29 Oct 06
Originally posted by drumset04
it is physicily impossible to travle the speed of light.
i think you mean theoretically impossible. Unless you're physically talking about the human body moving at the speed of light relative to everything else then yeah, you'd become a very fast puddle.
29 Oct 06
Originally posted by danandi1I've been reading up on this to make sure, and special relatitvity relates to how an observer sees light being reflected back to him, regardless of his own velocity. The problem here is that there is no light being reflected back before the observer reaches the point from which reflection will take place..
You nare able to see the light reflected of other objects as in a normal car as explained in my last post (if you do not understand special relativity the it can be confusing)
29 Oct 06
Originally posted by Ian68Your second statement contradicts the first. The observer in the car observes the light to travel at 'the speed of light' relative to himself regardless of his own velosity. As far as he is concerned the photons from his headlights travel away from the car at the same speed as if the car was stationary.
I've been reading up on this to make sure, and special relatitvity relates to how an observer sees light being reflected back to him, regardless of his own velocity. The problem here is that there is no light being reflected back before the observer reaches the point from which reflection will take place..
29 Oct 06
Originally posted by danandi1I've always thought physicians went wrong there.
Your second statement contradicts the first. The observer in the car observes the light to travel at 'the speed of light' relative to himself regardless of his own velosity. As far as he is concerned the photons from his headlights travel away from the car at the same speed as if the car was stationary.
If the photons of the headlight would indeed go at the speed of light relative to the driver then the photons would travel at twice the speed of light relative to a observer out of the car (standing still).
If not, then the speed is a constant for wich c + c = c. This cannot be true (well except for c = infinite, wich isn't the case now).
I passed special relativity theory with 90% right, but this bit never stopped confusing me.
29 Oct 06
Originally posted by danandi1You can only see light waves which are travelling towards you. If you and the light source are together and travelling at the speed of light then light waves from that source are never travelling towards you because there is no time for them to be reflected back to you.
Your second statement contradicts the first. The observer in the car observes the light to travel at 'the speed of light' relative to himself regardless of his own velosity. As far as he is concerned the photons from his headlights travel away from the car at the same speed as if the car was stationary.
29 Oct 06
Originally posted by TheMaster37This is the very essence of spesial relativity, it contradicts clasical physics and, to some extent, logic. The explanation of this is fairly confusing. Basically the car and the photons are in different inertial frames and the time that has passed at any given moment need not be the same in each inertial frame. So after a certain time the car and the photons will have been travelling at the same speed but the photons may hve been travelling for twice as long, if that makes sence.
I've always thought physicians went wrong there.
If the photons of the headlight would indeed go at the speed of light relative to the driver then the photons would travel at twice the speed of light relative to a observer out of the car (standing still).
If not, then the speed is a constant for wich c + c = c. This cannot be true (well except for ...[text shortened]...
I passed special relativity theory with 90% right, but this bit never stopped confusing me.
note: i'm also studying spesial relativity as part of my physics course and i find it confusing and logic defying too - hopefully I also get
90%!
NOTE: physicians are doctors
physicists study physics
29 Oct 06
Originally posted by Ian68Imagine another car, also travelling at the speed of light, constantly just ahead of you. Light can reflect off that, which removes your objection.
You only see light if:
a. you have a direct line of sight to the source, which in this case you don't.
or
b. you see the light reflecting off something else, which cannot happen for the reason I gave before.
29 Oct 06
Originally posted by TheMaster37The problem here is you're assuming you can apply a Galilean transformation, in other words you can just add the speeds together. Which is what your intuition says you can do.
I've always thought physicians went wrong there.
If the photons of the headlight would indeed go at the speed of light relative to the driver then the photons would travel at twice the speed of light relative to a observer out of the car (standing still).
If not, then the speed is a constant for wich c + c = c. This cannot be true (well except for ...[text shortened]...
I passed special relativity theory with 90% right, but this bit never stopped confusing me.
But the whole point of special relativity is that you can't do this. Unfortunately the universe is a bit more complicated than that.
29 Oct 06
Originally posted by mtthwThankyou for saying what i am trying to say much more clearly
The problem here is you're assuming you can apply a Galilean transformation, in other words you can just add the speeds together. Which is what your intuition says you can do.
But the whole point of special relativity is that you can't do this. Unfortunately the universe is a bit more complicated than that.
29 Oct 06
1 edit
My major is mathematics, defying logic is not easy :p
Thanks for the clearup though (and the later posts as well). I wish you well with the exam. For me it was merely applying the correct formulas (and trying not to let your mind rebel against the theory).
Originally posted by danandi1
NOTE: physicians are doctors
physicists study physics
I am deeply ashamed. My english should have been good enough to be able to spot such a mistake...
29 Oct 06
Originally posted by vance554Thanks I am 17, I started university a month ago and special relativity is part of my course, i found it facinating, by far the most interesting part so i made sure i understood the basics fully.
danandi1 sounds like a physics professor. Until someone can prove Albert Einstein wrong, danandi1 answered the question in his/her first statement, no arguement.
30 Oct 06
Originally posted by danandi1pretty advanced stuff for a 17 year old. Keep it up.
Thanks I am 17, I started university a month ago and special relativity is part of my course, i found it facinating, by far the most interesting part so i made sure i understood the basics fully.