Space
Moon’s Birth: Planetary Collision That Formed Moon May Have Been More Violent
uBmuse
First Posted: Sep 13, 2016 05:40 AM EDT
Our moon was formed about 4.5 billion years ago, out of the debris thrown into orbit by a massive collision amongst a proto-Earth and another planetoid that was about the size of Mars. The Earth would have been a very different place if the moon wasn't there. But, after studying the chemical composition of lunar rocks, scientists now believe they have found new evidence that disproves the leading theory of our moon formation.
Most astronomers have believed that the Moon was formed as the result of a huge collision between the Earth and a Mars-sized planetoid, called the impactor. But not everyone agrees on the mechanics of that collision. At present, a popular theory suggests that the impact had been a relatively low-energy, one so as to leave Earth mostly intact but leading the impactor to melt. This magma eventually turned into the form of Moon. It was not only Earth that slowed down the Moon's rotation, but the Moon is slowing down the rotation rate of the Earth as well, according to a report on NASA's official site.
The new theory was detailed in a study published in Nature. The study is a radical concept that could totally change our understanding of the planetary system. Study author Kun Wang believes that the potassium signatures they found in a lunar rock paints a different scenario. "The collision that formed the Moon was not a low energy one", he explains. "The impact was highly violent, pulverizing a large part of Earth as well as the impactor turning them into vapor. The vaporized matter mixed together into a giant dense atmosphere, cooled and condensed into Earth and its satellite."This model is totally different," Wang who works as a geochemist at Washington University told The Verge. "The impact being much larger."
Problem with the old model:
The original hypothesis suggested that 80 percent of the matter on Moon came from the impactor and the remaining from Earth. That became a question when researchers started studying the composition of the Moon and found that the Moon and Earth share a lot of the same chemical composition.
To solve this problem, astronomers modified the giant-impact hypothesis but only a bit. A new model proposed in 2007 stated that a silicate atmosphere surrounded our planetary system after the impactor had collided with Earth. This atmosphere could have acted like a conduit, hence allowing exchange of materials between the Earth and the impactor's magma.
However, Wang says that new potassium measurements he has taken don't agree with this model either. The researchers have analyzed seven lunar and eight Earth rocks from which they measured two different isotopes of potassium: potassium-41 and potassium-39. These findings don't agree with the giant-impact hypothesis, Wang explains. "The Moon should have been richer in potassium-39 but its the other way around".
The only way to explain this higher abundance of potassium-41 in the Moon's composition is to accept that there was a more violent impact, says Wang. "Our paper is the first hard, real evidence to support that theory."
Wang and his team have already braced themselves for some harsh feedback on their research. They believe it's normal for people to be resistant to accept a new theory at first. "It will take time for people to accept a new idea," says Wang. "It took decades to accept the giant-impact hypothesis and now we're saying that giant impact hypothesis is not correct, so it may take 20 years to accept this new model."
See Now:
NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone
TagsBirth, Moon, planetary, Collision, formed, more, violent, Scientists, believe, New Study, giant impact hypothesis, New study challenges the giant impact hypothesis, Formation of Moon ©2024 ScienceWorldReport.com All rights reserved. Do not reproduce without permission. The window to the world of science news.
More on SCIENCEwr
First Posted: Sep 13, 2016 05:40 AM EDT
Our moon was formed about 4.5 billion years ago, out of the debris thrown into orbit by a massive collision amongst a proto-Earth and another planetoid that was about the size of Mars. The Earth would have been a very different place if the moon wasn't there. But, after studying the chemical composition of lunar rocks, scientists now believe they have found new evidence that disproves the leading theory of our moon formation.
Most astronomers have believed that the Moon was formed as the result of a huge collision between the Earth and a Mars-sized planetoid, called the impactor. But not everyone agrees on the mechanics of that collision. At present, a popular theory suggests that the impact had been a relatively low-energy, one so as to leave Earth mostly intact but leading the impactor to melt. This magma eventually turned into the form of Moon. It was not only Earth that slowed down the Moon's rotation, but the Moon is slowing down the rotation rate of the Earth as well, according to a report on NASA's official site.
The new theory was detailed in a study published in Nature. The study is a radical concept that could totally change our understanding of the planetary system. Study author Kun Wang believes that the potassium signatures they found in a lunar rock paints a different scenario. "The collision that formed the Moon was not a low energy one", he explains. "The impact was highly violent, pulverizing a large part of Earth as well as the impactor turning them into vapor. The vaporized matter mixed together into a giant dense atmosphere, cooled and condensed into Earth and its satellite."This model is totally different," Wang who works as a geochemist at Washington University told The Verge. "The impact being much larger."
Problem with the old model:
The original hypothesis suggested that 80 percent of the matter on Moon came from the impactor and the remaining from Earth. That became a question when researchers started studying the composition of the Moon and found that the Moon and Earth share a lot of the same chemical composition.
To solve this problem, astronomers modified the giant-impact hypothesis but only a bit. A new model proposed in 2007 stated that a silicate atmosphere surrounded our planetary system after the impactor had collided with Earth. This atmosphere could have acted like a conduit, hence allowing exchange of materials between the Earth and the impactor's magma.
However, Wang says that new potassium measurements he has taken don't agree with this model either. The researchers have analyzed seven lunar and eight Earth rocks from which they measured two different isotopes of potassium: potassium-41 and potassium-39. These findings don't agree with the giant-impact hypothesis, Wang explains. "The Moon should have been richer in potassium-39 but its the other way around".
The only way to explain this higher abundance of potassium-41 in the Moon's composition is to accept that there was a more violent impact, says Wang. "Our paper is the first hard, real evidence to support that theory."
Wang and his team have already braced themselves for some harsh feedback on their research. They believe it's normal for people to be resistant to accept a new theory at first. "It will take time for people to accept a new idea," says Wang. "It took decades to accept the giant-impact hypothesis and now we're saying that giant impact hypothesis is not correct, so it may take 20 years to accept this new model."
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone