JF Mezei wrote:

On 2016-10-11 23:42, Fred J. McCall wrote:

The "ultra thin atmosphere" is quite a lot of protection, actually,
and eliminates over 60% of the radiation.


I read that lack of magnetic field was a far greater problem in terms of
providing protection from radiation.


True. If Mars had a magnetic field like Earth's there would be orders
of magnitude less surface radiation.


Could a Mars colony dig deep to get geothermal energy ? Or has Mars
cooled to a point where its core is no longer molten ?


They could always drill to get geothermal energy, regardless of
whether the core is still molten or not. Temperature will always
increase with depth. However, that's a lot of trouble to go to. Solar
and nuclear are more likely power sources. Solar cells could probably
be produced locally. Nuclear fuel would probably have to be imported.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw