Computer Simulation Explores Why the Moon's Far Side Looks So Different

CNET points out the far side of the moon — the one that never faces earth — is "rugged, spotted with tons of craters" and "filled with totally different elements."

"In essence, our moon has two faces, and scientists are still trying to solve the mystery of why they're so different." But a paper published Friday in the journal Science Advances might finally have an explanation for one major aspect of this enigmatic lunar duality. It has to do dark shadows, a massive impact many billions of years ago, and... lava....

They used computer simulations to see what might've gone on long, long (long) ago, way before there was any volcanic activity on the moon's surface. More specifically, they re-created a massive impact that, billions of years ago, changed the base of the moon, forming a gigantic crater that we now refer to as the South Pole-Aitken (SPA) basin.... What they found is that this huge smash would've created a plume of heat that carried a bunch of specific chemical elements to the near side of the moon, and not the far side. "We expect that this contributed to the mantle melting that produced the lava flows we see on the surface," Jones said.

In other words, those elements presumably contributed to an era of volcanism on the lunar face we can see from Earth but it left the far side untouched.

Easy! Since no one would see it!

[oldgraybeard]

The contractors cut corners!

Re:

[cusco]

That's not how orbital dynamics work, and I'm not sure that the moon was tidally locked yet when the Aitken Basion was formed anyway. IIRC that didn't happen until after the Moon's center of gravity was changed by the lava flows of the lunar mare. .

I've seen all sorts of ideas

[jd]

Including there originally being two moons that collided. What we need, now, are a set of experiments that can be performed that would definitely rule out some of the models.

It has to do with having with in the summary too?

[q_e_t]

Or something

far side

[belmolis]

I figure its because the aliens have been living there where we couldn't see them, digging it up and leaving their detritus.

Re:

[kmoser]

I'm not saying it was aliens. But it was aliens.

I still like the idea of a metallic atmosphere

[jfdavis668]

Soon after the Moon formed from a planet impacting Earth, both were very hot and very close together. Hot enough to have what we think of solids were still gases in the atmosphere. Things like aluminum and silicon. As the Moon cooled, it tidally locked to the Earth, keeping one side always pointing at the still red hot Earth. The far side of the Moon cooled quicker, and this hot metallic atmosphere precipitated out on the far side. This made the crust on that side thicker, and later impacts didn't break through to release the still molten mantle onto the surface, which had created the maria on the near side.

Isn't it obvious?

[Iamthecheese]

One side of the moon has had some protection from meteors. One side has not had as much. A child could point this out. Of course it's more complicated than that but I'm surprised the article didn't point this out as the primary reason for the difference.

Re:

[mmell]

I do agree; a glance at even a child's orrery will make the situation pretty plain.

Still good research, though. Nothing here that's going to make gasoline cheaper or pay the mortgage, but the better we can model what happened in the past, the better we can model what's going to happen in the future.

Re:

[iikkakeranen]

A child with no understanding of the scale of the solar system might come to such a conclusion, but it wouldn't be right.

The Moon orbits at ~384000km from the Earth and the Earth's diameter is 12742km, resulting in the Earth covering less than two degrees of the sky as viewed from the Moon's near side. Area-wise this is just 0.012% of a hemisphere so it's not a meaningful shield in the sense that many objects that would impact the moon will hit the Earth instead. Gravitational scattering (by Earth's gravity

First principles: Occam's Razor

[passionplay]

Objects impacting the side of the moon that faces us, can only originate from the conical section that is oblique to the majority of the face of the moon pointing towards the earth. This means, most impacts on our side are glancing since things cannot come from earth directly (90 degree impacts) toward the moon from the conical area covered by the earth. By contrast, the rest of the surface of the moon has no such limitations on direct 90 degree impacts. So it stands to reason that more of the kinetic energy of objects hitting the moon are going to affect the surface on the far-side rather than the near side. We don't need a computer simulation to figure this out. Just Kepler, Newton, Descartes and Copernicus.

Minerva

[Morfiend1]

Has it not been established that the far side of the moon is different because it is covered by the remains of the planet Minerva?

Duh?

[BoFo]

How about any objects that are headed toward our moon from the side always facing the Earth will be competing with the force of gravity from a much larger object -- the Earth itself? No such countermanding force exists for the dark side. This would seem the simplest explanation -- objects passing between the Earth-Moon system might be more likely to strike Earth than the Moon.