Cientists want 600 million people to jump at the same time all around the world... isn't that extremely dangerous? I mean...i've always heard that massive movements like those can result in major earthquakes... They say that it changes the earths'orbit around the sun, just enough so that the global warming problem is postponned for a couple of centuries more... What do you think about it?? You can check it out at www.worldjumpday.org
I don't see how this will work, wont it just cancel out by having the earth pulling on all those people, who after jumping, are now above the earth?
A letter for the whole humantiy: Please, let's not jump and end up in the sun. Thank you. Best regards, Nelson
All the humans on the entire globe added together would weigh the tiniest fraction of .1% of the earth's mass... so no, it wouldnt do a dam thing, at all.
When you jump you push off from the earth sending you up and the earth down, from the time you leave the ground to when you come back down, the earth is being pulled towards you, and when you hit the ground the earth would have moved back to the position it was when you jumped, travelling towards you, your impact would stop the Earth. The net effect on the earth is zero, no matter how many fat people jump (or giant over weight cyborgs) or the size of the earth. It would only work if you could jump at escape velocity. The weight of all living things on the planet is less than one ten billionth the weight of the planet.
Yet the movement of a jump increases severely the amount of pressure and also causes waves of motion...that must influence a lot more than plain weight, no? I mean..for example, when you are inside an elevator, it holds your weight quite well, but if you start jumping the pressure on it increases to the point having to stop it. i am really not a scientist but i think that mass jumping can have some effect at some level...
does anyone here even remotely understand how large the earth is in comparison to a single human being? This shouldnt even be a serious discussion. Even 6 billion people jumping at the same time would caust absolutely nothing to happen.
Blindman and and Cato are both right. Read up on impulse and especially conservation of momentum. Simple concepts that apply almost directly to this scenario. Also what might help is Newton's third law of motion: "For every action (applied force) there is an equal but opposite reaction(force)". As above with the mention of escape velocity, you would have to leave the earth to apply a tiny unbalanced force on it for a tiny amount of time. Resulting in an extremely low change in orbit for the earth.
if you wanted this to actually work, instead of jumping, you would have everyone lay down at a specific time, then get back up about 12 hours later. that way, the earth is pulled up when you lay down, and pushed down on the other side when you stand again. this would still have minimal impact, but it will work better than jumping, which will not work at all. moreover, if you get everyone on earth to jump, people living near fault lines will probably be the only ones to notice anything, if you see what I am getting at.
It might trigger earthquakes, but with enough preparation I think we would rather have them them 'weak and early' than 'late and strong', where full elastic rebound occurs in the latter. According to Wikipedia, World Jump Day will not work because of Newton's third law. Well, that was what I thought at first, but I gave it a second thought: Their interpretation of Newton's third law assumes the earth to be a perfectly elastic object with 100% efficiency of kinetic energy conversion. This is not true in either the case of humans or the earth itself; some energy invested in kinetics will be lost to the fluids in and on the earth/ourselves. But the deciding factor goes this way- it seems that for a larger magnitude of acceleration of a solid envelop containing a fluid interior, the object will begin to behave more and more elastically, but I'm not really sure about that. So in an oscillation system where we are moving at a substantially faster velocity than the earth, some of the reaction motion will be lost from the fluid damping of the earth's magma and oceans- so it never really moves the entire way opposite from our jump (Whatever that distance may be). And so then it would move even less 'on the way back' to the new CM because of my supposed assumption in the last paragraph. The effect of 600,000,000 of these oscillations out of sync may help convert much of this damping motion into heat energy. Suppose a human can do somewhat over 1 HP when he/she jumps (about 1000W). So this would amount to 600 GW of power, of which maybe a fraction of it will be invested in actual distance moved. Just a stab.
