May 13, 2009 -- Here's the good news for all those "Star Trek" enthusiasts out there -- a couple of physicists think they've figured out how to travel faster than the speed of light without breaking the laws of physics.
But here's the bad news -- we may have to sacrifice Jupiter to get there.
Gerald Cleaver, associate professor of physics at Baylor University, and his post-doctoral researcher, Richard Obousy, have combined some of the most elusive fields in physics, including string theory and general relativity, to concoct a scheme to move "Star Trek's" warp speed a little closer to reality. Very little, that is.
The folks who produce the "Star Trek" flicks have never explained how the good ship Enterprise can speed through the universe faster than a beam of light. That minor achievement is necessary if humans are ever to explore the galaxy's back yard, not to mention the distant reaches of the universe.
The only problem is Albert Einstein said it couldn't be done.
"Objects that have mass cannot travel at the speed of light," Cleaver said in an interview. According to Einstein's famous equation, "as an object travels faster and faster, its mass increases," he added. "As an object approaches the speed of light its mass becomes infinite."
'Warp Bubble' Needed for Interstellar Travel
In other words, a speck of dust traveling at the speed of light would have infinite mass, and it would take an infinite amount of energy to get it moving anywhere near that fast. So that pretty well knocks humans off the passenger list on the Starship Enterprise.
Not so fast, say Cleaver and Obousy, who have expanded upon a theory first proposed in 1994 by Michael Alcubierre, a Mexican physicist. Never mind warp drive, Alcubierre declared, what we really need for interstellar travel is a warp bubble. Alcubierre theorized that mass may be limited by Einstein's calculations, but that doesn't necessarily apply to space.
It might be possible, the Baylor researchers contend, to expand space behind a vehicle, say the Enterprise, and shrink space in front of it, thereby creating a bubble that could move through Einstein's space-time fabric at speeds much greater than the speed of light.
Surfing a Wave, Space-Time Style
The craft would ride inside the bubble as the bubble moved through space, but the craft itself would remain stationary, thus avoiding that little problem suggested by Einstein. Cleaver, who earned his doctorate at the California Institute of Technology, in the heart of surfing country, likens it to "surfing a wave."
But how does one create such a bubble? At this point, the story gets a little complicated.
The universe, which includes all sorts of stuff with mass, is itself expanding at speeds greater than the speed of light. We've known that since the 1970s, Cleaver said.
A fraction of a second after the Big Bang, the universe began expanding faster than the speed of light "in a very, very short time because if it had not we would not have seen the overall very, very uniform temperature cross the universe in all directions."
Throwing in a little string theory (the current rage among physicists who are searching for a reliable theory of everything) Cleaver said the universe "grew from something a billionth of a trillionth the size of the nucleus of an atom to about the size of a basketball," during its first second. "When it did that, space itself was expanding faster than the speed of light."
Replicating the Early Seconds of the Universe
Cleaver, who studied under the legendary John Schwartz at Caltech, a leader in string theory, postulated that it might be possible to partially replicate that early second by manipulating positive and negative dark energy, believed to be the driving forces behind the expansion of the universe.
Put positive energy behind the spacecraft, and negative energy in front of the spacecraft, and that should propel the craft along at warp speed.
"Space in front of the ship is shrinking faster than the speed of light, and behind it, space is expanding faster than the speed of light," and that should push the bubble along with the ship inside, "just like riding a wave."
But how do you do that? Not all the answers are in yet, but the Baylor pair theorizes that with enough energy, it might be possible to alter the 11th dimension, a key part of string theory, which maintains that there are far more than the three dimensions we common folk see on earth.
Converting Jupiter Into Energy?
With enough energy, the "space-time dimension" in front of and behind the Starship Enterprise could at least start the bubble on its way, Cleaver suggested.
"The initial energy required would be on a par with the total mass of Jupiter," he said. "If you could convert Jupiter into energy," the bubble could be launched.
But it would probably require much more energy to stabilize the system and keep the bubble moving toward an infinite number of other universes, according to string theory, that are so far away their light has not reached us yet, and thus cannot be seen.
Cleaver admits he doesn't expect to see that happen.
"This is purely a theoretical discussion of how the Alcubierre effect could theoretically be achieved through string theory," he said.
But there's a few more problems. Scientists are at odds with each other over whether string theory should even be considered science.
Many maintain that the theory cannot be proved, or disproved, as far as is known, so it isn't science. Others hold out hope that some very expensive machines in the future may verify, or debunk, the theory.
So the Starship Enterprise is coasting through very thin air, to say the least. Even if it could travel at near the speed of light, it would take more than four years to reach the nearest star beyond our solar system, and hundreds of years to reach very many stars that could have planets with life.
But "Star Trek" is a movie, after all. It doesn't have to be based on facts. Besides, how many Jupiters can we spare?