View Full Version : Spacecraft Searching for Remains of Mystery Planet

2009-Apr-10, 02:10 PM
How did our Moon form? The leading hypothesis, the Giant Impact Theory, proposes that in the formative years of the Solar System, a Mars-sized protoplanet crashed into Earth. Debris from the collision, a mixture of material from both bodies, spun out into Earth orbit and coalesced into the Moon. Soon, this theory will [...]

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