Earth Once Had a 2nd Moon: Scientist
Theory gets new life breathed into it
By Kate Seamons, Newser Staff
Posted Jul 8, 2013 7:38 AM CDT
Updated Jul 14, 2013 7:39 AM CDT
In this photo taken June 23, 2013, the moon rises behind the Washington Monument.   (AP Photo/NASA, Bill Ingalls, File)

(Newser) – Earth may have once looked a little more like Mars: a planet with two moons. It's not the first time the theory has been trotted out by Erik Asphaug, but it's getting new life thanks to an upcoming conference about our natural satellite. The University of California at Santa Cruz professor will share the theory at the September conference, and the Telegraph has a preview. Asphaug says the second moon would have been much tinier—about 1/30th the size of our moon. But after orbiting Earth for a few million years, it would have had quite the impact, literally, on its larger twin.

Asphaug believes that "it would have collided with the moon to leave the one large body we see today." And what PhysOrg terms the "strange terrain" on the moon's far side could very well be the remnants of that little moon, which could have left a layer "tens of kilometers deep" upon impact. A neat factoid from PhysOrg: Mars may one day look more like ... Earth. The bigger of its two moons, Phobos, is expected to crash into the planet sometime in the next 10 million years. (In other moon news, astronomers have named two Pluto moons—and ignored the people's No. 1 choice in the process.)

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Showing 3 of 27 comments
SPHeroid
Jul 14, 2013 11:24 PM CDT
Well what the hell...We have a new moon every month........ (every 28.4 days for you purists; more or less)......
iq145
Jul 14, 2013 10:17 PM CDT
Damn. We could've had TWO amusement parks!: http://www.newser.com/story/170716/new-national-park-on-the-moon.html
jeangnome
Jul 14, 2013 1:59 PM CDT
I've always heard that scientists dealt in facts. This is nothing but supposition and conjecture without any empirical evidence! I'm not buying it.