The Moon may have originated in a collision between Earth and a celestial body that were strikingly similar in composition.
A new study has been released detailing new theories of the Moon’s origin and evolution. Based off of the analysis of moon rocks and samples from our own planet, scientists have found striking similarities between the two that have led to two new main theories as to how the moon originated – the “Great Impact” hypothesis and the “Late Veneer” hypothesis. The full details of these theories can be found outlined in the journal, Nature.
The Great Impact hypothesis essentially states that as the earth was forming, it collided and merged with many other forming planets. As the Earth took shape, the final collision would have been with a celestial body 10 times lighter than the earth, and the surrounding debris from that impact would have gathered in the formation of the Moon. Author of the study, Dr. Perets states that the composition of the Earth and Moon “are almost identical, this is one of the major challenges for this really beautiful giant impact hypothesis.” But, if the body that made the final impact with Earth was made of similar matter as the Earth, issues with the theory as solved.
The Late Veneer hypothesis theorizes that a long time following the great impact, both the Moon and Earth had been showered by a huge onslaught of meteorites, creating a veneer of foreign matter in the late stages of celestial development. Although, due to the Earth’s larger field of gravity, the Earth should have accumulated a thicker veneer of foreign matter than the Moon. This carries true as shown by two unrelated moon rock investigations by America and Germany in which the studies both look at tungsten isotopes from the Earth and Moon rocks and discovered correlating ratios of matter.
The two hypotheses actually support each other, as the American and German studies found that the Earth and Moon had the same composition prior to the meteorite onslaught. While This congruous composition can be explained by an impact with a planetary made of similar matter as the Earth.