NASA’s Kepler spacecraft has been roaming around the cosmos snapping pictures we never could manage when earthbound. According to the January 7, 2015 New York Times, so far Kepler has located 4,175 planets that might harbor life as we know it. These discoveries will provide welcome support for people who look at the multitude of stars and planets and wonder what the odds are of finding something resembling life on other planets.
Those odds depend on what we’re looking for. Humanoid types that look more or less like us, as in Star Trek? The odds against that are much greater than if we are just looking for life in general, in the biological sense.
How do we define life? Life is things that are born, grow up and reproduce, and wither away and die, in a cycle that continues through replication over multiple generations. It means things that evolve through natural selection, as defined by Darwin and refined since then.
Conceivably, such life could be based on silicon rather than carbon, and there may be other chemical foundations for life that we haven’t yet discovered. The more inclusive our definition of life, the better the odds of finding some form of it out in the stars somewhere.
Do we have to limit our search to life in the biological sense? If we expand the scope of our search to anything on an evolutionary track, as I defined evolution in my “Short History”, this should further improve our chances of finding something. That ‘something’ might not look ‘alive’, but if it looks like it’s evolving, in the sense of becoming more complex, with more power concentrated in the individual entity, it would be worth a close look. After all, our own ability to produce the ideas that have enabled us to achieve what we call civilization arises not from brain’s living matter, but from neural electromagnetic patterns complex enough to enable consciousness and creativity. Could there be other evolutionary tracks capable of leading to this level of complex thought patterns? Would such a track necessarily have to be biological as in our case?
Even on a planet similar to ours, there’s no logical reason to expect that life has evolved along the same lines as the ones familiar to us. In fact, even on favored planets we cannot reasonably expect that life has evolved at all, given what we know about the origin of life here at home, and the amazingly improbable sets of circumstances that made it possible. It is more reasonable, however, to expect that if there are millions such planets, life will have started on at least a few. Even on those exceptional few, however, life would likely branch out in ways that made it very different from the flora and fauna here on earth.
It is reasonable to expect that on a few of the planets that are capable of sustaining life as we know it, we can seed them with life forms capable of sustaining themselves in their new home. In a distant future, prospects for terraforming may become a reality.
In that distant future we might finally run into some form of alien intelligence. Perhaps it would be indigenous to its home planet, or it might be a planet the alien intelligence seeded, having arrived ahead of us.
All the above Star Trek-like speculation will remain fantasy until and unless we learn to travel a lot faster than the speed of light. We have to have a warp drive of sorts or we’ll never get beyond a minute corner of our galaxy, within which the possibilities of engaging with extraterrestrial intelligence will remain very limited.
We define life itself in these terms: if a plant or animal is born and reproduces and dies, it lives. An automobile gets old and ends up as scrap, but it is not parented like living things, it doesn’t grow and learn and then reproduce iself, and so it isn’t alive. But the concept of an automobile evolved over multiple gererations, as newer and more efficient models replaced older ones. It follows that evolution as we have defined it is a process that can operate under various ways, according to a varity of rules.
Human culture evolved out of natural selection and made possible a different form of evolution in which ideas, theories, and techniques evolved and flourished according to their own patterns, distinct from the ones governing biological evolution through natural selection.
So, first question: is evolution possible without life? If so, could it have evolved independently or must it have evolved out of something we would consider alive, as in our case?