October 15, 2013 - Dave Stevenson, professor of planetary science at Caltech, gave an intriguing speech at the Origin of the Moon
conference in London
this week. The most widely accepted theory about the Origin of the Moon
is called the "giant impact theory," which is pretty much what you think it is: two giant objects smashed into each other in the early days of our solar system. One of those became Earth, and one became our moon. But Stevenson
has an alternate explanation: what if the Earth
simply swiped another planet's moon?
has a moon. Mars has two. Jupiter has nearly 50. But Venus? No moon. Stevenson's theory is that the Earth
pulled Venus's moon
out of Venus
orbit and into our own. The moon's size suggests this is possible; calculations have indicated that a collision would require two fairly large bodies moving at an enormous speed, and at a very specific angle, otherwise one or both of the two original objects would be pulverized. The moon is much larger compared to our planet than other satellites are to their planets.
Did Venus Give Earth the Moon? Wild New Theory on Lunar History
By Katia Moskvitch, SPACE.com Contributor September 27, 2013 11:57am ET
This illustration shows the still-molten moon just after its formation about 4.5 billion years ago.
Credit: NASA Goddard Space Flight Center
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LONDON - The Earth's moon may be a present...