The Eternal Thing

The consequences of the special theory of relativity are Time dilation and Length contraction - let us try to understand a bit about them: Time dilation: When a body is traveling from one point to another in space at near light speeds, the body can arrive the destination in lesser time than what we generally (intuitively) expect. This is called time dilation. Below is an example: Assume that we are required to travel a distance of 5 light years. Even if we were to go at light speed, our intuition says it has to take 5 years. So we will be older by 5 light years upon reaching the destination. But it does NOT work that way. In fact, it is completely possible that we cover the distance in 3 years. So we will age 3 years only. Now, if we are covering a 5 light-year distance in 3 years - it may seem like we are traveling at more-than light speed. But this should not be possible right? Is this some kind of violation? No. So what's happening exactly here? Here comes the other consequence:...

Special relativity states that the light speed is always fixed. This was (and is) very counter intuitive to understand, but it is what it is.  For example, if you are going at a speed of 0.8c (c = speed of light) along the direction of light,  then the conventional (newtonian) physics says that the relative velocity between you and the light is 0.2c only! That light appears to go slower if you are travelling faster.  But special relativity says NO! Irrespective of our speed, we always measure the speed of light as 'c'. It's just that. Light speed never gonna change (in this universe). Also it's the maximum limit of anything that can move. Especially, if any particle has a mass (or to be more specific, rest-mass), then they can never reach speed of light. Now, see it in the other way around. If anything is going at less than speed of light, it should have a mass (again, rest mass) right? How about when light itself is slowing down?? Yes. Refraction. Does light gain mass ...