Hubble's law is the name for the observation in physical cosmology that:
- Objects observed in deep space - extragalactic space, 10 megaparsecs (Mpc) or more - are found to have a red shift, interpreted as a relative velocity away from Earth;
- This Doppler shift-measured velocity, of various galaxies receding from the Earth, is approximately proportional to their distance from the Earth for galaxies up to a few hundred megaparsecs away.
Hubble's law is considered the first observational basis for the expansion of the universe and today serves as a form of evidence for the birth of the universe at a singularity. The motion of astronomical objects due solely to this expansion is known as the Hubble flow.
- ↑ Riess, A. (September 1998). "Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant". The Astronomical Journal 116 (3): 1009–1038. doi:10.1086/300499. Bibcode: 1998AJ....116.1009R.
- ↑ Perlmutter, S. (June 1999). "Measurements of Omega and Lambda from 42 High-Redshift Supernovae". The Astrophysical Journal 517 (2): 565–586. doi:10.1086/307221. Bibcode: 1999ApJ...517..565P.
- ↑ Overbye, Dennis (20 February 2017). "Cosmos Controversy: The Universe Is Expanding, but How Fast?". New York Times. https://www.nytimes.com/2017/02/20/science/hubble-constant-universe-expanding-speed.html. Retrieved 21 February 2017.
- ↑ Coles, P., ed (2001). Routledge Critical Dictionary of the New Cosmology. Routledge. p. 202. ISBN 0-203-16457-1. https://books.google.com/?id=BgNGWVr5yhIC&pg=PA202.
- ↑ "Hubble Flow". The Swinburne Astronomy Online Encyclopedia of Astronomy. Swinburne University of Technology. http://astronomy.swin.edu.au/cosmos/h/hubble+flow. Retrieved 2013-05-14.