Speed of light

Swampy

Swampy

Member
OK this have been on my mind lately, let's just say you were driving your car through space at the 3 times speed of light, and you had your headlights on. Would your headlights fall behind your car, because you're going faster than the speed of light? Or would the initial velocity of your car be added to the light, making it 4x the speed of light, can light have an initial velocity? It's confusing me, because can light go faster than the speed of light? can it have an initial velocity?
 
No I don't think it would. I think you'd see no light coming from your headlights... considering that most laws of physics don't apply to the car itself.
 
light can not go faster than the speed of light. Its a constant. Someone asked the exact same question in my astronomy class today
 
They haven't accelerated anything with a significant amount of mass, at least that's the last I've heard.
 
The speed of light is measured to be the same no matter what your frame of reference is. This is scientific fact (relativity) and has been measured and confirmed, no matter how weird it might sound. It leads to a lot of strange effects.

There are some quantum effects that might allow information to travel faster than light, and under certain experimental circumstances it might be possible to make some particles appear as if they are traveling faster than light. But macroscopic objects (like your car) will definitely not be going faster than light any time soon, and I really doubt such a thing will ever be possible.

So your question is sorta irrelevant.

p.s. i just found this, maybe it will explain some things I don't want to:

http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/FTL.html
 
the only way one can surpassing the speed of light would be by the medium of which it travelled through. Light travels slower through a denser barrier such as water or air compared to a vacuum. There's a name for this effect, but I can't remember it off hand. But your still not beating the speed of light in a vacuum, so well yeah , you cannot travel faster than light, atleast from my understanding.
 
but the question is fundamentally invalid because according to the current forumlation of physics such a thing absolutely can't happen, so why don't you tell me how I'm supposed to figure out what would happen if it did?
 
Well, besides the fact that you can't go faster than the speed of light, I very much doubt you would survive driving a car at the speed of light. 1.) the Gs would kill you. 2.) the lack of air-tight cabin would kill you 3.) ITS NOT POSSIBLE.

Though theoretically, if you could go the speed of light, but lets say with a SPACE SHIP with lights on the front, you probobly wouldnt be able to see the lights, they would probobly be shining back on your space ship. But then again, if you were in space, you probobly wouldnt have anything to shine the light on anyways, so you couldnt see them even if they were in front of you.

 
t first its not even possible to be as fast as light. The explanation for this effect is pretty simple.

Everybody knows Einsteins E=mc² which means Energy = mass x lightspeed².

That

says if you add energy to a subject its mass will encrease. So, the

more energy you add to your car to accelerate it, the heavier it

becomes. If it becomes heavier becauese you added energy, you have to

add more energy for further acceleration. This means, you need even

more energy to accelerate, and this energy will make your car heavier.

In the end, you would need infinite energy to get your car even at 99% lightspeed, and this energy would add infinite mass to your car.

Thats the reason why no mass can go faster, or even as fast as the

light. The only reason why light can go at a speed of 300 000 km/s is

that it behaves like a particle and a wave at the same time, but doesnt

have a mass.

So, if you were a genius and would be able to build a car that could go at 3time lightspeed, you wouldnt see any light coming out of your headlights, because if a star goes at 90% lightspeed the light that goes off the star in the same direction the star goes only has a speed of 1 time lightspeed, simply because nothing, not even the light can be acceleratet at mor than 1time lightspeed.
 
they did make a chain of electrons shift faster than the speed of light, if thats what you are referring to. they basically moved one at one end of a series, and that moved the end one instantly. but, this has no real practical application, because even if we were to develop that technology for larger objects, you still wouldn't be able to reach other planets and solar systems (you would need to get there first, and even then you would only be able to move stuff on the end)
 
there would be no light. The bulbs would be burning, but as soon at it was visible light, like even in the bulb, it would be flying past you backwards at twice the speed of light. So you just see complete darkness.

That's the answer, so you can stop thinking about it. And this is assuming the whole, car, space, living thing. hypothetical question tho
 
i read an article about some scientists got a special beam of light to travel through a vacuum faster than the speed of light. so light was going faster than light.

i think if you were traveling any speed over the speed of light in your sweet space car and turned on the headlights, you would see nothing...maybe. it makes sense to me that you would see nothing behind you because all the light reflected from objects behind you wouldn't be able to catch up with you. i can't think of this more right now...gotta study for finals.
 
Yeah, Huygen's principle, the whole refractive index n = c/v deal.

I think that the scientists accelerated the light faster than itself, but like SteezePatrol said, they did it through switching mediums, from what i know.

