Question

what is theory of relativity which discovered by Albert Einstein?

Answer 1

In 1905, Albert Einstein determined that the laws of physics are the same for all non-accelerating observers, and that the speed of light in a vacuum was independent of the motion of all observers. This was the theory of special relativity. It introduced a new framework for all of physics and proposed new concepts of space and time.Albert Einstein, in his theory of special relativity, determined that the laws of physics are the same for all non-accelerating observers, and he showed that the speed of light within a vacuum is the same no matter the speed at which an observer travels. As a result, he found that space and time were interwoven into a single continuum known as space-time. Events that occur at the same time for one observer could occur at different times for another.

As he worked out the equations for his general theory of relativity, Einstein realized that massive objects caused a distortion in space-time. Imagine setting a large body in the center of a trampoline. The body would press down into the fabric, causing it to dimple. A marble rolled around the edge would spiral inward toward the body, pulled in much the same way that the gravity of a planet pulls at rocks in space.

Answer 2

HEY FRIEND
First of THEORY OF RELATIVITY was not something that was discovered by Einstein but he made the theory of relativity .
He took out a paper in 1905 that stated the theory of special relativity (that has an equation E=mC² which is one of the most famous equations of the world) in theory of special relativity Einstein proved that the speed of light in vacuum was same for all non accelerating observers.(this is just a part,there are many other things that I have not stated)
And in 1915 came his paper on theory of general relativity that proved the definition of gravity Newton gave wrong . But the reason u still read Newtonian gravitation physics because it's simple !!!! Einsteinian physics is way more complex and difficult .
HOPE THIS HELPS
(this is just the tip of an iceberg there are many definitions like Lorentz transformation , time dilation which are way to complex for a student if u want to study these things wait till college cause then u have a lot of free time but speaking from experience don't study this now if u are a student or u will definitely affect your studies)