Over the past year, we've been wowed by the existence of gravitational waves (you know, the whole two black holes colliding thing), anxious about whether or not Juno would safely enter Jupiter's orbit, and excited about the progress of commercial space companies, SpaceX and Blue Origin.
But what about Tabby's Star? Looking back through my news recaps over the past six months, besides everything I've mentioned above, Tabby's Star, formally known as KIC 8462852, has also dominated the space news channels. Why? Because the star's odd behavior might suggest the presence of aliens.
WHAT?! (Yes, yes, I know. It's exciting stuff. More on the aliens a little later.)
Tabby's Star is an F-type main-sequence star, meaning it fuses hydrogen and looks yellow-white in the night sky. These types of stars typically are slightly more massive than the Sun (1.0 to 1.4 times to be exact) with surface temperatures ranging from 6,000 to 7,200 degrees Kelvin. The yellow-white dwarf star is located in the constellation Cygnus, 1,480 light years away. While the star is too dim to be seen by the naked eye, in a dark sky with little to no light pollution, it can be seen by a 5-inch (130mm) telescope.
According to the WISE astronomical catalogs, the star was first discovered in 1890 but didn't reach infamy until 2015. As part of the Planet Hunters project, citizen scientists used Kepler Space Telescope data to discover its unique dimming patterns and unusual light curves, resulting in a 15% loss of light. According to astronomers, that percentage is HUGE! The dimming aspects of the star are so unique that the scientific community is struggling to explain them.
In September of 2015, Tabetha S. Boyajian, currently a faculty astronomer at Louisiana State University, published a paper called Where's the Flux? that explores what could possibly be causing these unusual patterns. Several hypotheses have been made. Because of the limited amount of observed infrared light, one of the strongest suggests that dusty and cold comet fragments are circling the star in eccentric orbits. Some say that what we're seeing is the effect of a lot of small masses orbiting the star in a very tight formation. But neither of these fully explain the light curves.
There is another possible theory…that extraterrestrial life has created a Dyson sphere. Just what is a Dyson sphere you ask? It's a megastructure that encircles a star, designed to harness the star's power. The idea was first introduced by science fiction writer, Olaf Stapleton in his novel Star Maker, published in 1937. It wasn't until 1960, however, that the idea became more widely known. In a paper titled Search for Artificial Stellar Sources of Infrared Radiation, Freeman Dyson, an English-born American theoretical physicist and mathematician, hypothesized that, for an advanced technological society in need of increased amounts of energy, such a structure would be necessary to that civilization's survival.
When this hypothesis about Tabby's Star was first introduced, the SETI (Search for Extraterrestrial Intelligence) Institute debunked the claim. Using the Allen Telescope Array located at the Hat Creek Radio Observatory about 300 miles north of San Francisco, they found no evidence of technology-related radio signals coming from the star.
However, scientists recently discovered that dimming patterns aside, the star's overall brightness is fading. During the four years of Kepler's mission, the star faded a whopping 3%. Looking at additional data, some researchers claim the star has faded almost 15% in the past 100 years. That's something that would definitely happen if a Dyson sphere was absorbing the star's energy, right?
People are really excited about the star, so excited in fact, that Boyajian successfully raised $107,421 in a Kickstarter campaign to continue researching the star. The money allowed the team to secure the Las Cumbres Observatory Global Telescope Network for an entire year.
Even though just last year SETI's research negated the presence of intelligent, extraterrestrial life, they have decided they want back in on the action. Through their UC Berkeley Breakthrough Listen Initiative, the organization has pledged to spend $100 million dollars over the next 10 years to study Tabby's Star. They believe they have the best telescope for the job, the Green Bank Telescope in West Virginia. Not only is it perfectly positioned to examine the star, it's the largest steerable and most sensitive telescope on the planet.
Do astronomers think they're going to find aliens? No. It is widely accepted that Tabby's Star's strange luminosity is likely the byproduct of comets, dust, or the formation of a nearby star. The possibility of extraterrestrial life is small…but it isn't non-existent.
If it IS aliens, one question bugs me: If the megastructure is as technologically advanced as we speculate it should be, why haven't the sphere's "creators" contacted us? Surely they would have the technology to do so, right?
Maybe they already have…
Sources: Wikipedia, Space.com, Astronomy Magazine, Wired