By David K. Johnson, Ph.D., King’s College
There are so many alien-themed movies that one might be mistaken in thinking that alien life is quite common. But, how many alien civilizations could be there in the universe, and what are the chances of finding them, or of them finding the Earth? More importantly, how would people react if they were finally able to communicate with an alien civilization?
Drake Equation
To determine the possibility of finding alien life, scientist Frank Drake developed an equation to determine the likelihood of radio contact with aliens. It’s called the Drake equation.
Take the rate of formation of stars in our galaxy capable of supporting intelligent life, multiply by the fraction of those stars with planets, then by the fraction of those planets capable of supporting any sort of life, then by the fraction of those on which any life evolves, and then the faction of life that evolves into intelligent life, and this gives a figure of how many intelligent species there are in our galaxy.
Next, estimate what fraction of intelligent life will develop civilizations capable of sending communications, and factor in how long those alien civilizations will survive, and how likely it is that radio contact will ever be made can be calculated.
The problem is, although there is a rough estimate on some of these numbers, there is not enough information to fill them all in. How often does life evolve on planets like Earth? Are planets like Earth the only ones capable of supporting life? How often does it become intelligent? How long does it last? This can really only be estimated.
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No Alien Civilization?
On liberal estimates, the galaxy should be teeming with intelligent life sending out signals. But the absence of such signals is said to be evidence that all civilizations, including alien civilizations, annihilate themselves almost as soon as they develop such capabilities. This wouldn’t bode well.
On conservative estimates, however, the possibility of intelligent life in our galaxy is relativity rare; humans might be all there is. Of course, the universe contains about two trillion galaxies—so it’s likely that alien civilizations evolved somewhere else in the universe.
But given the long distances between galaxies, detecting signals from them shouldn’t really be expected. So not hearing any signals isn’t necessarily a warning.
This is a transcript from the video series Sci-Phi: Science Fiction as Philosophy. Watch it now, on Wondrium.
The Problem of Interstellar Travel
Given the enormous distances between stars and the fact that faster than light travel is theoretically impossible, it just doesn’t seem that physical travel from one planet to another is easy. Still, given other considerations, visits from alien civilizations might at least be possible. Sci-fi writer Arthur C. Clarke put it best in 2001: A Space Odyssey:
Even if it took centuries to travel from star to star … this might be no obstacle to sufficiently determined explorers. The technique of hibernation … was one possible answer. Another was the self-contained artificial world, embarking on voyages that might last for many generations. [And] why should one assume that all intelligent species were as short-lived as Man?
There might be creatures in the universe to whom a thousand-year voyage would present nothing more than slight boredom… ‘[And a]re we certain that the speed of light is an unbreakable barrier?’ … even if [it] could not be defied, [it] might be evaded.
Indeed, what would make such long journeys difficult is the fragility of biological bodies. But what if those bodies are replaced with machines? Or what if intelligent machines could be built and sent out to explore?
Even journeys that would take millions of years would be easy. It’s no coincidence that the first explorers of the universe were machines—the Voyager spacecrafts, which set off in 1977.
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The Effect of Discovering Alien Civilization
How would the discovery of alien civilizations affect society? Wouldn’t aliens likely want to destroy humans? After all, every time indigenous lifeforms on Earth have come into contact with ‘alien life’—like when the British found the aborigines and the Europeans found the Native Americans—things did not go so well for the natives.
Why would it be any different with ‘outer space aliens’? The effect on society could be devastating. On the flip side, an alien visitation could turn out to be the best thing that ever happened to humans.
Even an alien radio signal would affect society in both good and bad ways. On one hand, there might be fighting over who gets to send a reply. On the other, it might make the differences that have been traditionally fought over seem insignificant.
Aliens and Religious Beliefs
Astronomer David Weintraub thinks knowledge of aliens would be damaging to Western religions. Traditionally, they’ve held that humans are special, and at the center of God’s attention. This is why the Church so vehemently objected when Copernicus and Galileo overturned that notion.
But that was merely a symbolic defeat. After all, if humans are unique in the universe, their status is still special. But if the universe is full of life, the discovery of alien life would undo the assumptions of Western religion. Christianity seems especially susceptible. Think about it: Did Jesus die for the sins of aliens, too?
It would seem so since most Christian denominations maintain that Christ redeemed all of creation. Of course, if the aliens say that 2000 years ago, they received a divine revelation that said, “Your sins can be forgiven because of the sacrifice of a god/man on the planet Earth; here’s directions, go now”, that would be pretty good evidence in favor of Christianity!
But if aliens have never heard of Jesus, wouldn’t that be evidence against Christianity? Anyway, contact with alien life would change the way so many things are viewed.
Common Questions about the Drake Equation and Contacting an Alien Civilization
To determine the possibility of finding alien life, scientist Frank Drake developed an equation to determine the likelihood of radio contact with aliens. It’s called the Drake equation.
The Drake equation reveals several possibilities. On liberal estimates, the galaxy should be full of intelligent life sending out signals. But the absence of such signals is said to be evidence that civilizations annihilate themselves almost as soon as they develop such capabilities. On conservative estimates, the possibility of intelligent life in our galaxy is relativity rare. But given the long distances between galaxies, detecting signals from them shouldn’t really be expected.
It is possible that contact with an alien civilization would be disastrous, as the aliens may want to destroy humans.
