Did the Earth once have two moons? And did they collide?


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Did the Earth once have two moons?

Both satellites would have formed from debris that was ejected when a Mars-size protoplanet smacked into Earth late in its formation period. Whereas traditional theory states that the infant Moon rapidly swept up any rivals or gravitationally ejected them into interstellar space, the new theory suggests that one body survived, parked in a gravitationally stable point in the Earth–Moon system.

This new model also posits that the two moons eventually collided, producing the moon we have today.

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2 comments

  • LINO

    More likely, one of them was eliminated through spending cuts.

  • this story was on the front page of today’s newspaper in denver . while I am glad to see space and science get on the front page i am bit a confused of all the exciting space and science news these days this story is not as exciting to me . the dawn or messenger missions beat it easily in my book

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