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The galactic year, also known as a cosmic year, is the duration of time required for the Sun to orbit once around the center of the Milky Way Galaxy.Estimates of the length of one orbit range from 225 to 250 million terrestrial years.
Matching up rock types, examining magnetic signatures, and cataloging fossils have allowed scientists to trace the cycle of supercontinents forming and breaking apart back at least a billion years. Earth is believed to be about 4.5 billion years old.
The data show there were two supercontinents before Pangaea called Rodinia and Gondwana that formed and broke up hundreds of millions of years ago.
originally posted by: Ophiuchus 13
a reply to: intrptr
I'm not sure where the added mass would come from if the mass of the planet changed its size.
It seems like the planet recycles its land and seas.
In theory the planet continent crust is basically absorbed and the lithosphere pushes new land up from below. Recycling replenishing the planet.
But are there changes in the cosmos that agitate these processes?