SFWRITER.COM > Futurism > Y3K: Interstellar Travel
Y3K: The Science of the Next Millennium
by Robert J. Sawyer
Copyright © 2000 by Robert J. Sawyer
All Rights Reserved
A hundred years ago we didn't even have airplanes and now
we have space shuttles and interplanetary probes. Suppose it
takes an additional hundred years until A.D. 2100 to
develop starflight. And another hundred years until A.D. 2200
before we begin sending out colonists who have no intention of
ever returning to Earth.
By this time, we will likely have defeated aging (see my speculations on the
future of the human body, so that humans can
easily endure centuries-long space voyages. Alternatively,
travel could be done in suspended animation. Or we may simply
send our genetic blueprints, and have shipboard computers
reassemble humans once the destination world is reached.
Regardless of how we choose to travel, we will probably
never go faster than the speed of light the laws of physics
seem unlikely to allow that. But even if we don't, we can still
voyage widely. At just a tenth of lightspeed, a one-way 800-year
journey (from A.D. 2200 to A.D. 3000) can take you 80 light-years
away. We will certainly establish colonies around nearby sunlike
stars, including Alpha Centauri A (4.4 light-years away), Epsilon
Indi (11.8 light-years away), and Tau Ceti (11.9 light-years
away). Radio communication albeit with lags of up to 24 years
between sending a message and receiving a reply will keep
these colonies in touch with each other and the home world. But
for most travelers such journeys will be one-way trips;
interstellar commerce is unlikely to ever develop.
The sole barrier to traveling even faster and going even
farther is energy production. Thanks to relativity, as you
approach lightspeed, your mass increases, requiring even more
energy to continue to accelerate. Just one year of acceleration
at 1 g (9.8 meters per second per second) should bring you very
close to the speed of light (while at the same time simulating
normal gravity aboard the starship) if you can find the
power to keep accelerating as your mass increases.
Matter-antimatter annihilation the old Star Trek
standby will provide enough power to do just that, making
speeds in excess of 99.9999% of light possible. At such speeds,
profound relativistic time dilation occurs. A starship launched
in A.D. 2500 would by the time the calendars on Earth read A.D.
3000 have made it almost 500 light-years out, to the
neighborhood of the supergiant red star Betelgeuse (where we may
decide to undertake steps to prevent that star, a prime candidate
to go supernova, from ever doing so, since such an explosion
might be harmful to Earth).
But according to relativity, the calendars aboard a starship
are just as valid as those on Earth and, with five hundred
years of travel at just below the speed of light, by the time the
shipboard calendars read A.D. 3000, a starship could have
traveled as far as the Andromeda galaxy two million
The defining moment of the second millennium happening
within one third of one percent of the millennium's end
occurred in December 1968, when humans aboard Apollo 8 finally
got far enough away from Earth that they could cup the entire
planet in an outstretched hand, seeing it as one fragile whole.
The defining moment of the third millennium will be similar,
but on a grander scale: the passengers aboard a starship heading
to Andromeda will be able to look back, through optical sensors
that adjust for the profound redshift, and cup the entire Milky
Way galaxy in their hands. And just as the Apollo 8 astronauts
could not discern any cities from that far away, even with
powerful telescopes the starship passengers will be unable to
resolve the average yellow star, one of a hundred billion in the
galaxy they are leaving behind, that had long ago been the
ancestral home of humanity.
More Good Reading
Rob's speculations on the future of:
Rob's essay on life in the future: "The Age of Miracle and Wonder"
HOME • MENU • TOP
Copyright © 1995-2016 by Robert J. Sawyer.