why and how does Einstein's theory of relativity say that no object can exceed beyond the speed of light

Einstein's theory of relativity, specifically the special theory of relativity, states that no object can exceed the speed of light. Here's why and how:

1. The Speed of Light is Constant: One of the two postulates of special relativity is that the speed of light in a vacuum is constant, regardless of the motion of the light source or the observer. This means that everyone, no matter how fast they are moving, will always measure the speed of light to be approximately 299,792 kilometers per second.

2. Time Dilation: As an object moves closer to the speed of light, time begins to slow down relative to a stationary observer. This is known as time dilation. If an object were to reach the speed of light, time would stop completely from the perspective of a stationary observer.

3. Mass Increase: As an object moves faster, its mass effectively increases. This is due to the object's kinetic energy adding to its total mass. As an object approaches the speed of light, its mass would become infinite.

4. Infinite Energy: To accelerate an object with mass to the speed of light would require an infinite amount of energy, according to the equation E=mc^2, where E is energy, m is mass, and c is the speed of light. Since we can't supply an infinite amount of energy, we can't accelerate an object with mass to the speed of light.

So, in summary, Einstein's theory of relativity says that no object can exceed the speed of light because doing so would require an infinite amount of energy, cause time to stop, and increase the object's mass to infinity.