Theory of relativity?

Question

Could someone outline the basics of Eintstein's theory of relativity? I'm not very good at physics so please try to be as general as possible.

Answer 1

Einstein proposed that, no matter where you are and how fast you are going, the observation you would do about the speed of light would retrun that it is travelling at the same speed.
The consequence of that is that there is no preferential area, no location that is better than another one for obeserving the universe. If I am moving that way and you are standing still, I can claim that I am the one not moving and that you are the one moving the opposite way, and that my claim that I am the one not moving is just as valid and your claim to be the one not moving. In a word, that all observations are relative to the position of the observer.

It gets a lot more complex when factoring gravity and acclerations, but that would be for next time.

Answer 2

How to explain the theory of everything simply, but that’s how my brain works so here goes. What do you use to measure a ruler, OK another ruler? But at some point you have to use some thing to measure everything else by. It's been seen the only thing that doesn't change when it's hot or heavy or moving fast etc. is light. With light as the starting point everything else is measured against it. Not a full explanation but read all the other answers they’re good. Then think if you do not want to use light which ruler would you use. Einstein’s first observation was along these lines. If a wagon is moving toward you and another rams it in the side why do we see the event happen for both at the same time. One you see at the speed of light plus the speed of the wagon, one you would only see at the speed of light. That might not make sense at first sorry but try to imagine now we see things. All happen relative to each other based on how far we are away not on the direction or speed of the object. Hope that helps it took me a while to visualise. Or you can watch “Red dwarf” and listen to Lister's explanation which is much better:-)

Answer 3

There have been a lot of books written on the subject, but actually, one of the most easily understandable (notwithstanding the maths) is Einstein's own book, 'The theory of relativity'. Give it a go. As others have said, the two theories, special and general, are completely different things. Anyone with fourteen-year-old maths can understand Special Relativity - it is based on a very very simple piece of maths called the Lorentz Transformation. Look up a simple explanation of this on Google - you will impress yourself and your friends when you have mastered it.
General Relativity is much more hairy, and you shouldn't worry about the maths unless you already have at least one mathematical degree. Basically it is a theory of gravity based on the geometry of spacetime. Massive objects, like stars and planets bend space, so that objects fall to Earth, not because of a force pulling on them, but becuase their straight line movement through space is bent round by the presence of the Earth curving space. There are no simple texts on this, but many of the pop-science books can give you a flavour of its effects.
If you have the will to find out, then you have the intelligence to understand it - don't give up, forget how bad you are at physics - interest is by far the best starting point. Good luck.

Answer 4

Well, this is just one facet of it, but time is different for everyone. It's a matter of perception. Time also is different depending onb how fast a body is traveling. The closer you get to the speed of light, the slower time goes. So if, for example, you got in a spaceship and flew somewhere near the speed of light around the galaxy for a few years, and came back to earth, then you would find that hundreds of years had gone by (maybe more, I'm not sure) while you only aged a few. That's just one part, though. The Theory of Relativity (and I don't think it's just a theory anymore, but I digress...) isn't really something you can explain on Yahoo Answers...

Answer 5

Theory of Relativity comes in two stages.

Stage 1 - Special Relativity

This deals with objects moving (but ignoring gravities effects) and the differences your 'frame of reference makes to moving objects'

Imagine a bouncy ball bouncing inside a glass box and the box is on a train. If you were on the train you would see the ball bouncing straight up and down.

However if you were standing on a platform and looked at the ball through the window you would see it following a triangular path (up and down as before, but yet moving with the train). Special relativity deals with the difference in the distance the ball has to travel in both instances).

These difference cause things to shrink or move slower the faster they move.

Stage 2 - General Relativity

An extension on special relativity to include gravity.

Einstein postulated that if you moved in a car with the correct acceleration then the force you felt on your back would be exactly the same as if you were in the same seat only lying back facing the sky.

He was then able to extend the theories and equations in special relativity to include gravity by usiing an appropriate acceleration to substitute gravity.

Answer 6

Lots of good answers about relativity, so can I be allowed a different take without causing offence? Newton's theories of motion and gravity are actually still quite a lot to take in and many, many people go through school without achieving a good grasp of them in theory or in practice, even though they explain the everyday world around us extremely well. It's as well to know that Newton's laws become inaccurate under some conditions, such as extremely high speeds (thousands of miles per second), and that Einstein formulated some new theories that account for this and restore accuracy. To those who are "not very good at physics" I would say leave it at that. But, for goodness' sake, understand Newton!

Answer 7

First of all there are two theories of Relativity. The special theory of Relativity is a theory that explains how different observers see things in the Universe. The general theory deals more with 'what is space' and 'how do mass and gravity affect things'. If you want a full description of the concepts and findings of relativity I would read some books first. It takes a lot of information to explain these theories without using any math.

Answer 8

Imagine a laboratory inside a train at rest. We measure the speed of light.

Next the train moves with some high speed. Now we measure the speed of light which is coming toward us. Again we get the same value.

Then we measure the speed of light which is moving away from us. Again we get the same value.


Whatever is our speed and which ever is the direction of light, we get the same value.

This shows that the speed of light is not affected by our speed.

This is possible only if the length and time in a moving train is reduced so to enable us to measure the speed of light as constant.

That is time and length is relative concepts. They change according to one’s speed; whereas the speed of light is an absolute value.

This is the basis for the theory of relativity.

Answer 9

Sure. The basics are that gravity exists because the mass of an object distorts the surrounding space. The speed of light is limited but if you were moving very fast you would still measure the speed of light as being the same because things shrink in the direction of motion. Mass contains a huge amount of energy. Those are the basics.

Answer 10

Lee is sort of correct, but very complicated.

In the late 1600s, there was a Dude call Issac Newton who sorted out lots of things with the world in terms of answers, with one or 2 tiny cracks.

Then in 1900s, there was another dude (an office Clerk) called Albert Einstein. Al evaluated all of Izzys ideas and re-arranged them, and came up with the General Theory of Relativity.

I don't have the time or will to re-type the maths he did, and few understand it anyway, but it is possible to explain the answers.

The major point of Relativity is that nothing can travel Faster than Light. Since time travel would require you to exceed the speed of light, time travel is impossible.

The parts include:
E=mc^2;
Curved Space;
The Mass of Light;
Time Warping;

Each of these components is an essay unto itself. There are other parts.

If there is a part of the Theory you are interested in knowing more on, you are advised to ask specifically about that part.