This is probably old, but I decided to create a new thread since its going to happen in 2 days.
What is WJD?
Some morons have calculated that if 600 000 jump at the same time, the force of all of them jumping and landing will push the earth out of its current orbit and into an orbit a few meters wider in diameter. This reduce global warming, extend the day time and do a lot of other good things (according to them).
Why it wont work.
If you have had simple high school physics you will realise that when you jump, you excert a force on the earth, pushing it away. As you land you will push on it with the same force in the same directions. But what they fail to take into concideration is that while you are in the air the earth pulls on you, and you pull on the earth. In fact the force of attraction between you and the earth while you are in the air will be exactly the same as the force of you jumping and landing. Hence the total force is zero.
World Jump Day
