Beyond UFOs by Bennett Jeffrey O

Author:Bennett, Jeffrey O.
Language: eng
Format: epub
Publisher: Princeton University Press
Published: 2008-06-15T00:00:00+00:00

BEYOND UFOS

If we step back to summarize what our study of life on Earth tells us about the possibilities for life elsewhere, I believe we can draw two key lessons. First, while the single example of Earth can never prove anything, since we are dealing with statistics of one, our understanding of life on this planet gives us good reason to think that microbial life will prove to be common throughout the universe. A century from now, I suspect we’ll know of many other worlds with microbial life, including a few right here in our own solar system and many more beyond. The second lesson is that the transition from microbial to complex is much more difficult, and we do not yet understand it well enough to be able to make clear statements about whether such a transition would be rare or common. But there is one thing we can say, and it will bring us to the topic of the next chapter.

Even if you accept my guess that intelligence is an inevitable outcome once you get animal life, there’s no guarantee of ever getting even that far. Moreover, life on most worlds probably cannot get that far, because the nature of the worlds themselves won’t allow it. For example, if Venus or Mars ever had life, the current conditions on those planets would limit any surviving life to living in only a few places, such as in water-infiltrated underground rocks on Mars, or in droplets of acidic water in the clouds of Venus. It’s hard to imagine anything beyond microbial life surviving under such constraints.

If life is going to get beyond the basics, it needs a planet not only where hospitable conditions make possible an origin of life, but where those conditions remain stable for the billions of years necessary to give life a chance to take itself to the next level. In our solar system, Earth is the only world that has had such conditions over the long haul. Indeed, because we have not yet discovered any Earth-size planets around other stars, let alone Earth-like planets, for the moment Earth remains the only planet we know of in the universe on which the planetary conditions gave evolution the opening it needed to produce intelligence. It is therefore time for us to explore just what it is that makes Earth so unique among the known worlds.

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