Super Gravity Theory

[Royce]

I'm reading a book by Hawking and Penrose. I'm afraid it is a bit beyound me; but, I am getting the jist or is it jest of their thoughts, I think. In the book Hawking memtioned the Super Gravity Theory. I've run across it before but don't know what it is. Can someone briefly and basically explain it to me? One of the other of the many things I'm not sure about that is mentioned both in the book and here in this forum in other threads in "The Metric."
Can someone define the metric again briefly and basically to me?[8)]

[garytse86]

does it combine relativity with quantum mechanics?

[Royce]

Don't know. The book is "The Nature of Space and Time." It's is a dialog of lectures about singularities and certainly involves relativity and Quantum Machanics.

[instanton]

In nut shell SUGRA is a kind of gauge field theory with many different fields combined as a one field, called super-multiplet. "super" is from the fact that the theory has a property called supersymmetry - it is a symmetry between fermion and bosons. "Gravity" part is from the fact that the theory has graviton in it. There are many different kinds of possible SUGRA. Arguably the most beautiful one is 11 dimensional SUGRA for its mathematical beauty and uniqueness. Also, recently it is considered as a low energy limit of not-yet -known M theory.

Instanton