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### What happens with time when we travel at the speed of light? [closed]

I always wonder how time is related to traveling at the speed of light and what actually happens when we travel at the speed of light. Why does time slow down and what can be the physical explanation ...
90 views

### Why does the speed of light in vacuum never change? [duplicate]

why does the speed of light in vacuum never change? Under any circumstances, The speed of light in vacuum never change, why?
220 views

### Why is the speed of light in vacuum a universal constant? [duplicate]

While getting familiar with relativity, the second postulate has me stuck. "The speed of light is constant for all observers". why can't light slow down for an observer travelling the same direction ...
72 views

### Holding the total velocity below speed of light

If a hydrogen atom accelerates to near the speed of light, the total velocity of the system must not exceed that limit. Even if the electron has no net angular momentum around the proton, as it could ...
3k views

### Why Speed of light in vacuum remains constant? [duplicate]

I know that the speed of light remains constant irrespective of whether the light source is moving or not. But it's very difficult for my brain to visualize it. Light has dual characteristics, i.e. of ...
157 views

### We all accept/believe in $c$. But what happens when light travels away from the center of gravity of a heavy star? Does it slow down?

I'm basically trying to understand a mysterious characteristic of the universe. Why light has to travel at $c$? I understand and accept that from experiment. Not arguing that it does not. Just saying ...
127 views

### Is a finite lightspeed necessary for cause and effect to exist? [duplicate]

In this question I asked in somewhat unclear (unclear enough to be closed) fashion about the relationship between an infinite speed of light and the existence of cause and effect. In thís question, I ...
1k views

### Is the second postulate of Einstein's special relativity an axiom? [closed]

I'm trying to grasp Einstein's special relativity theory and can't seem to find a clear answer as to why Einstein concluded that the speed of light is constant to observers in different inertial ...
5k views

### Can a photon get emitted without a receiver?

It is generally agreed upon that electromagnetic waves from an emitter do not have to connect to a receiver, but how can we be sure this is a fact? The problem is that we can never observe non-...
436 views

### Light cone argument for speed of light

Using light cones to state that nothing can travel faster than light to me seems like a flawed argument. (I understand other reasons why the speed of light cannot be broken.) However, it seems to me ...
219 views

### Why a body can not be accelerated to speed of light in vacuum? [duplicate]

Well i know that it needs infinite energy..but the term infinite is itself not physical so i am not satisfied with this answer ...but what would happen if we provide a constant acceleration to an ...
179 views

### Different approach of time dilation explanation

Suppose you are going to a distant star, and there is an observer on earth. Usually the answer to the question how long would it take to travel to a distant star is explained this way : You cannot ...
14k views

### Can Newton's laws of motion be proved (mathematically or analytically) or are they just axioms?

Today I was watching Professor Walter Lewin's lecture on Newton's laws of motion. While defining Newton's first, second and third law he asked "Can Newton's laws of motion be proved?" and according ...
When we derive gravitational potential it is dependant only on (rest) mass $m$, but i have seen a derivation of gravitational redshift equation placing relativistic mass $\widetilde{m}$ instead of ...