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[1]  A-L-I-E-N-S

Over the last year one particular star has been getting a lot of buzz, especially in the nerdier corners of the internet. Articles about the mysterious star began appearing in late 2015. And then over the summer the articles started to appear again. Articles like “The Mystery of Tabby’s Star” and “The Most Mysterious Star in the Galaxy Doubles Down on Its Mystique”. Or this one from Gizmodo: “The So Called Alien Megastructure Just Got Even More Mysterious.”

Yes, you read that right. Alien. Megastructure. It could be a thing. Probably not, but some astronomers have deemed it worthy of serious consideration.

Even if, at the end of the day, this ‘mystery’ turns out to have a rather benign explanation — which it almost certainly will — don’t we owe it to ourselves to take this opportunity to learn whatever we can about aliens and megastructures, from the perspective of actual scientists, not Hollywood producers?

Oh, the places this discussion could go, though. So, let’s do this in two pieces, shall we? In this week’s piece we’ll discuss aliens, because despite what you may believe, it isn’t only conspiracy theorists that think aliens probably exist, somewhere, out there. In a follow up post, we’ll tackle megastructures. Because even if aliens don’t exist, megastructures could still be something that we humans do someday.

Ok, first things first – how did we get to this point where actual astronomers are talking about aliens in scientific papers?

[2]  Star Search

They call it the WTF Star.

In September 2015, some astronomers posted a paper on the pre-print archive (arXiv) about a particular star. The paper was titled: “Planet Hunters IX. KIC 8462852 – Where’s the Flux?”

The pre-print archive is like limbo for scientific papers. It allows other scientists to have a sneak peek at their results before the long and arduous publication process is complete. These papers haven’t been peer reviewed yet, so you have to take them with a grain of salt. Still, in many fields, exciting new results can be found in the archive before they appear in print.

Let’s parse the title of this paper before we continue.

First, the star’s name is officially KIC 8462852, which tells all you need to know about how boring astronomy can be. It’s not all planetariums and black holes and isn’t the universe just like a beautiful cathedral where our minds can worship nature? like Neil DeGrasse Tyson wants you to think. It’s a lot of tedious finding and naming and tracking of stars. And I don’t want to offend anyone here – but can we agree they all sort of look alike?

Next, there’s that “Planet Hunters” in the title. Well, let me tell you what, if HGTV had a show called “Planet Hunters,” I would burn a hole in my DVR watching that show. Susan and Gregory are trying to decide between the small icy planet with the nice view of a nearby white dwarf star, and a larger gaseous planet with balmy summer temperatures of 500 degrees. We’ll have their decision when we return!

Unfortunately, Planet Hunters is not that. It’s a scientific project that attempts to crowdsource the search for new planets using pictures collected by high-powered telescopes, like The Kepler telescope, which rides in a spacecraft orbiting the sun. So Joe Schmoe, who dreamed of a Ph.D. in astronomy but never quite got it, can still play his role as a ‘citizen scientist’ by helping actual scientists pore over an astronomical number of astronomical images to spot interesting looking patterns.

Now we get to the flux part. Flux is a fancy way of talking about the amount of light emitted from a star. You see, astronomers have been tracking KIC 8462852 for years using the Kepler space telescope along with 150,000 other stars. And with their fancy 95 megapixel telescope/camera, what glorious insights into the heavens can the astronomers learn about stars? Well, despite what Simba and Timon think, at the end of the day a star is just a dot of light in the sky. There isn’t a whole lot you can track other than its position and its brightness.

Raise your hand if you still wish you’d become an astronomer.

When astronomers looked at the brightness of KIC 8462852 over time, they saw this (and stay with me):


A light curve. On the X-axis is time (in days here) and the Y-axis is a measure of the brightness (here the value 1 just represents the ‘usual’ or ‘typical’ brightness measured for this star). You can see most of the time the brightness is pretty steady, and then at a few places, it takes sharp dips down to 85 percent of its usual brightness.

You totally get it, right?

Here’s the good news: you and I don’t need to understand this plot. What we do need to understand is what knowledgeable astronomers see when they look at this plot. You see, if I showed you the ‘light curves’ for most of the other stars among the 150,000 being studied you’d see a whole bunch of nothing. They’d look like this chart does between day 0 and day 600 – Steady Eddie. Nothing to see here. No big dips.

