Might As Well (Not) Jump

Remember that urban legend about how you can save your life in a plummeting elevator by jumping just before impact? According to the experts, it doesn’t work. But that doesn’t seem to be stopping some people from trying a similar trick to stop global warming today, on World Jump Day.

Apparently the jump was scheduled for 11:39:13 Greenwich Mean Time, so if you’re reading this you’ve already missed it, which is fine because apparently it’s a hoax.

But just for laughs, here’s how it’s supposed to work.

World Jump Day

Hans Peter Niesward, from the Department of Gravitationsphysik at the ISA in Munich, says we can stop global warming in one fell swoop — or, more accurately, in one big jump.

The slightly disheveled professor states his case on WorldJumpDay.org, an Internet site created to recruit 600,000,000 people to jump simultaneously on July 20 at 11:39:13 GMT in an effort to shift Earth’s position.

Niesward claims that on this day "Earth occupies one of the most fragile positions in its orbits for the last 100 years." According to the site, the shift in orbit will "stop global warming, extend daytime hours and create a more homogeneous climate."

And according to Phil, here’s why it wouldn’t work.

First, there’s the problem with mass. 600 million people sounds like a lot, but the Earth is big. Really, really big. Let’s say each person weighs 100 kilograms to make it easy (that’s 220 pounds, so we’re already being generous). 600 million people times 100 kg = 60 billion kilograms. That’s a lot of meat! But the Earth masses 6 x 1024 kg, or 6,000,000,000,000,000,000,000,000 kg. In other words, the Earth weighs (well, masses) 100 trillion times the total mass of all those people!

…The second problem is one of placement. Even if 600 million people could move the Earth, they’re located all over the world. The Earth being a ball, that means that people in, say, northern Spain will be perfectly canceled out by people in New Zealand. You’d need to get all 600 million people in one place on Earth to do this. Not only that, you’d have to find the right place so that when the Earth moved, it went in the right direction. Global warming won’t be stopped if you accidentally move the Earth closer to the Sun. That also means timing the jump perfectly, since the Earth rotates.

…Finally, there is another basic reason this won’t work, even if everyone on the Earth weighed 100 trillion times as much. The problem is that we’re a closed system. If we get everyone to jump up, they’ll fall back down. So even if we were able to push the Earth in one direction by jumping, when we come back down we’ll move the Earth back to where it was!

Are there more reasons it wouldn’t work? Anyway, it sounds like fun, and if my timing hadn’t been off I might have joined in. The physics of it all are a bit beyond me, and I’m willing to bet that’s true of most people. So, if I’d jumped how many people would have been jumping with me?