Research into the formation of the moon was conducted by scientists at the Weizmann Institute of Science in Rehovot, Israel and the Technion-Israel Institute of Technology located in Haifa. Results of the research go contrary to the long-held belief of how the moon came into being.
The prevailing theory was an object about the size of Mars struck the Earth millions of years ago causing debris to shoot into space. This debris eventually coalesced and formed the moon. But researchers said this theory relies on a number of specific criteria that do not hold up. These include the object colliding with the Earth must have been a definite size, have travelled at a specific velocity and strike the Earth at a particular angle. The researchers found one problem with the “giant impact” theory of the moon’s birth.
According to Raluka Rufu, lead author of the study, if the moon was created by a Mars-like object hitting the Earth, it would be expected the moon would contain materials from that large body. It had already been determined other planets and bodies have different chemical compositions. But analysis of moon rocks brought back from the moon by astronauts shows the chemical composition of the moon is similar to that of the Earth. The match of isotopes in both bodies is nearly identical.
In conducting their work, researchers ran more than 800 simulations to show how smaller objects hitting the Earth could give rise to moonlets being created. From the simulations, the researchers concluded at one time the Earth had several moons orbiting it, each one created by a different collision.
The researchers believe at least 20 asteroids hit the Earth during this time, spewing debris into orbit that appeared similar to the rings of Saturn. It has long been believed asteroids strikes were more numerous millions of years ago than they are today. Eventually this debris joined together and formed moonlets.
As a result of tidal forces over hundreds of years, these moonlets moved further out into space. Eventually the moonlets collided with each other and formed the moon as it is today.
The results of the research were published Monday in Nature Geoscience.
