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SETI@home

Millions together, searching for a signal from the stars

SETI@home is by far the most successful public participation project ever undertaken by The Planetary Society. In fact, it is the most successful public participation science project in history! As of 2012 more than 6 million people in 226 countries have taken part in the experiment, each contributing their computer processing time to the search for a signal from intelligent beings in the depths of space. More than a decade after its 1999 launch the project is still growing fast, attracting new participants with each passing day. But had it not been for the timely intervention of The Planetary Society, SETI@home would never have gotten off the ground.

Arecibo Radio Observatory

NAIC - Arecibo Observatory, an NSF Facility

Arecibo Radio Observatory
The 300-meter (1,000-foot) Arecibo Radio Telescope in Puerto Rico, where SETI@home collects its data.

SETI@home is the answer to one of the most persistent problems in the search for extraterrestrial intelligence: how to process the masses of data collected by SETI searches? Giant radio telescopes scan the skies, detecting radio emissions with remarkable sensitivity and recording all of them. Quite possibly, somewhere within all this radio noise there also a signal sent by intelligent beings light years away. Unfortunately, finding this needle of a signal in the enormous haystack of data requires almost unlimited computing time even on the largest and fastest computers in existence. SETI scientists, working with limited resources and even more limited computer time, usually have to severely restrict their analysis of the data just to arrive at any results at all. Sadly, this increases the risk that the true signal from ET, the signal that might be hiding in the data, will be completely overlooked.

But in 1998 two researchers from U.C. Berkeley. computer scientist David Anderson and SETI scientist Dan Werthimer, approached The Planetary Society with a novel idea. Instead of relying on strictly rationed time on one of the world’s overbooked supercomputers, why not turn to a massively underutilized computing resource: the millions of personal computers sitting on desks and offices the world over, spending much of their time running mindless screen savers. If even a small portion of this computing power could be harnessed to process the mountain of SETI data they reasoned, then much of SETI’s computing problem would be solved at a stroke. It was a simple yet audacious idea, and they had the perfect name for it: SETI@home.

Here’s how it works: a sensitive receiver collects data at the Arecibo radio observatory in Puerto Rico, the largest radio dish in the world. The data is recorded on magnetic tapes (later disks) and shipped to U.C. Berkeley, where a mainframe computer chops it up into thousands of standard-sized “work units,” and makes them accessible through the internet. Meanwhile, anyone with access to a personal computer is invited to download a simple SETI@home program from the web and install it on their computer. This “client” program automatically downloads a work unit from the web, and proceeds to process it whenever the PC is not otherwise occupied. When the processing is complete, the program sends the processed data back to Berkeley, and downloads a new work unit to process. The process continues indefinitely, and the mountains of SETI data are slowly but surely analyzed. If ET is hiding somewhere in there, it will surely be found.

When Anderson and Werthimer approached The Planetary Society, the fate of the project was hanging in the balance. For over a year they had been trying to raise money for their idea, approaching numerous companies in nearby Silicon Valley but coming up empty. The idea of involving the public in scientific research was a novel one and the Silicon Valley visionaries found it difficult to believe that many people would lend their personal computers to a SETI search. But The Planetary Society reacted differently: SETI was in the Society’s DNA from the very beginning, and public involvement in science was at the core of its mission. SETI@home, which combines the two, seemed perfect. After careful consideration the Society donated $50,000 to help launch the project. It also arranged for a similar grant from Paramount Pictures, which was promoting its “Star Trek” movie franchise. SETI@home was off and running.

The rest is history: SETI@home went online on May 17, 1999, and was an immediate and unprecedented hit. Within a few months more than a million people across the globe were processing work units on their personal computers, and within a year the number was approaching two million. No one had expected this explosive growth, least of all Anderson and Werthimer, who had dreamed of recruiting perhaps 100,000 people. But the numbers just kept growing and growing, and there is no end in sight. With SETI@home, the search for extraterrestrial intelligence had captured the public’s imagination.

SETI@home has come a long way since the early days of 1999. The old and near-obsolete receiver at Arecibo had been replaced by a state of the art multi beam receiver at the apex of the giant dish. The client program has been updated and searches for more types of signals with a greater sensitivity than ever before. On two occasions the search’s most promising signals have been gathered together, and a special search conducted to look for an alien signal coming from their direction. ET’s call has not yet been detected as yet, but at this rate, if it is hiding somewhere in SETI@home’s work units, it will surely be found.

SETI@Home: The

SETI@Home: The "Wow!" Signal as it would appear on SETI@home

But SETI@home did something else as well, something that no one expected: It launched a radically new way of doing science. The project’s explosive success opened scientists’ eyes to the fact that the public is eager to take part in cutting edge scientific research, and is happy to donate its computers and other resources for the cause. And so, where SETI@home first tread, a long line of scientific projects has followed, each engaging the public in different and creative ways. Today the public is invited to take part in studies of climate change, cancer cells, protein folding, gravity waves, interstellar dust particles, and many many others. Thanks to SETI@home, researchers have begun to tap into the almost unlimited resource of public enthusiasm for science.

It was a modest $50,000 grant from The Planetary Society that made it all possible, and over the years we have stayed with the project, handing out additional grants to help it expand and grow. To us, SETI@home epitomizes something we have always believed in: that even a modest sum, invested in a grand vision, can have an outsize impact. At the Planetary Society we make it happen.

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