How to search for aliens near bizarre dimming star, according to scientists

Forty-two antennas are now pointed toward the universe's latest mystery, searching for what some researchers speculate could be an alien megastructure that may surround a star 1,500 light-years from Earth. 

Astronomers from the Search for Extraterrestrial Intelligence Institute (SETI) have started to look a bit closer at the star using their Allen Telescope Array (ATA), a system of relatively small radio dishes with a total of 42 antennas that lies about 300 miles northeast of San Francisco, Space.com reports. They are hoping to hear radio signals coming from the vicinity of KIC 8462852, a star first detected by NASA's Kepler space telescope.

KIC 8462852 caught the attention of the larger scientific community after researchers noticed an irregular dimming in the light produced by the star. The Planet Hunters, who recently published a paper, noticed the star dimmed dramatically several times over the past few years, a stark contrast to the hundreds of thousands of other stars Kepler captured in its four-year run as "the people's telescope," searching for planets far away that may be similar to Earth.

The dimming of up to 20 percent of the light of the star is not easily explained by existing models. Some have speculated that the cause could be an artificial structure built by intelligent life.

And now the hunt is on.

But for SETI, this is all in a day's work. The dish system that is monitoring the mysterious star also has several other space spying missions underway. Among them is what the SETI Institute calls a "reconnaissance" of other unusual star systems that Kepler observed on its mission, according to the organization.  

The ATA is also listening in on a star grouping near the center of the Milky Way galaxy, where the density of stars is the highest. The institute believes "it’s conceivable that truly advanced societies might place a 'beacon' there."

When the ATA was first built, researchers wanted to build 350 individual antennas. But cost constraints – the SETI Institute is a nonprofit that relies on private funding – kept it at 42. 

“These are dynamic times for SETI,” says Andrew Siemion, the director of the University of California-Berkeley’s SETI Research Center in an interview earlier this month with The Atlantic. Fueling the optimism is a pledged $100 million from Russian billionaire Yuri Milner to fund a new research program, spread across several academic institutions. That’s the largest cash gift in SETI’s history, and Mr. Siemion says he hopes it will inspire others.

Milner’s pledge, The Atlantic reports, will fund an international cohort of SETI institutions that will use the money to point radio telescopes at thousands of nearby stars, listening for radio signals directed at Earth. Known as Breakthrough Listen, the program will investigate each star more thoroughly than ever before. 

At a congressional hearing on the possibility of life on other planets that took place earlier this month, NASA's Chief Scientist Ellen Stofan told lawmakers that Mars is her top candidate for finding life beyond Earth.

"We now know that Mars was once a water world, much like Earth, with clouds and a water cycle and indeed some running water currently on the surface. For hundreds of millions of years about half the northern hemisphere of Mars had an ocean possibly a mile deep in places," Stofan said.

"Life as we know it requires liquid water that has been stable on the surface of a planet for a very long time. That's why Mars is our primary destination in our search for the life in the solar system," she added.