Scripps Howard News Service
Would-be Star-Trekkers: Forget about warp speed and hyper-drive, wormholes or star-gates.
Any trip that humans might make into deep space in the foreseeable future would be very slow goingas in several hundred years for a round trip.
Barring major advances in longevity, this means that several generations of astronauts would have to be born, raised, trained, and kept healthy in pretty tight quarters.
Experts unfolded such a scenario at a seminar on interstellar travel held last weekend at meetings of the American Association for the Advancement of Science in Boston.
"An interstellar ship bringing everything capable of forming a settlement would literally be an interstellar ark, carrying with it all the forms of Earthly life the colonists might need, at least in the form of embryos. The whole thing might have to weigh a million tons,'' said Geoffrey Landis, a propulsion expert at NASA's Glenn Research Center near Cleveland, Ohio.
"And as much as I love to contemplate relativistic voyages," he added, "it would be very difficult to send such a ship at a significant fraction of the speed of light. It would likely be a slow voyage to the stars, perhaps many hundreds of years."
Humans and anything else known to science can't go faster than the speed of light. Most fanciful propulsion systems proposed so far only get up to speeds of about 100 to 300 kilometers (62 to 186 miles) a second, or perhaps 10 percent of the speed of light, noted Scottish spaceship designer Robert Forward.
What that means, said Charles Sheffield of Earth Satellite Corporation, is that at a relatively plodding 5 percent of the speed of light, the next-closest star, Alpha Centauri, is 88 years away, and the center of the Milky Way a daunting 600,000-year trip.
Getting to the moon, on the other hand, would require just half a minute, compared to nearly four days for the Apollo astronauts.
So at least for now, it appears that humans would have to endure a multi-generation journey to reach any place interesting. And that raises some interesting questions about crew selection, according to John Moore, an anthropologist at the University of Florida-Gainesville.