But let’s bring this back down to Earth, where Stephen Curry can help us understand this anomaly. Let me explain. To the astronomical cognoscenti, this star’s light curves are to the other humdrum stars what Stephen Curry’s 3-point shot statistics are to every other NBA player ever:


So, when basketball analysts and fans consider Steph Curry’s 3-pointer exceptionalism, they have the same reaction as seasoned astronomers looking at the light curves for KIC 8462852. In their careers they may have seen some big dips. But these dips are almost literally off the chart. Unexplainable by normal means.

And these astronomers find themselves wondering aloud, in a scientific paper, WAIT, WHAT THE F*CK JUST HAPPENED? Thus, KIC 8462852 gets the nickname the WTF Star, which is easily the most provocative name for a heavenly body since the Death Star.

Now, dips in brightness are actually common and easily explainable, usually due to some planet or similar body passing in front of the star, the way the moon can eclipse the sun at times.

But a passing planet doesn’t explain the changes in brightness from the WTF Star. Astronomers estimate a planet as large as Jupiter would only dim the brightness by about 1 percent as it passed. So, no conceivable planet could be large enough to cause the degree of dimming observed in the WTF Star.

So what are other possible explanations? Well, here is a sampling that have been seriously discussed:

  • Planetary debris field
  • A cloud of disintegrating comets
  • A megastructure

The first two are, for our purposes, just boring.

But that last one? Megastructure? When I think of megastructures I think of a show I once watched on Discovery about the Japanese trying to build some Jetson-ish mile-high apartment building to cope with urban overcrowding. Megastructure. Even just the word itself gives me a full blown case of the future creeps.

Yes, megastructure as an explanation to the strange behavior of the WTF Star is very intriguing. Because of course megastructures don’t just build themselves. And if Japanese engineers didn’t do it, then, well…

Cue the aliens.

[3]  What Are the Odds?

I know what you’re thinking. Aliens? This guy’s watched one too many episodes of The X-Files. But here’s the thing. It’s not just me. There are legitimate scientists, Nobel Prize winners even, who think that not only is it possible that aliens exist – but that it‘s highly probable.

Just ask Enrico Fermi, one of the greatest physicists of the 20th century. You see, in 1950 Enrico Fermi was discussing extraterrestrial life with some colleagues at the Los Alamos National Laboratory (where the Atomic Bomb had been built just five years prior). Eventually, the conversation turned to other less speculative topics — like the internal structure of the proton and where they should eat lunch.

But Fermi couldn’t stop thinking about that earlier conversation. “WHERE ARE THEY?!” he finally blurted out, apparently without context or pretense. By ‘they,’ he, of course, meant the aliens.

Unlike your uncle who loves the X-Files, Fermi went on to calculate the actual probability that life had to exist somewhere and concluded that the probability of life existing in the universe, and even in the Milky Way, is very much not zero. Or, put another way…


So you’re telling me there’s a chance!

And there’s more. Fermi also pointed out that if you give any advanced civilization enough time, say a million years or so, they should be able to colonize much of the Milky Way. According to this way of thinking, aliens are like hipsters – it doesn’t matter how remote your corner of the universe is — eventually they will find where you live and gentrify it.

All this leads to something that has been called Fermi’s Paradox. The paradox is this: if it’s likely that aliens exist, and if the universe is old enough for at least some of those aliens to have explored our entire galaxy by now, why haven’t we seen any evidence of aliens yet? Or, to quote Enrico Fermi, “WHERE ARE THEY?!”

This is a serious question that many folks think demands serious consideration. Really smart people like Elon Musk. And Stephen Hawking.

On one hand, this is a bit thrilling. Maybe aliens do exist after all. On other other hand, it’s also a bit disconcerting. Because once you buy into the idea of Fermi’s Paradox, the question Where Are They? is no longer a lighthearted musing. It’s the sort of thing people utter in horror movies right before they are slaughtered.

[4]  Next Time On Planet Hunters

Ok, so maybe aliens do exist. What does that have to do with the WTF Star, exactly? And what is the connection with megastructures?

Great questions. That’s what we’ll be discussing in Part II, tomorrow.

In the meantime, if you are interested in diving deeper on The Fermi Paradox, I highly recommend this post (by one of my all-time favorite bloggers) on the topic. It goes way deep on the paradox and proposed ‘solutions’. I think it is pretty damn convincing. After reading that post I went from thinking “sure I guess aliens might exist” to now feeling like it’s ABSOLUTELY CREEPY that we haven’t observed any yet.

Jesse Stone

Jesse B. Stone loves science and writing. Apologies if you were looking for the "Jesse Stone" played by Tom Selleck in the CBS movies.

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