Location of Earth

Knowledge of the location of Earth has been shaped by 400 years of telescopic observations, and has expanded radically since the start of the 20th century. Initially, Earth was believed to be the center of the Universe, which consisted only of those planets visible with the naked eye and an outlying sphere of fixed stars.^[1] After the acceptance of the heliocentric model in the 17th century, observations by William Herschel and others showed that the Sun lay within a vast, disc-shaped galaxy of stars.^[2] By the 20th century, observations of spiral nebulae revealed that the Milky Way galaxy was one of billions in an expanding universe,^[3][4] grouped into clusters and superclusters. By the end of the 20th century, the overall structure of the visible universe was becoming clearer, with superclusters forming into a vast web of filaments and voids.^[5] Superclusters, filaments and voids are the largest coherent structures in the Universe that we can observe.^[6] At still larger scales (over 1000 megaparsecs^[a]) the Universe becomes homogeneous, meaning that all its parts have on average the same density, composition and structure.^[7]

Earth Location

Without annotation With annotation Older version (non-clickable) Older version (non-clickable) with legend Logarithmic representation of the universe centered on the Solar System. Celestial bodies on this graphic are clickable and shown with their sizes enlarged. v t e

Since there is believed to be no "center" or "edge" of the Universe, there is no particular reference point with which to plot the overall location of the Earth in the universe.^[8] Because the observable universe is defined as that region of the Universe visible to terrestrial observers, Earth is, because of the constancy of the speed of light, the center of Earth's observable universe. Reference can be made to the Earth's position with respect to specific structures, which exist at various scales. It is still undetermined whether the Universe is infinite. There have been numerous hypotheses that the known universe may be only one such example within a higher multiverse; however, no direct evidence of any sort of multiverse has been observed, and some have argued that the hypothesis is not falsifiable.^[9][10]

Details

Earth is the third planet from the Sun with an approximate distance of 149.6 million kilometres (93.0 million miles), and is traveling nearly 2.1 million kilometres per hour (1.3 million miles per hour) through outer space.^[11]

Table

Feature	Diameter			Notes	Sources
	(most suitable unit)	(km, with scientific notation)	(km, as a power of 10, Logarithmic scale)
Earth	12,756.2 km (equatorial)	1.28×104	4.11	Measurement comprises just the solid part of the Earth; there is no agreed upper boundary for Earth's atmosphere. The geocorona, a layer of UV-luminescent hydrogen atoms, lies at 100,000 km. The Kármán line, defined as the boundary of space for astronautics, lies at 100 km.	[12][13][14][15]
Orbit of the Moon	768,210 km[b]	7.68×105	5.89	The average diameter of the orbit of the Moon relative to the Earth.	[16]
Geospace	6,363,000–12,663,000 km (110–210 Earth radii)	6.36×106–1.27×107	6.80–7.10	The space dominated by Earth's magnetic field and its magnetotail, shaped by the solar wind.	[17]
Earth's orbit	299.2 million km[b] 2 AU[c]	2.99×108	8.48	The average diameter of the orbit of the Earth relative to the Sun. Encompasses the Sun, Mercury and Venus.	[18]
Inner Solar System	~6.54 AU	9.78×108	8.99	Encompasses the Sun, the inner planets (Mercury, Venus, Earth, Mars) and the asteroid belt. Cited distance is the 2:1 resonance with Jupiter, which marks the outer limit of the asteroid belt.	[19][20][21]
Outer Solar System	60.14 AU	9.00×109	9.95	Includes the outer planets (Jupiter, Saturn, Uranus, Neptune). Cited distance is the orbital diameter of Neptune.	[22]
Kuiper belt	~96 AU	1.44×1010	10.16	Belt of icy objects surrounding the outer Solar System. Encompasses the dwarf planets Pluto, Haumea and Makemake. Cited distance is the 2:1 resonance with Neptune, generally regarded as the outer edge of the main Kuiper belt.	[23]
Heliosphere	160 AU	2.39×1010	10.38	Maximum extent of the solar wind and the interplanetary medium.	[24][25]
Scattered disc	195.3 AU	2.92×1010	10.47	Region of sparsely scattered icy objects surrounding the Kuiper belt. Encompasses the dwarf planet Eris. Cited distance is derived by doubling the aphelion of Eris, the farthest known scattered disc object. As of now, Eris's aphelion marks the farthest known point in the scattered disc.	[26]
Oort cloud	100,000–200,000 AU 0.613–1.23 pc[a]	1.89×1013–3.80×1013	13.28–13.58	Spherical shell of over a trillion (1012) comets. Existence is currently hypothetical, but inferred from the orbits of long-period comets.	[27]
Solar System	1.23 pc	3.80×1013	13.58	The Sun and its planetary system. Cited diameter is that of the Sun's Hill sphere; the region of its gravitational influence.	[28]
Local Interstellar Cloud	9.2 pc	2.84×1014	14.45	Interstellar cloud of gas through which the Sun and a number of other stars are currently travelling.	[29]
Local Bubble	2.82–250 pc	8.70×1013–7.71×1015	13.94–15.89	Cavity in the interstellar medium in which the Sun and a number of other stars are currently travelling. Caused by a past supernova.	[30][31]
Gould Belt	1,000 pc	3.09×1016	16.49	Projection effect of the Radcliffe wave and Split linear structures (Gould Belt),[32] between which the Sun is currently travelling.	[33]
Orion Arm	3000 pc (length)	9.26×1016	16.97	The spiral arm of the Milky Way Galaxy through which the Sun is currently travelling.
Orbit of the Solar System	17,200 pc	5.31×1017	17.72	The average diameter of the orbit of the Solar System relative to the Galactic Center. The Sun's orbital radius is roughly 8,600 parsecs, or slightly over halfway to the galactic edge. One orbital period of the Solar System lasts between 225 and 250 million years.	[34][35]
Milky Way Galaxy	30,000 pc	9.26×1017	17.97	Our home galaxy, composed of 200 billion to 400 billion stars and filled with the interstellar medium.	[36][37]
Milky Way subgroup	840,500 pc	2.59×1019	19.41	The Milky Way and those satellite dwarf galaxies gravitationally bound to it. Examples include the Sagittarius Dwarf, the Ursa Minor Dwarf and the Canis Major Dwarf. Cited distance is the orbital diameter of the Leo T Dwarf galaxy, the most distant galaxy in the Milky Way subgroup. Currently 59 satellite galaxies are part of the subgroup.	[38]
Local Group	3 Mpc[a]	9.26×1019	19.97	Group of at least 80 galaxies of which the Milky Way is a part. Dominated by Andromeda (the largest), the Milky Way and Triangulum; the remainder are dwarf galaxies.	[39]
Local Sheet	7 Mpc	2.16×1020	20.33	Group of galaxies including the Local Group moving at the same relative velocity towards the Virgo Cluster and away from the Local Void.	[40][41]
Virgo Supercluster	30 Mpc	9.26×1020	20.97	The supercluster of which the Local Group is a part. It comprises roughly 100 galaxy groups and clusters, centred on the Virgo Cluster. The Local Group is located on the outer edge of the Virgo Supercluster.	[42][43]
Laniakea Supercluster	160 Mpc	4.94×1021	21.69	A group connected with the superclusters of which the Local Group is a part. Comprises roughly 300 to 500 galaxy groups and clusters, centred on the Great Attractor in the Hydra–Centaurus Supercluster.	[44][45][46][47]
Pisces–Cetus Supercluster Complex	330 Mpc	1×1022	21.98	Galaxy filament that includes the Pisces-Cetus Superclusters, Perseus–Pisces Supercluster, Sculptor Supercluster and associated smaller filamentary chains.	[48][49]
Observable Universe	28,500 Mpc	8.79×1023	23.94	At least 2 trillion galaxies in the observable universe, arranged in millions of superclusters, galactic filaments, and voids, creating a foam-like superstructure.	[50][51][52][53]
Universe	Minimum 28,500 Mpc (possibly infinite)	Minimum 8.79×1023	Minimum 23.94	Beyond the observable universe lie the unobservable regions from which no light has yet reached the Earth. No information is available, as light is the fastest travelling medium of information. However, uniformitarianism argues that the Universe is likely to contain more galaxies in the same foam-like superstructure.	[54]

