As far as we know right now we’re alone in the universe. However the staggering size of the universe suggests that life should be prevalent elsewhere and we (or they) have the unenviable task of tracking it (or us) down. We’re also not quite sure to look for as whilst we have solid ideas about our kind of life there’s no guarantees that they hold universally true across the galaxy. So when it comes to observing phenomena the last reason researchers should resort to is “aliens did it” as we simply have no way of verifying that was the case. It does make for some interesting speculation however like with the current wave of media hysteria surrounding KIC 8462852, or Tabby’s star as it’s more informally called.
KIC 8462852 was one of 145,000 stars that was being constantly monitored by the Kepler spacecraft, a space telescope that was designed to directly detect exoplanets. Kepler’s planet detection method relies on a planet transiting (I.E. passing in front of) its parent star during its observation period. When the planet does this it ever so slightly drops the brightness of the star and this can give us insights into the planet’s size, orbit and composition. This method has proven to be wildly successful with the number of identified exoplanets increasing significantly thanks to Kepler’s data. KIC 8462852 has proved particularly interesting however as its variation in brightness is way beyond anything we’ve witnessed elsewhere.
Indeed instead of the tiny dips we’re accustomed to seeing, an Earth-like planet around a main sequence star like ours produces a chance of about 84 parts per million, KIC 8462852 has dipped a whopping 15% and 22% on separate occasions. Typically this isn’t particularly interesting, there are many stars with varying output for numerous reasons, however KIC 8462852 is a F-type main sequence star which is very similar to ours (which is a G-type if you’re wondering). These don’t vary wildly in output and the scientists have ruled out issues with equipment and other potential phenomena so what we’re left with is a star with varying output with no great explanation. Whatever is blocking that light has to be huge, at least half the width of the star itself.
There are a few potential candidates to explain this, most notably a cloud of comets on an elliptical orbit that happens to transit our observation path. How that exactly came to be is anyone’s guess, and indeed it would be a rare phenomenon, but it’s looking to be the best explanation we currently have. A massive debris field has currently been ruled out due to a lack of infrared radiation, something which would be present due to the star heating the debris field. This has led to some speculation as to what could cause something like this to happen and some have looked towards intelligent life as the cause.
How could an alien race make a star’s output dip that significantly you ask? Well the theory goes that any sufficiently advanced civilization will eventually require the entire energy output of their star in order to fuel their activities. The only way to do that is to encase the star in a sphere (called a Dyson Sphere) in order to capture all of the energy that it releases. Such a megastructure couldn’t be built instantly however and so to an outside observer the star’s output would likely look weird as the structure was built around it. Thus KIC 8462852, with its wild fluctuations of output, could be in the process of being encased in one such structure for use by another civilization.
Of course such a hypothesis makes numerous leaps that are not supported by any evidence we currently have at our disposal. The research is thankfully focused on finding a more plausible explanation, something which we are capable of finding by engaging in further observations of this particular star. Should all these attempts fail to explain the phenomena, something which I highly doubt will happen, only then should we start toying with the idea that this is the work of some hyper-advanced alien civilization. Whilst the sci-fi nerd me wants to leap at the possibility of a Dyson sphere being built in our backyard I honestly can’t entertain an idea when I know there are so many other plausible options out there.
It is fun to dream, though.