"Climate changes melting tourism in Swiss Alps"

Vincent Walker wrote:
lal_truckee wrote:

Vincent Walker wrote:
The theory is that the reversing of polarity was the
reason that Mars eventually lost its atmosphere.
What theory is that, pray tell?

I saw this on Nova on PBS. Basically besides gravity the atmosphere is believed to be held in
place by magnetic forces. As the molten cores of the terran planets cool over time their
magnetic fields reverse and weaken. Mars, by the combination of its smaller size and
position in the solar system - theoretically of course - eventually lost its ability to hold an
atmosphere in place.

You do know you either hoaxed yourself or they hoaxed you? (I won't
comment on which I think happened.) The Earth's mag field has reversed
numerous times; it has nothing to do with the atmosphere. Cooling cores
are not the driver, either.

The last reversal was about 780,000 years ago.