Mar 17, 2018
“If there’s a third world war we want to make sure there’s enough of a seed of human civilization somewhere else to bring it back and shorten the length of the dark ages” – Elon Musk, founder of SpaceX, March 11, 2018, discussing the need to colonize Mars.
Let me start by saying that colonizing other planets has been a romantic staple of science fiction going back over a century, but it is still just that – fiction. I think the potential for an extraterrestrial colony to survive let alone become self-sustaining is very small, given the hazards. Putting a Tesla roadster into solar orbit is child’s play by comparison.
In the early 2000’s I read a book called “Rare Earth”, which argued that planets like ours were rare and that the circumstances which lead to the evolution of humans and the development of civilization were thus also rare.
Then came the Kepler probe, launched in 2009, which subsequently discovered thousands of planets in a very small section of the sky. Astronomers now estimate that some 40 billion Earth-like planets may orbit the habitable zones of their stars, where water could exist as a liquid, 11 billion of which would be orbiting stars like our own. Our Earth may not be so rare.
Geologists have recently pushed back the origins of life on Earth to over 4 billion years ago, which would mean that life started on Earth very soon after the solar system formed and the planet cooled from its molten state. Although biologists have yet to create life de novo in the lab, they have determined that the biochemistry needed to form self-replicating organic molecules is pretty straightforward. Life may not be so rare.
Indeed, life may already exist elsewhere in our solar system, buried deep under the sands of Mars, which used to be an Earth-like planet, or in the vast oceans which underlie the ice-covered moons of Jupiter’s Ganymede and Saturn’s Europa.
But how about complex life and self-aware beings that create civilizations? Why has SETI, the Search for Extraterrestrial Intelligence not heard any radio signals from other civilizations, despite listening for the last 50 years or so?
Which brings us to the “Fermi Paradox”. The famous physicist’s postulate that if there are so many stars and so many planets, “Where is everybody?” Recent UFO videos notwithstanding, there is really no conclusive evidence that we have been visited by extraterrestrials and we sure haven’t heard from any.
Life may not be rare, but life like us may be because planet-sterilizing cosmic events are common or civilizations destroy themselves through ecological mismanagement and/or war.
Back to Mr. Musk and his concern that we may send ourselves the way of the dinosaurs, so we should therefore not confine ourselves to one planet. Note that dinosaurs existed over 100 million years. We have been around for only 160 thousand.
Musk’s goal is to save humanity, but what about everything between honey bees and humpback whales? Aren’t these lifeforms worth preserving? Musk ignores the fact that humans evolved in an interdependent ecological web within a very thin shell of a biosphere which would be almost impossible to artificially replicate. Stepping outside that shell anywhere else means stepping into an environment that is actively trying to kill you.
Colonizing the Moon or Mars means burrowing into the subsurface or building sealed domes. I ask, why go to Mars to do that when we can bury ourselves on Earth if things go south? Heck, let’s just avoid the need to do so in the first place. The cheaper alternative is to avoid nuclear war and to preserve our biosphere.
I close with the sage words of the late Carl Sagan, from his 1994 book, “Pale Blue Dot”, inspired by a view of Earth from the Voyager Probe, then 6.4 billion miles from Earth:
"The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand. . . There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known."