Radioactive dating moon
Computer simulations of a giant impact have produced results that are consistent with the mass of the lunar core and the present angular momentum of the Earth–Moon system.These simulations also show that most of the Moon derived from the impactor, rather than the proto-Earth.
The far side of the Moon has a crust that is 30 mi (48 km) thicker than the near side of the Moon.Studies of meteorites originating from inner Solar System bodies such as Mars and Vesta show that they have very different oxygen and tungsten isotopic compositions as compared to Earth, whereas Earth and the Moon have nearly identical isotopic compositions.The isotopic equalization of the Earth-Moon system might be explained by the post-impact mixing of the vaporized material that formed the two, Similarly, the newly formed Moon would also have been affected and had its own lunar magma ocean; estimates for its depth range from about 500 km (300 miles) to its entire depth (1,737 km (1,079 miles)).The most widely accepted explanation is that the Moon formed from the debris left over after a giant impact between Earth and a Mars-sized body called Theia.The Moon is in synchronous rotation with Earth, always showing the same face, with its near side marked by dark volcanic maria that fill the spaces between the bright ancient crustal highlands and the prominent impact craters.The Soviet Union's Luna programme was the first to reach the Moon with unstaffed spacecraft in 1959; the United States' NASA Apollo program achieved the only staffed missions to date, beginning with the first staffed lunar orbiting mission by Apollo 8 in 1968, and six staffed lunar landings between 19, with the first being Apollo 11.
These missions returned lunar rocks which have been used to develop a geological understanding of the Moon's origin, internal structure, and later history.
In 2007, researchers from the California Institute of Technology announced that there was less than a 1% chance that Theia and Earth had identical isotopic signatures.
The Moon is a differentiated body: it has a geochemically distinct crust, mantle, and core.
Following Jupiter's satellite Io, the Moon is second-densest satellite among those whose densities are known.
The Moon is thought to have formed about 4.51 billion years ago, not long after Earth.
This is about thirty times the diameter of Earth, with its apparent size in the sky almost the same as that of the Sun (due to it being 400x farther and larger), resulting in the Moon covering the Sun nearly precisely in total solar eclipse.