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Did A Second Moon Crash With Our Moon?

August 3, 2011


The remnants of a second moon that orbited around the Earth billions of years ago may be splattered across the far side of our moon, scientists claim. 

The two moons are believed to have been created at the same time and followed a similar path to the moon we’re familiar with today, but after tens of millions of years of peaceful co-existence, the two moons appear to have crunched together in a gentle collision that left the smaller moon, just a third of the size, spread across the larger like a cosmic pancake. 

Researchers put forward the idea after computer simulations found that a collision with a second, sibling moon in Earth’s early history might solve the longstanding puzzle of why the two faces of the moon differ so dramatically. 

While the near side, which always faces the Earth, is low-lying and relatively flat, the far side is high and mountainous, with a crust tens of kilometres thicker. 

The idea builds on what planetary scientists call the “big impact” model of the moon, in which a planet the size of Mars slammed into the Earth in the early days of the solar system and knocked out a vast shower of rocky debris, which later coalesced as the moon.

One Comment
  1. August 4, 2011 9:40 AM

    I’m going to read that article right now. I wonder how two moons would have influenced earth’s tides and weather?

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