# Thread: See you on the other side...

1. Senior Member Always Around
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Umm, I don't know if you were being serious or trying to be funny, but I'm just going to assume you're being serious.

If you were 1000km below the Earth's surface (roughly 5300km away from the centre), imagine dividing the Earth into two separate pieces:
1. A sphere centered on the Earth's core, with a radius of ~5300km (i.e. everything "below" you)
2. The shell created by everything "above" you, with a hollow section in the middle (where the sphere from the point above would go)

Assuming that the Earth's surface is a uniform sphere (i.e no irregular shape, as close to a proper sphere as possible) then the shell described by point 2 would have no gravitational effect on you while you're inside it, as it is exerting a uniform gravitational pull on you from all directions at once. You would only feel the gravity from what is "below" you (the sphere from point 1). Therefore for any calculations we can disregard the outer shell that is "above" you and replace what is "below" you with a point mass (since the gravity is centred on a single point in the centre of the mass, from your perspective).

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Originally Posted by dhjana
Maybe she meant anti-matter.
Antimatter weapon - Wiki

Bad quality vid - antimatter as a weapon

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^ Producing antimatter would be even less of a problem though.

It'll annihilate immediately unless sequestered, and it's pretty much impossible to produce in any significant quantity.

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Since you people seem to be smarter than time, space, and several Steven Hawkins in a High School debate...

Can anyone explain to me what anti-matter is?

I always thought it was just the opposite of matter. A void substance if you will. I can't conceive why anti-matter would "explode." Why can't it be classified under the same elements? Why would anti-Oxygen explode?

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^ Antimatter is formed from antiparticle analogs to matter (positron, antiproton, and antineutrons).

Each of those have equivalent or inverted properties, for example, same mass as their matter analogs, but opposite charge.

When they come into contact with their matter analog, they annihilate, converting their entire mass to energy and ceasing to exist (E=mc^2)

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...So that's the reason they could theoretically be used for weapon purposes? The energy release generated in the "canceling out" process?

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an antiparticle is a particle traveling backwards in time. light (ie photon) is the only substance that doesn't have an antiparticle because time is meaningless at the speed of light.

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Originally Posted by Terasiel
...So that's the reason they could theoretically be used for weapon purposes? The energy release generated in the "canceling out" process?
Theoretically, yes.

In real life, antimatter would make a crappy weapon. First off, it's extremely difficult to create and store. It's only true advantage is that it's an efficient conversion of mass to energy (it has more power/mass compared to other weapons), and it's clean (when compared to nuclear or chemical explosives). However, since the delivery mechanism also has to incorporate a containment mechanism, that completely defeats the purpose of having a small but powerful weapon.

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