5. Introduction to General Relativity
Description
This article is from the Relativity and FTL Travel FAQ, by Jason W. Hinson jason@physicsguy.com with numerous contributions by others.
5. Introduction to General Relativity
Thus far, we have confined our talks to the realm of what is known as
Special Relativity (or SR). In this section I will introduce a few of the
main concepts in General Relativity (or GR). The difference between the two
is basically that GR deals with how relativity applies to gravitation. As it
turns out, our concept of how gravity works must be changed because of
relativity, and GR explains the new concept of gravity. It is called
"General" relativity because if you look at General Relativity in the case
where there is little or no gravity, you get Special Relativity (SR is a
special case of GR).
Now, GR is a heavily mathematical theory, and while I will try to
simply give the reader some understanding of the physical notions
underlining the theory, some mathematics will inevitably come into play. I
will, however, try to give simple, straight-forward explanations of where
the math comes from and how it helps explain the theory. I will start by
discussing why we might even think that gravity and relativity are related
in the first place. This will lead us to change our concepts of space and
time in the presence of gravity. To discuss this new concept of space-time,
we will need to introduce the idea of mathematical constructs known as
Tensors. The two tensors we will talk about in specific are called the
Metric Tensor and the Stress-Energy Tensor. Once we have discussed these
concepts, we will look at how it all comes together to produce the basic
ideas behind the theory of general relativity. We will also consider a
couple of examples to illustrate the use of the theory. Finally, we will
mention some of the experimental evidence which supports general relativity.
Continue to:
My Books
