 29 May 2007.
129. Curtice, Brian (2021). "New Dry Mesa Dinosaur Quarry Supersaurus vivianae (Jensen 1985) axial elements provide additional insight into its phylogenetic relationships and size, suggesting an animal that exceeded 39 meters in length" (PDF).
130. "Longest Animal". Guinness World Records. Retrieved 15 June 2019.
131. "Driver Location Signs – Frequently Asked Questions". Highways Agency. Archived from the original on 10 August 2012. Retrieved 10 February 2010.
132. "Kingda Ka (Six Flags Great Adventure)". Archived from the original on 26 March 2009. Retrieved 18 April 2009.
133. "Eiffel Tower grows six metres after new antenna attached". Reuters. 15 March 2022.
134. Campbell, Marilyn (17 February 2018). "How Tall is the CN Tower?". TripSavvy. Retrieved 20 May 2017.
135. "Burj Dubai all set for 09/09/09 soft opening". Emirates Business 24-7. Archived from the original on 19 January 2009. Retrieved 17 January 2009.
136. "Tallest tree in the world: coast redwood". Monumental Trees, an inventory of big and old trees worldwide.
137. Fujiwara A, Kawaguchi J, Yeomans DK, Abe M, Mukai T, Okada T, Saito J, Yano H, Yoshikawa M, Scheeres DJ, Barnougin-Jha O, Cheng AF, Demura H, Gaskell RW, Hirata N, Ikeda H, Kominato T, Miyamoto H, Nakamura AM, Nakamura R, Sasaki S, Uesugi K (June 2006). "The rubble-pile asteroid Itokawa as observed by Hayabusa". Science. 312 (5778): 1330–4. Bibcode:2006Sci...312.1330F. doi:10.1126/science.1125841. PMID 16741107. S2CID 206508294.
138. "long wave". Oxford Dictionaries. Archived from the original on 1 March 2019. Retrieved 12 March 2011. wavelength above one kilometre (and a frequency below 300 kHz)
139. "Bridge Design and Construction Statistics". Golden Gate Bridge. Archived from the original on 14 June 2012. Retrieved 10 June 2012.
140. "nautical mile". Merriam-Webster.com Dictionary. Merriam-Webster. Retrieved 12 March 2011.
141. Akashi Kaikyo Bridge @ Everything2.com, Everything2, 9 September 2002, retrieved 19 April 2009
142. Friedl, Jeffrey (9 December 2008), Supporting the Longest Suspension Bridge in the World, archived from the original on 3 March 2009, retrieved 19 April 2009
143. New height of world's railway born in Tibet, Xinhua News Agency, 24 August 2005, archived from the original on 3 June 2009, retrieved 19 April 2009
144. "Aucanquilcha 6176m". Andes. Retrieved 3 July 2024.
145. "Russians in landmark Baikal dive". BBC News. 29 July 2008. Retrieved 12 March 2011. current record of 1,637m was set in Lake Baikal in the 1990s
146. "Kosciuszko National Park lookouts and scenery". Office of Environment & Heritage: NSW National Parks & Wildlife Service.
147. "Carstensz Pyramid details". Carstensz Pyramid Site. Archived from the original on 16 December 2014.
148. Appell, Wolfgang (16 September 2009) [2002]. "Königreich Frankreich" [Kingdom of France]. Amtliche Maßeinheiten in Europa 1842 [Official units of measure in Europe 1842] (in German). Archived from the original on 5 October 2011. (Website based on Alte Meß- und Währungssysteme aus dem deutschen Sprachgebiet, ISBN 3-7686-1036-5)
149. Brewster, David (1830). The Edinburgh Encyclopædia. Vol. 12. Edinburgh, UK: William Blackwood, John Waugh, John Murray, Baldwin & Cradock, J. M. Richardson. p. 494. Retrieved 9 October 2015.
150. Brewster, David (1832). The Edinburgh Encyclopaedia. Vol. 12 (1st American ed.). Joseph and Edward Parker. Retrieved 9 October 2015.
151. Dingler, Johann Gottfried (1823). Polytechnisches Journal (in German). Vol. 11. Stuttgart, Germany: J.W. Gotta'schen Buchhandlung. Retrieved 9 October 2015.
