Sorry Folks There Aren't Any Space Aliens

What happens when science actually does get religious?

One of my least favorite rhetorical “gotchas” is when conservatives call science or other lefty beliefs “a religion”. Of course, part of my negative reaction to this is to the sheer hypocrisy of it all— since when do conservatives think that religion doesn’t generate epistemic truths? But I also think it is wrong on the merits. Science isn’t a religion, because at the center of religions is a concept antithetical to science— the idea that no matter what your empirical observation, you should believe what your group traditionally believed on the strength of that tradition. In science, tradition and blind belief are antithetical to the enterprise, where truth is only established through observation and experiment.

However, there is one aspect of science that definitely has some religious overtones, and it connects to what you might call a broader civic religion. And this has to with extraterrestrial intelligence.

The popularity of various forms of science fiction that tell stories of beings coming from space is, by itself, proof that humans are fascinated with the possibility of extraterrestrial intelligence. Movies like E.T. and Arrival and The Day the Earth Stood Still and Close Encounters of the Third Kind all became huge hits, with audiences connecting with the notion that the Earth would be visited by some strange beings from another world.

Nothing wrong with telling stories, of course. The problem comes when it seeps into our public policy and government, and especially when people start making claims about humans already being visited by aliens. Claims that recently have gotten a lot of publicity.

So I have to throw some cold water on this. There are no space aliens, in any sense that is relevant to humankind. (I add the latter caveat because of course it is possible that somewhere in the vast universe, at some point in time, there is, was, or will be intelligent life forms. It’s just that such life forms, if they did, do, or will exist, are not relevant to humans.)

Maybe we should start with that caveat I just threw out there. Why did I say “did, do, or will exist”? Well, because of something called the speed of light. People, I am sure, understand that light takes time to travel a distance of ground, but Einsteinian physics says much more than that. The speed of light is an absolute speed limit for the transmission of information, including matter, through the universe. You can’t go faster than light.

And this poses a problem for positing interstellar travel of any sort by any beings. The closest star to Earth is 4 light years away, meaning if you somehow accelerated a spacecraft from it, traveled at light speed, and slowed down to reach Earth, it would take 4 years to get here. Every other star is farther away- tens of light years, hundreds of light years, thousands of light years, millions of light years, etc. The farthest objects away from us in the known universe are over 13 billion light years away.

Think about what that means. It means that if there’s intelligent life on some random world somewhere, it would take those beings tens or hundreds or thousands or millions or billions of years just to get here. But there’s also two other implications of the speed of light.

First, in actuality, you can’t even travel at light speed. Remember Einstein’s famous equation E=MC squared? Well, the point of that is that as you propel matter closer and closer to light speed, you have to expend more and more energy. Indeed, the reason the speed of light is the universe’s speed limit is because it is the point where you would need infinite amounts of energy to propel mass. Obviously infinite amounts of energy do not exist; therefore, you cannot go that fast. So in the real world, you can only accelerate to a speed that commensurate with the amount of energy available. That energy either has to be brought on board (resulting in an extremely heavy spacecraft as you try to accelerate faster and faster) or it has to be collected (resulting in, perhaps, an astronomically large bank of photovoltaic cells to collect starlight). Or, most likely, you just have to go much slower because of the energy constraints. So if you go 1/10th light speed (a speed no Earth spacecraft has come close to achieving), you are dealing with 40 years to get from the closest star to Earth, and longer and longer times beyond that. (In fact, the energy needs are even greater than I am saying, because having reached super-fast speed, you will need to decelerate again when you get to earth. A spacecraft crashing into Earth at 1/10th light speed would explode like a giant thermonuclear bomb and do massive destruction. We would know about it. So the spacecraft would have to carry enough fuel on its premises to slow the craft down.)

The second thing to understand is that the reason we know about planets and stars, and the reason anyone hypothetically on such planets and stars would know about us, is because of radio and light waves, which travel at the speed of light. The premise of alien visit theories, after all, is that the aliens detect us on earth and send a craft to investigate. Well, we started using radio waves extensively early in the 20th Century. So it has been just over 100 years. Which means that for the vast vast majority of stars and planets out there, our radio waves haven’t even reached them yet. They would not know we are here.

And of course they would have to both have the technology and energy resources and the time to put together a spacecraft that could come visit us, and then take the time to travel over here. So much of that 100 year window is taken up with that, meaning the alien civilization would have to be at a very nearby star. But even more notably, such a civilization would also need to do this while not using radio waves themselves, because if they were using it, we would have detected the signals during the same window! Seems highly unlikely.

And especially unlikely when it comes to the claims that the alien visits happened long ago and were covered up by the government. If aliens arrived at Area 51 in the 1950’s (a popular theory), instead of a 100 year window of radio signals, the window would be 40 years. So someone must have literally heard our signals at Alpha Centauri, 4 light years away, and immediately sent out a craft at 1/10th light speed that we nonetheless never detected. It’s physically impossible.

I might add there are other unrealities relating to the claims of alien visits. For instance, if aliens did visit, why would they do it secretly? Why would they appear briefly over some farm in North Dakota, or crash a single spacecraft into Area 51? I would assume that were alien intelligence actually going to send craft to Earth, we would know it. They would announce themselves. And they would send enough aliens and enough spacecraft to protect themselves in case earthlings turned out to be hostile. The premise of all these space alien theories is that the beings are intelligent enough to build spacecraft we cannot build to travel speeds we cannot travel, but are otherwise complete idiots.

But, you might say, don’t a lot of professional astronomers believe in space aliens? Yeah, they do, and this gets me back to the point of science and religion. There’s no science behind the belief in space aliens. There have been no signals, there is no evidence of spacecraft that have visited Earth. There’s nothing in terms of actual empirical evidence. What there is, is a wish. People like Carl Sagan got into astronomy, in part, because the notion of making contact with space aliens appealed to them. It’s the dream, in the same way a Christian dreams of Heaven.

But the harsh reality is this— even if there is extraterrestrial intelligence, we will never contact them. We don’t know how long human civilization will last, but bear in mind there are all sorts of threats, from the climate to asteroids to super-volcanos to nuclear war. We might last thousands of years longer. Perhaps we will last longer than that. But due to the speed of light, it will take over 13 billion years for our radio signals to reach the farthest ends of the observed universe, and of course, by that time, the universe will have expanded farther still. By the time our radio signals cross the observed universe, the Sun will have incinerated the Earth and gone through its stellar death cycle itself. We will be long gone.

So suppose there is intelligent life somewhere right now. Well, it might be on a planet 6 billion light years from us. And because of that, our paths will never cross. By the time our signals reach there, and its signals reach here, we will be long gone. The vastness of the universe and the vastness of time means that even if there is extraterrestrial intelligence, the chances of it ever coming into contact with us is basically nil. Civilizations destroy themselves in too short a time frame, or get felled by natural disasters.

As I said, the religious aspect of this filters into our public policy as well. We actually spend money trying to contact space aliens. We have a Search for Extraterrestrial Intelligence (which hasn’t, and won’t, find any) and we actually attached messages to the space aliens on the Pioneer and Voyager spacecraft. The dream shall, apparently, never die.

But we need to get real. And that includes astronomers. It isn’t that we are necessarily “alone in the universe” in the entire sense of the term, but we are functionally alone. If anyone else is out there, they won’t be calling and they won’t be visiting. We have all sorts of human problems to solve. Let’s put aside the talk of space aliens and solve them.