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The moon may be tectonically active

nationalgeographic.com

21–30 of 50 posts

Re: The moon may be tectonically active

#22
I wonder if

“Without water, the lunar surface instead gets deformed, stretching from a spherical shape into a more oblong one and back again.”

Is enough energy to keep the core of the moon hot? Like maybe the moons mass alone for for 4+ billion years would have cooled but the additional force of the earth stretching the moon like a rubber band creates heat energy...

Re: The moon may be tectonically active

#23

I’m a bit out of my depth here, so someone more knowledgeable correct me if my understanding is wrong. In the article, they’re stating they believe it’s seismic activity because it’s occurring within some distance of these fault scarps, which also appear to be where the surface displays lines in the images shown in the article? How are they dismissing it’s not a result of material from space striking the surface? Is…

Yes, you can estimate the depth below the surface by reading the seismic arrival times. There are compressional waves that travel along the surface, which travel at different speeds than the pressure and compressional waves going straight through the moon.

Re: The moon may be tectonically active

#24

I’m a bit out of my depth here, so someone more knowledgeable correct me if my understanding is wrong. In the article, they’re stating they believe it’s seismic activity because it’s occurring within some distance of these fault scarps, which also appear to be where the surface displays lines in the images shown in the article? How are they dismissing it’s not a result of material from space striking the surface? Is…

I think quakes last noticeably longer than impacts, at least if they are large enough. On Earth, there's a fairly well-established empirical correlation[1]. Putting a magnitude of 5.5 into the formula given here suggests a duration of about 70s, if that relationship holds on the Moon.

[1]https://en.wikipedia.org/wiki/Earthquake_duration_magnitude

Re: The moon may be tectonically active

#30
post #12

I’m a bit out of my depth here, so someone more knowledgeable correct me if my understanding is wrong. In the article, they’re stating they believe it’s seismic activity because it’s occurring within some distance of these fault scarps, which also appear to be where the surface displays lines in the images shown in the article? How are they dismissing it’s not a result of material from space striking the surface? Is…

> How are they dismissing it’s not a result of material from space striking the surface? The earthquakes are magnitude 5.5, plugging that into an energy calculator ( http://earthalabama.com/energy.html#/ ) gives a result of 0.2 Hiroshima bombs, which I think would be noticeable.

>> 0.2 Hiroshima bombs, which I think would be noticeable.

Maybe not. Hiroshima wasn't all that big on geological scales. A medium-sized meteor stroking the moon would have equivalent energy. Tidal forces can also break meteors up, spreading them into streams of smaller bits that land over a period of time. So I am not so dismissive of potential impacts.

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