What Is Exotic Matter?

What is exotic matter? What is the proof of its existence?
Why is it thought to be repelled by gravity?

Answer1:

exotic matter is actually hypothetical and is believed to have negative mass , exert a sort of negative gravity i.e. opposite to properties baryonic matter.
and yes it is said to repel gravity.
It is purely hypothetical with no experimental proof yet.

Answer2:

physics has been a bunch of proved as well as hypothetical materials.
If there is STR, there is Aether wave theory!
if there is black hole , there is white hole and wormhole !
if there is quark , there is string !
if there is singularity , there is naked singularity !
if there is Quantum theory, there is string theory !
and the list goes on and on...
==
does it explain anything..
i think it is used for showing and exploring about negetive gravity and related things.
have a look here
http://en.wikipedia.org/wiki/Exotic_matter

Question2:

how can any matter be repelled by gravity, exotic or otherwise...after all, all particles must follw the path in spacetime as normal matter, how then will it be repelled?

Answer:

What wikipedia says:

http://en.wikipedia.org/wiki/Exotic_matter#Exotic_matter_in_General_Relativity