Re: Searching for Theia, the mother of the Moon

N:dlzc D:aol T:com (dlzc) wrote:
Also if a Mars-sized object hit Earth, wouldn't we
see a somewhat lopsided Earth? They say that
most of Theia sunk to the core of Earth, but that
would require displacement of everything that was
already at the core of the Earth. It would require
the Earth to have blown up and come back
together for such perfectly round mixing of the
combined bodies to happen again. And the Earth
would look a bit younger than the other planets in
the Solar System, because it would look like it
formed later.

There is no need for Earth+Theia to do more than melt. There was plenty of extra energy to permit that. Then the products spin, with a very oblate shape, a lobe starts to form as the system is unstable, the lighter materials get pulled up into the lobe, and the lobe parts. See it in lava lamps sometimes.

The Earth-Moon Lava Lamp Theory. I think this was actually the popular theory about the Moon's formation back in the 60's, wasn't it? They were very familiar with lava lamps back then. :-)

But still wouldn't we see some sort of tail or other formation on Earth at the point where the Moon might have plopped off? I think we see a difference in crustal thickness on the Moon between its Earth-facing side and its space-facing side. But we don't see a similar crustal difference on Earth. Unless, we talk about the crustal diffences between the oceanic plates and the continental plates, but they're distributed all over the place. I wonder if the formation of the Moon started this entire continental plate business?

Now if Theia was actually a Mars-sized black
hole instead, then it could easily make its way
to centre of the Earth and provide power source for
the magnetic field that Earth has.

Mars *massed* black hole, you mean. No the structure of the Earth is not solid enough to permit that... we'd flow in.

Then I wonder if we'd flow in and become part of a black hole, or would the mass of the Earth, being greater than the black hole, turn the black hole into a neutron star (neutron planet, maybe)?

I mean a merger of two solid planets can't be
nearly as simple as say the merger of galaxies,
which have large gaps in between.

Agreed. I would expect quite a bit of debris. Locally, the Moon would sweep that. But in our solar L4 and L5...

Our own Trojan asteroids.

Besides the collision theory, and the capture theory,
why can't the Moon have simply formed where it is
now? That would seem to be the simplest answer.

We have records that date back to 2.2 Gy ago that says the Moon was much closer.

I don't mean really in the exact orbital position it is in right now. I meant that it formed naturally somewhere in orbit around the Earth.

There's a lot of rules about how large a satellite can get given the main planet's mass. Apparently the Moon is too large to fit those models. But why?

Yousuf Khan
.

Relevant Pages

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