Published: Sun, March 04, 2018
Science | By

Moon may have been formed inside the Earth

Moon may have been formed inside the Earth

A synestia forms when a collision between planet-sized objects results in a rapidly spinning mass of molten and vaporized rock with part of the body in orbit around itself.

"Our model can also help explain why Earth and the Moon appear to have formed from the same material and why our Moon is so big", he added.

"Over time, the whole structure shrinks, and the Moon emerges from the vapour".

The researchers did say that tests indicate that the "isotopic "fingerprint" of Earth and its moon are nearly the same, which probably means their origins are the same.

"This is the first model that can match the pattern of the Moon's composition", said Stewart. However, a breakthrough new theory, proposed by researchers at the University of California-Davis and Harvard, claims to solve all of these issues by posing a totally new model for how the Moon (and Earth) formed: a synestia. Briefly about work of scientists is told in a press release on EurekAlert!.

One caveat to the new hypothesis: Synestias remain theoretical objects that have never been observed in the universe.

Synestias haven't been spotted in the sky yet, but the authors suggest that's because the objects are relatively short-lived.

Back in 2017, the team was focused on how planets could be formed after huge impacts. Giant impacts that produce potential Moon‐forming synestias were common at the end of terrestrial planet formation.

Until now, astronomers have believed the collision tore off a chunk of the Earth that turned into the Moon.

A new study has suggested the moon was actually created before our planet and is slightly older than Earth. Over time, the small bits of debris coalesced into the moon.

The moon then "hatched" from the early Earth like a chick from an egg, the theory suggested. This created a synestia. They shrink rapidly as they radiate heat, causing rock vapor to condense into liquid, finally collapsing into a molten planet.

"The rate of rainfall is about 10 times that of a hurricane on Earth", Lock said.

The idea is that the Moon emerged from this synestia along with the Earth, which explains why they seem to be made of similar material.

"This is a basic model", said Mr Lock. The Moon has a very similar composition to Earth in the major rock-forming elements (e.g., Al, Mg, Si) but depleted in elements that are more easily vaporized.

Researchers assumed that the lack of volatile elements on the moon can be explained by the fact that the moon formed, surrounded and pressured by tens of atmospheres of vapor and at high temperature.

Better yet, Lock explained, the collision doesn't have to take place from a certain angle to form a synestia. Particularly, the two are interested in what happens during the collisions of massive spinning objects. "This is a dramatically different way of forming the moon".

"And even then, some impacts still don't work", they added. How does the vapor flow past the moon? This has been the canonical model for about 20 years", said Lock, co-author of the study published in Journal of Geophysical Research: "Planets.

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