How did Einstein know the properties of space and time

[Niaboc67]

How did he figure out the many properties of the Universe such as time dilation/relativity and energy matter equivalence and his numerous other contributions. This might be a dumb question but was this all just done on paper? I don't recall reading that Einstein ever conducted experiments. Therefore, was it really just held in his mind and a pad of paper?

 

[phinds]

How did he figure out the many properties of the Universe such as time dilation/relativity and energy matter equivalence and his numerous other contributions. This might be a dumb question but was this all just done on paper? I don't recall reading that Einstein ever conducted experiments. Therefore, was it really just held in his mind and a pad of paper?

He had an amazing intuitive grasp of complex topics and did not himself do experiments (as far as I know) BUT much of his work was based on physics and math that had been tested empirically (particularly Maxwell's Equations) so I don't think your question has as simple an answer as you might like.

 

[Niaboc67]

He was going off others work which was proven and then used those to formulate greater ideas of the Universe? Fascinating how this was all in his head. Even more so with someone like Stephen Hawkins, where it is truly mental calculations of the Universe.

 

[k9b4]

By thinking about it a lot, thinking of possible models of reality, testing the models against empirically 'proven' models of reality to see if they make sense.

 

[Khashishi]

Einstein did a lot, but he didn't come up with everything himself. The math for special relativity mostly comes from Hendrik Lorentz' aether theory, which he developed to explain the null result of the Michelson-Morley experiment. So SR certainly has a basis in the MM experiment. GR, though, was pretty much all Einstein just reasoning it out, and was developed before the confirmation via Mercury precession measurements.