In my last Post, I talked about the existence of
extraterrestrial life, and where and how we may find it. In this one, I
speculate what may happen if we discover it.
To start out, what exactly is “life”? This itself is a hotly
debated topic and there are lots of definitions and debates. A good source of
information on this topic is a series of lectures titled “Origins of Life” by
Robert Hazen, available through The Great Courses. According to him, here is
the definition used by NASA: “Life is a self sustained chemical system capable
of Darwinian evolution." So, a key question in research being done on
origin of life is---How did a geochemical world with ocean, air and rocks
containing organic molecules transfer itself into a biochemical world
containing self-replicating chemical molecules that compete and evolve? At this
point no one knows for sure how this happened but there are three scenarios, according
to Professor Hazen: metabolism first scenario, genetic first scenario and a
cooperative scenario (which combines the previous two). No need to go into
details but the fact that we are down to just three possible scientific
explanations is quite heartening.
There are two reasons why I mention all this. First, since
we still have not found out exactly how life began on earth, there is still a
possibility that life has emerged only once in the universe, just on earth,
because the final step is so complex, and requires so many preconditions. I
think this is highly unlikely, but it is possible. The second reason is that
since we are so close to finding
scientific theory of how life emerged from a bunch of chemicals; it is highly
unlikely that there was a supreme being involved in creating us, “in his
image.”
Finding life outside of earth will put an end to both these
debates. Even though the exact transition from geochemical to biochemical may
remain a mystery for a few more years, the fact that there is life elsewhere
would prove that the final step is not that complex and the universe may be
teeming with life. Also, the religious people may need to rethink some of their
assumptions.
The most likely place where we would find evidence of
primitive life would be Mars. It is likely to be microbes or their fossils, not
Martians. If they look like our microbes, there are two possibilities. One is
that the same process that created life on earth did so on Mars. Also, it is
possible that life emerged on Mars and came to earth on a meteorite that
originated on Mars. If that turns out to be the explanation, we would be back
to square one on the question of life’s existence elsewhere, besides Mars. Of
course, if we find similar life on, say Europa or Enceladus, the assertion of
more than one origin of life would be quite conclusive.
As I had mentioned in my previous Post, it is highly
unlikely that we would find life that is at the same stage of evolution as us.
We separated from apes only seven million years ago, and Homo Sapiens have been
around for only 200,000 years. In the same amount of time in the future,
perhaps much less, we would be unrecognizable. A few million years are nothing
in the life of our universe, so how can we expect to find a civilization to
looks like ours at this narrow slot of time? Or communicates using electromagnetic
signals?
That would explain why the SETI program---one that listens
to signals coming from outer space as evidence of intelligent life---has
yielded nothing thus far. A wonderful book written by Paul Davis, “The Eerie
Silence” refers to that fact.
That means that if we
don’t find microbes, we will find life at another extreme…so advanced and
sophisticated that we cannot even imagine. Thosee are the stages that are not
as transient as our current one.
In his above referenced book, Paul Davis cites three Types of
civilization as defined by a Russian astronomer, Nikolai Kardashev. These Types,
based simply on energy consumption are: Type I that uses all energy resources
from its home planet, Type II which requires total energy output from its
parent star, and Type III, from whole galaxy. One would be able to detect Type
II and III civilizations based on the energy footprints they leave.
Of course, it is entirely possible, according to Davis that
“biological intelligence is only a transitory phenomenon, a fleeting phase in
the evolution of intelligence in the universe. If we ever encounter
extraterrestrial intelligence, it is overwhelmingly likely to be
post-biological in nature.” It is not clear what impact such intelligence would
create on its physical surroundings and how we would be able to detect it. In fact, it does not even fit the definition
of life that NASA is using in its search.
The most likely scenario is that we will find such advanced
civilizations not the other way around. I do not believe in UFOs and curious
aliens snooping around. Why would they? We are an insignificant planet of an
insignificant star, virtually undetectable.
Sure, we have been emitting TV and radio signals for a few decades, but
they have not reached far and are most likely undetectable from noise. That
eliminates most of the science fiction type of close encounters.
After finding an advanced civilization, it may take forever
to establish contact, given how far in the universe they are likely to be, and
our ability to emit a powerful enough signal so they would detect us. There are
eminent scientists, like Stephen Hawkins, who say that we should not try to contact them. Just stay silent. They may not be
benevolent and wipe us out in an instance. He cites what happened to the Native
Americans as an example of what can happen to us.
So, it may be that we will not have any interactions with
aliens even if we detect them. So, we will not befit from their advanced
technologies, and the only practical impact of such a monumental discovery will
on our religious beliefs. That could be significant, but a more important
effect such a discovery will be to give us confidence
that we may survive our self-destructive tendencies.
That by itself would
be great news.
