Crash and mars dating
Using Newtonian mechanics, he calculated that the Moon had orbited much more closely in the past and was drifting away from the Earth.
This drifting was later confirmed by American and Soviet experiments, using laser ranging targets placed on the Moon.
They proposed that in the aftermath of the giant impact, while the Earth and the proto-lunar disk were molten and vaporized, the two reservoirs were connected by a common silicate vapour atmosphere, and that the Earth–Moon system became homogenized by convective stirring while the system existed in the form of a continuous fluid.
The highly anorthositic composition of the lunar crust, as well as the existence of KREEP-rich samples, suggest that a large portion of the Moon once was molten; and a giant impact scenario could easily have supplied the energy needed to form such a magma ocean.The Earth would have gained significant amounts of angular momentum and mass from such a collision.Regardless of the speed and tilt of the Earth's rotation before the impact, it would have experienced a day some five hours long after the impact, and the Earth's equator and the Moon's orbit would have become coplanar.Because of the thick crust of the far side, lunar magma cannot pierce through the crust there, causing less lunar maria while the near side of the Moon has a thin crust so that lunar magma can pierce through the crust resulting in the large maria we observe.In 2001, a team at the Carnegie Institution of Washington reported the surprising finding that the rocks from the Apollo program carried an isotopic signature that was identical with rocks from Earth, and were different from almost all other bodies in the Solar System.