Subject: Why does the sun reverse its magnetic poles?

I read recently on cnn.com that the sun's magnetic poles have reversed as 
part 
of its normal 11-year solar maxium cycle. Why does this happen? How does 
it 
happen? What effect does it have on the sun? I also read that the earth's 
magnetic poles reverses from time to time, but with less predictability, 
the 
last one occuring around 800,000 years ago. Why is the earth's behavior 
less 
scheduled? What effect would the reversal of the magnetic poles have on 
earth's 
ecology, and humans' technology? 

I'm not a science major, but I do have a strong interest in all fields of 
study. Thank you for your time. :)

Re: Why does the sun reverse its magnetic poles?