Galactic Year (period of rotation of the Milky Way galaxy)

Galactic Year (period of rotation of the Milky Way galaxy) (225 million y)

/fact/galactic-year-period-of-rotation-of-the-milky-way-galaxy

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If Galactic Year (period of rotation of the Milky Way galaxy) (225 million y) was a standard unit ...

Age of the Earth (4.54 billion y)...more would be 20 x Galactic Year (period of rotation of the Milky Way galaxy)
Time since the end of the Ordovician geologic period (444 million y)...more would be 2 x Galactic Year (period of rotation of the Milky Way galaxy)