The project, called the Allen Telescope Array (ATA) after benefactor and Microsoft co-founder Paul Allen, went live in 2007.
It was designed to scan for broadcasts from alien civilizations with more consistency and a wider field of view than any previous effort.
Run jointly by the SETI Institute and the University of California, Berkeley, from a site in northern California, the ATA is ultimately intended to comprise 350 dishes.
But, even with its current complement of 42, it has an impressively wide field of view. It uses relatively small, 6-metre dishes that together can take in five square degrees of sky at a time – a box as wide as 10 full moons.
“At any one moment, you look into a very large piece of the sky,” said Jill Tarter, director of the SETI Institute. “At 350 (telescopes), the ATA just blows any other survey telescope out of the water. Even at 42, it’s interesting,” she told New Scientist.
According to Joeri van Leeuwen, an ATA team member who presented the project’s first results at a conference in the Netherlands in June, “You can see entire galaxies within one shot.”
One question the ATA aims to answer is a mystery of missing gas.
Star-forming regions don’t seem to have enough molecular gas to keep up the star-formation rates we observe.
Some researchers think atomic hydrogen might make up the difference.
ATA team members have searched for it in four groups of galaxies so far, but have not yet found any new intergalactic gas, deepening the mystery.