I'm not so easily dazzled by elaborate worldbuilding anymore. Having read countless space operas and fantasies, I need things to be thought through and very detailed, nuanced and subversive or I just don't see any reason to bother. Fortunately, Forsaken Skies easily meets my high demands, and while it might be better suited for hardcore sci-fi readers, it will undoubtedly find a much wider audience.
Today I have the pleasure of sharing with you a guest post by D. Nolan Clark. Enjoy!
Finding Alien Worlds: from Tabby’s Star to Titan
by D. Nolan Clark
Astronomers have studied the stars for thousands of years. Just by collecting the light they shed and analyzing it in clever ways, we’ve been able to describe other suns in incredible detail. In the last few decades, we’ve also been discovering exoplanets—planets that circle stars other than our own—and now, with the help of instruments like the Kepler Space Observatory and the James Webb Space Telescope (set to launch in 2018), we can even detect moons orbiting planets around other stars. It seems like it’s just a matter of time before these observations discover life on other worlds. It could happen sooner than we think.
Before we get ahead of ourselves, though, let’s be clear on one thing: it hasn’t happened yet. You may have heard about Tabby’s Star (also known as KIC 8462852, or, if you’re feeling excitable, the WTF Star). An F-Type star in Cygnus about 1300 light years away, famous because it flickers. It flickers a lot. One of the main ways astronomers detect exoplanets is to find stars whose light periodically dims, as the planet crosses in front of the stellar disk. If the flickers are regular, happening once in so many days, it means a large object is orbiting the star—most likely a planet. Tabby’s Star flickers much more frequently than most, and sometimes it flickers when we don’t expect it to. This suggests that there’s not just a planet out there, but a lot of very large objects, orbiting the star at various speeds.
A lot of people, some of them very smart, got excited when they heard this. They started talking about “alien megastructures”. Very large artificial objects surrounding the star. Artificial being the key term. Some people even started suggesting that aliens out there are trying to build a Dyson Sphere around the star.
It’s unlikely. It’s far more plausible that Tabby’s Star is being swarmed by comets, or that it’s in the process of forming new planets. But even the possibility of a Dyson Sphere is interesting, and worth talking about.
The mathematician and physicist Freeman Dyson first described his hypothetical sphere in 1960. His idea was that advanced civilizations need a lot of energy—much more than they can produce with fossil fuels or even atomic power. He felt that eventually they would have to harness all the energy of their home stars. He suggested they could do this by constructing a shell around a star, completely enclosing it. The skin of the sphere would be made of something like concrete and the interior would be completely lined with solar panels. Every photon the star put out would be converted into energy, which the civilization could use.
If we look out into the night sky and saw Dyson Spheres, we would have real proof of alien life. It would change everything. Sadly, we’ve never detected one. We would know right away. Such a structure would be invisible to the naked eye—it completely encloses its light source, after all. It would generate an enormous amount of heat, however (imagine a campfire burning inside a house on a chilly night). Some of that heat would escape the sphere. Infrared telescopes would see the sphere blazing like a fireball. We would also know the Dyson Sphere by its size. Because any such object has to be much larger than the star it contains, it would be one of the largest individual objects in the sky, much, much bigger than the stars we see. Again, we’ve never detected anything like that.
Many scientists and science fiction authors have developed Dyson’s original idea and suggested that you don’t have to completely enclose the star. There are Dyson Swarms (clouds of solar panels orbiting a star, but not touching each other), and perhaps most famously Larry Niven’s idea of the Ringworld, a structure that surrounds a star with a solid band of material, like Saturn’s rings but one continuous mass. Such objects would be even easier to spot than a Dyson Sphere because they would let at least some light escape. From Earth, they would look something like what we see around Tabby’s Star… except for one problem. The flickers they cause would be very regular. The observations of Tabby’s Star suggest that whatever’s out there isn’t following any kind of regular pattern. Most likely the objects we see out there are bumping into each other, constantly colliding like popcorn kernels bouncing off each other in the microwave. That’s far more suggestive of a natural process, rather than the work of aliens.
Looking for megastructures is still worthwhile—all we need to find is one, to know we aren’t alone in the universe. But if we want to find life in space we have other methods at our disposal. For one thing, we can look at alien atmospheres. This is real cutting edge science, but we can for the first time start doing chemistry on objects light years away. This is where the hunt for alien life really gets interesting.
Megastructures can only be constructed by incredibly advanced species—those with technology far outstripping our own. What if you wanted to find aliens on our own level, or planets where life exists, but hasn’t yet developed intelligence? You’d want to look for unstable atmospheres. Most dead planets in our experience are surrounded by envelopes of carbon dioxide, or nitrogen, or are gas giants shrouded by thick blankets of hydrogen. That’s because those gases are pretty stable. You almost never find a planet with a thick oxygen atmosphere because oxygen doesn’t last. Ultraviolet light from the sun, for instance, constantly breaks down oxygen molecules in our atmosphere. Our ozone layer protects our atmosphere somewhat, by absorbing the UV, but even ozone breaks down eventually. Within a few million years, the sun should destroy all the oxygen in Earth’s skies. The fact we’re still here and breathing is due to the constant activity of plant life, which takes stable carbon dioxide and converts it into oxygen. If you find a planet with a rich oxygen atmosphere, it’s extremely possible that you’ll find plant life there, too—and maybe even animals, and maybe, just maybe, intelligent life.
But what about worlds where oxygen just doesn’t exist? Is it possible that life could exist in such a place? The answer is maybe, leaning toward a probably, and that might be the most exciting discovery so far. Scientists have shown in the laboratory that it could be possible for life to exist that breathes hydrogen rather than oxygen. Such an organism would use complex hydrocarbons as the basis of its chemistry, and would thrive in freezing cold seas of liquid methane. Nothing like that exists anywhere on Earth, but it describes exactly the environment of Titan, Saturn’s largest moon. Life could—at least hypothetically—exist in the subzero seas and thick smoggy atmosphere of that world. Incredibly, we’ve even seen signs that suggest it does. When the Cassini mission flew by Titan and dropped the Huygens probe there in 2004, it discovered a strange anomaly in Titan’s atmosphere. Down near the surface of the planet, there was less hydrogen than we expected to find—and more free methane. It’s distinctly possible that the readings were wrong, or that there’s some other explanation.
This anomaly could also indicate that something is down there, in Titan’s dark seas. Something that breathes. Something that is shaping the atmosphere. Something very much alive.
The hunt for alien megastructures goes on—and Tabby’s World at the very least is a wonderful reminder that there are mysteries in space we haven’t begun to understand. Yet how encouraging is it that, if we want to find life out there, we may not even have to go 1300 light years to find it? What if it turns out it was in our cosmic backyard the whole time?
Every day we make new discoveries, and every day we get closer to finding our neighbors. It’s really just a matter of time.
About the book:
From the dark, cold void came an unknown force. Their target a remote planet, the home for a group of people distancing themselves from mankind and pursuing a path of piety and peace. If they have any chance at survival a disparate group of pilots must come together to fight back any way they can. But the best these aces can do might not be good enough.
Forsaken Skies was released in paperback on February 23rd. You can buy your copy from Amazon or The Book Depository.