SETI: Power to the people
Posted: 11 April
The search for radio signals from beings on other worlds reaches its half century this April. Over the last fifty years, the Search for Extraterrestrial Intelligence has surveyed many thousands of stars; in that time we have encountered new worlds around other planets, learnt more about how life may have arisen on Earth, and conditions possibly suitable for primitive life elsewhere in the Solar System, but we have yet to hear from other life forms amidst the stars. Are they out there, somewhere, undetected, or as the physicist Enrico Fermi feared, is there no one out there at all? The anniversary of SETI is the ideal opportunity to assess its progress, explore some of its ideas, and find out how close we are to answering the question, are we alone?
Fancy being the one to make history and discover extraterrestrial intelligence? It’s not as far-fetched as it sounds. Citizen science, facilitated by increasing computer power and technologies on the Internet, is fast become the buzzword in areas of groundbreaking research. Members of the public are logging on and counting galaxies, searching for interstellar dust grains brought back to Earth by the Stardust spacecraft, bird-watching to track the population levels and distributions of our feathered friends, and devoting spare computer processing power to modelling climate change scenarios, searching for cures to cancer and mapping the Milky Way’s structure. Now Dr Jill Tarter of the SETI Institute plans to take citizen science one step further with the launch of setiQuest, a project that will enable members of the public to not only visually search radio observations for anomalous transmissions, but also to create new computer algorithms and methods to analyse the data, potentially altering the way the search is conducted. And it is worth remembering that the pathfinder for this recent explosion of public science was the phenomenally successful SETI@home project, which blazed onto the scene in 1999.Hidden in this image of radio static is a signal from the Voyager 1 spacecraft. Can you find it? (Scroll down to end of article for the answer).
Modern-day SETI searches have grown far more complicated than Frank Drake’s original 1960 search, Project Ozma, that searched two stars on a single radio channel. With computing power so integral to our ability to analyse data from radio telescopes, the trend has been for SETI to follow Moore’s Law, which describes how computer processing power (in the form of the number of transistors that can be squeezed inexpensively into an integrated circuit) doubles roughly every two years. Today’s SETI surveys scan millions of channels all at once, producing 100 terabytes of data per day. The somewhat quaint impression of SETI scientists wearing headphones as they listen to one single channel, as they are seen to do in the movies, would result in them ignoring the other million-plus channels that are being recorded (though no one can deny that there isn’t something hugely symbolic in the image of an astronomer ‘listening’). SETI has moved on from the days of Ozma.
To process all the data from all those channels, you ideally need a supercomputer. Trouble is, supercomputers are pretty darn expensive. So in 1999 scientists at the University of California, Berkeley came upon the idea of networking thousands of home computers across the world in a grand effort to analyse the data that was piling up on the servers of the Arecibo radio telescope in Puerto Rico. Since then, SETI@home has grown exponentially, with more than eight million people in 226 different countries having downloaded the software that allows their computers to analyse data from Arecibo.The SETI@home screensaver, analysing data from the Arecibo radio telescope.
SetiQuest now aims to take this one step further. Computers can identify narrowband signals fairly easily, but they have pretty lousy pattern recognition skills, resulting in them being blind to any complex broadband signals. Part of setiQuest is about opening up the source code for the detection software to the public, so people can develop new code to improve its detection capabilities. SetiQuest’s other facet is to actually involve members of the public looking at data and searching for anomalies amidst the raw static, or developing new techniques to visualise the data to make it easier and more fun for members of the public to search. For instance, citizen scientists that have already signed up to setiQuest are suggesting that the radio data be converted somehow into graphics or audio files to make it more intuitive to search through (and audio files will allow visually impaired users to take part). Plans are also being put in place to develop some kind of computer game that will make it even easier for people to log on and take part in the search. It’s like taking the basics of the hugely successful Galaxy Zoo, and ramping up user participation and interaction to the nth degree.
What’s more, and this is the crucial part, it will all be done in real time. Data will immediately be sent to you direct from the SETI Institute’s giant Allen Telescope Array (ATA). If you see anything unusual in it then, after flagging it up, it will be sent to another ten people, who each will automatically send it onto another ten people. If most of those 111 people see something in the data, then instructions will automatically be sent back to the ATA commanding it to get on the source of that data as quick as a flash in case it vanishes like the ‘Wow!’ signal of 1977.
This is fantastic news. SETI captures the public’s attention in unique ways that other science doesn’t always do – it has street cred from popular science fiction, a little bit of mystery to spice things up, and it transitions across many disciplines. For those of us who long to become a part of SETI it offers fantastic opportunities, and within months of the foundations for the project being set up, before any data has even been released to analyse, more than a thousand people from around the world have signed up to take part in the quest.
“My sense is that the question “are we alone?” is something that humans have been asking for thousands of years,” says Dr Dan Werthimer, one of the founders of SETI@home from UC Berkeley. “SETI@home has enabled people to really participate in it. SETI@home is now one of the world’s biggest supercomputers, and we’re able to do much more sensitive searches and look for a much richer variety of signal types.”VoyagerÕs signal, having travelled 106 astronomical units (i.e. 106 times the distance between Earth and the Sun), is visible as a faint diagonal line amidst the static. SetiQuest will challenge users to find signals like this.
But trouble brews on the horizon for SETI@home. The National Science Foundation, which runs science in the United States, has declared that in 2011 the great Arecibo telescope will be closed down. The impact on SETI could be huge. All the while, SETI has not had a dedicated experiment at Arecibo, but instead ‘piggybacks’ on the telescope as it conducts its everyday science operations. The SETI@home project concentrates on the ‘water hole’ frequency of 1,420MHz, but another experiment named SERENDIP analyses a wider chunk of the radio spectrum on site, while a third project, Astropulse, is keeping an eye out for any pulsed radio signals that may fall onto the enormous 305-metre Arecibo dish. So SETI has a lot to lose, although stepping into the breach will be the ATA, with 42 of its planned 350 radio dishes already completed. Furthermore, the upcoming Atacama Large Millimetre Array and the Square Kilometre Array will possess sensitivity and gathering power far in advance of Arecibo.
Perhaps losing the famous Puerto Rican bowl in the ground will end up merely a blip on the road to a brighter future, and you can help SETI to enjoy that future by joining in the quest. Just sign up to the website (http://www.setiquest.org/) and let the guys and gals at the SETI Institute know what you think, tell them your ideas for how to view the data or develop coding to help the analysis, and spread the word to your friends, families, workmates and anyone else who will listen. The chances are that any unusual signals that you identify through setiQuest will, annoyingly, be terrestrial interference, but perhaps you might stumble across a new kind of astrophysical phenomena, or the microwave burst from a pair of merging black holes in a faraway galaxy. At the very least your input could help transform the way we search, and maybe, just maybe, you will be the one who identifies a radio signal from another world.
Stay tuned throughout April for more SETI articles.