By Mark Rollins
I wish I could be as sanguine about the possibility of finding life on other planets as The Davis Enterprise is in its recent editorial. In fact, I find it disconcerting that making contact with life elsewhere in our galaxy is now a foregone conclusion, even though the editors were not referring specifically to intelligent life.
I believe that is what was implied in the piece and in any case, that is where our ultimate interest lies. But is it realistic and should we do it?
Decades ago, exobiologists calculated, using the Green Bank formula, that there were billions of planets that could sustain life, so this new calculation of 40 billion is more specific but not surprising. In 1992, biologist Jared Diamond estimated conservatively, based on that formula, that there should be 1 million planets within a few dozen light-years of us that have advanced life. So, he asked, where are the radio signals that we should be receiving and where are the flying saucers?
In his book “The Third Chimpanzee,” Diamond argued that it is extremely unlikely there is advanced life elsewhere because of convergent evolution. His fascinating theory is based on woodpeckers. Woodpecking is an obviously valuable adaptation on this planet but has been extremely difficult to evolve, as has digesting cellulose efficiently (microbes in cow’s intestines), and growing one’s own food (humans and leafcutter ants).
So the point is that splendid opportunities are not always taken, including the invention of radio transmission. Not many animals converged to evolve these beneficial traits like they did flight and sight.
Are our radios a fluke, Diamond asked, unlikely to have come about on other planets? In other words, if not very many animals on Earth exploited these behavioral niches, why would we expect species on other planets to have exploited the radio transmission niche as an evolutionary adaptation?
As far as the chances of finding life on other planets, it may be more a question of how many planets have life going on at the precise time that we spot them. After all, it has only been a very short time that we have had radios to send messages and search outer space — only several decades since we could send a radio signal a very short distance. And we may not exist much longer as a species based on the weaponry we have developed and how we are decimating the biosphere.
So it is not just a matter of finding the right place in our galaxy where there may be life. It is also a matter of discovering something at precisely the right time. We are more likely to stumble on a planet that used to have life, or that doesn’t have life yet, than one that has life now.
Astrobiologists today have decided that life on other planets is inevitable, which is the opposite of the consensus of a few decades ago. However, this new belief is only based on a hunch. There is no new evidence of the likeliness of life forming elsewhere. In fact, there are those who still believe that the appearance of life from simple chemicals is so rare an event and relies on so many unlikely things happening in a perfect sequence that it is almost a foregone conclusion that it happened only once. The chances for life appearing may be one in a trillion trillion. There are nowhere near that many possibilities in the Goldilocks corridor.
The right conditions for life is only one element to consider. Somehow, chemicals had to start forming zipper-like chains that could replicate themselves. How and why that happened here on Earth is still a guess at best, despite the good explanation of how it may have worked, by Richard Dawkins in “The Selfish Gene” in 1976.
As regards whether we should be feverishly searching for extraterrestrials, we know that societies that deem themselves superior to other societies always exploit and try to dominate or simply destroy those “inferior” societies.
Why should we think that beings on other planets who are advanced enough to make contact with us would be benevolent? I think we should be glad that we have this quiet little corner of the galaxy to ourselves for the time being.
Homo sapiens became highly intelligent because they had a huge brain and because they became highly social, which involved discovering fire and cooking and eating meat. We needed to eat meat because we needed more calories than we could get from just eating simple wild plants. Wild plants were just not high enough in nutrients to fuel big brains. Our brains use up 25 percent of our caloric intake. We are unique in this way compared to all other animals.
We also could advance our culture and have more free time to innovate and plot and scheme when we didn’t have to spend most of the day searching for wild plant food.
If other intelligent life in the galaxy advanced by eating meat, their brains may use up 75 percent of their calories, and they may need much more meat than we do. And maybe they, like humans, are at the top of the food chain.
One thing is sure, if we do find space aliens, we’d better hope they did not follow the same meat-eating, aggressive, patriarchal evolutionary path that we did, and that they can get energy for their huge brains from the ambient radiation. We’d better keep our fingers crossed that they became advanced in a totally different way that entailed using wisdom that we do not possess, like the wisdom that says “don’t do things just because you can.”
But that, I believe, is a tall order.
— Mark Rollins is a Davis resident.