Yes, but photons - the particles that transmit electromagnetic radiation, exist. This is an odd occurrence because it exists and it transmits energy, but it has no mass, does not decay, and it has no electric charge. That is why I find it confusing, they transmit energy, but they don't have mass, and can travel at light speed as they are, essentially, the "physical" body of light.

Sadly, you'll never reach c, since the addition at that high speed is a bit more complicated, while 0.5mp/h + 0.5mp/h equals 1mp/h, 0.8c + 0.8c will result in a velocity which is still lower than c. You'll speed up to c asymptotically (or however the exact translation is :S), that means, you'll never reach it (or after spending an infinite amount of energy).



Well, with the same term that says time will go in reverse, you easily can prove that c is unreachable (its the Lorentz factor, Vio-Lewis posted it)

This post was edited by Lampee on Dec 10 2008 04:34pm

It makes perfect sense. It can also be experimentally tested by observing the decay of cosmic ray muons. I'll admit, when I first took relativity, it was really counter-intuitive. You get used to it though.

why would light have anything to do with time

we dont even knoe what time is

This post was edited by Potassium_LLD on Dec 10 2008 04:34pm

theez gaize kno wut there talking about k, nn interupshins

Speed is dependent on time. If there is a maximum speed something can go, there will be consequences (such as infinite momentum).

i dont kno wut there talking about k, you i thundershock

Yeah, I understand where you're coming from.

lol I just came across this, which further complicates things:

The Sagnac experiment long ago demonstrated that faster-than-light speeds are possible. In addition, charged particles can pass through an optically transparent medium at speeds greater than the speed of light in that medium, producing Cherenkov radiation. Cherenkov radiation is analogous to the shock wave (sonic boom) produced when an airplane travels through the air faster than the speed of sound. Various researchers have argued that the gravitational force must propagate many times faster than light, otherwise planetary orbits would slowly and noticeably decay.

However, wouldn't these particles, in essence, be going back in time?

But the same journal has this retort:

It is sometimes claimed that if something travels faster than light, it will travel backward in time. However, the direction of time is defined by the sequence of cause and effect, and since effects cannot generate their causes, the idea of time going into reverse is nonsense. If an object were to travel from point A to point B faster than the speed of light, it’s true that observers at point B would see it arrive at B before they see it leave A; in fact, it would appear to travel backwards from B to A. This is because their observations are dependent on light, which would not be able to keep pace with the object in question. But if they could make their observations by means of superluminal signals travelling even faster than the object in question, everything would appear normal again and they would see the object move from A to B. Although it is impossible to literally travel into the past or future, it is possible to view clairvoyantly the images of past events imprinted on the invisible substance of nature, and the shadows of probable future events that are already being cast in the present

Tom Van Flandern, ‘The speed of gravity – what the experiments say’, Physics Letters A, v. 250, 1998, pp. 1-11, www.metaresearch.org/cosmology/speed_of_gravity.asp; Paulo N. Correa & Alexandra N. Correa, ‘The gravitational aether, part II: Gravitational aetherometry (7) – Antigravity lift and exotic flight (II): critical overview of theories and technologies’, monograph AS3-II.9, Akronos, 2006, section 3.

why would light have any thing to do with speed

Yea, classic problem where they ask you if a msisile launched off of a ship going at close to v=c, what would be its speed? And lampee...it is useless - - sorry not to bash theoretical physics but its practical application is out of reach...but I will admit that theoretical physicists have definately improved alot of current physics and chemistry.