Magma is the key to the moon's makeup

Magma is the key to the moon's makeup
The image is a snapshot of numerical modeling of the moon formation by a giant impact. Proto-Earth is at the center; red points indicate materials from the ocean of magma on a proto-Earth; blue points indicate the impactor materials. Credit: Hosono, Karato, Makino & Saitoh

For more than a century, scientists have squabbled over how the Earth's moon formed. But researchers at Yale and in Japan say they may have the answer.

Many theorists believe a Mars-sized object slammed into the early Earth, and material dislodged from that collision formed the basis of the . When this idea was tested in computer simulations, it turned out that the moon would be made primarily from the impacting object. Yet the opposite is true; we know from analyzing rocks brought back from Apollo missions that the moon consists mainly of material from Earth.

A new study published April 29 in Nature Geoscience, co-authored by Yale geophysicist Shun-ichiro Karato, offers an explanation.

The key, Karato says, is that the early, proto-Earth—about 50 million years after the formation of the Sun—was covered by a sea of hot magma, while the impacting object was likely made of . Karato and his collaborators set out to test a new model, based on the collision of a proto-Earth covered with an ocean of magma and a solid impacting object.

The model showed that after the collision, the magma is heated much more than solids from the impacting object. The magma then expands in volume and goes into orbit to form the moon, the researchers say. This explains why there is much more Earth material in the moon's makeup. Previous models did not account for the different degree of heating between the proto-Earth silicate and the impactor.

"In our model, about 80% of the moon is made of proto-Earth materials," said Karato, who has conducted extensive research on the chemical properties of proto-Earth magma. "In most of the previous models, about 80% of the moon is made of the impactor. This is a big difference."

Karato said the confirms previous theories about how the moon formed, without the need to propose unconventional collision conditions—something theorists have had to do until now.

For the study, Karato led the research into the compression of molten silicate. A group from the Tokyo Institute of Technology and the RIKEN Center for Computational Science developed a computational model to predict how material from the collision became the moon.


Explore further

How scientists are piecing together the history of the moon

More information: Terrestrial magma ocean origin of the Moon, Nature Geoscience (2019). DOI: 10.1038/s41561-019-0354-2 , https://www.nature.com/articles/s41561-019-0354-2
Journal information: Nature Geoscience

Provided by Yale University
Citation: Magma is the key to the moon's makeup (2019, April 29) retrieved 23 September 2019 from https://phys.org/news/2019-04-magma-key-moon-makeup.html
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Apr 29, 2019
Oh, boy, just what we need... Another! Speculation to confuse the issue of Luna's origins.
Yes, the model seems reasonably possible.
However, I am not certain that the evidence the Astronauts brought back from the Moon's surface strongly supports the hypothesis?
I opinionate that the surface rocks support the original conjecture of the Theia Impact event.
That the collision reduced the mass of Theia captured in Earth orbit assembling into the core of Luna.
The rest pulled down to mix with the Earth's magma.

Some Theia debris slung out into interstellar Space.
Some Theia material scattered across Solar System.

Now as I understand the possible orbital mechanics. Most of the flyoff of Theia & Earth, would eventually get dragged in-system by our Sun's gravitational pull.
Just a wild speculation here. But I wonder if a sizable percentage of infalling rock intersected Venus?
Possibly interfering with that planet's evolution?
One more cause for Venus becoming lifeless?

Apr 29, 2019
'A' says I have seen God. 'B' says I have seen God. 'C' says, I have seen the God. A, B, and C each claim that their God is superior to other Gods. 'D', a man of wisdom, comes and says all of you are childish and absolutely wrong. God is not there at all.

Now and then there are new theories of Moon formation. It might give the proposers some scientific mileage within the community, but the man of wisdom knows that all of these theories are childish and absolutely wrong, and also knows how it all happened.

Apr 29, 2019
The theories of an object hitting earth and then forming the moon have 1 key aspect missing: there has been no offer of explanation as to how this new moon could start rotating around earth. None of the theories can explain this. They just assume that somehow it starts a rotation. Without this explanation all of these theories fall flat on their faces.

Apr 29, 2019
The theories of an object hitting earth and then forming the moon have 1 key aspect missing: there has been no offer of explanation as to how this new moon could start rotating around earth. None of the theories can explain this. They just assume that somehow it starts a rotation. Without this explanation all of these theories fall flat on their faces.
says Bart A

But isn't the Moon tidally locked where one side always faces Earth? Even so,, the Moon orbits around Earth due to the gravitational pull that Earth has on it, just as Earth orbits around the Sun.

I have a hypothesis that when the Mars-size object hit Earth and caused large chunks of Earth to be pushed away to become the Moon, at the same time, the object pushed Earth out of its own orbit and created a NEW orbit around the Sun for Earth. It also caused the new Moon to increase its distance from Earth to 239,000 miles (384,000 km) mol. I have no way to prove it, though.

Apr 29, 2019
'A' says I have seen God. 'B' says I have seen God. 'C' says, I have seen the God. A, B, and C each claim that their God is superior to other Gods. 'D', a man of wisdom, comes and says all of you are childish and absolutely wrong. God is not there at all.

Now and then there are new theories of Moon formation. It might give the proposers some scientific mileage within the community, but the man of wisdom knows that all of these theories are childish and absolutely wrong, and also knows how it all happened.
says guptm

Who is this 'man of wisdom'? I would like to meet him. He would be wrong in saying that "God is not there at all". The Creator God is, indeed there, and in fact, is everywhere and knows everything. That is why it is folly to try to hide your thoughts, words and deeds/actions from the Creator God and His Holy Angels, because there is no place to hide. You will ALWAYS be found out.

Apr 30, 2019
Oh jeebus! Now we got the fakir looneytoons arguing over which of their delusions could be more believable.

More unbelievable?

You jeebus cultists may see something in your doped-out hallucinations?

However, I actually talk to the deity.
Or, to be more accurate.
I have to endure the infantile prattle of the cosmic kid.

Yeah, I know. Give it a hundred billion years or two?
Maybe by then it will mature enough to have something sensible to contribute?

Right now, the smartest thing I've heard from the kid?
Is resentment that the religious monkeys are blaming the baby deity for this kludged-up mess of a Stochastic Universe.

Can't say as I blame the kid. It's going to be one hell of a job the next trillion years getting this mess cleaned-up
& organized tidy.
Ship shape & Bristol fashion!

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