I have written several blogs on the origin or emergence of life—here on Earth or anywhere. With every passing day science gets closer to having some answers about how life began. We are deriving better and better hypotheses about life's origins. Where just a few decades ago science had little idea of how it could have happened, we now seem to be closing in on an explanation.
We are beginning to understand that the universe is filled with all kinds of organic molecules, and we're also discovering that these molecules seem to have a predilection for coming together and growing evermore complex, and even to reproduce. Reproduction is a basic quality of life. It almost seems as if the emergence of life is inevitable, given favorable conditions.
Although we may soon reach the point where we can say with confidence that, given the right conditions, life will arise, we may never be able to describe quite how. It may be that the beginning of life is what's termed an “emergent process”—something that cannot be predicted from initial conditions. As an example, each ant in a colony is an extremely simple critter—responding to only the most primitive stimuli; but put thousands of ants together and you have a superorganism that performs sophisticated tasks. As another example, a starling is no match for a hawk, if caught flying alone. But put thousands of starlings together in what's called a “murmuring,” and you observe the group shifting its shape instantaneously, to confuse an attacking hawk. These are examples of emergent processes in nature.
All we know at present is that life emerged on Earth, not long after the planet was formed. We are hard at work to figure out how. But are we an example of life that arose many places, or are we alone in the universe? The answer to that question seemed remote until recently. We now know that conditions for life seem to be present on Jupiter's moon Europa and Saturn's moon Enceladus. Before long we will send spacecraft to these moons that will measure for and possibly detect life. We may soon have similar answers for Mars. Was there once life on Mars? Is it still there now—maybe not running around on the surface, but in the form of microbes underground?
Step by step, science closes in on answers to these questions. Just as we once did not know that microorganisms inhabit our bodies and sometimes lead to diseases—until we built microscopes and medical theories to prove it—someday in the future we may look back with the solid knowledge of how life began, and even that it began elsewhere too. While a mystery to us, it may be seen as obvious to our distant heirs.