By
Rudresh Pandey
Some
of these stellar systems could have formed 5 billion years before the Earth. So
why is the galaxy not crawling with self designing mechanical or biological
life forms?
Why
hasn't the Earth been visited, and even colonized?
Is
it possible that we humans will come across any aliens?
Or
we already have aliens, ETs and UFOs visiting our planet?
To
me answer to the last question is simple with a very simple logic. Ay visit by
a UFO, any ETs or any aliens from outer space would be much more obvious, and
probably unpleasant.
If
you buy this logic the obvious question, which must be answered to support this
logic, is –
What
is the explanation of why we have not been visited?
One
possibility is that the argument, about the appearance of life on Earth spontaneously,
is wrong. Maybe the probability of life spontaneously appearing is so low, that
Earth is the only planet in the galaxy, or in the observable universe, in which
it happened.
Another
possibility is that there was a reasonable probability of forming self
reproducing systems, like cells, but that most of these forms of life did not
evolve intelligence. We are used to thinking of intelligent life, as an
inevitable consequence of evolution.
But
it is more likely that evolution is a random process, with intelligence as only
one of a large number of possible outcomes.
It
is very important to understand if intelligence has any long-term survival
value. Bacteria, and other single cell organisms, will live on, if all other
life on Earth is wiped out by our actions.
There
is support for the view that intelligence, was an unlikely development for life
on Earth, from the chronology of evolution. It took a very long time, two and a
half billion years, to go from single cells to multi-cell beings, which are a necessary
precursor to intelligence. This is a good fraction of the total time available,
before the Sun blows up. So it would be consistent with the hypothesis, that
the probability for life to develop intelligence is low. In this case, we might
expect to find many other life forms in the galaxy, but we are unlikely to find
intelligent life.
Another
way, in which life could fail to develop to an intelligent stage, would be if
an asteroid or comet were to collide with the planet. It is thought the collision
of a rather smaller body with the Earth, about 70 million years ago, was
responsible for the extinction of the dinosaurs. A few small early mammals
survived, but anything as large as a human, would have almost certainly been
wiped out.
It
is difficult to say how often such collisions occur, but a reasonable guess
might be every twenty million years, on average. If this figure is correct, it
would mean that intelligent life on Earth has developed only because of the
lucky chance that there have been no major collisions in the last 70 million
years. Other planets in the galaxy, on which life has developed, may not have
had a long enough collision free period to evolve intelligent beings.
Another
possibility is that there is a reasonable probability for life to form, and to
evolve to intelligent beings and develop themselves to inter planetary travel but
at that point, the system becomes unstable, and the intelligent life destroys
itself. We too may end up with a nuclear war or something similar.
Maybe
there are other forms of intelligent life out there, but that we have been ignored.
This part of universe is like an African desert which gets very few tourists.
The
most important part in this debate is not if there is any life out there. We
should really think, Should we be look forward to meet a more advanced
civilization?
Don’t
forget what happened to people of America meeting Columbus.
