Expert: Paul Wagner - 6/2/2004

Question
Hello sir,
My name is anup & I want to ask you very baffling questions.

1)If a train on the earth moves with light speed keeping itself on the earth's
 surface then what speed of train would a person on the sun measure?

2)For someone on the sun,the earth & the train would be revolving around the sun
 itself with the same speed.Now what distance would both earth & train
would travel in space?Would it be different?What does relativity say?
Please explain.

3)Mass/gravity bends space,so light rays around the sun follow curve path in 3D.
although they travel straight path in 4D.So what matter is present there between
the sun & the curve space?Is it fully empty?can any one be able to see
that space without light rays entering there?is that absolute space or
dynamic?what amount of force would be required to enter there if light cann't enter there ?

4)Is there any completely isolated matter present in our universe,which
 will not be affected by any force not even by space-time?It will be
 fixed & completely absolute.Could it be center of our universe?


Answer
Dear Anup;

I was not quite serious enough in my answer to #4--so have revised it.

1. The person on the sun would measure the Earth at its normal velocity...but the train, if it could be measure separately, would have a completely different speed. WE see this in stars which spin very quickly---the star itself is moving at one speed, but the rotation of the star means that some parts appear to be moving towards us, other parts away from us....

2.  In simple terms, the Earth would be moving in a simple orbit, the train would be moving much farther,on a spiral track that follows the path of the orbit.  I don't think this has to do much with relativity...although even if you combine velocities,. you can never go faster than the speed of light.

3.  There is no matter between the sun and the curve of space...the sun is part of that space.  The matter in that space is curved, because space itself is curved.  

4.  Maybe.  Have you found it?  I don't know of anything that meets this criteria....How would you detect it?  I you cannot detect it in any way, how can you know it exists?  

Paul Wagner