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
This is an intro-type of article (from Scientific American) that may get you going in the right direction:
Misconceptions about the Big Bang.
That was inflation, a different mechanism from expansion, acting on space itself rather than on the material bodies in space.
Though in order to accelerate through time one would presumably have to alter the entire universe's expansion.
That is, shrink it to go back, or expand it to go forward.
This may well be impossible.
Chuck Schumer to the lens of a TV camera.
Not the entire universe, just the part between where you are and where you want to be for reasons known only to yourself.
One pill makes you larger and one pill makes you small.
But the ones that mother gives you don't do anything at all.
;-)
I just want to add that, whereas tachyons and wormholes remain purely speculative, there is nothing about them that violates the Theory of Relativity. Einstein himself very swiftly recognized that his equations permitted wormholes - indeed, one might say certain of his equations predict wormholes (or the equivalent), although that is quite controversial.
Now, 'warp drive' on the other hand..
John Edwards can, we he spots an ambulance.
Thanks for the ping!
Too tough for me.
An American Express Gold card on Black Friday during a blue light special at Macy's cosmetics counter!
There is a scientist working on using light/lasers looped on each other in a clinder shape to warp time and space to possible time.
I am just cannot remember the man's name. But it's interesting in that he uses Einstein's theory that time and space can be warped by speed, gravity and light.
Speaking of trains traveling at the speed of light, if the headlight of the train was turned on would it light the tracks in front of the train?
To visualize this, one can think of Stargate SG-1. When the characters step through the Stargate, they might end up on the other side of the universe, but they haven't travelled anywhere. The just took one step.
So, a better way to put it is: When stepping through a wormhole, one arrives at one's destination faster than if one had travelled there at the speed of light.
But, if you step through a wormhole to the other side of the universe, you haven't travelled across the universe to get there. It's as if the universe is folded up like a sheet of paper with two distant points touching one another. All you did was take a step from one end of the folded paper to the other end it touches.
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