magnetic poles

[tigerlily11]

I Watched a show last night about the core of the earth and how it would affect the world if it stopped. We would end up similar to Mars.
They said that the poles had changed places about 170 times so far.
They started to explain what would happen when the poles begin to change but didn't explain the consequences of a total change.
What would be the affect on us if it did? Apart from the obvious such as travel and certain things like bids becoming confused, what physical affect would it have on us if any?
Thanks for your time.

[Tom Braider]

I don't think anybody knows for sure. The "like Mars" thing is a bit odd, cos Mars doesn't have a magnetic field at all. The evidence for the magnetic poles shifting now is that the magnetic field of Earth has been reducing in strength. The magnetic field is what keeps cosmic radiation from the planet so if it reduces to zero before coming back the opposite way round we'd all be zapped. Effects of cosmic radiation on a human body would not be good: much like radioactive fall-out, I think.

[tigerlily11]

The show I was watching stated that Mars once had a magnetic field. Then for some reason it disappeared. Mars then became the planet it is now, with no atmosphere, and no water.
So I assume having no magnetic feild means certain death for us.