Exoplanets, the planetary bodies found in other star systems, are very difficult to spot. The best way to find them is to monitor the brightness of stars and watch for any dips. If an exoplanet has an orbital plane that occasionally brings it between its star and us, it blocks some of the star’s light that reaches us. If we find stars that periodically dim and brighten, we might be onto an exoplanet. It’s an exciting time to be a planet hunter and NASA just announced the verification of 1,284 new exoplanets.
The brightness of a star usually differs by less than 1% when an exoplanet blocks some of its light. Astronomers were recently staggered when citizen scientists at Planet Hunters found a star that dims by up to 20%. KIC 8462852 (or “Tabby’s Star”, named for lead researcher Tabetha Boyajian) has excited astronomers due to the bizarre fluctuations in its brightness and the lack of a reasonable explanation. The best hypothesis so far is a huge group of giant comets but that doesn’t explain all the data. The star caught the attention of the mainstream media when astronomer Jason Wright and colleagues proposed a more controversial hypothesis: an alien megastructure.
Ok, it does sound like tinfoil hat time but it’s a fascinating idea given the lack of an explanation. A Dyson sphere is a hypothetical alien technology for harvesting the energy of a star. If an alien species is to survive in the long-term and explore the cosmos, they will need more energy than they get from the resources available on their home planet. One way to do that would be to build megastructures around a star to capture some or all of its energy. Presumably such a technology would start as numerous giant structures (a Dyson swarm) or a ring around the star. At its most efficient, the technology would take the form of a sphere around the entire star. Wright suggested that a Dyson structure could be causing the fluctuations we’re seeing at Tabby’s Star.
The idea has captured the imagination of many and spurred scientists into action. SETI listened for radiowaves coming from Tabby’s Star but didn’t detect anything that could be evidence of intelligent life. There was talk of historical data suggesting that the star had dimmed considerably every century but this has been refuted and the long-term dimming was due to the differences in telescopes. This makes the comet hypothesis more plausible again but not everyone is giving up on the possibility of an alien megastructure.
Crowdfunding the science
Getting access to government-owned telescopes isn’t easy. Researchers all over the world are competing for access and making pitches for why their project deserves the time. This is a problem for Tabetha Boyajian, who wants to get to the bottom of the mystery. Nobody knows how frequent the fluctuations are so the only solution is to monitor the star continuously to guarantee we see it at the right time. That means accessing the best telescopes for a considerable amount of time. Remember, we’re spinning. To keep Tabby’s Star in sight we need to use telescopes all around the globe.
Boyajian turned to Las Cumbres Observatory Global Telescope Network, which has offered use of its telescope network until autumn. The network is privately-owned so the project can continue if Boyajian can raise £100,000. The weirdness of Tabby’s Star was discovered thanks to crowd sourced science, so why not turn to crowdfunding to keep the science going? Boyajian has started a Kickstarter campaign to fund the telescope. There are backing options from $5 to $50 and the rewards range from a thank you email to spending time with the research team.
Most astronomers are obviously refusing to jump to conclusions. An alien megastruture is just one hypothesis and it’s likely that the fluctuations are caused by some other natural phenomenon, but that makes it even more exciting. What could possibly block 20% of a star’s light? Let’s hope Boyajian can get enough funds so we can learn more about the most mysterious star in the galaxy.
Main image: capnhack.com