Mya (unit)

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For other uses of mya, see mya (disambiguation).

In astronomy, geology, and paleontology, mya is an acronym for million years ago and is used as a unit of time to denote length of time before the present. Specifically, one mya is equal to 10⁶ years ago. The term 'mya' is now replaced in scientific literature with Ma (mega annum).

Like the related unit bya ("billion years ago"), mya is traditionally written in lowercase. This is different from the related unit Gya, which capitalizes the first letter. The term bya is now replaced in scientific literature with Ga (giga annum).

Contents 1 Events around 1 mya: 1.1 Astronomical deep time: 1.2 Geologic periods (Neogene): 1.3 Prehistoric Paleontology: 2 See also

Events around 1 mya:

Astronomical deep time:

• The light we see now from the Andromeda Galaxy started 2.5 mya
• The light we (do not) see now from the centre of the Milky Way started 0.026 mya

Geologic periods (Neogene):

• Pliocene 5.3 to 1.8 mya
  • The Grand Canyon mostly formed 2-6 mya
• Pleistocene from 1.81 to 0.011 mya
  • The last magnetic pole reversal was 0.78 mya
  • The (Eemian interglacial) Ice Age started 0.13 mya
• Holocene started 0.01 mya

Prehistoric Paleontology:

• The Stone Age started 3 mya
• Homo erectus existed from 1.8 to 0.07 mya
  • and learns to control fire from 1.5 to 0.5 mya
  • and colonized Asia from 0.5 to 0.3 mya
• Homo sapiens appeared 0.5 mya
  • and emerges out of Africa from 0.1 mya on
  • and colonized all of Eurasia and Oceania 0.04 mya
  • and forms cultures since the Upper Paleolithic Revolution 0.04 mya
  • and colonized all of America 0.01 mya

See also

• annum
• Before Present
• bya
• tya

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