The possibility of life on other planets might encourage us to think rationally and prudently about our lives on this humble globe that we call Earth.
The subject of extraterrestrial life came up last week with the publication of research in the Proceedings of the National Academy of Sciences. Geoff Marcy, an astronomer at the University of California, Berkeley, and his co-authors spent four years using the Kepler telescope to examine 42,000 sunlike stars in the Milky Way.
They discovered that about 22 percent of them have planets that appear similar in size to Earth and, more important, that orbit within the so-called Goldilocks Zone — at a distance from their stars that would permit water, if there is any, to exist in a liquid state. As we understand life, liquid water is a prerequisite for its origin.
Extrapolating from their data, these astronomers calculate that among the hundreds of billions of stars in our galaxy, some 8.8 billion planets orbit in a zone and under conditions similar to those on Earth. And our Milky Way is only one of perhaps 200 billion galaxies in the universe.
In these terms, life beyond our Earth seems not only possible, but almost inevitable.
This is an enticing prospect. Humans have long been intrigued by the possibility that our Earth isn’t the only place in the universe where life exists. This fascination has expressed itself in countless books and movies, as well as in a persistent passion for UFOs and supposed visitations by extraterrestrials.
Our hope that any intelligent life we find elsewhere in the universe will be friendly probably outweighs our fear that extraterrestrial beings will be as malevolent and scary as those depicted in books and movies like “War of the Worlds.” In fact, rather than our finding extraterrestrial beings, perhaps they will find us, because they’re more advanced than we are; indeed, maybe they can help us resolve some of our current earthly dilemmas.
But even if we’re unique in the universe, we might take some pleasure in discovering that in our (comparative) neighborhood, almost 9 billion other planets could feature conditions similar to those on Earth. These may be places that we’ll want to go someday.
Here’s the problem: Our Earth-bound civilization seems to be pushing up hard against all sorts of limits. Some believe the Earth has already exceeded its population carrying capacity, while others disagree.
But no one can reasonably argue that the planet’s resources are unlimited.
Despite meager gestures toward conservation and renewable energy, our rate of consumption continues to increase, and few real efforts are being made to bring consumption into balance with the Earth’s productivity and limited resources.
Although the perils of this imbalance are obvious — pollution, climate change, starvation, war — we’re reluctant to acknowledge them. But even those who argue that we’re not at a point of crisis can’t deny that we’re doing very little to prevent the inevitable bad effects of too many people desperate for too few resources.
The complacent assumption is that technology will rescue us, but I suspect that if there is any answer, it will be philosophical rather than technological. The story of America is consistent with the story of civilization: When local resources are exhausted, we move to new territory and take it away from the natives — by force, if necessary. When we reach territorial boundaries, we push technological limits. Philosophy might help us get over this.
But we shouldn’t let the discovery of billions of Goldilocks planets distract us from the fact that we evolved to live on this one.
Our problems will be solved here — or not at all. In the event of an extraordinarily unlikely extraterrestrial intervention, I stand corrected. But if we don’t live in the only isolated spot in the vast reaches of the universe where intelligent life can exist, still, we’d be prudent to act as if we did.