"Ask us ANYTHING!!"


Will your headlights work?

From:  "Donnie"

If your car could travel at the speed of light, would your headlights work??

TB answered with words of wisdom: 

Only mass less objects, like a photon, can travel at light speed. An object with mass requires an infinite amount of energy to accelerate to light speed. If a car could travel at the speed of light then its headlights would be useless.

Edwin did his homework and wrote this: 

No massive object (objects that have mass, which is all matter) can move at the speed of light. Massive objects can be accelerated closer and closer to the speed of light, but can never actually achieve light speed. Therefore there is no answer to the question. The logic of our understanding of light (Einstein's Special or Specialized Theory of Relativity) simply does not allow for massive things to travel at light speed. It's like asking someone what would happen if 1 + 1 actually equaled 3 - it's completely contradictory to the basic logic upon which the current understanding is based, and so the question just cannot be answered in terms of the current understanding. If anybody else answers differently and tries to give you some weird answer, they're definitely wrong, because the fact of the matter is that the headlight can't reach light speed according to our understanding of light - the only way this question is answer-able is if we are wrong about light. And note that thi! s just isn't "my interpretation" of the law - it's a scientific law, so there is only one right answer.---- On the other hand, if you want to know what happens if you are CLOSE to light speed, that is simple. The Second Postulate in Einstein's Special Theory of Relativity says that the speed of light is always c, no matter how you move relative to the light source. So if you were traveling at like .999c, you would still see the light speeding away from you at speed c.

I know all attempted with this: 

yes they would but they would be behind you because you are moving faster then them

amr shalakani added his thoughts: 

yep they would...cause your headlights are traveling at the speed of your car plus their own speed makes it double the speed of light.

KatieBlahblah shared her views: 

if your car was going the speed of light, I think your lights would be blown out, but even if they still worked, you wouldn't last long in a car going that fast in the first place.

I know all believed this idea:

yes they would but they would be behind you because you are moving faster then them

Catt simply answered with this: 

Yes they would work, even if your too fast to see the light

MyHeadHurts joined the team and helped out with this: 

If you were traveling at the speed of light you would be infinitely heavy and squashed into a giant disc in the direction you were traveling in, so i doubt that you would care very much. However, i suppose theoretically your headlights would not work in the conventional sense of illuminating the ground in front of you, seeing as the light cannot travel faster than you

pavolka responded with this: 

Your question is academic, because by the time you saw, say, a deer on the road in front of you, you wouldn't have time to stop.

light mumbled something like this: 

yes they would but you will be moving at them same speed as the light

elah rattled off this answer: 

yes your car's head lights would work, just the light would not get there and back to you in time for headlights to make any difference

askmo sent us their views: 

Yes your headlights will work! ( surprise surprise ) However they will not illuminate anything because you are traveling at the same speed as the light that they emit. Just because you somehow managed to get your car traveling at the speed of light that would not make your headlights suddenly not turn on.

C.H.U.D. concluded with: 

The speed of light is the maximum speed at which anything can travel.
If your car were moving at the speed of light the headlights would not
work because the light couldn't escape from them. And also because your
car would have to be made of pure energy to go that fast.

Click here to send this page to a friend! Back to main page

2001 - 2003 Stupid Questions Answered