• According to the World Jump Day website, if 600 million people in the Western hemisphere jump in synch (as opposed to jumping N*Sync, which would also be fun), it could jiggle the earth's orbit enough to "stop global warming, extend daytime hours, and create a more homogenous climate."
• Jumping is fun.
• We Gristies are all practiced up!

Jumping Cons

• The professor whose theories are behind World Jump Day doesn't actually exist.
• In Seattle, jumping time is 4:39 and 13 seconds -- a.m.
• Jumping duration must be at least two minutes. At 4:39:13 in the morning? Really?
• As of this posting, less than 600 million people have signed up to jump, so it might not work anyway.
• As the deadline approaches, people appear to be signing up at a rate of one per second, according to the counter on the site. One could be forgiven for being skeptical.
• Lengthening the earth's orbit could make the Gregorian calendar obsolete.
• Other scientific folk suggest that even if the feat of coinciding jumping was pulled off, 'twould shift the earth all of the radius of a hydrogen atom.