Monday, April 26, 2010

Will Science Discover Earth?

In the science news the other day was this headline: “Astronomers Spy 32 New Exoplanets, Galaxy Packed with 'Super-Earths.'” That brings the total of confirmed planet discoveries to 400. The European Southern Observatory made the discoveries using a technology called the High Accuracy Radial Velocity Planet Searcher, or HARPS. The smallest planet in the group was five times the size of Earth.

Most of the time, I’m out of step with the conventional wisdom, a fact that hasn’t bothered me for a long time. So I’ll ask: this may be news, but why is there so much interest in planets outside our solar system? Why this research? Because we have the technology? Because we can?

Aside from the usual scientific curiosity about the true nature of the universe, what drives this effort is the possibility that there may be intelligent life on other planets. That’s what grabs people’s attention. That’s what captures the imagination, gets people excited and gets budgets approved. Scientists fan the flames of this interest by claiming that there may be millions of earth-like planets throughout our galaxy.

Even if this were true—and I certainly doubt it—there are a few things they always fail to mention.

First, a planet identical to earth in size and orbit is no guarantee at all that intelligent life exists there. Single-celled life appeared on earth after a billion and a half years—a momentous event. But life didn’t evolve into multi-celled creatures until another billion and a half years later. This all-important change happened because of an extraordinary event—a thick layer of ice covered the entire planet. This killed off nearly all the single-celled creatures. The only survivors were mutants that had greater resilience—the first multi-celled creatures. The existence of these new species pumped oxygen into the atmosphere, slowly changing it to the air mixture we enjoy today. If that global glaciation hadn’t occurred, there might still be only single-celled life forms on Earth today.

This was just one of many chance events that changed the course of Earth’s history. Another was the large asteroid that struck Earth about 65 million years ago, causing the death of most species, including all the dinosaurs. A few small mammals species somehow survived and flourished, and we evolved from these creatures. Without this random catastrophe, humans would not exist today.

So by chance, Intelligent life did happen on our planet. But how long has it existed? What defines “intelligent”? Well, humans developed writing about 6,000 years ago, but to be generous, let’s go back about 100,000 years to the early Neanderthals. Even though they probably had no spoken language and their mentality was more like that of animals, we’ll say that intelligent life has been on this planet for that entire period. That means that Earth has had no intelligent life for 99.99% of its 4.5 billion-year existence.

And then there is the matter of what form intelligent alien life could take. Conditioned by Hollywood, we imagine human-like creatures with pairs of eyes and ears, walking upright, grasping with hands similar to our own. The truth would be nothing like that. Intelligent life could take any form at all to survive on an alien planet. If intelligent life exists out there, it will have evolved in a different atmosphere, a different gravity, and under vastly different conditions. The words “culture,” “values,” and “intelligence” would certainly seem strange when applied to such creatures, they will be so unlike us.

Contrary to the popular view, I believe that if intelligent life does exist beyond our solar system, it would not make sense to reach out and make contact with it. I think of the Aztecs, who encountered the alien Spanish, fellow human beings who arrived on their shores over 500 years ago. The Spanish nearly destroyed them all. But not with their weapons. With their germs.

And of course we couldn’t reach out to it. It’s too far to go.

So to me, all this effort to seek life on alien worlds is ridiculously romantic. It’s a dead-end, unworthy goal. From a practical, realistic perspective, as a culture we should ask ourselves how much more of this kind of science we want to pay for. When can we just say, yes, there probably is intelligent life out there somewhere, but we are never, ever going to communicate with it.


Jim said...

Hi Denny,

Just discovered your blog and found it interesting. I completely disagree with your statement, "So to me, all this effort to seek life on alien worlds is ridiculously romantic. It’s a dead-end, unworthy goal" in your blog post entitled "Will Science Discover Earth?"

Luckily, there are enough people who think it is a good idea that it will continue. If life is found elsewhere, it would provide an enormous opportunity to learn. The life we find will either be very primitive or vastly more advanced than we. In either case, could begin to learn about another biology, and, in the process, begin to understand much more about our own. If the other life is intelligent and very advanced, we could learn about how they survived and if they have made contact other civilizations in the universe.

The discovery of extra-terrestrial life would be the single most important discovery of our species. As you say, there is probably very little chance we could ever "meet up" so there would be nothing like a War of the Worlds type of scenario to worry about.

Just wanted to post my response. I do see and understand your "so what?" perspective but I think the possibility and opportunity for the human species to advance as a result of such contact are far to great to be ignored.

Sean said...

I agree completely that searching for E.T. is a big waste of money. While I do think life is very probable out there, it would be so, so far away that the chances of its brief civilized period matching ours in such a way that we'd receive a signal is pretty absurd.

Alien however is probably more like us that you might think. Many aspects of life... RNA, DNA, organisms, etc... are pretty much not chance but basically the only way atoms and molecules could form replicating systems. So it wouldn't surprise me at all if other planets have fish, plants, mammals.

But we've only been civilized a few thousand years and only been transmitting signals for a few decades. In astronomical time that's a drop in the ocean.

All the funds and computing power wasted on SETI could have been put forth towards researching cures for cancer and other diseases... or researching more efficient energy production... or dozens of other big, real-life problems.