and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference...

the temperature of the universe was still too high to allow quarks to bind together to form hadrons. The quark epoch began approximately 10−12 seconds after...

annihilated each other at the end of the hadron epoch. During the lepton epoch, the temperature of the Universe was still high enough to create neutrino and electron-positron...

In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the...

seconds that have elapsed since 00:00:00 UTC on 1 January 1970, the Unix epoch. For example, at midnight on January 1 2010, Unix time was 1262304000. Unix...

The first picosecond (10−12 seconds) of cosmic time includes the Planck epoch, during which currently established laws of physics may not have applied;...

theosophist authors, have called the time periods associated with these races Epochs (Steiner felt that the term "race" was not adequate anymore for modern humanity)...

-⁠stoh-; often referred to colloquially as the Ice Age) is the geological epoch that lasted from c. 2.58 million to 11,700 years ago, spanning the Earth's...

In physical cosmology, the electroweak epoch was the period in the evolution of the early universe when the temperature of the universe had fallen enough...

Holocene (/ˈhɒl.əsiːn, -oʊ-, ˈhoʊ.lə-, -loʊ-/) is the current geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period...