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Information about this web site => Question related to Physics or physics related simulation => Topic started by: PanicAttack on September 12, 2009, 04:21:02 pm



Title: Speed of Light question
Post by: PanicAttack on September 12, 2009, 04:21:02 pm
Hi,

I'm new here and I have a question that has been bothering me for a long time - I just couldn't get the answer.

If a car is driving at the speed of light and switches on its head-lights, what will happen?  Will the head-light still be able to "light" the areas in front?


Title: Re: Speed of Light question
Post by: Fu-Kwun Hwang on September 12, 2009, 09:29:32 pm
According to special relativity: There is no way a car (any object with rest mass which is not zero) can reach speed of light in vacuum c.
However, particle can be accelerated to very closer to speed of light.

If a small object being accelerated near speed of light, for example: 0.9c (where c is the speed of light in vacuum), and the object switch on a head light.

Because light need to be reflected to be seen.
The object might be able to see light reflected from some distance within small angle.
The angle will be smaller if the speed is closer to speed of light.


Title: Re: Speed of Light question
Post by: FGZstar on October 27, 2009, 05:38:38 pm
One thing which has always puzzled me about this is if, theoretically, an object were to travel at the speed of light, would it become invisible?


Title: Re: Speed of Light question
Post by: dwiphy on March 29, 2010, 10:58:36 am
Invisible or unseen by human eyes?


Title: Re: Speed of Light question
Post by: Fu-Kwun Hwang on March 29, 2010, 11:42:49 am
One thing which has always puzzled me about this is if, theoretically, an object were to travel at the speed of light, would it become invisible?
To the driver: the time is freezed.
However, to other people, if the light enter my eye then I will see it. If it is not entering my eye, I would not be able to see it.

At night, the sun still emitting light to the sky. However, teh sky is dark because those ray moving away from us and it did not enter our eye.
Light has to enter our eye to be seen!