Astrophysics (index)about


(Gy, Gyr, eon, aeon)
(a billion years)

A gigayear, a billion years, is a common unit for cosmological times and time intervals, convenient as the current age determination of the universe being between 13 and 14 gigayears. Abbreviations include Gy and Gyr. The word eon (or aeon) has also been used to indicate a gigayear.

A gigayear is on the order of 1016 seconds, more specifically 3.15576 × 1016.


Referenced by:
astronomical quantities
black hole merger
47 Tucanae (47 Tuc)
Messier 15 (M15)
NGC 3201
neutron star merger
quenched galaxy
redshift (z)