Solar System in 1986 and will next appear in mid-2061. Officially designated 1P/Halley, it is also commonly called Comet Halley, or sometimes simply Halley
This article is a list of notable unsolved problems in astronomy. Problems may be theoretical or experimental. Theoretical problems result from inability
In cosmology, recombination refers to the epoch during which charged electrons and protons first became bound to form electrically neutral hydrogen atoms
the cosmological legacy of Planck", Astronomy and Astrophysics, 641: A1, arXiv:1807.06205, Bibcode:2020A&A...641A...1P, doi:10.1051/0004-6361/201833880,
Universitaetssternwarte zu Berlin Babelsberg. 1: 1.i. Bibcode:1927KVeBB...1....1P. "UY Sct (UY Scuti)". kusastro. Retrieved 15 January 2016. Van Loon, J. Th