Either way, photons are massless, so if anything could travel faster, it's be them.
 
these people are thinking about it to much. if you could go that fast then the headlights on the car would also be traveling with your car going 3x the speed of light. so the light would be ahead of you going 4x the speed. i think
 
WRONG. Even though you could go at 0.99 lightspeed the headlight wouldnt go at 1,99 lightspeed, but at 1.0 lightspeed, cuz lightspeed cant be added. It´s constant
 
Actually, that's just the thing. When your car is moving down the road, at V, and the light is going from your headlights at c (speed of light), you might think that the speed of light relative to a stationary observer in front of the car is (c+V).

You'd be right if it were sound we're talking about (the Doppler Effect), but with light, you actually have the total speed of the light to be simply c, 3 x 10^8 m/s (roughly, as in air it is actually slower than in a vacuum). V doesn't affect it at all.

It's one of the of the first things you learn about light.
 
I've always kind of thought of the same concept, just differntly. I've always wondered if you are travelling faster than the speed of sound, i.e. the Concord, military jets, etc, if the noise you hear is a result of the actual propulsion system or merely the vibrations caused by it.
 
In theory, you could have a particle with an imaginary mass, and its speed would always exceed the speed of light. It would be impossible to slow this particle down below light speed.

As for how you would interpret imaginary mass, no idea. But basically, it hasn't been proven, but it also hasn't been proven not to exist.

If someone points to that experiment where scientist made the light go 300 times faster than its normal speed of light, it didn't technically exceed the speed of light. Even though it went faster, it was traveling exactly at the speed of light because it is light.
 
i havent read an answer thats 100% correct, or at least explained clear enough to seem that way. so heres the ACTUAL RIGHT ANSWER.

the most basic fact that the entire theory of relativity depends on is that the speed of light is constant, no matter what. every observer, everywhere in the universe, regardless of velocity, location, direction, etc, will measure the speed of light as 300000 km/s. that being said, what would actually happen if you were able to drive a car at the speed of light...

the person inside the car see nothing out of the ordinary. the light beams would come off of his headlights and go in front of him, as usual, and he would measure their speed to be 300,000 km/s.

however, the weird part about it is if there was a "stationary" observer, watching this car go past, they would also measure the light coming out of his headlights at 300,000 km/s, the same speed as the passing car. so this observer would see no light in front of the car, even though the driver sees the light as normal.
 
stuff can go faster than the speed of light, but light cant go faster than the speed of light even if its already moving (I.E. a spot light on a car) so yes, the light would be delayed to people from a frame of reference outside the car, but to you, driving the car, you would see the light, its relativity, crazy shit
 
No, that's not what would happen if you were going "3 times the speed of light" as per his original question.

What you describe is what happens as your speed approaches the speed of light.
 
ummm... we've broken the sound barrier a few times... X-1 aaaaaringing a bell? That was way back, 70s or something. The Concorde could fly over mach, mach 2.1 even.
 
yeah, it makes sense to think there'd be some sort of Doppler, but there just isn't.

still weird to think about. I have a test on this tomorrow. Woot!
 
Light does have a "doppler effect". One example is "redshift" in astrophysics... lets us figure out how distant bodies are moving in relation to us.
 
yeah, you can get infinatley close to the speed of light, but you cant go as fast or faster.However, like you said, it is possible for information to travel faster than the speed of light (there was a thread on a chemical reaction that was something like 3 times faster than the speed of light).

but what happens as you approach the speed of light, is time slows down and objects appear to be skewedTime was for a long time thought to be constant around the universe, but Einstein theorized that time is effected by gravity, and light is the only constant thing in our universe.

there is also some crazy cool shit that happens with black holes. Apparently, if you were to enter a black hole, everything would appear the same, but to the outside veiwer, you appear to get sucked in. Im not too knowledgable about this, but what I can remember is something like in the space between the person that is in the black hole, and the information horizon (the begining of a black hole) the light will get sucked into the black hole, producing a skewed image to the outside observer.

crazy cool shit. This is what Hawking discovered, and he is currently working on a mathmatical formula to prove it.
 
sorry, when i said nobody had read it, i meant the people that are still arguing about it. what i quoted is the correct answer to the question.

and as to what drew said about the doppler effect on light - he was right, it does happen. someone else mentioned "redshifting", which is when a the light from a star moving away from us appears more red colored, because the wavelengths of the light are in a sense "stretched out" by the star moving away from us. the same is true with a star moving towards us, except it becomes "blueshifted", as the wavelenths are "squished together", sort of.
 
clearly you didn't read my reply to your post earlier.

No, that's not what would happen if you were going "3 times the speed of light" as per his original question.

What you describe is what happens as your speed approaches the speed of light.
 
you cant go the speed of light, and when you approach the speed of light... yad yada yada, read my post.
 
yes, believe me, i know you cant actually go the speed of light. this is all theoretical. as in, what would happen if you DID go the speed of light. i think i even said that in my original post.
 
but that's simply a moot point, because it cannot happen!

you can't assume something hypothetically if it cannot happen, or at least it's absurd to even discuss it.
 
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