What is the giant impact hypothesis?
Q: What is the giant impact hypothesis?
A: The giant impact hypothesis is that the Moon was created out of the debris from a collision between the young Earth and a Mars-sized protoplanet.
Q: What is the evidence for the giant impact hypothesis?
A: The evidence for this hypothesis comes from Moon samples which show that the surface of the Moon was once molten, the Moon's apparently relatively small iron core and a lower density than the Earth, and evidence of similar collisions in other star systems (which result in 'debris disks').
Q: What is the name given to the colliding body in the giant impact hypothesis?
A: The colliding body is sometimes called Theia for the mythical Greek Titan who was the mother of Selene, the goddess of the moon.
Q: What are the unanswered issues with the giant impact hypothesis?
A: The unanswered issues with this hypothesis are that lunar oxygen isotopic ratios are essentially identical to Earth, with no evidence of a contribution from another solar body, lunar samples do not have expected ratios of volatile elements, iron oxide, or siderophilic elements (chemical elements which bond with iron), and there is no evidence that the Earth ever had the magma ocean implied by the hypothesis.
Q: What is the favoured scientific hypothesis for the formation of the Moon?
A: The favoured scientific hypothesis for the formation of the Moon is the giant impact hypothesis.
Q: What is the density of the Moon compared to the Earth?
A: The Moon has a lower density than the Earth.
Q: What is the mythical Greek Titan associated with the Moon in the giant impact hypothesis?
A: In the giant impact hypothesis, the colliding body is sometimes called Theia for the mythical Greek Titan who was the mother of Selene, the goddess of the moon.
