"Ross A. Finlayson" wrote in message om...

I'm wondering about "lava tubes on the moon". I guess I was under the
impression that besides Earth only Jupiter's moon Io had active
volcanic activity, and I was thinking Luna was a cold chunk of rock.

It used to be volcanic a long, long time ago. And it's been totally
stable ever since, meaning those lavatubes are literally billions of
years old. Only large meteorite impacts could destroy them, and they
are bound to have randomly missed a few tubes.


Yet, I read here that Luna has a molten, presumably iron, core, thus
that it would have similar magnetic fields to Earth.

Hardly! The Moon rotates at the rate of once a month as opposed to
Earth's once a day. That alone would diminish the magnetic field
greatly.

But it's not even the rotation of the planet that's thought to cause
the magnetic shield but convective forces in the Earth, causing magma
to float around in circles. On the Moon there's hardly any seismic
activity. It's rather cool on the inside. And it's tidally locked
with Earth, making it even more inert, with anything deep down unlike-
ly to move.



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