Astronomers are offering the general public a once-in-a-lifetime opportunity: the chance to discover a new planet in our solar system.
Many astronomers now think there may be a massive, undiscovered planet lurking in the far reaches of our solar system. Right now, however, the existence of this planet is theoretical. So the hunt is on to actually capture an image of it.
The obvious way to look for the new planet is to point large telescopes at the patch of sky where theory says it ought to be.
But there's another way: scour images of the sky that have already been taken, hoping one of those images contains the planet.
Astronomer Adam Schneider of Arizona State University is trying the latter approach. He's new to planet hunting: "I'm more of a brown dwarf person myself, brown dwarf and low mass stars," he says. But brown dwarfs and low mass stars have something in common with the putative planet ... they give off infrared light. And NASA's WISE telescope views the sky at infrared wavelengths. WISE has taken a trove of pictures of the sky.
"We have the entire sky to go through," says Schneider. That's both good and bad news. "It's a bonus, in that we have the whole sky, so we're not going to miss anything," he says. "But it's also why we need citizen scientists because it's just too much to look at for one scientist or even a group of scientists."
By citizen scientists, Schneider means anyone — no special skills required. You just go to a website called Backyard Worlds: Planet 9, sign up, and start scanning the WISE images.
The images are presented like a flip-book. You see four images of the same patch of sky, taken at different times. Because they're so far away, the bright stars in the image appear to remain in the same place from one picture to the next. But a closer moving object such as a planet or a wandering brown dwarf will appear to move against the starry backdrop.
Now you may be wondering, why do they need people to search for moving objects? Can't a computer do this?
"Computer algorithms are not very good, the more and more stars that get involved," says Jacqueline Faherty, an astronomer at the American Museum of Natural History and another member of the citizen science project. "The human eye helps tremendously. It's much faster, it can be very trustworthy," more than a computer algorithm, she says.
That doesn't mean spotting moving items is easy. I went to the website and tried. I was terrible at it. Faherty told me not to feel bad.
"To be honest I'm really bad at it as well," she says. "But I want people with good eyes to do it, because when they're good at it, they're really good at it."
Even if you correctly spot something moving in the images, in might not be the undiscovered planet. It could be a brown dwarf star or some other faint object fairly close to the sun.
But Adam Schneider says you could hit the jackpot.
"Literally anyone — you, me, anyone you talk to — can potentially log on and make that discovery," he says.