But, seriously, that alien signal…
No. Seriously. That so-called “alien” radio signal is, by pretty much every measure available, a big nothingburger with extra nothingsauce.
So in case you’ve missed it, this little story came out the other day: the discovery of an extremely strong radio signal coming from a relatively nearby star system. Cool.
Now before we go too deep into alien territory here, there’s a few important caveats to dispense with.
- Said signal was detected once, at 6:01 p.m., on May 15, 2015, from a telescope in Zelenchukskaya, Karachay-Cherkess Republic, Russia. (Why the Russians sat on it for more than a year, we don’t know, and that’s neither here nor there.) The key to these strange signals is to see if they were detected elsewhere as well, to make sure the signal isn’t the product of a mechanical fault in the telescope and/or a mischievous post-grad having a little fun at the scientists’ expense, and if they repeat. Neither of these things has happened.
- The other thing that isn’t known is if this signal actually came from this star system, or if in fact it came from much farther away and was only bent on a path to Earth by the gravitational pull of the star, a process called gravitational lensing. Or if it originated closer in, say from a passing satellite, or from a software error in the telescope.
So, yeah. Let’s cool it with the alien stuff. Unless you’re a science and science fiction geek like me and like to tease out these ideas to their logical extremes.
With those caveats out of the way, here’s the cool stuff.
- The star system that is the purported signal, HD164595 in the constellation Hercules, is only 94 light years away. It’s still a long ways off, considering that the closest star, Proxima Centauri, is still about four light years off, and impossible for us to reach with any of our current technology. But on a galactic scale, it’s right next door. You can even see it with binoculars if you know where to look.
- HD164595 is pretty similar to our own sun: Its mass is 99 percent of ours, it has a similar spectral type (meaning, the kind and type of radiation it puts out, which provides a clue to its composition), and it’s about 6.3 billion years old, which is a bit older than our own sun’s 4.5 billion, and would be pleasing news to those who favor a slow form of evolutionary development of life that assumes it would take a world like Earth around a star like the Sun a similar amount of time to develop life forms intelligent enough and curious enough to wonder about who else might be out there. In that context: 6.3 billion years may be plenty of time for a really advanced civilization to develop.
- The star is already known to have at least one planet, a “warm Neptune” gas giant in a tight orbit around the parent (its year is 40 days long, less than half of Mercury’s). This may or may not be the source of the signal, but it tells us that HD164595 is, like many other stars with planets found in the past several years, further evidence that planets are pretty common in the universe.
So with all of that, this is definitely a star that warrants further attention. It’s cool stuff. It’s almost as cool as the recent discovery that a planet orbits Proxima Centauri, the closest star to Earth, in the “Goldilocks zone,” where water could exist in liquid form (assuming the planet had the right sort of atmosphere and a few other conditions). That’s the one to watch. Really. It’s a lot closer, and we know there’s a planet there. Next step is to work out a way to determine if it has an atmosphere, probably by visually imaging it in some fashion. (Such as was done in another example here.)
Let’s play with this a bit, just for shits and giggles. What if it is aliens?
The scientists who did the number crunching on this calculated that the signal has a wavelength of 2.7 cm (about 11.1 GHz, up in the microwave range and well above anything we use for radio or communications). On the overall electromagnetic spectrum, it’s on the long-wavelength, low-energy end of radio waves, rather than the short-wavelength, high-energy end that includes X-rays and gamma rays. So it’s kind of in the area where we’d think to look for extraterrestrial signals.
The pros think a good place to look for those signals is in the 18-21 cm range, the so-called “waterhole” because interstellar hydrogen emits radiation at about 1.4 GHz, which has a wavelength of 21 cm, and the hyroxyl ion does the same at about 1.7 GHz, with an 18-cm wavelength. The two together give you water, which, the thought goes, an intelligent water-based life form (like us) would recognize as significant and therefore would use those frequencies if they wanted to reach out across the cosmos to contact us with a kind of interstellar shorthand.
