Subject: Is it possible to change the earth's rotation with man-made

explosions?  Specifically (and I know this is sort of stupid) if every 
country set of as many rockets as possible in the opposite direction of the  
earth's rotation, could the earth's rotation be affected?  And this is even 
more silly, but add to it that every person on the earth jumped into the 
air at the same time and landed using force in opposition to the earth's 
rotation - would there be any effect?

Re: Is it possible to change the earth's rotation with man-made