152. Haugen, Einar, Norwegian English Dictionary, 1965, Oslo: Universitetsforlaget and Madison: University of Wisconsin Press, s.v. mil
153. "What is a farsakh or farsang?". sizes.com.
154. "IAAF Competition Rules 2008" (PDF). IAAF. p. 195. Archived (PDF) from the original on 25 March 2009. Retrieved 20 April 2009.
155. Kennedy, Gregory. "Stratolab, an Evolutionary Stratospheric Balloon Project".
156. Wise, Jeff (1 October 2009). "Turkey Building the World's Deepest Immersed Tube Tunnel". Popular Mechanics. Retrieved 1 May 2017.
157. "Facts and History about the Panama Canal". Archived from the original on 14 March 2016.
158. Highest and lowest points on Mars Archived 31 January 2016 at the Wayback Machine NASA
159. Plescia, Jeff (1 October 1997). "Height of Martian vs. Earth mountains". Questions and Answers about Mars terrain and geology. Archived from the original on 14 October 2008. Retrieved 20 April 2009.
160. "High Speed 1 Project Hoem". www.betchel.com. Betchel Corporation. Retrieved 8 February 2015.
161. "Bordeaux-Paris | the event". www.bordeauxparis.com. Archived from the original on 28 March 2017. Retrieved 30 April 2017.
162. "FAQ-Alaska Highway Facts". The MILEPOST. Archived from the original on 29 September 2007. Retrieved 25 August 2007. 1,390 miles ... Alaska Route 2 and often treated as a natural extension of the Alaska Highway
163. Downward, R.J.; Bromell, J.E. (March 1990). "The development of a policy for the management of dingo populations in South Australia". Proceedings of the Fourteenth Vertebrate Pest Conference 1990. University of Nebraska–Lincoln. Archived from the original on 24 May 2024. Retrieved 31 August 2009.
164. "China's Great Wall far longer than thought: survey". AFP. 20 April 2009. Archived from the original on 27 April 2009. Retrieved 20 April 2009.
165. CIS railway timetable, route No. 002, Moscow-Vladivostok. Archived 3 December 2009.
166. CIS railway timetable, route No. 350, Kyiv-Vladivostok. Archived 3 December 2009.
167. McGourty, Christine (14 December 2005). "Hubble finds mass of white dwarf". BBC News. Retrieved 13 October 2007.
168. NASA Staff (10 May 2011). "Solar System Exploration – Earth's Moon: Facts & Figures". NASA. Archived from the original on 7 November 2011. Retrieved 6 November 2011.
169. "Sun Fact Sheet". nssdc.gsfc.nasa.gov.
170. Sun Fact Sheet
171. Akeson, Rachel; Beichman, Charles; Kervella, Pierre; Fomalont, Edward; Benedict, G. Fritz (2021). "Precision Millimeter Astrometry of the α Centauri AB System". The Astronomical Journal. 162 (1): 14. arXiv:2104.10086. Bibcode:2021AJ....162...14A. doi:10.3847/1538-3881/abfaff.
172. Liebert, James; Young, Patrick A.; Arnett, David; Holberg, J. B.; Williams, Kurtis A. (2005). "The Age and Progenitor Mass of Sirius B". The Astrophysical Journal. 630 (1): L69–L72. arXiv:astro-ph/0507523. Bibcode:2005ApJ...630L..69L. doi:10.1086/462419. S2CID 8792889.
173. Neuroscience: The Science of the Brain"IBRO Brain Campaign". Archived from the original on 2 February 2011. Retrieved 8 June 2011. p.44
174. Yoon, Jinmi; Peterson, Deane M.; Kurucz, Robert L.; Zagarello, Robert J. (2010). "A New View of Vega's Composition, Mass, and Age". The Astrophysical Journal. 708 (1): 71–79. Bibcode:2010ApJ...708...71Y. doi:10.1088/0004-637X/708/1/71. S2CID 120986935.
175. Tkachenko, A.; et al. (May 2016), "Stellar modelling of Spica, a high-mass spectroscopic binary with a β Cep variable primary component", Monthly Notices of the Royal Astronomical Society, 458 (2): 1964–1976, arXiv:1601.08069, Bibcode:2016MNRAS.458.1964T, doi:10.1093/mnras/stw255, S2CID 26945389
176. Baines, Ellyn K.; Armstrong, J. Thomas; Schmitt, Henrique R.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Tycner, Christopher; Belle, Gerard T. van (2017). "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 155 (1): 30. arXiv:1712.08109. Bibcode:2018AJ....155...30B. doi:10.3847/1538-3881/aa9d8b.
