Speed of Light?

Question

If you are travelling at the speed of light in a car, and you switch on your headlights - would you see the beam?

Answer 1

Please don't listen to the first 3 posters. The speed of light is a relative constant. In other words, if you were traveling at the speed of light, and then turned on a flashlight, the beam of light from the flashlight, to you, would look like it is going the speed of light away from you. However, to a stationary observer, it would look like it were traveling the same speed as you.

So yes, you WOULD see the beam of light, and it WOULD be going the at the speed of light away from you.

Most individuals are accustomed to the addition rule of velocities: if two cars approach each other from opposite directions, each traveling at a speed of 50 km/h, relative to the road surface, one expects that each car will perceive the other as approaching at a combined speed of 50 + 50 = 100 km/h to a very high degree of accuracy.

However, at velocities at or approaching the speed of light, this rule does not apply. Two spaceships approaching each other, each traveling at 90% the speed of light relative to some third observer between them, do not perceive each other as approaching at 90% + 90% = 180% the speed of light; instead they each perceive the other as approaching at slightly less than 99.5% the speed of light.

*Thanks for the thumbs down for a correct answer.*
http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970102c.html

Answer 2

What is up with you people? If you do not know the answer, kindly desist from making **** up.

The speed of light is a invariant--- meaning it is measured to be the same by ALL observers. If you are traveling at nearly the speed of light (relative to someone on the side of the road I suppose) and you turn on your headlights, you will see the light beams travel in front of you at 30 billion meters per second, just like normal. The guy on the side of the road measures the speed of your light flash as 30 billion meters per second. EVERYONE measures the speed of the light flash as 30 billion meters per second.

Answer 3

You cannot travel at the speed of light because you have mass and it takes an infinite amount of energy to reach the speed of light. Light has no (rest) mass.
To qualify...if you were in a rocket going 99.99% the speed of light, then to you, everything inside your rocket is moving with you. I say 99.99% the speed of light, but actually it is relative to what? The earth is spinning about it's axis while rotating around the sun which is rotating around the galaxy, which is rotating around it's galaxy cluster and yet we think we are not moving. Motion is relative to something. It is not absolute. If you were going 99.99% the speed of light relative to say, the sun (yes, professor Wheeler I said THE sun), and a ray of light from outside your rocket made it's way through your window so that you could measure it's speed, you would measure 299 792 458 m / s. You would mesure that speed no matter what constant velocity you have. That number does not change (in a vacuum). But if your rocket is traveling towards the source of light, the energy of the light would be greatly increased. If your rocket were traveling away from the light source it's energy would be greatly reduced. For example if the source were immitting green light, it may appear to you as purple or red, depending if the source was moving towards you or away from you.

Answer 4

To answer your question, a number of assumptions have to be made. One is the car travelling in a medium like air or is it travelling in a vacumn.
If it is travellling in a insulator. The formula is cerenkov radiation forms a cone the apex angle is given by
cos(θ)=1/(nβ) where n is the index of refraction for the medium. β is the v/c. v is the phase velocity and c is the speed of light.
Now if we assume a phase velocity and group velocity equal to c and index of refraction equal to 1 for the medium. Like it was a vacumn the angle of the cone would be 0 and the light from the headlights would go at the speed of light in a perpendicular direction to the velocity for an observer at rest in the medium. For a person in the car he/she would never be able to see the light emitted by the headlights reflect from anything except what he/she had already passed.
This of course assume that a some point in future the car decelerates to below the speed of light in the medium.

Answer 5

well the light from the headlights is light so travalling at the speed of light anyway and the car is also travaling at the speed of light so i guess it would look the same as any other time you turn your lights on all the funny effects like it not casting a beam would only happen if the car was travelling faster than the light but its not ,

Answer 6

If we assumed (incorrectly) that it was possible for a human being to travel at the speed of light, then that person would neither see, nor hear, nor otherwise experience anything at all, since, in his reference frame, time would not be passing.

But if we change the question to what you would see if you were traveling at nearly the speed of light, then Prof Zikzak's and xmoj14x's answers are the best.

Answer 7

Yeah and the speed of light is 299 792 458 m / s

Answer 8

If the Car is traveling at a speed of light (assuming that it stays in one integral mass structure without breaking apart) and its speed is measured from the same frame of reference that the speed of light is measured, and then you turn your light on what happens?
First of all your car's head light is the source of light .
Now both the source and the light speed are measured from the same frame of reference.
Therefore by the Principle of Relativity both the source of light and the light are both traveling at the same velocity ,it implies that their relative velocity is zero.
Hence light relative to the car is simply not moving at all.

Its called relative motion. This Principle of Relativety is very Elegant and was formulated by Galileo Galilei , and Italian Scientist in the 17th Century.

Its very vely simple

Answer 9

If you want to be really technical, the answer is yes.
Why?
Like someone else said, it is all relativity. The headlights are situated infront of you by about one metre. So the lights woud travel at the speed of light but at a distance of one metre in front of you. In the time it takes to travel that one metre, the light travels one metre extra forward as you are travelling at the same speed.

Answer 10

very interesting question..i would think that yes you can since you are travelling at the same speed as the light.