Earth jumpers

"If the entire Chinese population (well over a billion souls) jumped at the same time their collective force could effect the Earth's orbit."

This is the way Robert Wolke (What Einstein Told His Barber) explains the negative side:
"Assuming a population of 1.2 billion...weighing an average of 150 lbs each, their collective pounce would hit the ground with an energy of 1.6 trillion...units of energy (joules)." In short, that would be the equivalent of a 5.0 earthquake measured on the Richter scale. So jump away; the earth will be in good hands.