If it was possible to be at the precise centre of the earth, would you still be subject to a gravitational pull? Presumably you would not be weightless at that point? If there is a pull, what is it exerted by i.e. which part of the earth? So are you at that point being pulled outwards away from the centre of the earth? How do gravitons work?
Please ignore the problems of temperature and pressure at the core, I know in reality it's not survivable. Also I'm talking only about the earth's gravitational pull, not that of the sun or other bodies.
2006-11-09 06:47:36 · 13 answers · asked by Ashoka 2 in Science & Mathematics ➔ Physics
Please be warned - there are MANY incorrect responses above.
The theoretical answer to your theoretical question is that you would be weightless at the centre of the earth because the forces of attraction would exactly cancel out.
To address some of the errors above:
You would not be pulled apart because the mass of the earth is not enough. Similarly, you are not pulled apart when standing ON the earth, even though the earth is pulling your feet more strongly than your head. If the earth were enormously massive then you would be (it's called being spaghettified, although it ought to have a different name if you are the centre!).
The force of attraction does NOT increase as you get closer to the centre of the earth. The responder is thinking about Newton's Law of Gravitation which applies to POINT masses. If you apply it to a large body such as the earth then you find that only the sphere underneath you attracts - the rest of it cancels out. ie The earth is roughly 6400km in radius. If you are 5000km from the centre then you will feel the force of attraction of a 5000km radius sphere of the Earth at a distance of 5000km - the force of attraction of the remaining 1400km 'shell' exactly cancels out.
You would not 'feel' the force of the sun (any more than you do on the earth) since its force of attraction is providing the centripetal force required to move you in a circle around the sun.
The force of gravity is NOT caused by the rotation of the earth. In fact, if the earth stopped rotating we would all be a little bit heavier since a part of the force of gravity is being used to provide the centripetal acceleration necessary to keep us spinning around once per day, with the earth (on the equator this amounts to about 0.3%).
You also ask about gravitons!! How they work is a difficult question since they are theoretical! According to classical Newtonian theory, gravity is simply a fundamental property of matter - matter attracts other matter and that's that. Newton himself was always uncomfortable about the idea of "action at a distance" but even his genius could not solve the problem, given the limitations of the time that he lived in. Along came Einstein and gave a solution - matter distorts the shape of space and the apparent force of gravity is actually simply the result of an object moving in the distorted space. Think of a heavy ball on a rubber sheet and another ball moving along. It does not 'know' about the heavy ball but it changes its path towards the ball because the surface on which it is rolling has been distorted.
The graviton is an attempt to explain the phenomenon of gravity without recourse to considering distortions of space-time. Bodies with mass emit particles called gravitons. They interact with other massive particles. The degree of ineraction can be calculated and reasonably easily represented on a Feynman diagram. Try an internet search. Huge tanks full of washing up liquid have been built down abandoned deep mine shafts to try to detect these particles. Some 'events' have been noted but they remain elusive, as far as I know.
Hope this goes some way to answering your interesting questions.
2006-11-09 11:57:33 · answer #1 · answered by Perspykashus 3 · 0⤊ 0⤋
There is attraction between any two objects. If you were at the centre of the earth you would feel equal attraction to every point on the surface. So you would be weightless. But you would feel slight pull from the moon and the sun.
2006-11-09 08:23:27 · answer #2 · answered by helen g 3 · 0⤊ 0⤋
This is a thorectical question, so here is a theorectical answer:
According to the law of gravity, if the mass of the earth is unchange then you will feel heavier if you are nearer to the centre of the earth. ie. Gravitational force is stronger and stronger as you move even closer to the centre. Therefore, if you are at the centre of the earth then the gravity force exerted on you should be tending towards infinity and your weight would be tending to infinity as well.
Generally, Force is proportional to mass and inversely proportional to distance.
2006-11-09 09:55:08 · answer #3 · answered by Anonymous · 1⤊ 0⤋
cool question! but i think you should mean being at the center of the pull which doesnt mean being at the center of the earth does it? but i think this gets weird cos if you were at the center wouldnt the mass of what was outside you start to pull you away?? Each atom has a mass which pull you individually( and this pull weakens over disatnce) so while you are on the surface, say in london the atoms that make australia wouldnt have much pull on you, at the center you are surrounded by mass, not just walking on the surface so i think you would be pulled apart in all directions
Hang on!! why doesnt the atom at the center of the pull get pulled apart?? if it did the earth wouldnt be would it?, maybe the mass and pull of whats outside is balanced with what is pulling in?it must be absorbing the pull of each atom connected to it and vice versa, thus if your fragile human body was at the center I now think that you would be weightless.
2006-11-09 06:59:38 · answer #4 · answered by SCOTT B 4 · 0⤊ 0⤋
It's zero at the centre of the earth, so you would be weightless. In fact the force of gravity varies linearly with your distance from the centre. If you dug a hole through the earth from one side to the other and dropped down it you would oscillate back and forth, from one side to the other, taking 90 minutes to get there and back. So that's Australia in 45 minutes! You'd be a bit giddy though as you would pass through the centre of the earth at about 17,500 mph.
2006-11-09 07:11:05 · answer #5 · answered by Martin 5 · 1⤊ 0⤋
You would be essentially weightless, because all the mass pulling on you in all directions would cancel out. (You would not feel stretched either -- because the "cancelled zone" would be pretty large). This is actually the same thing that happens in space at 5 special places, called Lagrangian points. They are places where the Sun-Earth-Moon gravities all cancel each other out.
2006-11-09 07:04:03 · answer #6 · answered by Michael 4 · 1⤊ 0⤋
The gravitational pull would be zero and theoretically you would be weightless. It doesn't matter whether the earth is spinning or not. If it stopped spinning gravity wouldn't change, but the earth's magnetic field would become zero
2006-11-09 07:03:53 · answer #7 · answered by Anonymous · 1⤊ 0⤋
Assuming that the density of the earth is the same in any direction, you will be weightless. All gravitational forces will cancel out.
2006-11-09 06:49:33 · answer #8 · answered by Gene 7 · 1⤊ 0⤋
The is all IFs,
If the earth was perfect round, build in all directions of equally dense material and have a perfectly equally gravitational field (none of which are true), then the THEORY you would be pulled equally in all directions, and theoretically suspended, as no one direction would draw you more than another.
Perhaps!
2006-11-09 06:51:20 · answer #9 · answered by dsclimb1 5 · 0⤊ 0⤋
At ground level 1 Kg per Sq cm, but I don`t know about the centre.
2006-11-09 07:17:40 · answer #10 · answered by CLIVE C 3 · 0⤊ 0⤋