Sorry about that, curious_cat, but you’ve asked a question that according to our current knowledge of physics is not just unanswerable, but meaningless.
Traveling at “C” has inescapable consequences. It’s not just that nothing that has mass can move at C. It’s also that time does not apply to an object moving at C. You cannot even speak of “doing” something at C. According to physics that is meaningless. There is no possible “what if” something happened while at C that is answerable.
Massless particles move at C from the instant they are created until they interact with another particle. That is the only possible sentence that is related to C.
You got the only possible answer to your question. Physics has a million great “what if” questions in it, but yours is not one of them.
If you want to talk about traveling close to C and the amazingly crazy effects that occur, and the differences in reference frames and observers at high speeds, then the physicists on the Boards can go on for hours. Want to try again?
A possible answer: while accelerating, time would pass more and more slowly for the driver, and when driving at the speed of light, time would stop entirely.
In other words, the driver couldn’t even turn on the headlights because the whole universe would age and die before they took one hand off the steering wheel.
So, what would happen if the headlights were ALREADY ON? In that case the light would become more and more blue-shifted, more and more energetic as the car drove faster. What happens to light that’s 100 times higher frequency than gamma rays? How about 1000 times higher? How about millions of billions of times higher? Wouldn’t the light start emitting matter spontaneously (the reverse of particle/antiparticle collisions?)
Hey curious_cat You keep asking questions and if you don’t like the answers you get…dig a little deeper. Not all laws of physics are absolute, even light speed.
Perhaps the question might have been: Is the speed of light cumulative? ans. No
or Is faster than lightspeed possible? ans. Yes
How about: Is the speed of light constant? ans. Yes and No, It depends on the situation and setting. Lightspeed varies with different mediums and variables. BUT in a vacuum with no interference it is constant.
Of course your example is an absurdity, evidenced by your dubious smiley. Next time phrase your question a bit more realistically (at least in this forum). General Questions require a higher standard, in theory, than say IMHO, or MPSIMS.
Actually, photons that start at or near the speed of light theoretically can exceed lightspeed temporarily. So, in theory your question is not completely without merit. Except for that part about the car. <heh>
BTW Welcome to the SDMB. If you have a thirst for knowledge. This is a pretty good place to help quench it. Fourteen does not equal ignorant in my opinion. My son is also fourteen and too damned smart for his own good sometimes. (just kidding, he’s quite brilliant in fact)
Regarding your OP. Some food for thought. Check these links and enjoy.
You certainly can. If you were a patent clerk at the turn of the century, and you just happened to ask yourself “what would happen if I rode along with the light waves,” it might lead to some interesting concepts.
What if that patent clerk was browbeaten for daring to ask such a “meaningless” question?!!
Yes, a patent clerk at the turn of the century thought to ask himself that question. And after putting a bit of thought into it, concluded that the question was meaningless. Your point?
I think his point is that the search (and would call the effort more than “a bit of thought”, even for the patent clerk) produced a very astounding insight in to the very nature of time and space it’s self. Maybe if curious_cat looks into the question something would come of it. Why the hostility at thought of the question being asked?
As for the OP. my guess is (assuming the car can take being infinitly massive) nothing. since time is a point at that speed the headlights would be, for lack of a better word, dark. there is no cause and effect outside of time, just like there is no liters outside of space. now the car it’s self is interesting. since time and length are a point for the car if anything is, was, or will be along it’s line of travel there would be an infinitly powerfull explosion, caused by the infinite energy the car had to be charged up with to get to that speed, from the collusion. since it’s infinitly powerfull the explosion would constantly exapand and destroy the universe as we know it. ether that collapse into an infinitly massive singularity that ‘suck’ the rest of the universe into it at the speed of light. this is becouse with an infintly massive object everything in the universe would now have infinite potential energy.
Just to expand a little. Light must travel at light speed with respect to all reference frames and light can’t travel at light speed with respect to light.
Just to expand a little more; what Einstein realized with this thought experiment is that if he were riding on a light beam he would see it as a non time varying spatial waveform. But a non-time varying Electric field won’t create a magnetic field and vice versa, and therefore the EM wave couldn’t exist. No inertial reference frame for light tonight.
If you were standing on a planet that was moving at a relativistic speed with respect to another object do you think you’d weigh any more? Would you feel a stronger gravitationa attraction to planet you were standing on?
and if you don’t like the answers you get…dig a little deeper. Not all laws of physics are absolute, even light speed.
If you have a thirst for knowledge. This is a pretty good place to help quench it. Fourteen does not equal ignorant in my opinion. My son is also fourteen and too damned smart for his own good sometimes. (just kidding, he’s quite brilliant in fact)