and yeah some people have messed around with this idea enough to find that its effects in general relativity are even odder, which could lead to (as stated before me) the creation of wormholes!
But I keep trying to answer this question in my head:
What would happen if you exposed a normal atom of positive mass to an exotic particle?
would they just sit there and not do anything if thier gravitation are both equal and opposite?
logic says yes but I dunno, something isn't fitting perfectly in my head...hmmmm....
oh and when I said:
I was actually on about exotic atoms, which arn't as funTretarn wrote:2) particles that are oddly composed

http://en.wikipedia.org/wiki/Exotic_atoms