177. Howes, Louise M.; Lindegren, Lennart; Feltzing, Sofia; Church, Ross P.; Bensby, Thomas (1 February 2019). "Estimating stellar ages and metallicities from parallaxes and broadband photometry: successes and shortcomings". Astronomy & Astrophysics. 622: A27. arXiv:1804.08321. Bibcode:2019A&A...622A..27H. doi:10.1051/0004-6361/201833280. ISSN 0004-6361.
178. Ramírez, I.; Allende Prieto, C. (2011). "Fundamental Parameters and Chemical Composition of Arcturus". The Astrophysical Journal. 743 (2): 135. arXiv:1109.4425. Bibcode:2011ApJ...743..135R. doi:10.1088/0004-637X/743/2/135. S2CID 119186472.
179. Richichi, A.; Roccatagliata, V.; Shultz, Matt; Williamson, Michael H.; Moya, Andres (2005). "Aldebaran's angular diameter: How well do we know it?". Astronomy & Astrophysics. 433 (1): 305–312. arXiv:astro-ph/0502181. Bibcode:2005A&A...433..305R. doi:10.1051/0004-6361:20041765. S2CID 119414301. They derived an angular diameter of 20.58±0.03 milliarcsec, which given a distance of 65 light-years yields a diameter of 61 million km.
180. Kallinger, T.; Beck, P. G.; Hekker, S.; Huber, D.; Kuschnig, R.; Rockenbauer, M.; Winter, P. M.; Weiss, W. W.; Handler, G.; Moffat, A. F. J.; Pigulski, A.; Popowicz, A.; Wade, G. A.; Zwintz, K. (April 2019). "Stellar masses from granulation and oscillations of 23 bright red giants observed by BRITE - Constellation". Astronomy & Astrophysics. 624: A35. arXiv:1902.07531. doi:10.1051/0004-6361/201834514. ISSN 0004-6361.
181. McDonald, Iain; Zijlstra, Albert A.; Watson, Robert A. (11 October 2017). "Fundamental parameters and infrared excesses of Tycho-Gaia stars". Monthly Notices of the Royal Astronomical Society. 471 (1): 770–791. arXiv:1706.02208. doi:10.1093/mnras/stx1433. ISSN 0035-8711.
182. Chesneau, O.; Dessart, L.; Mourard, D.; Bério, Ph.; Buil, Ch.; Bonneau, D.; Borges Fernandes, M.; Clausse, J. M.; Delaa, O.; Marcotto, A.; Meilland, A.; Millour, F.; Nardetto, N.; Perraut, K.; Roussel, A.; Spang, A.; Stee, P.; Tallon-Bosc, I.; McAlister, H.; Ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J. (2010). "Time, spatial, and spectral resolution of the H α line-formation region of Deneb and Rigel with the VEGA/CHARA interferometer". Astronomy and Astrophysics. 521: A5. arXiv:1007.2095. Bibcode:2010A&A...521A...5C. doi:10.1051/0004-6361/201014509. S2CID 10340205.
183. Woodruff, H. C.; Eberhardt, M.; Driebe, T.; Hofmann, K.-H.; Ohnaka, K.; Richichi, A.; Schertl, D.; Schoeller, M.; Scholz, M.; Weigelt, G.; Wittkowski, M.; Wood, P. R. (July 2004). "Interferometric observations of the Mira star o Ceti with the VLTI/VINCI instrument in the near-infrared". Astronomy & Astrophysics. 421 (2): 703–714. arXiv:astro-ph/0404248. Bibcode:2004A&A...421..703W. doi:10.1051/0004-6361:20035826. ISSN 0004-6361.
184. Lau, R. M.; Herter, T. L.; Morris, M. R.; Adams, J. D. (2014). "Nature Versus Nurture: Luminous Blue Variable Nebulae in and Near Massive Stellar Clusters at the Galactic Center". The Astrophysical Journal. 785 (2): 120. arXiv:1403.5298. Bibcode:2014ApJ...785..120L. doi:10.1088/0004-637X/785/2/120. S2CID 118447462.
