The ratio of the speed of recession of a galaxy (due to the expansion of the universe) to its distance from the observer. The reciprocal of the constant is called Hubble time and represents the length of time for which the universe has been expanding, and hence the age of the universe.
- ‘The HST key programme on the distance scale is expected to fix the value of Hubble's constant to an accuracy of about 10 per cent.’
- ‘The questions in the exam paper itself were a mixture of modern cosmology, such as calculating Hubble's constant from a graph of recent data, and more traditional fare about the various forces acting on the balloon.’
- ‘Spectral studies requiring dedicated Hubble time would be routine with every one of SNAP's supernova observations.’
- ‘The teams have recently announced conflicting measurements of the Hubble constant, a number which represents the expansion rate of the Universe.’
- ‘All nearby galaxies are members of this cloud and the low value of Hubble's constant is due to the mutual gravitational attraction of these relatively nearby galaxies.’