The only telescope array in the world that is focused on the search for extraterrestrial intelligence has produced its first scientific results â but unfortunately thereâs still no word from ET.
Astronomers hope to continue adding telescopes to the system to search for alien transmissions, but in the meantime, they are also surveying intergalactic space for âmissingâ star-forming gas and other astronomical phenomena.
The project, called the (ATA) after benefactor and Microsoft co-founder , went live in 2007. It was designed to scan for broadcasts from alien civilisations with more consistency and a wider field of view than any previous effort.
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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 â a box as wide as 10 full moons.
âAt any one moment, you look into a very large piece of the sky,â says , director of the . âAt 350 [telescopes], the ATA just blows any other survey telescope out of the water. Even at 42 itâs interesting.â
, an ATA team member who presented the projectâs first results at a conference in the Netherlands in June, agrees: âYou can see entire galaxies within one shot.â
âMissingâ gas
One question the ATA aims to answer is a mystery of missing gas. Star-forming regions donât 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.
âThis paper was our first science paper, so weâve answered some questions but weâre finding new questions again,â van Leeuwen says. âThis paper really shows that our setup is working, we have all the algorithms working, and we could easily upgrade to a more powerful system still.â
Such surveys do not distract from the search for aliens, which â if they exist and are attempting to communicate â may send out broadcasts at wavelengths not commonly emitted by astrophysical objects. The ATA can observe a wide range of wavelengths, so it can check stars in the foreground for ETI signals while it watches background galaxies for clouds of atomic hydrogen. The telescope often runs three or four projects in parallel.
âA telescope like the ATA is just a superb instrument. The fact that it can do astronomical and SETI work at the same time is really just icing on the cake,â Tarter told 51¶ŻÂț. âThereâs no other telescope that can do this.â
Limited funds
But the array is limited in sensitivity and could only detect fainter, more distant objects if it were expanded to include more telescopes, Tarter says. And the funds for that arenât in yet.
âWe just submitted last week a proposal to the NSF that would double the size of the ATA if funded,â she says. âWe have any number of requests out to private donors. Weâre knocking on a lot of doors, but so far theyâre all closed.â The telescopes cost between $150,000 and $250,000 each, depending on how many are built at a time, and filling out the array would cost $40 million, Tarter says.
Until then, Tarter, who recently received a prestigious (Technology, Entertainment, Design) prize, is trying to harness the âwisdom of the crowdsâ to optimise the SETI pipeline and analyse the data.
Volunteer scientists
She plans to make the ATAâs detection algorithms open-source so engineers around the world can help improve them. And she wants to enlist volunteers to study visualisations of the radio data to âuse their eyeballs as pattern detection devicesâ.
âWe want to get signals out in front of the worldâs eyes, have people tell us if they see patterns, get a decision about whether thereâs any interesting signal in the data, and get it back to the observatory in time to make changes at the telescope,â she says.
This is an improvement over the distributed computing project because it engages peopleâs minds, not just their CPUs, she says.
âWe actually want their âthink-onsâ, not their electrons,â Tarter says. âFor me, the reason that that is so necessary is because if youâre not creatively involved, we canât have a conversation about what SETI really means ⊠I canât encourage you to see yourself in a more cosmic perspective unless youâre actually intellectually involved.â
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