185. Anugu, Narsireddy; Baron, Fabien; Monnier, John D.; Gies, Douglas R.; Roettenbacher, Rachael M.; Schaefer, Gail H.; Montargès, Miguel; Kraus, Stefan; Bouquin, Jean-Baptiste Le (5 August 2024). "CHARA Near-Infrared Imaging of the Yellow Hypergiant Star $\rho$ Cassiopeiae: Convection Cells and Circumstellar Envelope". arXiv:2408.02756v2 [astro-ph.SR].
186. Joyce, Meridith; Leung, Shing-Chi; Molnár, László; Ireland, Michael; Kobayashi, Chiaki; Nomoto, Ken'Ichi (2020). "Standing on the Shoulders of Giants: New Mass and Distance Estimates for Betelgeuse through Combined Evolutionary, Asteroseismic, and Hydrodynamic Simulations with MESA". The Astrophysical Journal. 902 (1): 63. arXiv:2006.09837. Bibcode:2020ApJ...902...63J. doi:10.3847/1538-4357/abb8db.
187. Gull, Theodore R.; Hillier, D. John; Hartman, Henrik; Corcoran, Michael F.; Damineli, Augusto; Espinoza-Galeas, David; Hamaguchi, Kenji; Navarete, Felipe; Nielsen, Krister; Madura, Thomas; Moffat, Anthony F. J.; Morris, Patrick; Richardson, Noel D.; Russell, Christopher M. P.; Stevens, Ian R. (July 2022). "Eta Carinae: An Evolving View of the Central Binary, Its Interacting Winds and Its Foreground Ejecta". The Astrophysical Journal. 933 (2): 175. arXiv:2205.15116. Bibcode:2022ApJ...933..175G. doi:10.3847/1538-4357/ac74c2. ISSN 0004-637X.
188. Montargès, M.; Homan, W.; Keller, D.; Clementel, N.; Shetye, S.; Decin, L.; Harper, G. M.; Royer, P.; Winters, J. M.; Le Bertre, T.; Richards, A. M. S. (2019). "NOEMA maps the CO J = 2 − 1 environment of the red supergiant μ Cep". Monthly Notices of the Royal Astronomical Society. 485 (2): 2417–2430. arXiv:1903.07129. Bibcode:2019MNRAS.485.2417M. doi:10.1093/mnras/stz397. S2CID 119423161.
189. Table 4 in Emily M. Levesque; Philip Massey; K. A. G. Olsen; Bertrand Plez; Eric Josselin; Andre Maeder & Georges Meynet (2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal. 628 (2): 973–985. arXiv:astro-ph/0504337. Bibcode:2005ApJ...628..973L. doi:10.1086/430901. S2CID 15109583.
190. van Genderen, A. M.; Lobel, A.; Nieuwenhuijzen, H.; Henry, G. W.; De Jager, C.; Blown, E.; Di Scala, G.; Van Ballegoij, E. J. (2019). "Pulsations, eruptions, and evolution of four yellow hypergiants". Astronomy and Astrophysics. 631: A48. arXiv:1910.02460. Bibcode:2019A&A...631A..48V. doi:10.1051/0004-6361/201834358. S2CID 203836020.
191. Bauer, W. H.; Gull, T. R.; Bennett, P. D. (2008). "Spatial Extension in the Ultraviolet Spectrum of Vv Cephei". The Astronomical Journal. 136 (3): 1312. Bibcode:2008AJ....136.1312H. doi:10.1088/0004-6256/136/3/1312. S2CID 119404901.
192. Shenoy, Dinesh; Humphreys, Roberta M.; Jones, Terry J.; Marengo, Massimo; Gehrz, Robert D.; Helton, L. Andrew; Hoffmann, William F.; Skemer, Andrew J.; Hinz, Philip M. (2016). "SEARCHING FOR COOL DUST IN THE MID-TO-FAR INFRARED: THE MASS-LOSS HISTORIES OF THE HYPERGIANTS μ Cep, VY CMa, IRC+10420, AND ρ Cas". The Astronomical Journal. 151 (3): 51. arXiv:1512.01529. Bibcode:2016AJ....151...51S. doi:10.3847/0004-6256/151/3/51.
