This is my understanding of Relativity, based on the books I have read on this subject. I don’t claim to be an expert. I find the subject very intriguing and have done a bit of reading on it.
Relativity is based on the premise that there is no such thing an absolute motion. Everything in the universe is moving only relative to something else. This idea has been discussed so much that it seems pretty obvious now. At the time it was postulated, it was a paradigm shift from the Newtonian concept of absolute rest and absolute motion. Another corollary of relativity is that there is no way of knowing whether we are at rest or motion. If you are traveling in your car and you see things wiz past you, it is equally correct to say I am stationary and the things outside are moving.
When we get to the speed of light we can drive some absolutely mind blowing corollaries based on these two assumptions. Let us say you are in a room and the room is moving at the speed of light. You should not be able to see the wall of the room because reflected light from the walls will never reach your eyes. (We see object, because the light from the object reaches us). At this point, the theory of relativity should break down. You will be able to conclusively claim that you are moving. Einstein says that the speed of light would remain the same for a person(observer) in motion and rest, it will never change relative to any object. You can actually see your carriage walls and hence will not be able to say whether you are at rest or at motion.
* We know that speed is a measure of the distance traveled in time.
* We know the speed of light cannot increase
* It will have the same speed even in a moving object (it will not increase or decrease relative to the speed of the moving object)
What do we have now? The only other parameter that can change in this equation is time. So if the speed of light has to remain constant in a moving object, time has to slow down. This is the only way the distance traveled would remain the same in time.
Isn’t it a quantum leap in thought – begin with motion being relative and end up slowing down time.
My first knowledge of the slowing down of time was from Cosmos teleserial of Carl Sagan. I still vividly remember the scene of twin brothers; one travels in the space ship and the other is left behind. When the twin brother returns from his journey he finds his brother very, very old. I always resented being the eldest child and thought this was one sure way of getting to be the youngest 🙂
I will let you mull over these facts in relative time until my next post.
Albert Einstein by Dr Mike Goldsmith
Brief History of Time by Stephen Hawking
Theory of Everything by Stephen Hawking