Faster-Than-Light Travel
Faster-Than-Light Travel
Whether science fiction novels refer to it as warp speed, hyperspeed, or lightspeed, the prospect of traveling at the speed of light or faster has enthralled humanity for decades. The possibility of traveling at speeds millions of times faster than those at which people travel today has been the focus of much debate and research. Faster-than-light travel is necessary for space journeys because of the huge distances between stars and star systems. The nearest star to Earth, not including the Sun, is 4.3light-years away. This means that at the speed of light it would take 4.3 years to get there and 4.3 years to return. The Milky Way Galaxy is more than 100,000 light-years across and is only one galaxy in what is believed to be billions. No human could survive for 100,000 years with current medical techniques, and so faster-than-light propulsion would be necessary to make such a trip.
The science of faster-than-light travel is based on the equation E = mc 2 determined by physicist Albert Einstein. According to this equation, energy (e ) is equal to mass (m ) multiplied by the speed of light (c ) squared, meaning that energy and matter can be converted from one to the other. A major tenet of physics is that matter can neither be created nor destroyed. Nuclear explosions are a prime example of matter being converted into energy. Amazingly, however, atomic weapons have a very low rate of matter-to-energy conversion.
Using this equation, one can see the near impossibility of faster-than-light travel with today's technology. To travel in a ship at that speed or faster requires a great deal of energy. But according to Einstein's special theory of relativity equation, mass will increase as an object goes faster. As one approaches the speed of light, one will become so heavy that no fuel will be able to propel the ship fast enough to keep up. That rapid increase in mass prevents faster-than-light travel for humans aboard starships today, yet research is under way to determine ways to get around this limitation.
Small subatomic particles such as photons, particles of light, and hypothetical particles called tachyons—faster-than-light travelers with no mass—seem to have no problem reaching lightspeed. In fact, tachyons are widely believed to be a science fiction concept because it would take an infinite amount of energy to slow down a tachyon to the speed of light. Whether or not tachyons exist, the ability of particles to travel at higher speeds has not gone unnoticed by scientists. If a bubble could be created around a spaceship ship, it is hoped that the weight of the object could be lowered while its speed increased.
see also Accessing Space (volume 1); Antimatter Propulsion (volume 4); Interstellar Travel (volume 4); Laser Propulsion (volume 4); Power, Methods of Generating (volume 4); Science Fiction (volume 4); Vehicles (volume 4).
Craig Samuels
Bibliography
Bodanis, David. E = mc 2: A Biography of the World's Most Famous Equation. New York:Walker & Co., 2001.
Greene, Brian. The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory. London: Vintage, 2000.
Krauss, Lawrence M. The Physics of Star Trek. New York: Basic Books, 1995.
Internet Resources
"Ask a High-Energy Astronomer."Imagine the Universe. NASA Goddard Space Flight Center.<http://imagine.gsfc.nasa.gov/docs/ask_astro/ask_an_astronomer.html>.
"Ask the Experts."Scientific American.<http://www.sciam.com/askexpert/physics/physics57/physics57.html>.
The Speed of Light. University of Tennessee.<http://csep10.phys.utk.edu/guidry/violence/lightspeed.html>.
Warp Drive, When? Frequently Asked Questions. NASA Glenn Research Center <http://www.grc.nasa.gov/WWW/PAO/html/warp/warpfaq.htm#tach>.