2
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0answers
57 views

About the speed of light

If Mr. E is aboard a spaceship traveling near the speed of light the usual reason for the spaceship not going faster than $c$ is the (relativistic) mass of the ship increases without bound, I think. ...
2
votes
2answers
60 views

Is speed of light ( Sun-to-Earth ) related to the movement speed of solar system?

The speed of light has been measured to be 299 792 458 m/s. Now, the Solar System is traveling at an average speed of 828,000 km/h (230 000 m/s). Summing up the numbers we get close to 300 000 000 m/s ...
1
vote
1answer
79 views

Does the light speed change in media? [duplicate]

Does the light speed change? The Theory of Relativity says that the speed of light in vacuum is the same and unchangeable, while I read that the speed of light in glass is lower than in air, and that ...
2
votes
2answers
105 views

What will be the relative speed of a photon in a light ray to another photon of opposite direction light ray?

If two light rays start simultaneously in the space from exactly opposite ends in opposite direction that is separated by a distance of 600000 km in a way they meet at the mid point (300000 km from ...
0
votes
3answers
60 views

Question about relative speeds on a different “scales of perception”

I was kind of puzzled yesterday when thinking about this. If we observe an object moving away from us with 10m/s we would say the object is moving away from us really slowly But if we (humans, ...
0
votes
2answers
194 views

Nothing can travel faster than the speed of light. In what frame of reference? [duplicate]

Since frames of reference are arbitrary, I can define a frame of reference that moves backwards with a speed greater than $c$, then any static object in that frame of reference is already traveling ...
1
vote
3answers
186 views

Why Sun light can reach us if Time is dilating?

I understand that if something is moving with constant speed in respect to an observer, the time of the moving one runs slower, so the more your speed is, the more your time ticks slower. Which ...
3
votes
4answers
250 views

What does 99.9% speed of light mean when there is no absolute velocity?

So when people say: 'I am approaching the speed of light, and to get to 100% light I would need infinite energy' they are essentially saying that this situation is impossible? I read this in ...
3
votes
3answers
192 views

Speed of light travel

I have just started special theory of relativity. The limiting speed known as speed of light fascinated me most. I asked my teacher: Consider two massless objects moving in the same direction at ...
1
vote
0answers
45 views

Clocks tick steadily, so why is there no photon time? [duplicate]

Consider a photon bouncing left and right between two mirrors in a photon clock. Seen from inside the clock, the photon bounces at a constant frequency. Time ticks regularly. No matter whether the ...
0
votes
1answer
110 views

What is the significance of Einsteins postulate on speed of light?

Einstein postulated that the speed of light in free space is the same for all observers, regardless of their motion relative to the light source, where we may think of an observer as an imaginary ...
1
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2answers
142 views

Variance in speed of light

While discussing this question (Does light have an unending journey?) I stumbled on the fact that light's speed is constant only in inertial frame. What I happened to do was add up the expansion of ...
-2
votes
1answer
126 views

What do subatomic particles look like for a 'speed of light - observer'?

Let's say that an observer is moving with the speed of light relatively to an atom that he wants to look into. He has equipment that precise that he can observe the atom and what is inside. From ...
6
votes
3answers
395 views

The reference frame of $c$

I don't have a lot of knowledge of special relativity and associated topics; some of the few things I know are that "all motion is relative" (that is, there is no 'stationary reference frame'), and ...
3
votes
2answers
330 views

If I travel close to the speed of light and come back, why is everyone else dead, and not me? [duplicate]

Consider the following scenario: I get in a spaceship, and travel really close to the speed of light for a while, and then come back. A lot of time has passed on the Earth, but since I was traveling ...
0
votes
1answer
358 views

Frame of reference of the photon? [duplicate]

In the frame of photon does time stop in the meaning that past future and present all happen together? If we have something with multiple outcomes which is realized viewed from such frame? Are all ...
0
votes
2answers
120 views

Relative to the speed of light

Einstein's relativity tells us that light always travels at the speed of light relative to me, no matter how fast I'm going. Right? This really confuses me though. If light travels from A to B in one ...
4
votes
1answer
136 views

Quantum Mechanical Effects of an object accelerating near speed of light $c$?

Consider a space ship, undergoing constant acceleration (which for our purposes means that the same amount of energy is being used per second to increase its speed). According to special relativity ...
0
votes
3answers
190 views

Stuff can't go at the speed of light - in relation to what? [duplicate]

We all know that stuff can't go faster than the speed of light - it's length becomes negative and all kinds of weird stuff happens. However, this is in relation to what? If two objects, each moving ...
1
vote
3answers
240 views

Special Relativity - speed of light question

Just a basic question: I know that if you are traveling at $x$ speed the time will pass for you slower than to an observer that is relatively stopped. That's all just because a photon released at the ...
0
votes
0answers
115 views

About the theory of relativity

Why is speed of light constant in every non inertial frame of reference? Is there any theoretical explanation behind this postulate Since we cannot completely depend upon the experimental results?
0
votes
0answers
95 views

Determining Ether Drag - Aberration of Starlight

In order to determine the relative motion between the Earth and the ether (the medium through which light supposedly propagated. It has zero density and complete transparency), scientists used the ...
-3
votes
1answer
110 views

How would time duration and space distance change when we move in the speed of light? [closed]

It is possible to figure out how time duration and space distance change when we are close to the speed of light - but I am not sure what happens to them if we travel in the speed of light.
0
votes
1answer
187 views

What is the maximum time dilation between two objects, if one is standing still and the other is moving at $c$?