Gallery

Logarithmic depiction of Earth's location

Location of Earth in the Universe

Earth-Moon System

Inner Solar System with Near-Earth objects

Solar System and Oort cloud

Nearest stars

Local Interstellar Cloud and neighbouring interstellar medium

Star associations and interstellar medium map of the Local Bubble

Molecular clouds around the Sun inside the Orion-Cygnus Arm

Orion-Cygnus Arm and neighbouring arms

Orion-Cygnus Arm inside the Milky Way

The Sun within the structure of the Milky Way

Satellite galaxies of the Milky Way in Local Group

Virgo SCl in Laniakea SCl

Laniakea SCl in Pisces–Cetus Supercluster Complex

Observable Universe of the Universe

Clickable image of the Location of Earth. Place your mouse cursor over an area in the image to see the related area name; click to link to an article about the area.

(view • discuss)

A logarithmic map of the observable universe. From left to right, spacecraft and celestial bodies are arranged according to their proximity to the Earth.

With annotation

A logarithmic map of the observable universe. From left to right, spacecraft and celestial bodies are arranged according to their proximity to the Earth.

Without annotation

A logarithmic map of the observable universe. From left to right, spacecraft and celestial bodies are arranged according to their proximity to the Earth.

Compact version with annotation

A logarithmic map of the observable universe. From left to right, spacecraft and celestial bodies are arranged according to their proximity to the Earth.

Compact version without annotation

Stereoscopic view of the universe (805 x 416) for cross-eyed viewing

See also

• Cosmic View
• Cosmic Zoom
• Galaxy Song
• History of the center of the Universe
• Orders of magnitude (length)
• Pale Blue Dot
• Powers of Ten (film)
• List of nearest stars and brown dwarfs
• Solar System § Galactic context

Notes

1. A parsec (pc) is the distance at which a star's parallax as viewed from Earth is equal to one second of arc, equal to roughly 206,000 AU or 3.0857×10¹³ km. One megaparsec (Mpc) is equivalent to one million parsecs.
2. Semi-major and semi-minor axes.
3. 1 AU or astronomical unit is the distance between the Earth and the Sun, or 150 million km. Earth's orbital diameter is twice its orbital radius, or 2 AU.

References

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