Einstein's Theory Of Special Relativity

The biggest equation to come out of Einstein's theory of special relativity is E = mc^2, which tells us how E, the energy, M, the mass, and C, the speed of light, are related to each other. This mass we are using is not the same as weight. An object's mass is how much stuff is inside of it, while its weight is how hard gravity is pulling on it. This is why when you measure your weight in outer space, it is close to zero.
Einstein's theory states that, the speed of light becomes a sort of ultimate speed limit. In fact, objects with mass, be they cars or neutrinos, can't reach the speed of light because they would need infinite energy to do so, according to the theory.
According to Einstein, when objects approach the speed of light, time for
them seems to slow down when measured by an observer that is not moving. Also, when measured by an observer, objects traveling at a faster speed will measure shorter than if the objects weren't moving with respect to the observer. For example, I'm sitting on my front porch, and I'm watching cars drive by me. The faster the car is driving by, the shorter the car will look to me. Also, the faster the driver is driving, the slower time will seem to pass for him when compared to me. As an object gets close to the speed of light, time will seem to stop, and its length will seem to shrink to nothing.