Moon was born from collision between baby moonlets, new study contradicts giant impact theory

Have you ever wondered how moon was formed? You must have, for sure. A new study may be an answer to this question. It claims that the Moon, that we see today, may have been formed from the collision of tiny moonlets.

The new study is contradictory to the prevalent theory that suggests that Moon, the natural satellite of the Earth, was formed from a giant impact that was caused between a small Mars-like planet and the ancient Earth.

The Moon is actually not the first moon of the Earth but the last in the series of Moons that orbited the planet, the study claims.

Researchers at the Technion Israel Institute of Technology and Weizmann Institute of Science in Israel have proposed this new theory, which contradicts the commonly held “giant impact” paradigm.

The giant impact theory claims that Moon was a single object to have formed after a giant collision between a small Mars-like planet and the Earth.

“Our model suggests that the ancient Earth once hosted a series of moons, each one formed from a different collision with the proto-Earth,” said Hagai Perets from the Technion.

“It is likely that such moonlets were later ejected, or collided with Earth or with each other to form bigger moons,” said Perets.

The researchers ran 800 simulations of impacts with Earth in order to find out the conditions for formation of such mini-moons or moonlets.

The new model is consistent with science’s current understanding of the formation of Earth. Earth experienced many giant impacts with other bodies in its last stages of the growth.

The proto-Earth hot more material from each of these impacts until it reached its current size.

“We believe Earth had many previous moons, a previously formed moon could therefore already exist when another moon-forming giant impact occurs,” said Perets.

Moons may slowly migrate outwards because of the tidal forces from Earth. The current Moon is slowly doing that at a pace of about one centimetre a year.

By the time another moon forms, a pre-existing moon would slowly move out.

However, their mutual gravitational attraction would eventually cause the moons to affect each other and change their orbits.

“It is likely that small moons formed through the process could cross orbits, collide and merge,” said lead author Raluca Rufo from Weizmann.

“A long series of such moon-moon collisions could gradually build-up a bigger moon - the Moon we see today,” said Rufo.

The study was published in the journal Nature Geoscience.(With inputs from PTI)