

Light Speed?
#1
Posted 06 February 2008 - 17:00

#2
Posted 06 February 2008 - 17:09
Secondly, Cherenkov postulated particles faster than the speed of light in certain media.
Light travles at c (3*10^8 ms^-1) in free space.
In air it's a bit slower, water slower still. however in water it's possible to give an electron enough energy to move faster than light in water. In this case Cherenkov radiation is emitted.
Another way is the expansion of space in the early universe, while something can't travel faster than light in free space, if the space itself is expanding, nothing in physics can stop it.
Proving the claim would be something to watch, since it would indeed cause a black hole...
#3
Posted 06 February 2008 - 17:15

#4
Posted 06 February 2008 - 17:21
#5
Posted 06 February 2008 - 21:28
The speed of light = 299 792 458 m / s
speed of light in a vacuum is an important physical constant denoted by the letter c for constant or for the Latin celeritas ("swiftness"). It is the speed of all electromagnetic radiation, including visible light, in a vacuum. More generally, it is the speed of anything having zero rest mass.
In metric units, the speed of light in vacuum is exactly 299,792,458 metres per second (1,079,252,848.8 km/h). The fundamental SI unit of length, the metre, has been defined since October 21, 1983, as the distance light travels in a vacuum in 1/299,792,458 of a second; any increase in the measurement precision of the speed of light would refine the definition of the metre, but not alter the numerical value of c. The approximate value of 3×108 m/s is commonly used in rough estimates. In imperial units, the speed of light is about 670,616,629.2 miles per hour or 983,571,056 feet per second, which is about 186,282.397 miles per second, or roughly one foot per nanosecond.
The speed of light when it passes through a transparent or translucent material medium, like glass or air, is slower than its speed in a vacuum. The ratio of c to the observed phase velocity is called the refractive index of the medium. General relativity explains how a gravitational potential can affect the apparent speed of distant light in a vacuum, but locally light in a vacuum always passes an observer at a rate of c.

#6
Posted 06 February 2008 - 21:57

Medve

#7
Posted 06 February 2008 - 22:21
SolidSpartan117, on 6 Feb 2008, 22:28, said:

The brave hide behind technology. The stupid hide from it. The clever have technology, and hide it.
—The Book of Cataclysm


#8
Posted 06 February 2008 - 23:37
I think it may be something to do with the interactions but I'm not sure which characteristics cause the light to slow.
@SolidSparta117, all the information there is correct, but I assumed that sort of knowledge when I posted my response.
@Medve, sudden expansion very early on is called inflation (and is the reason why the cosmic microwave background radiation is the same in all directions - well close enough).
Yes dark matter is thought to be driving the expansion of the universe - don't worry not in our lifetimes, but i'll have more detail after my course on the early universe.
For those interested, light obeys the wave equation, use wiki it's correct as of this post, and in free space this can be derrived from Maxwell's equation very easily.
#9
Posted 06 February 2008 - 23:53

#10
Posted 07 February 2008 - 01:47
Edited by Teron, 07 February 2008 - 01:48.
#11
Posted 07 February 2008 - 08:37
It's known as the EPR paradox and i'll explain it when I have more time, that being said reflections can travel faster than the speed of light, however information cannot, I doubt very much they'll get anything through it.
#13
Posted 07 February 2008 - 14:12
#14
Posted 07 February 2008 - 15:08
Disreguard that comment
From a Historical perspective someone as always claimed that something was imposible, until someone did it. Just wait out acheiving faster than light travel may still be acheived.




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#16
Posted 07 February 2008 - 16:11
General Kirkov, on 7 Feb 2008, 16:08, said:
This is why I think it will not happen:
Something that has mass will never go at the speed of light because it will take an infinite amount of energy.
Something that has no mass will never go faster then the speed of light, because you can't accelerate it.


#17
Posted 07 February 2008 - 16:25
Back to (un-credible?) info, i do belive hearing yo would reach the destination before you left it and youd catch fire from over-heating due to the strain on your body.
For example take a Suzuki Hayabusa (also known as the GSX1300R)
The hayabusa (bugly as biukers know it) it one of the fastest road legal bikes out. The point of this? At stock a new one will do 200 mph. if one added nitrous or a turbo/supercharger to it, it would hit around abouts 220 mph, in human terms that 98.3488 meters per second thats a kilometer in just over 10 seconds; imagaine the standards of the bbike to withstand that
do u REALY think a human cld withstand more than that?
#18
Posted 07 February 2008 - 16:58
#19
Posted 07 February 2008 - 17:28

#20
Posted 07 February 2008 - 18:06
Energy cannot be created or destroyed.
Energy is equilivent to mass, so an intense amount of energy also has a gravitational field, infited energy = infite mass = end of the universe.
#21
Posted 07 February 2008 - 18:12

#22
Posted 07 February 2008 - 18:23
Fusion released dramiatcially more energy per nucleus.
Fission you get about 200eV / nucleus
Fusion you get about 2.2 Mev / nucleus.
#23
Posted 07 February 2008 - 18:30

#24
Posted 07 February 2008 - 18:36
But Infinite energy is stupid, lots of energy makes sense, fusion is better than fission but a time away, however the energy fusion relaeses still won't get you to light speed, just closer.
#25
Posted 07 February 2008 - 18:56

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