This is too simple, I haven't read any previous posts so I hope this hasn't already been said.
If you followed someone at the speed of light, and you turned on your headlights, you'd light up the back of his car, because the light beam from your car would be travelling at the speed of light compared to your relative speed. Easy.
Is that right? I have a grade school education.
Originally posted by howardbradleyThat one I know Photons impart MOMENTUM but have no mass, rest or not. It only ACTS as if it had mass.
Strictly speaking they have no [b]rest mass. When they are travelling at the speed of light they do have a mass. Or at least they behave as if they do. Two for instances: The so called "solar sail" - the momentum of photons from the sun is used to drive a ship with a huge reflective sail. And, light is affected by gravity.
How they get fr ...[text shortened]... g is yet another facet of their sneakiness. Along with all that wave/partical duality stuff.[/b]
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Originally posted by uzlessThe light will never get out of my headlights and will never illuminate my friend. However I will not realise this because time will have stopped for me. As far as I can tell, I am merely waiting the spit second it takes for the light to get to my friends car That split second goes on for ever though.
If you were closely following your friend in his car and you were in your car, and the two of you were in outerspace, and could somehow get your cars to travel at the speed of light and then you turned on your headlights, would your headlights light up the back of your friends car, or would they do nothing?
To travel in the (exact) speed of light is like dividing with zero - it can't be done.
In fact - its because you cant divide with zero the light speed is unachievable.
On of the equations in relativity has the denominator sqrt(1-c2/v2) (if I remember right). When v=c then the denominator is zero, which then will be a division by zero, illegal.
But curiously the equation doesn't forbid velocities over the speed of light but some bizarre effects will happen.
Originally posted by FabianFnasInteresting effects like what? Time going backwards or something?
To travel in the (exact) speed of light is like dividing with zero - it can't be done.
In fact - its because you cant divide with zero the light speed is unachievable.
On of the equations in relativity has the denominator sqrt(1-c2/v2) (if I remember right). When v=c then the denominator is zero, which then will be a division by zero, illegal.
But c ...[text shortened]... uation doesn't forbid velocities over the speed of light but some bizarre effects will happen.
Originally posted by AThousandYoungLike the mass having an imaginary mass component.
Interesting effects like what?
If you putting a v larger than c in sqrt(1-c2/v2), you’ll get a negative number inside the square root and taking square root of a negative value results in a complex value outside the Real number system generating mass of an imaginary component. Weird isn’t it?
But you can never gain such a superluminal speed of the sole reason you cant traverse the speed of light itself. The only way to travel faster than light is to be born in this velocity. Whit an imaginary mass component and all.
The hypothetical particles called tachyons are thought to have these properties. They have never been found. No one knows if they really exists.
Originally posted by FabianFnasI found some tachyons on my dog after he rubbed his ass in a thistle bush
Like the mass having an imaginary mass component.
If you putting a v larger than c in sqrt(1-c2/v2), you’ll get a negative number inside the square root and taking square root of a negative value results in a complex value outside the Real number system generating mass of an imaginary component. Weird isn’t it?
But you can never gain such a superlu ...[text shortened]... hought to have these properties. They have never been found. No one knows if they really exists.
Originally posted by General PutzerI think the issue is that with light you can't have additive velocities, becsause if you did then the light would be travelling at faster than the speed of light, and nothing can do that.
This is too simple, I haven't read any previous posts so I hope this hasn't already been said.
If you followed someone at the speed of light, and you turned on your headlights, you'd light up the back of his car, because the light beam from your car would be travelling at the speed of light compared to your relative speed. Easy.
Is that right? I have a grade school education.
Works for things slower than the speed of light (e.g. sound, which gives you the Doppler effect) but not light.
Originally posted by ivangriceIf you drive a car near the velocity of sound and you honk - in what velocity does that honk propagate in front of the car?
... you can't have additive velocities, becsause ...
Works for things slower than the speed of light (e.g. sound, which gives you the Doppler effect) but not light.
No, not even sound velocities are additive in its nature.
no no no guys, I did not say the velocities were additive.....I said they were RELATIVE. A stationary person viewing the car and it's headlight beam would see both travelling at the same velocity, the speed of light. The person in the car would observe the same thing, his headlight beam moving away from him at the speed of light.
Scientific American has a great special Time issue this month about everything you are discussing. Paradox's, relativity etc.
It makes you have a new appreciation of time, our perception of time, and especially Einstein.
http://www.sciam.com/special/toc.cfm?issueid=40&sc=rt_nav_list
I bought it and its really worth a read.
Originally posted by FabianFnasThat's for a different reason. Sound needs to travel in some medium - in this case air. Since the air around the car is not moving then you are correct the sound will not propagate forward.
If you drive a car near the velocity of sound and you honk - in what velocity does that honk propagate in front of the car?
No, not even sound velocities are additive in its nature.
For light, however, there is no "luminiferous aether" - as demostrated by the famous Michelson Morley experiment.
Unlike sound waves, photons of light travel at the speed of light and are affected by the speed of the object that they leave from so just like if you threw an egg at 5mph from a car going 40mph the egg would go 45 mph, if you turned on your lights in that car then the light would go the speed of light relative to you. Sound waves on the other hand always go at a constant speed in a given medium. That's why sonic booms are possible.