Thread: Relativity

I am having trouble understanding general relativity and special relativity. I know they are important and play a part in understanding physics. I think some people have said it's simple, but I can't find a simple, exact definition. Can anyone explain general and special relativity, please?

A good (but fairly long) explanation of special relativity can be found here:

http://www.thescienceforum.com/physi...ty-primer.html

I have not taken the time to read the whole thing.

Welcome to the forums!

I know you don't like wikipedia, but I found a good quote from it that I think gives you a general idea of general relativity:

"According to general relativity, objects in a gravitational field behave similarly to objects within an accelerating enclosure. For example, an observer will see a ball fall the same way in a rocket (left) as it does on Earth (right), provided that the acceleration of the rocket provides the same relative force."

This goes along with an image:

400px-Elevator_gravity.png

Thanks a lot! That was really helpful, but I have another question. What's the difference? That excellent thread explained special relativity, but it didn't explain general and I don't know the difference or what general relativity is at all. Any answers?

Never mind my last post because I posted at 2:39 just after you posted so I didn't realize you posted. Thanks! Is your post at 2:34 general relativity?

Yeah, that's about general relativity. Also, I should have mentioned in my first post that in general relativity, energy bends spacetime in order to cause gravity to happen. Here's a video describing it:

http://www.youtube.com/watch?v=0rocNtnD-yI

Thanks Fen-man! (Fenlon/Feynman)