What kind of a frontier is space? Is there ever a final frontier?
Or is that the one we cross just before we get hit by Armageddon? And,
which is more likely to come first: Armageddon, the natural extinction
of man as a species, or the evolution of man into something else?
We do know quite a bit about space. This we have learned just by
watching. Which is fortunate. This is not a frontier that’s easy to
cross. We’ve been watching space for thousands of years, first with
our naked eyes, then, for the past several hundred years with ever more
powerful telescopes. If we spent the equivalent of the Apollo project
every ten years, we could probably make a manned landing on one
additional object in our solar system at least once every decade. It’s
a lot cheaper just to watch, but it’s not the same as being there.
Judging by the amount of traffic that visits our solar system (not
one confirmed incident, ever), space travel is either very hard, or
there aren’t many spacefarers in the first place. The best guesses of
our best scientists are that life arose on earth soon after the earth
was formed. One can only gather so much from a single data point, but
if life didn’t have a strong tendency to arise when the conditions are
right, it would seem that it could have taken much longer than it
actually did. That life began so promptly lends credence to the
possibility that life is likely to occur, given the right conditions.
If so, the question is: how likely are the right conditions? One of
the things we have learned by watching is that there is nothing
terribly special about our planet, earth. The sun is a pretty average
star. We aren’t located any special place within our galaxy. The
other planets in our solar system don’t seem too special. Granted,
each one of these objects is unique, but at the same time there is
nothing we know of that makes any of them special. So, just by
watching, we jump to the tentative conclusion that there ought to be
lots of other worlds that can support life. And, of all the worlds
with life, some fraction of those worlds actually has intelligent life.
We have been sending radio and TV signals for over fifty years. We
have also been listening for quite a few years, trying to pick up the
signals that might be coming from elsewhere. It seems a safe
assumption, based on this, that there is not another life form,
superior in intelligence and technology to us, within ten or twenty
light years. At least not one that has heard our signals and has
signalled us with a response. Let’s say that the best we could hope
for, assuming that we want company in the first place, is that the
nearest intelligent life is at least ten light years away. Of course,
out of all your nearest neighbors how many are good friends? That cuts
it down even more. So, if you are gregarious, the question is how hard
is it to make a new friend? If you are paranoid, or severely
anti-social, the question is how soon should you brace yourself for a
knock on your door?
Let’s imagine that we survive our ability to self-destruct, and that
we master the exploration of our solar system over the next thousand
years or so. By then, there are two reasons that we might mount an
expedition to another star. One is to explore objects farther out in
space. The other is to answer a signal. In the first case we only
need to travel a few light years (four to ten). In the second case we
will likely have to go twice as far, or farther. The minimum distance
is four light years and the maximum speed we will probably be able to
achieve is a very small fraction of the speed of light. That means a
fairly large multiple of the number of light years. The operative
words are: “large multiple…of years.”
It’s nice to delude ourselves otherwise, but there simply isn’t a
shred of evidence leading us to hope that a journey to another star
could be accomplished in less than a lifetime or two. Even the
exchange of email with another compatible lifeform is going to allow
only one or two responses in a lifetime! Let’s assume that the limits
of physics and the realm of possiblity are pretty much as we believe
them to be. Let’s speculate about the really distant future anyway.
In a few hundred (perhaps as many as a few thousand) years a new
species, nay, a new “kingdom” will emerge on this earth and begin to
compete with man. The earliest forms of this new “life” are the
computers we know today. Someday, man as a species will become
extinct. Whether we ever give rise to a new biological species before
that time is an open question. This would occur many hundreds of
thousands of years in the future. In any case, the life of this earth
will never be “crossed” or bred with life from another planet, but
there is no reason that our machines can’t be. My guess is that a
galaxy like ours gives rise to intelligent life on the order of a few
hundred to a few thousand times, starting a few billion years after it
forms into a spiral shape and over the course of its perhaps ten to
twenty billion year lifetime. In the span of this twenty billion
years, however, I would guess that organic species from different
worlds seldom, if ever, have a physical encounter. But, this would not
be true for the inorganic lifeforms that they spawn. They would not
only have encounters, but they would absorb and cross fertilize each
other.
Before a galaxy runs its lifecycle, inorganic life may be pretty
much united throughout its extent. These events in our own galaxy will
occur billions of years from now. Any trace of ourselves will be
retained only in data banks and as copies made for museums. The last
human being and the last original human artifact will have been dust
for countless millenia. As the life in our galaxy nears maturity, it
will, no doubt, attempt intergalactic crossings. These latter day
frontiers will only be crossed because of the inhuman lifespans and
attention spans eventually attained by the distant descendants of the
new lifeforms spawned by ourselves and other organic species.
Day-to-day life that far in the future will not only be stranger than
we now imagine, it will be vaster and stranger than we are equipped to
imagine.
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