193. Wittkowski, M.; Hauschildt, P.H.; Arroyo-Torres, B.; Marcaide, J.M. (5 April 2012). "Fundamental properties and atmospheric structure of the red supergiant VY CMa based on VLTI/AMBER spectro-interferometry". Astronomy & Astrophysics. 540: L12. arXiv:1203.5194. Bibcode:2012A&A...540L..12W. doi:10.1051/0004-6361/201219126. S2CID 54044968.
194. Parthasarathy, M. (2000). "Birth and early evolution of planetary nebulae". Bulletin of the Astronomical Society of India. 28: 217–224. Bibcode:2000BASI...28..217P.
195. radius = distance times sin(angular diameter/2) = 0.2 light-year. Distance = 3.3 ± 0.9 kly; angular diameter = 20 arcseconds (Reed et al. 1999)
196. Reed, Darren S.; Balick, Bruce; Hajian, Arsen R.; Klayton, Tracy L.; Giovanardi, Stefano; Casertano, Stefano; Panagia, Nino; Terzian, Yervant (1999). "Hubble Space Telescope Measurements of the Expansion of NGC 6543: Parallax Distance and Nebular Evolution". Astronomical Journal. 118 (5): 2430–2441. arXiv:astro-ph/9907313. Bibcode:1999AJ....118.2430R. doi:10.1086/301091. S2CID 14746840.
197. Szpir, Michael (May–June 2001). "Bart Bok's Black Blobs". American Scientist. Archived from the original on 29 June 2003. Retrieved 19 November 2008. Bok globules such as Barnard 68 are only about half a light-year across and weigh in at about two solar masses
198. Sandstrom, Karin M; Peek, J. E. G.; Bower, Geoffrey C.; Bolatto, Alberto D.; Plambeck, Richard L. (1999). "A Parallactic Distance of 389+24
     −21 parsecs to the Orion Nebula Cluster from Very Long Baseline Array Observations". The Astrophysical Journal. 667 (2): 1161–1169. arXiv:0706.2361. Bibcode:2007ApJ...667.1161S. doi:10.1086/520922. S2CID 18192326.
199. diameter=sin(65 arcminutes)*1270 light-years=24; where "65.00 × 60.0 (arcmin)" sourced from Revised NGC Data for NGC 1976
200. distance × sin( diameter_angle ), using distance of 5kpc (15.8 ± 1.1 kly) and angle 36.3', = 172 ± 12.5 ly.
201. van de Ven, G.; van den Bosch, R. C. E.; Verolme, E. K.; de Zeeuw, P. T. (2006). "The dynamical distance and intrinsic structure of the globular cluster ω Centauri". Astronomy and Astrophysics. 445 (2): 513–543. arXiv:astro-ph/0509228. Bibcode:2006A&A...445..513V. doi:10.1051/0004-6361:20053061. S2CID 15538249. best-fit dynamical distance D=4.8±0.3 kpc ... consistent with the canonical value 5.0±0.2 kpc obtained by photometric methods
202. van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
203. Neuhäuser, R; Torres, G; Mugrauer, M; Neuhäuser, D L; Chapman, J; Luge, D; Cosci, M (29 July 2022). "Colour evolution of Betelgeuse and Antares over two millennia, derived from historical records, as a new constraint on mass and age". Monthly Notices of the Royal Astronomical Society. 516 (1): 693–719. arXiv:2207.04702. doi:10.1093/mnras/stac1969. ISSN 0035-8711.
204. Harris, Hugh C.; Dahn, Conard C.; Canzian, Blaise; Guetter, Harry H.; et al. (2007). "Trigonometric Parallaxes of Central Stars of Planetary Nebulae". The Astronomical Journal. 133 (2): 631–638. arXiv:astro-ph/0611543. Bibcode:2007AJ....133..631H. doi:10.1086/510348. S2CID 18261027.
205. Reid, M. J.; et al. (2009). "Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions". Astrophysical Journal. 700 (1): 137–148. arXiv:0902.3913. Bibcode:2009ApJ...700..137R. doi:10.1088/0004-637X/700/1/137. S2CID 11347166.

External links

• How Big Are Things? – displays orders of magnitude in successively larger rooms.
• Powers of Ten – Travel across the Universe.
• Cosmos – Journey from microcosmos to macrocosmos (Digital Nature Agency).
• Scale of the universe – interactive guide to length magnitudes
• Video (4:29) on YouTube – Orders of Magnitude (March 2020).