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Date: 1991 

What is anti-matter? Is it the opposite of matter in the sense that it has a 2> force insted of a gravitational force, and does time go slower in close proximity to it?

Yours is a complicated question that I can best answer with an example. A positron is anti-matter for an electron. Try looking up positron in an encyclopedia, and take it from there. We believe that anti-matter and matter behave the same way with gravity, On the surface of the earth both matter and anti-matter fall toward the center of the earth. This belief is currently being tested experimentally.
I believe that one of the experiments is being done at Fermilab.

Jack L. Uretsky

One way of viewing antimatter is as matter going backwards in time. However, that really only works on a microscopic scale (a microscopic piece of matter which could be thought of as annihilating with a piece of antimatter could also be thought of as switching directions in time, with the same effects). Macroscopically antimatter is expected to behave exactly the same as matter (gravity works the same, and the mass of a piece of antimatter is always exactly the same as the mass of its corresponding piece of matter) except that electrical things will all be backwards, since antimatter has opposite electrical charges from matter.

Arthur Smith

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