Relativity: Changes & Extensions - 3 Questions Answered

[ShayanJ]

Hi people

I have three questions about relativity
1-Is the Relativity used now different from the one proposed by einstein?If yes,what are the changes?
2-Is Kaluza's theory accepted and being used now?
3-Is there other extensions to relativity like Kaluza's theory?What are they?Which of them is accepted and being used now?

thanks

 

[phyzguy]

I would answer these as follows. Others may have different answers:

I have three questions about relativity
1-Is the Relativity used now different from the one proposed by einstein?If yes,what are the changes?

Much work has been done since Einstein's time, and many things are much better understood, especially in General Relativity. Black holes, cosmology, and gravitational waves are three examples of things that are much better understood today than they were when Einstein proposed the theory. However, the basics of both Special and General Relativity have not changed, and have passed every experimental test to which they have been subjected.

2-Is Kaluza's theory accepted and being used now?
3-Is there other extensions to relativity like Kaluza's theory?What are they?Which of them is accepted and being used now?

Kaluza-Klein theory, as originally proposed, is not believed today to be a correct theory. String theory, however, is the logical extension of Kaluza-Klein theory. String theory postulates multiple hidden dimensions instead of the one hidden dimension postulated by Kaluza-Klein theory. Whether these theories will ultimately turn out to be the desired "Theory of Everything", is still an open question. Many people have worked on this, but there is today no consistent theory that describes the other forces of nature in a geometric way, as General Relativity describes gravity.