But because the radio pulse from HD164595 was in the long-wavelength, low-energy part of the spectrum, it takes a lot of energy to send it across 94 light years at such a strength; more than we have on Earth, in total. The SETI types use the Kardashev scale to classify possible civilizations. A Type I civilization would be able to harness the entire energy output of its planet for communications. A Type II civilization would be able to use the entire energy output of its star. (By comparison, we’re not even on the scale, since we can’t even get together to agree that burning carbon is bad for us, much less harness all of the power on Earth to send a signal into space.)
So if the HD164595-ians had aimed their signal straight at Earth, that would imply they’re at least at the Type I level. If the aliens had broadcast it in all directions (like most broadcast radio towers), they’d have to be at Type II. One estimate of the energy required for that signal is 100 billion billion watts, more than all of the sun’s energy hitting the Earth. The signal is that strong.
Where does this leave us? With this calculus: if the signal comes from an alien civilization (and that’s a big if), that civilization is at a level of development that’s way way way above us. Since we can’t really send a signal back to them at the same level, it might be a safe assumption that they don’t know we’re here, and this was a Type II broadcast signal.
It could be cool to have some super-highly advanced aliens in our neighborhood, a science fiction dream come true.
But here’s the potential rub. Among the myriad possible solutions to the famed Fermi Paradox (the one that asks the question, “If alien life is a natural occurrence in the universe, given the billions upon billions of suns out there, where is everybody?”) there are what I call the “scary” answers. Such as: aliens don’t contact us because it’s the nature of intelligent life to destroy itself, or that communicating with other civilizations is just plain dangerous.
The Scottish writer Iain M. Banks once made an interesting point about the computer game Civilization, in which you build a civilization up from the Stone Age to the Space Age. I’m a fan of the game too, and I’ve also experienced what Banks termed the “outside context problem”: you could be happily cruising along through the medieval or renaissance period, developing your nation at a pace, when suddenly someone shows up on your shores in a battleship, and proceeds to stomp you like the insects you are. As Banks wrote in his novel Excession, “An Outside Context Problem was the sort of thing most civilisations encountered just once, and which they tended to encounter rather in the same way a sentence encountered a full stop.”
Banks’ novel was set the far future, but you only have to look at our own history to see that such events never turn out well for the less-advanced. The history of colonization of the western hemisphere was only the most egregious example: the Native Americans were slaughtered and displaced by the European colonists. Same with the Africans, who were also kidnapped and sent to the New World as slaves. It’s sad to say this, but neither of those peoples never really had a fighting chance against the firearms and organized armies and diseases of the Europeans.
Even among more closely “matched” civilizations, conflict is almost inevitable, with clear winners and losers, even if the losers are just the civilian populations and not the governments involved in prosecuting those wars.
With our hypothetical little green friends out in HD164595, there’s an order of magnitude (or more) difference between our two levels of civilization. We might not want to let them know we’re here, just to be on the safe side, at least until we know more. We wouldn’t survive an encounter unchanged unless they adhere to some kind of altruistic Star Trek-style Prime Directive. (Given our own history, such a code may be required in order for a civilization to even advance to that level.)
This is also my pet peeve about alien-invasion movies in which the plucky humans fight off the bug-eyed monsters with little more than a few rusty fighter planes and/or a clever computer virus. Please: if the aliens were advanced enough to cross all that distance to reach us, you can bet they’d have better defenses than last year’s Norton AntiVirus update. They could sit out in the asteroid belt and throw rocks at us until the crust of the Earth turns to lava and the best we’d be able to do is send a tiny space probe out to say hi to them that will get there a few years after we’ve all been incinerated.
That could be paranoid thinking, and maybe humans are uniquely violent in the universe. I’m not sure what the probabilistic odds are on that, since we have no one else to compare ourselves with.
The writer in me (and science fiction geek) likes to tease out these scenarios. The idea that there might even be aliens out there fascinates me.
That said, we’ve seen radio-frequency anomalies before. The classic SETI “Wow!” signal, detected in 1977, has never really been explained, but is widely believed to have been a natural phenomenon, possibly caused by a comet. It’s also never been repeated.
There have been other, weaker anomalous signals as well, none of which has amounted to anything. They’re still cool though, which is why people keep looking. If nothing else, we keep learning new things, and maybe even we’ll learn if anyone else really is out there.