How did Einstein come up with the theory of relativity?

Question

I want to know more. Why would he have guessed that. Was there any previously existing evidence to suggest that? Or was it just a random spark of intuition?

Answer 1

He had a lot of relatives.

Answer 2

Supposedly, he was day dreaming about what it would be like to ride on a wave of light. Supposing you were moving right along with it, what would the front of a wave of light look like?

From this, he jumped to the idea that the speed of light might be constant regardless of your own speed, which is core to the Theory of Relativity.

Answer 3

Your guess is as good as mine ...

Answer 4

The first post is almost correct.  Einstein did one his famous thought experiments in which he enivsioned himself sitting on a photon.  He then asked what would the electromagnetic field of the photon look like (all light - photons - is a propagating electromagnetic wave).  If you are at rest relative to the photon, you see it has a electric field and amgentic field both of which vary in space and time according to Maxwell's equations with no sources (charges or currents) present.  Now if you sit on the photon, you'd see a time varying magnetic filed and a time varying electric field but without any sources for either field.  This violates Maxwell's equations.

When he reached this conclusion, Einstein postulated that the laws of physics have to remain unchanged even if a person if in relative unioform motion to some one else.  Maxwell's equations have to be valid regardless of whether I am moving or stadning still relative to you.  That postulate leads to the derivation of special relativity, which in turns makes it impossible for a particle (or person) to accelerate from a sulight speed to the speed of light.