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22/04/13/043227 story

Huge Impact May be Why the Moon's Near and Far Sides Differ So Much

posted by Fnord666 on Wednesday April 13 2022, @02:31PM   
from the or-maybe-not dept.

upstart writes:

Huge Impact May Be Why The Moon's Near And Far Sides Differ So Much:

When spacecraft first journeyed around the Moon, something unexpected was revealed: the far side has almost none of the lava flows we call seas or maria, which dominate what we can see from Earth.

For almost 60 years, astronomers have sought to explain the discrepancy with many different theories. A new model proposes the answer lies in the Moon's largest and deepest impact crater.

The lunar seas are the result of immense lava flows that erupted recently enough they have not been completely covered in craters. The puzzle is why there were so many more such eruptions on one hemisphere than the other.

A new study in the journal Science Advances proposes that the formation of the South Pole-Aitken (SPA) basin triggered a heat plume in the lunar interior that produced the imbalance. The SPA is among the Solar System's largest impact basins, with a metal structure beneath that may be the asteroid that formed it. The SPA is not as well known as smaller lunar craters, both because it's on the far side, and its immense age (4.3 billion years) means subsequent impacts have partially obscured it.

[...] For much of the time since the absence of seas on the far side was discovered, attempts to explain the difference centered on the relationship of the two hemispheres to Earth. Examples include efforts to explain how Earth's gravitational field could have produced greater activity on the lunar near side, or the planet's bulk blocked incoming asteroids, reducing cratering.

However, if the study authors are right, it's all a coincidence, a consequence of where the impact that caused the SPA happened to take place.

Journal Reference:
Matt J. Jones, et. al., A South Pole–Aitken impact origin of the lunar compositional asymmetry, (DOI: https://www.science.org/doi/10.1126/sciadv.abm8475)

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Original Submission

• I always assumed the moon had a shieldI always assumed the moon had a shield (Score: 3, Insightful) by Snotnose on Wednesday April 13 2022, @08:11PM (1 child)

  by Snotnose (1623) on Wednesday April 13 2022, @08:11PM (#1236714)

  Namely, Earth. The moon is tidally locked to Earth, so any doohickies that want to hit the side of the moon we can see have to get through the Earth somehow.

  --
  Of course I'm against DEI. Donald, Eric, and Ivanka.

  • Re:I always assumed the moon had a shield(Score: 0) by Anonymous Coward on Friday April 15 2022, @03:59PM

    by Anonymous Coward on Friday April 15 2022, @03:59PM (#1237213)

    But the lava flows are on the FAR side not the shielded side.

    Parent

• just get a smaple(Score: 2) by bzipitidoo on Wednesday April 13 2022, @09:12PM

  by bzipitidoo (4388) on Wednesday April 13 2022, @09:12PM (#1236733) Journal

  Well, all we have to do is dig down to that metal structure, and, after preserving a sample for isotopic analysis, mine it. There's gold down there!

  Hmm, I wonder... we can't journey to the center of the Earth, but maybe, if the moon's core is solid and not too hot, we could journey to the center of the moon?

• DNADNA (Score: 0) by Anonymous Coward on Thursday April 14 2022, @02:07AM (1 child)

  by Anonymous Coward on Thursday April 14 2022, @02:07AM (#1236803)

  The SPA is among the Solar System's largest impact basins, with a metal structure beneath [iflscience.com] that may be the asteroid that formed it.

  It's the B ark.

  • Iron Sky, not DNA(Score: 2) by maxwell demon on Thursday April 14 2022, @04:28AM

    by maxwell demon (1608) on Thursday April 14 2022, @04:28AM (#1236824) Journal

    The B ark landed crashed on Earth, not on the Moon.

    No, that metal structure of course is the Moon Nazis' hideout.

    --
    The Tao of math: The numbers you can count are not the real numbers.

    Parent