Ha! ha! That is a really funny one. A tabloid newspaper which you see in grocery store cashier lines ran a headline plot of this nature in 2002 or early 2003. "World Weekly News". They had "photos" of all these people ready to jump.... Hilarious stories. "Elvis was an alien" type 'news'. There is a whole line by that publishing group; their history of successful growth marketing strategy is unique. While I personally despise the "rumor tabloids", I can't help but to chuckle on the ridiculous. By the way, classifieds are fairly inexpensive for a national publication. Back to the question: When it rains there is a tremendous amount of weight hitting the ground...our orbit is just fine.

If people weighed on average 1000 lbs, a billion people would weigh a trillion pounds. The earth "weighs" about six sextillion tons. That is more than a trillion times the weight of all the people on earth. So, if all the people on the earth jumped the same direction at the same time, the earth would move less than one trillionth as far in the opposite direction. For example, if everybody jumped two feet directly toward the north star, the earth would move less than a millionth of a millionth of a foot away from that star. The real kicker is that as soon as those people jump, they start falling back toward the earth and the earth falls back toward them and the net effect is immesurably close to zero. The earth running into hydrogen atoms, cosmic dust and the occasional meteor as it moves around the sun has a greater effect on its orbit than the mother of all coordinated jumps ever could.

No but,if everybody in china was outside jumping. trying to knock earth out of its orbit There would be a decrease in china's population.

No. Believe it or not, I'm actually going to answer this ridiculous question. But first we need to have a word. As you can imagine, I possess phenomenal scholarly resources. I've converted the spare bedroom in my house into a research library containing 16 million volumes, which are dusted twice a day by a team of robed acolytes holding candles. I have instant access via my Apple 380S GT to all the world's data banks. Why, right here on my writing table next to the box of spare quills I have a dog-eared copy of 16,000 Unbelievably Complicated Physics Experiments for the Home and Garden, With Answers, which has helped me out of many a jam. Despite this wealth of scientific knowledge, the Teeming Millions routinely write in with questions that, in 6,000 years of recorded history, no one has ever asked. As a result, my usual sources of information are useless. Nonetheless, I try. I've been in contact all week with the Beijing government in an effort to persuade them to get all 1,027,000,000 Chinese (1980 estimate) to jump off chairs. I've pleaded with them that will signficantly advance the cause of science. However, they refuse to cooperate. They point out that China is a poor country, and lacks sufficient chairs. Moreover, many of the chairs that are available are of nonuniform height, meaning that even if all the Chinese jumped off at the same time, they'd hit the ground at different times, throwing off the results. Finally, they point out that discipline among the Chinese people has become lax since the Cultural Revolution, and that many of the participants in the project would likely be distracted when they were supposed to be jumping. The Chinese government suggests that instead of having the entire nation jump off chairs, I should get one representative citizen to jump and multiply the results by 1,027,000,000. I have, needless to say, rejected this solution as grossly inadequate. The possibility of an actual test thus being remote, I've been forced to work this out on the basis of reason alone, to wit: given that every action has an equal and opposite reaction, when the Chinese get up on their chairs, they'd essentially be pushing the earth down in the process of elevating themselves. Then, when they jumped off, the earth would simultaneously spring back, attracted by the gravitational mass of one billion airborne Chinese, with the result that the Chinese and the earth would meet somewhere in the middle, if you follow me. The upshot of this is that action and reaction would cancel each other out and the earth would remain in orbit. Just for fun, however — after you've been doing this job for a while you get a pretty unusual notion of what constitutes a good time — suppose 1,000,000,000 Chinese, give or take 27,000,000, were somehow to materialize atop chairs without their having to elevate themselves thereto. And suppose they jumped off. Having performed feats of mathematics requiring the entire afternoon — sometimes I can't believe the crap I spend my time on — I calculate that the resultant thud in aggregate would be the equivalent of 500 tons of TNT. Not bad, but nowhere near enough to dislocate the earth, which weighs 6 sextillion, 588 quintillion short tons. What would happen if all the Chinese yelled at the top of their lungs I refuse to even discuss... http://www.straightdope.com/columns/read/142/if-all-chinese-jumped-at-once-would-cataclysm-result

No..cause most of them people are skinny and weigh under 150lbs.

Do not tempt them please.