What is the maximum ratio in the rate of change in time in reference to object $A$ which is standing still and object $B$ which is moving at the speed of light?
0
votes
1answer
174 views

Speed of light in a given direction based on frame of reference [duplicate]

Possible Duplicate: How is the speed of light constant in all directions for all observers? Is the speed of light constant regardless of frame of reference? If not, why is it still measured ...
6
votes
4answers
2k views

How is the speed of light constant in all directions for all observers?

Please imagine the following thought-experiment: Order of Events: Pulse - A single pulse of light is emitted from the light towards the mirror Reflect - The pulse hits the mirror and is ...
1
vote
1answer
906 views

Calculating the speed of an object moving relative to another moving Object (Frame of reference) [duplicate]

Possible Duplicate: How to deduce the theorem of addition of velocities? Let's say that you are in a rocket speeding at 90% the speed of light away from Earth. Now fire a bullet inside the ...
14
votes
2answers
545 views

What does a sphere moving close to the speed of light look like?

What shape does the viewer in a reference frame with $v=0$ perceive? I suppose that since the sphere moves in one direction only (oX only, not oY) its section would change into an ellipse, where the ...
3
votes
1answer
272 views

Is a preferred reference frame of the universe the old aether?

About two years ago I posted a question about a symmetrical twin paradox: Here. Recently a new answer was posted and an intense discussion ensued: Here. One of the points discussed concerns a ...
-2
votes
1answer
125 views

Faster than light due to reference position [duplicate]

Possible Duplicate: Travelling faster than the speed of light Please try to follow and clarify me I've been curious about this for a long time as it seems a bit paradox due to the rule that ...
0
votes
1answer
754 views

Two trains at the speed of light [closed]

Okay. Two trains travelling towards each other at the speed of light. So, from one train (let's call it train A), the other is moving towards it at the speed of light. The other train shines a torch. ...
2
votes
6answers
594 views

Does the (relativistic) mass change? Why?

I learned recently that when an object moves with a velocity comparable to the velocity of light the (relativistic) mass changes. How does this alteration take place?
10
votes
2answers
1k views

Does the speed of light vary in noninertial frames?

The speed of light is the same in all inertial frames. Does it change from a non-inertial frame to another? Can it be zero? If it is not constant in non-inertial frames, is it still bounded from ...
1
vote
1answer
226 views

What is the speed for an object that travel close to the speed of light?

I have some questions regarding Einsteins theory of Relativity that should be fairly easy to answer. Lets say we make an experiment where we have a rocket (with an astronaut inside) that travels very ...
-1
votes
3answers
225 views

Does the Lorentz transformation not apply to light?

Since you would know that light always travels at the constant velocity with respect to all frame of reference ....according to relativity whenever we are traveling at speed of light our time with ...
-1
votes
1answer
283 views

Time dilation at the speed of light

Does a massless particle travelling at the speed on light in a vacuum (c) experience an infinite time dilation effect? i.e. Would the time dilation extend from the perspective of the massless ...
11
votes
6answers
14k views

Would time freeze if you can travel at the speed of light?

I read with interest about Einstein's Theory of Relativity and his proposition about the speed of light being the speed limit for anything with mass. So, if I were ...
8
votes
3answers
2k views

Is a photon “fixed in spacetime”?

From what I've read, according to relativity, a photon does not "experience" the passage of time. (Can we say there is no past/present/future for a photon?) Would it be better to say a photon is ...
0
votes
1answer
164 views

What would happen to electronic circuits when traveling near the speed of light?

Imagine a space ship, loaded with all sorts of computer systems, traveling near the speed of light. Electricity itself is very fast, and can reach speeds close the speed of light. (up to 99% ...
5
votes
2answers
785 views

Einstein's Gedanken Experiment that lead to the Special Theory of Relativity

Once, I read that Einstein founded the special relativity theory by imagining how an observer moves at the speed of light. How does this thought experiment work? How to reach from this imagination to ...
12
votes
3answers
1k views

Does a photon in vacuum have a rest frame?

Quite a few of the questions given on this site mention a photon in vacuum having a rest frame such as it having a zero mass in its rest frame. I find this contradictory since photons must travel at ...
10
votes
6answers
5k views

Why and how is the speed of light in vacuum constant, i.e., independent of reference frame?

I was told that the Galilean relative velocity rule does not apply to the speed of light. No matter how fast two objects are moving, the speed of light will remain same for both of them. How and why ...