35 questions linked to/from (Almost) double light speed
11k views

### Breaking the speed of light relative to a moving object [duplicate]

You can't go faster than light, and light can't be additive (if you shine a light from a spaceship, the light is not going $c$+"speed of spaceship", it's just going like it always does). But what ...
10k views

### What is the relative speed of two near-light speed particles headed towards each other? [duplicate]

I understand that nothing can move faster than light due to time dilation. I want to build upon my understanding of Einstein's theory of Special Relativity, so I came up with this hypothetical problem ...
495 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 ...
591 views

### Speed of light paradox [duplicate]

If I send two rockets from the Earth in opposite directions, at, say, 60% of the speed of light relative to the Earth, then relative to each other they are travelling at 120% of the speed of light. ...
527 views

### Something almost faster than light traveling on something else almost faster than light [duplicate]

Possible Duplicate: Travelling faster than the speed of light Double light speed Lets say that an airplane can fly at 4/5 of the speed of light, and I can run at 2/5 of the speed of light, and ...
368 views

### Relativity and speed of light again - two opposite light sources [duplicate]

Two light sources emit light at the same moment but in opposite directions. At what speed the distance between two light fronts is increasing? c or c * 2? Note, that there is only one coordinate ...
204 views

### Driving car with (almost) the speed of the light and switch the headlights on [duplicate]

I'm curious what will happen if we 'drive' a car with (almost) the speed of light, and all of sudden we switch the car headlights on? Will the car headlights ray have double speed (speed of 600.000km/...
200 views

### Relative speed when approaching the speed of light [duplicate]

According to this chart of the Lorentz factor as a function of speed: If a spacecraft neared (roughly) 0.85c, would it appear to be traveling at 1.7x the speed of light from the perspective of those ...
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### Can relative speeds be greater than the speed of light? [duplicate]

I am trying to wrap my mind around special relativity and I have these questions: If I am moving at 70% of the speed of light (relative to the ground) to the right, and my friend moves at 70% of the ...
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### Speed of light and headlight [duplicate]

What will happen if you drive a car at the speed of light and keep headlights on? Will it be behind the car or just work like normal?
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### Reaching the speed of light, rockets [duplicate]

Possible Duplicate: Double light speed Someting almost faster than light traveling on something else almost faster than light Well I've been wondering quite a long time about this problem. If ...
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### Can relative velocity of a particle exceed the speed of light? [duplicate]

Consider two particles (having same mass) moving with constant velocity very close to speed of light, say $0.99c$ in opposite directions. Will the magnitude of their relative velocities exceed the ...
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### what does it truly mean for there to be a max speed? [duplicate]

Firstly, I apologize if this is the wrong place to post this question; I'm not a scientist, just curious. So: if the speed of light (299 792 458 m/s according to Google) is an absolute limit even for ...