It's best we don't spread our misery to the stars

Milky Way, photo by Philippe Donn

A few weeks ago, I wrote something about how it would be regrettable—as in undesirable, lamentable, unfortunate, sad—if we found out that life exists elsewhere in the universe. I was mainly referring to the possible discovery, made by the James Webb Space Telescope, of chemical compounds in the atmosphere of an exoplanet that could only be produced by living organisms. The confirmation of this discovery after peer review could reveal to us that the phenomenon of life is likely something common.

And even if most of it turns out to be microbial life, given the size of the observable universe, the possibility of Darwinian evolution producing sentient life many times over would be clearly present. That is, even if the rare Earth hypothesis is correct, the discovery of a nearby exoplanet with at least microbial life in it would open the doors to the possibility that, although rare, sentient life would arise here and there in the vastness of space.

That means that pain and suffering could be multiplied by an unimaginable number, especially when we consider deep time: the 14 billion years since the Big Bang and the future trillions upon trillions of years before the universe dies out. Yet, there's another way for this multiplication of suffering to occur, even if it turns out that there's no life out there, or—and this would be virtually impossible to ascertain—if somehow we could confirm that only microbial life existed outside of our own planet. I'm referring to interstellar travel, which could lead us to colonize different solar systems.

After reading someone discuss which they would rather have: the discovery of life on other planets or humanity inventing technology for practical interstellar travel, the thought arose again in my mind that neither would be desirable. But, assuming we must chose between one or the other, I guess I'd rather us never finding out abiogenesis occurred anywhere else in the observable universe while inventing interstellar travel than the opposite happening.

Let me explain the reason.

Unless we became gods capable of disregarding every law of physics, even in the best scenarios, we likely wouldn't be able to colonize multiple galaxies, no matter how incredible and advanced our technology becomes in the future. Most of the observable universe is already beyond our reach even if we could somehow travel at the speed of light, or even faster. Also, it's highly unlikely that we'd be able to technobabble our way out of the heat death of the universe, which will be the likely end of our cosmos. Heat death will happen in the far future, when universal entropy approaches a maximum point and no work can be performed.

So, even in amazingly optimistic scenarios, eventually humanity's future descendants will fade away together with everything else in existence. And, remember, even in this optimistic scenario, our ability to spread life across the stars will have a limit: we will never be able to reach most of the observable universe. We are unlikely to leave our own cosmic neighborhood, our own galaxy—and maybe Andromeda, which is headed our way and will collide with the Milky Way in 4 billion years.

Going back to our choice: let's assume we can either live in a reality in which we discover alien life or live in a reality in which we invent interstellar travel and colonize our galaxy. It is less bad to only have humanity invent interstellar travel and colonize the galaxy, because no matter how advanced we become technologically, we'll never be able to fill all corners of the universe with sentience—only nature would be able to do that, which is why one hopes the phenomenon of life is indeed something very rare.

However, it's still best that we don't spread our misery to the stars, even those we could maybe reach one day with interstellar technology, regardless of nature having sprung life elsewhere in the universe or not. The scenario we can hope for is that we'll neither discover life elsewhere in the universe nor invent practical ways to travel across interstellar space. The best scenario, given the amount of suffering the only planet we know to contain life has had for hundreds of millions of years, is for life to be confined here and, eventually, for life to die out in the next one billion years, with with the expansion of our Sun.

by Fernando Olszewski