Why is it that Einstein's theory of general relativity is so complicated?? Also, what does it state????

Question

I mean, I asked my science teacher and he said that he only partially understood the theory. So it made me wonder whether this so called theory is perhaps the hardest there is or something. Still, he described the theory partially and I was very intrigued and interested. It's amazing that space is so complex and "out of this world".

LAST THING!!!!! Do you know at what college level physics course you actually cover this theory in detail?

Answer 1

Basically the main observation of the theory stars that a massive body causes a warping of space, this was proved in an experiment. Newton's laws are still valid but Einsrein's refinement explains the slight anomalies of some planet's orbits.

Answer 2

In essence, the GTR says that there is no essential difference between an accelerating reference frame, and a reference frame that's in a gravity field.  A couple of main consequences of this are:

1. Anything that you would predict to happen inside an accelerating elevator (or space ship, etc.), such as light bending, time slowing down, etc., you ought also to see happen in a gravitational field. [and in fact you do, as experiment shows.]

2. When you accelerate, you put a dent in spacetime (just because of your changing motion).  Therefore, anything that acts like an accelerating reference frame (i.e. gravity) can be viewed as "simply" a dent in spacetime, rather than as a "force."

The basic idea behind GTR is fairly simple, but the mathematical details are horrendously complex.  As far as college courses go, you will probably not find an _undergraduate_ course that covers GTR in detail.  I have a B.S. degree in physics, and although we studied the _special_ theory of relativity in pretty good detail, we kind of just glossed over the _general_ theory.

Answer 3

GR is the relativistic theory of gravity.  It is motivated by the assumption that the pseudo-force you experience in an accelerating reference frame is equivalent to the force of gravity, and then works out all the consequences of that in a way consistent with special relativity.

It's complicated because it takes a lot of differential geometry to derive and interpret the final result--Einstein's field equations.  The force of gravity is modeled as a bending of time and space by energy.  But you can understand some of the simpler consequences of GR (like gravitational time dilation) without going that deeply into it.

Some colleges will offer an undergraduate elective in GR.  They'll probably teach it out of a book like Hartle, and won't go into too much detail in one semester.  Most physicists take it in grad school (if they take it at all--except for cosmologers, some astronomers, and the small handful that specifically study gravity, it's not terribly useful)