Posted on 03/26/2006 8:51:36 AM PST by PatrickHenry
Can anything travel faster than the speed of light? "No," is what Albert Einstein would likely say if he was alive today -- and he would be the man to ask, because scientists have been taking his word for it ever since the early 20th century.
According to Einstein's theory of special relativity, published in 1905, nothing can exceed the speed of light. That speed, explained Einstein, is a fundamental constant of nature: It appears the same to all observers anywhere in space.
The same theory says that objects gain mass as they speed up, and that speeding up requires energy. The more mass, the more energy is required. By the time an object reached the speed of light, Einstein calculated, its mass would be infinite, and so would the amount of energy required to increase its speed. To go beyond the infinite is impossible.
One hundred years of testing have only reinforced what Einstein wrote, said Donald Schneider, professor of astronomy and astrophysics at Penn State. "There is no experiment that has contradicted special relativity. We have accelerated sub-atomic particles to well over 99 per cent of the speed of light, but not equal to or exceeding the speed of light.
"Theoretically, strange things happen when you exceed the speed of light," Schneider added. Time travel, for one thing, and a breakdown in cause and effect. Schneider uses an example of hitting a target with a gun that shoots bullets faster than the speed of light. "Some observers would see the bullet hit the target before they saw the shooter fire the gun," he said. "Since one of the guiding principles of relativity is that all physical laws are the same to all observers, this violation of causality would be a big problem."
Another oddity: tachyons. In 1967, Gerald Feinberg, a physicist at Columbia University, proposed the existence of these faster-than-light particles. In their mirror world above the light-speed barrier, tachyons would require infinite energy to slow down to the speed of light.
Other concepts that have popped up include "wormholes" -- shortcuts through space-time that would permit point-to-point travel faster than light -- and "warp drives," a kind of bubble created in space in which relativity wouldn't apply.
Although they have become staples of science fiction, tachyons, worm holes and warp drives remain speculation, and many physicists dismiss their significance. There is, however, at least one real-world example of superluminal (i.e., faster-than-light) travel. It occurs when light passes through water.
In this dense medium, Schneider explained, light is slowed to three-fourths of its speed in a vacuum. In a nuclear reactor, charged particles flying off the radioactive rods through the water they are submerged in exceed this reduced speed.
Because these particles contain an electric charge, they emit energy, called Cherenkov radiation. Any particles they bump into become radioactive, giving the water a characteristic blue glow.
"It's not at all exotic," Schneider said. "Every time you look at the water in a nuclear reactor, the bluish glow you see is radiation produced by charged particles moving faster than the speed of light in the water."
Still, slowing light down in order to beat it is cheating, Schneider conceded. And although he's not closing his mind to the possibility that relativity will one day be amended, for now, he said, Einstein's theory is the final word.
Source: Penn State, by Joe Anuta
Plus, don't even think of trying it on Amtrak.
Actually, that does but it's wrong.
He said, 'The theory of relativity is often criticized for giving, without justification, a central theoretical role to the propagation of light, in that it founds the concept of time upon the law of propagation of light. The situation, however, is somewhat as follows. In order to give physical significance to the concept of time, processes of some kind are required which enable relations to be established between different places. It is immaterial what kind of processes one chooses for such a definition of time. It is advantageous, however, for the theory, to choose only those processes concerning which we know something certain. This holds for the propagation of light in vacuo in a higher degree than for any process which could be considered, thanks to the investigations of Maxwell and H A Lorentz.'
Is appears that many have taken the speed of light in vacuo to be the limiting speed of material objects, and that this may be an error of great significance for the progress of physics in the past century. SR describes how motion of material objects may appear.
lol Classic!
No, the speed of light is how fast my cat takes my chair when I get up.
Bad news.
Sure, God and other things not bound by the logic of this universe....excepting socialists of course.
Yes, but it's a bad analogy to the lightspeed barrier. It's long been known that things can and do go faster than sound (lightning, for one obvious example, which is often seen before it's heard). For human travel, it wasn't known if our bodies could take the stress, or if our machines could either. But that was just engineering. In principle, the speed of sound wasn't really a barrier that couldn't be passed.
Very interesting post. Considerations of maximum speed, from Einstein to the present, have been predicated upon travel through space-time. But what if the fabric of space-time, itself, could be compressed in the path of the traveling object, so that the traveling object would always be approaching space-time, but not traveling through it? Like I said, very interesting post!
Interesting you posed this question. A similiar question was asked of scientist Dr. Bill Wattenburg on his radio station Saturday Night. The answer is No.
For your info, he is on week-ends 10pm to 1:am KGO 810 on the dial.
"Light" is just waves of photons as processed by the human eyes and mind, right? Sure, I bet there's particles (a human conception) that travel "faster" (another human conception) than light. Of course, within the very limited context of human perception and conception, photons are supposedly the fastest moving particles, although I read a few years ago that scientists had found some particle or another that travels slightly faster.
Yes, DU tin foil hat conspiracy theories
My wife's nags?
Probably not a good example. That's just light going faster than sound, although the lightning is probably doing so as well.
A better example would be bullets, which had been flying supersonic for some time previously. (Not sure when muzzle velocities went super, but any center-fire rifle round from the age of the smokeless-powder Mauser on does so routinely.) Even the tip of a cracking whip is going supersonic, which is why it cracks.
One particular movie from the late 40s gives a very wrong impression of the quest. It has Ralph Richardon explaining to someone that no one even knew if the air molecules could or would get out of the way of a thing trying to fly faster than sound. That was just nonsense, especially since by the time that movie was shot Chuck Yeager had already flown faster than sound, although the Air Force had not publicized the event.
You would not have the energy required to accelerate even that small amount.
The closer to the speed of light (c) you are moving the more energy is required for additional acceleration.
This increase in required energy is exponential and if you were moving on this hypothetical train at 99.9999999...9% the speed of like that last tiny bit of speed needed to reach c would be equal to more energy than is available in the universe. I hope this was clear.
Like = light. I sounded like a valley girl. sorry.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.