No, because when they pushed upward and the earth went downward, in less than a second the earth's gravity would pull them back downward--but THEY would pull the earth back UP-ward. Think of it as a simple two-body problem. If the only thing in the universe were two giants with the soles of their shoes in contact, and one jumped, he would push himself up and the other down--but gravity would then bring him down and the other up. No change. Whenever an apple falls down to strike the earth, the earth rises an immeasurably tiny bit to meet it. (Of course this is cancelled out by the apple on the other side of the planet.) It takes a very big force to make earth wobble a little in its orbit (it still stays in the same orbit). A tsunami. A major dam break. Filling that dam in the first place.

1) "The question is not as silly as it looks, actually. Oscillations are present in many physical processes and sometimes they can have impressive consequences. They occur not only in physical systems but also in biological systems and in human society. For example, earthquakes are one of the most destructive oscillations known to man. They result from the sudden release of stored energy in the Earth's crust that creates seismic waves, they are often felt as vibrations of the ground. Smaller earthquakes can also be caused by volcanic activity, landslides, mine blasts and nuclear tests. In its most generic sense, the word earthquake is used to describe any seismic event-whether a natural phenomenon or an event caused by humans-that generates seismic waves. But could people really cause an earthquake just by jumping around? Standing next to a massive person while he jumps, one can sense a small tremble. What could happen if the entire population of China were to jump in the same time? China has an estimated population of 2.3 billions, so they should make an impact, right? To test that idea, the creators of a science program on German television asked themselves what would happen if the entire Chinese population engaged in synchronized hopping and enlisted the help of a rock band, to perform a small scale experiment. During a German music festival called Rock at the Ring, the band We Are Heroes told the thousands of rock fan/hoppers (total attendance 50,000) to jump, while the program's crew recorded the event on videotape and the Potsdam Geological Research Center recorded it on seismometers. The results were...disappointing. "A seismometer measured four oscillations per second, while the earth moved only one-twentieth of a millimeter. "We showed that people cannot start a (real) earthquake by hopping," remarks Ulrich Gruenwald, producer of the program. Well, the oscillations themselves are not as damaging as one particular effect, the resonance. Maybe the entire population of China wouldn't cause an earthquake just by jumping once, but if their jumps were to resonate, the effects could be much greater. It's a known fact that resonance can destroy bridges and buildings, the most famous example being an army marching over a bridge, that breaks up the march, even if they're not absolutely sure it would collapse the bridge. So, it seems that these applications proved that in the case of the planet, no, a bunch of people marching around aren't going to cause it to vibrate." Source and further information: http://news.softpedia.com/news/What-Would-Happen-if-the-Entire-Population-of-China-Jumped-at-Once-56580.shtml 2) "Anyhow, one billion people, each weighing 60 kg (~130 lbs), would have the weight of 6 ·1010 kg. Earth has the mass 6 ·1024 kg. The earth weighs 6 ·1024 / 6 ·1010 = 1014 times more than one billion people. That is 100,000,000,000,000 times more. This number is of course hard to comprehend, but it gives a hint that there would be no noticeable effect on Earth at all. Let's scale this down to something we can relate to: a housefly. We all know how it is when a fly lands on you. If you're lucky, you feel an itch, but often you feel nothing. The ordinary housefly does not make a noticeable impact on you; it does not make you stumble or lose your balance. A housefly weighs about 40 mg, 40 thousands of a gram, or 4 ·10-2 g, or 4 ·10-5 kg. Something weighing a factor 1014 times more would therefore weigh 4 ·10-5 kg x 1014 = 4 ·109 kg, or 4 million kilograms. Lead weighs 11 350 kg/m3, which means that it would take 4 · 109 kg / 11350 kg/m3 = 352 400 m3 of lead to come up in this weight. This corresponds to a cube of lead with the side 3√( 352 400) = 70 meters (76 yards or 230 feet). This is the side of the cube of lead that our imaginary fly would land upon. So, we therefore conclude that: The effect that one billion people would have on earth, is the same as a housefly would have on a lead cube with sides 70 meters long." Source and further information: http://everything2.com/title/If%2520all%2520the%2520Chinese%2520jumped%2520at%2520once%252C%2520would%2520cataclysm%2520result%253F

its just a strategy for catching titles about news or advertisement. But its interesting though..