by Paul Davies
Humans may choose
undertake interstellar colonization
our species, and the flame of our culture, alive.
DETLEV VAN RAVENSWAAY/getty images
apart from the practicalities,
serious ethical issues at stake...
One motivation for sending humans into space is as an insurance
policy against a mega-catastrophe on Earth.
Often cited is the impact of a large comet or asteroid which might
destroy our civilization or even our entire species. More likely in
my view is a sudden pandemic, either naturally occurring or through
the accidental release of a virulent bio-warfare pathogen.
In any case, over a period of millennia, there is no lack of
potentially species-annihilating hazards.
If all that stood in
the way of human survival were some indigenous microbes on
another world, few people would have scruples about ignoring
If a planet had complex plant and animal life, there should be
strong ethical objections to contaminating it with terrestrial
Even if the two forms
of life were so biochemically different that direct infection
was avoided, it may still be the case that the terrestrial
invaders would plunder some vital resource and deplete the
Earth organisms might
spread like the rabbits in Australia, and elbow the indigenous life
aside, driving it to extinction.
That issue would be greatly sharpened if a target planet is found to
host intelligent life. In the movie
Avatar, resource-hungry humans
muscle in on the planet Pandora to the extreme discomfort of its
indigenous population, although in the interests of Hollywood-style
justice, the pesky human invaders eventually receive their
There is no guarantee that future generations of humans would
exercise respect for the rights of alien beings, nor can we be sure
that aliens would respect ours.
aliens far in advance of us in technology and
social development may not share our ethical values.
Because we cannot begin
to guess the motives and attitudes of truly alien beings, when it
comes to the prospect of humans encountering an extraterrestrial
civilization, all bets are off.
It seems to be generally accepted that interstellar travel should,
and could, become part of our destiny. Why...?
A familiar answer is that humans have always had wanderlust, a sense
of curiosity, a desire to explore the world about them and to push
on to pastures new.
That may be true, but
people have always fought wars and oppressed minorities too; just
because something is deeply ingrained in human nature does not make
it a noble motivation.
Rather easier to justify is the argument that human society has
produced much that is good, which it would, therefore, be good to
preserve for posterity.
Humans may choose to
undertake interstellar colonization to keep our species, and the
flame of our culture, alive somewhere in the cosmos.
By establishing a permanent settlement on another planet, human
culture could continue even if disaster struck at home.
It could be countered
that this argument adopts an inflated view of human significance
and human worth, and that it is life, as opposed to our specific
species or culture, that should be perpetuated and perhaps
disseminated around the cosmos.
We could already begin sending microbes in tiny capsules out
of the Solar System if we were so minded, but it is hard to imagine
much enthusiasm for the project.
Seeding a barren galaxy
with DNA may one day fire people's imagination (assuming the galaxy
already teeming with life), but
today the appeal of interstellar travel is deeply rooted in ideals
of human adventure and advancement.
When Neil Armstrong took that first small step
the Moon, it was widely hailed as the initial step on a
stairway to the stars. Half a century on, with humans seemingly
stuck in low-Earth orbit, the prospects for interplanetary, let
alone interstellar travel, look bleak.
These microbiology problems compound what is already a formidable
Yet if humans wish to
secure a long-term future in an uncaring and occasionally dangerous
cosmos, some form of cosmic diaspora needs to be part of our