# Hollow Earth / no gravity

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Is it possible that at the center of the earth there is nothing?

I think that there may be empty space.

If you were a partical of mass at the center of the earth would you be gravitationaly atracted to the largest amount of mass. This mass would be in any direction towards the surface and you would be pulled away from the center. you would also be atracted equally in the opposit direction and these two atractions would cancel each other out and you would be weightless.

Lets take a look at a molicule that is two miles from the center. It would be atracted to the mass that would be closest and that would be in the direction away from the center of the earth thus leaving the center of the earth void of any material.

I know this goes against all teachings but why could it not be true?

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Scientists are pretty sure there is something in the middle of the earth if only because the mass of the earth is known, and the density of earth is known, so that space pretty much has to be filled.

Also, I think you are misapplying the no gravity in a hollow sphere rule. Everywhere on the inside of a uniform spherical shell there is no gravity. Your example of the particle 2 miles off center isn't right. Yes, it is closer to one side so that one side has a stronger pull, but there is more than just half of the shell on the other side. That more than half is farther away, but being that there is more, it exactly cancels out the closeless of the lcose side. Hence, everywhere inside a hollow sphere has no gravity.

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The proportion of the elemints under the crust is unknown therefore the solid (no voids) mass of this material is unknown. Meaning it could have voids plus more elements of high mass. We are limited to working up a average mass for the whole planet.

Also

If however the earth did have a hollow core then the hollow core could possibly sustain itself. That partical two miles from the center would no longer be pulled towards the center equaly because there would no longer a larger amount of mass puling it in that direction.

Not that I am correct but my argument sounds valid to me.

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You are also forgetting all the means of determing what is underground available to us. Take registering an earthquake. The most accurate detectors can detect earthquakes quite far away, i.e. detectors in the US detecting the quake that caused the 2004 tsunami. In order for those detectors to work, we have to know how the waves travel through the earth, meaning we have to know what the earth is composed of. Otherwise the detectors wouldn't work right. In fact, intentionally causing waves to form in the ground has allowed scientists to map out the entire crust of the earth to several hundred kilometers. They can locate convection cells and mantle plumes, using this method. As far as I know, no large voids have ever been found. Sure, there are cave systems, but I think you are talking about voids thousands of kilometers large, and I don't think that voids that big exist. For example, http://en.wikipedia.org/wiki/Mammoth_Cave_National_Park says that "if connections are found between the three giant caves ... the total mapped system would exceed 800 km" That is, if connections were found between some of the largest caves in the US -- and they haven't yet -- it still would add up to be pretty small on a global scale at 800 km. Compare that with the Earth's diameter of more than 12,000 km.

Your particle (<-- note the correct spelling), in a hollow earth would not be pulled anywhere. Again, inside a uniform hollow sphere there is no gravity at all. The pull from the shell sums to zero at all points inside the shell. This is a classic mathematical result.

Finally, RE: "Not that I am correct but my argument sounds valid to me." there are lots of people who want to make arguments that "sound" good, but fall short in terms of facts. Arguments and debates are NOT decided on what "sounds" the best -- despite how almost every politican acts or how almost every advertisement tries to sell to you. When you look at the established facts and evidence, the theory that the earth is not hollow is overwhelmingly supported by the facts while the theory that the earth is hollow has very little facts to support it at all.

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If however the earth did have a hollow core then the hollow core could possibly sustain itself. That partical two miles from the center would no longer be pulled towards the center equaly because there would no longer a larger amount of mass puling it in that direction.

Not that I am correct but my argument sounds valid to me.

But you are forgetting that the particle must carry the huge weight from everything above, on it's back, and with nothing to stand on it will be pushed down to the center.

The temperature and pressure deep inside Earth is IMMENSE, no hollow can sustain itself there.

If you imagine a planet made only of liquid water, could the center be hollow ?

Sure, there can be small hollows, bubbles, but buoyancy would push them towards the surface.

(You can test this by blowing bubbles in a glass of water.)

Now, add some gravel to the water, would gravity pull the gravel to the center ?

(You can test this by dropping small pebbles in a glass of water.)

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