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Ohioans Help NASA Find “Space Dust.”
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People from across Ohio and around the globe have been helping NASA find tiny specks of interstellar dust. In the final installment of our series on citizen science, WOSU’s Jonathan Hickman reports on how Ohioans are sifting through high-tech NASA instruments on the screens of their home computers.
In January, 2006, NASA’s Stardust space probe returned to Earth after collecting dust from a comet’s tail. Along the way, it also collected interstellar dust. But since the probe probably captured just a few dozen of the microscopic particles of dust, scientists like Berkeley’s Bryan Mendez knew finding them would be a challenge.
“When we started to realize the scope of the project one of the analogies that we’ll use often is that searching for the number of particles that we expect to find is kind of akin to looking for like 45 ants in a football field. But we can only look at that football field in a little 5 centimeters square at a time that’s about the equivalent size of our field of view when we use our microscope.” Says Mendez.
So the researchers needed to outsource the work. Mendez and other Berkeley scientists took inspiration from another project combing huge amounts of data the Search for Extraterrestrial Intelligence, or SETI program. In the SETI@Home program, volunteers download a screen saver that searches radio telescope signals for signs of intelligent life while their computers are not being used .
But locating captured interstellar dust would require a different approach.
“Instead of a distributed computing project, which is what SETI@Home was, it would need to be kind of a distributed thinking project. We’d actually need people to physically be looking at little movies taken from the microscope.” Says Mendez.
The Stardust@Home volunteers or dusters as they came to be called signed up in droves.
“Within that first month I think there was between 10,000 and 15,000 people that had signed up to participate. And over the next year we gained another 10,000 or so.” Says Mendez.
The dust was captured in bricks of a special material called aerogel. The scientists at Berkeley created hundreds of thousands of movies of the aerogel through a microscope, allowing volunteers to focus up and down on their computer screen just like they’re looking through the microscope themselves. The movies have racked up some big box office numbers.
“Each of those fields of views has been looked at now by hundreds of people, so we’re probably talking a few hundred million searches have been performed by the dusters.” Says Mendez.
One of those dusters is Rick Prairie, a Cincinnati biochemist and computer scientist who’s fond of space and large data sets.
“I just got involved in projects that had lots and lots of data that needed to be turned into results that are just a few sentences long.” Prairie says.
Prairie enjoyed trolling through images and contributing to scientific discovery, but was tripped up by Stardust@Home’s calibration movies. These were movies prepared by the scientists to test the home researchers. The calibration movies test how often dusters might be missing a dust track, or mistakenly identify a blemish in the aerogel as dust. But for a self-proclaimed perfectionist like Prairie, making a mistake on a test movie was a little demoralizing.
“After 7 minutes I was in it kind of for the fun of it, okay, I mean, the excitement of finding something. But when it got to be kind of like a long long exam, that took some of the fun out for me.” Says Prairie.
Still, Prairie searched through thousands of clips before turning his attention to another project. Though Berkeley’s Bryan Mendez points out that while watching more movies might increase your chances of finding dust, there’s always the chance of a little beginner’s luck.
“Anybody who comes to it, even if it’s their first day dusting as they call it, anyone could actually find something.” Says Mendez.
Searches of half of the aerogel blocks have been completed about half a million movies-worth. Some small aerogel slices have been sent for analysis to see what the dusters may have found. But if you’re looking for a chance to find dust that’s travelled from the void of interstellar space all the way to your desktop, you’ll have your chance in about a month, when the first of another half million movies will have their online debut.
Jonathan Hickman, WOSU News