Posted by Hughe (here)
We can't figure out what's inside the moon and the core structures just by calculating moon's mass with the data from NASA or Astronomy body.
All the mass calculations as I know, maybe there is a different way, for satellite or planet like Earth is treated as point mass. It means, a point of mass by Issac Newtons' principal.
Newton proved that even a hollow sphere can be treated a point of mass at the center.
Even the Moon's actual gravity became questionable since the Apollo missions by Moon researchers.
There are different tools to understand the internal structure of the Moon.
As I understand it.. this is not speculation of the moon's composition, or it being treated as a point mass. Yes, surely you could treat it as a point mass for gravitational computations.. but that's not what's being discussed here. That is, why would it "ring like a bell"? Is that because it is hollow? I have merely pointed out a potential mass for even a hollow moon would be many orders of magnitude greater than that of an impacting spacecraft. Even if you take a collossal impact velocity into account in that momentum - it seems unlikely that would be enough to make the whole satellite vibrate. . .
It would be interesting to know if there are any data relating to any hollow heavenly bodies. I think it would be rare for that to occur naturally, and as I said, if you're going to hollow out a rock 3476 Km across... that's a lot of rock to remove...
I'd be interested to see some scientific data on hollow astronomical bodies if anyone has any...
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