The team searching for signals from intelligent civilizations among the stars at the SETI Institute recently turned its radio telescopes to a mysterious star whose light output varies in an unusual way. Called by its catalog number KIC 8462852, the star is about 1500 lightyears away in the constellation of Cygnus the Swan. Observations with the Kepler space telescope had shown that the star’s brightness dipped at irregular intervals and with irregular amounts of darkening.
Such dips are how the Kepler telescope finds planets orbiting distant stars. Astronomers photograph huge numbers of stars regularly, and search for regular dips in a star’s light when a planet gets in front of the star, reducing its brightness. A planet circles its star regularly, and the dips in brightness come on a clockwork schedule. If the planet takes 100 days to orbit its star, astronomers would see a dip in brightness every 100 days – just while the planet is in front of its star. Here is a little animation to show you the idea: https://www.youtube.com/watch?v=pf9PjFQIpzU
But KIC 8462852’s dips in brightness are not regular at all and they vary in how much of the star’s light they block. One such dip in brightness took away more than 20% of the star’s light, indicating that whatever was causing it must be much bigger than a planet. What could be causing such unpredictable and large dips? It could, for example, be a huge swarm of comets that orbit the star in different clumps. It could be great clouds of dust from deep space which the star happens to be moving through. But there is another possibility, which got some astronomers and all science fiction fans excited.
What if there is an advanced civilization around that star, far beyond our own in technology? One thing such a civilization is likely to need is huge amounts of energy to carry out their projects. An easy way to get that is to build huge “solar panels” orbiting their star. Alternatively, perhaps they are building giant space habitats to house their excess population.
Just like our cities are irregularly spaced and irregular in terms of internal construction, so these space construction projects could be different in size and spacing, causing the irregular dips we see as they move in front of their star. While the explanation is most likely something natural in the universe, it’s fun to consider a cause that could be a signal for the existence of intelligent life.
The leading organization in the search for life beyond Earth is the SETI Institute (where I have the privilege of serving on the Board of Trustees.) They have an instrument, called the Allen Telescope Array (ATA), with 42 coordinated radio telescopes in Northern California, specifically designed to find intelligent radio or microwave signals from the stars.
For more than two weeks, the Institute team, led by Dr. Seth Shostak, trained the ATA on KIC 8462852, to see if any pattern of signals might be leaking from such an advanced civilization. At a distance of 1500 lightyears (where each lightyear is 6,000 billion miles), the alien transmissions would have to be awfully strong to be detectable from Earth. Still, a civilization able to build huge space structures might have powerful beacons to communicate with its own outposts, and we might be able to eavesdrop on one of their messages pointed our way.
So far, in the channels the Institute team searched, no intelligent signal was detectable. They also searched for a much broader beam of microwaves, which advanced aliens might use to push giant ships through space. No such beam was found either.
But what exciting ideas such observations bring to our minds! The possibility of detecting some kind of intelligent species that is out there in the Galaxy has intrigued humanity for centuries. Today, for the first time, we actually have the technology to do experiments in this area. I’d love to see us find evidence that we have “cousins” among the stars. This is why I have served on the SETI Board for many years now.
The Institute also does other wonderful research, in many areas of astronomy and planetary science. (One of our scientists, Mark Showalter, found two of the small moons of Pluto, for example.) There is also great work going on in education and public outreach, including the syndicated “Big Picture Science” radio show that Seth Shostak co-hosts.
December 1 is “Giving Tuesday” – a day designed for all of us to pause after the shopping frenzy that follows Thanksgiving, and consider giving to non-profit organizations whose work we believe in. Perhaps you’d like to join me in supporting the SETI Institute. For ways you can help, see their website at: http://www.seti.org/supportus
(NOTE: The photo shows a few of the radio telescopes that make up the Allen Telescope Array.)
And KIC stands for Kepler Input Catalog.