Is quantum gravity a main stream science? AFAIK it has not been tested yet but, the literature is full of it, almost as if it is factual.

Yes, there are three main approaches to the subject, outlined in Lee Smolin's book ``Three Roads to Quantum Gravity''. Every physics department with a decent graduate program (in America, at least) has at least one or two string theorists. This is the most popular way to get gravity to work.

The next most popular approach is the old Euclidean approach, used by Hawking and others. Most of those people moved to string theory in the early nineties, though.

Finally, Smolin and a few others have been touting Loop Quantum Gravity for quite a while. From what I know of Loop Quantum Gravity, I don't really like it. For example, they tend to sacrifice things like Lorentz Invariance. But I don't really know too much about the field, so I am not in a position to judge the work.

It's a legitimate research topic in physics, if that's what you're asking.

Ben, i am sure you are in a better position to judge the feelings of the scientific community, as an out sider i can only go by gut feelings, and they do not empathise to QG.

Well---some scientists would agree with you. The fact is, we need to find a way to test it before it is REALLY considered science.

It's a legitimate research topic in physics, if that's what you're asking.

Not so much legitimate, but why it carries so much clout, it is not as if it is a pure line of research, it seems to morph in an attempt to fit known testable
results, not that this is wrong, just the original idea did not fit.