A few weeks back, the internet was buzzing with talk of aliens. This is all thanks to the Kepler Space Telescope, which found that a star known as KIC 8462852 had a rather strange light pattern. The star seemed to be surrounded by a lot of matter. The problem with this is that the star is mature, and such patterns are typically only seen around young stars.
What's causing the strange light?
Tabetha Boyajian, a postdoc at Yale, published a paper that asserts that the blame should probably be given to another star. Boyajian notes that another star could have passed through the KIC 8462852 system and, as it continued on its travels, it may have dragged a swarm of comets into the inner solar system. Provided that there were enough comets and other leftover debris in the vicinity, this could be responsible for the dimming pattern.
The other (highly unlikely) possibility that was proposed it that there is a large alien megastructure surrounding the star collecting energy. Even the scientist who came up with the hypothesis, Jason Wright, an astronomer from Penn State University, said that it was extremely unlikely. But of course, the media didn't care. And aliens was the only thing they focused on.
You can read our original coverage here.
In any case, SETI (the Search for Extraterrestrial Intelligence) trained its Allen Telescope Array on this star for more than two weeks to test the hypothesis. That is what you do in science. You form a hypothesis, and then you test it. Nothing wrong with that. The only problem is how sensationalized it was in the media - as though the most likely answer was "aliens."
As Institute astronomer Seth Shostak notes, “The history of astronomy tells us that every time we thought we had found a phenomenon due to the activities of extraterrestrials, we were wrong. But although it’s quite likely that this star’s strange behavior is due to nature, not aliens, it’s only prudent to check such things out.”
And it turns out, it wasn't aliens. At least, we have absolutely no evidence of aliens.
The SETI release explains the findings:
Two different types of radio signals were sought: (1) Narrow-band transmissions, of order 1 Hz in width, that could be used as a “hailing signal” for societies wishing to betray their presence, and, (2) Broad-band signals produced by intense microwaves used to propel rockets servicing the megastructure.
Analysis of the Array data show no clear evidence for either type of signal between the frequencies of 1 and 10 GHz. This rules out omnidirectional transmitters of more than approximately 100 times today’s total terrestrial energy usage in the case of the narrow-band signals, and ten million times that usage for broad band emissions.
While these limits are relatively high, a fact due primarily to the large distance of KIC 8462852 (about 1500 light-years), there’s this to consider: If aliens are deliberately targeting our part of the galaxy, the necessary transmitter power for detection becomes very much less. In addition, any beings able to build such large structures will have access to far more energy than a fossil-fueled society like our own.
This is just another reminder that you need to always be skeptical. Question everything (even me), and always demand evidence.