@Freak

Quantum gravity is a field of physics which has the sole purpose of uniting quantum physics and general relativity or explaining why things like the quantum wave function do not apply to larger objects than just photons and atoms and things, currently there are 2 large theories that attempt to unite the quantum and general worlds, they are:

M-Theory (String Theory)
Loop Quantum Gravity

1. M-Theory
You all probably have a general knowledge of what string theory is and some of the things that it implies, but since some of you don't I'm going to explain all of it.  String theory states that all of matter and energy is actually made up of really really tiny "strings" of energy each of which is probably over 100 million times smaller than an electron; the ways that these little bands of energy vibrate decide the properties of the things they make up.  The theory would by far be my very favorite theory and most likely that of every other physicist there is if it weren't for a few things, the reason physicists would probably like this theory to be proven is because it has so many parts of it that would further physics so much if it could be true, even the bizarre things that make me doubt it i want to be true because of how useful they would be!  First of all string theory is a contender of being a theory of everything, meaning that if it could be proven it would successfully unite all of the forces to be considered manifestations of 1 single force, which a lot of physicists are striving to do, not only does it unite the forces we currently know (electromagnetism, weak nuclear force, strong nuclear force) but it added in gravity and manages to explain how it actually works! we all know that all matter attracts all other matter, but one thing you might be shocked to know is that we don't actually know [i]why[/i] matter attracts other matter.  string theory states that there are particles much smaller than electrons (but not as small as strings) called gravitons that puts out a field that attracts other gravitons, and gravitons are present in all matter. These things make string theory sound like the best thing in the world! however there are some other things that aren't so perfect...  such as: after further analysis of some of the math and stuff that is produced from string theory it turns out that there would need to be 11 dimensions of space, which by looking around you you can see there are only 3, does this disprove string theory? no! because apparently the extra dimensions are tied up and looped around the dimensions that we currently have so we cant see them.  Apart from that sounding a little too convenient, there's really no way to test this so we cant disprove it... that's pretty much a common thing in string theory, every time they come up with a new explanation it turns out to be virtually untestable.  I don't mean to make fun of string theory, i complimented it a lot, and if it could be proven i would be very happy, however we must face facts that its a little far fetched.

2. Loop Quantum Gravity
Loop Quantum Gravity is based on the idea that space-time itself is a "fabric" made from small loops of excited gravitational fields, put together these are called spin networks.  by this method it manages to preserve all of the important parts of general relativity and quantum mechanics. though Loop Quantum Gravity is much more rational than M-Theory in a lot of places, it is only a unification of the quantum and general worlds, it is [i]not[/i] a theory of everything, which is not a big deal breaker because technically even though it is a dream of physicists to create a theory of everything to unite the forces, there is no actual reason why they should be, it was just thought to be convenient. LQG doesn't say that there [i]can't[/i] be a way to unite the forces, it just lacks one.  This is the theory i currently believe to either be correct or the closest to the truth just because it seems a lot more reasonable than its contender String theory, because it is testable, and because it has actually had a multitude of successes, such as equations for useful things like entropy of black holes.  


There are other theories of quantum gravity, however these are the most famous, and if i included all of them it would have made for A LOT of writing since there's like 50 of them, but if you wish to learn about others, some of the theories or other related things are:
Causal Dynamical Triangulation
Supergravity
Regge calculus
Causal Sets
or you can just Google " Quantum Gravity", here!   http://lmgtfy.com/?q=Quantum+Gravity

for more talk about physics topics and things please visit the new darchoods irc channel #quantum