History of the Universe eBook. 398 pages, 300 illustrations only £5.99
In this website we show dates in the following formats.
ya means "years ago".
kya means "thousand years ago". K stands for kilo, the scientific name for thousand.
mya means "million years ago". A million is one thousand thousand.
bya means "billion years ago". One billion is one thousand million.
Note that geologists sometimes use the term Ga, meaning "giga-years ago", where giga is the scientific name for billion.
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