Time since the end of the Silurian geologic period

Time since the end of the Silurian geologic period (419 million y)

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Time since the end of the Silurian geologic period (419 million y)

is 1/5 of Time since the emergence of multicellular life (2.1 billion y)...more
is 10000 x Age of oldest musical instrument (42,000 y)...more

If this was a standard unit ...