Think you can find Planet 9? A new citizen-science project lets participants search for hidden solar system objects beyond the orbit of Neptune, where a possible ninth planet may lie.
The Zooniverse website enlists the public's help in performing scientific research. For example, the Planet Hunters project looked for signs of alien planets transiting their parent stars. The Zooniverse projects now span a wide range of topics, from space to literature.
For this project, participants are asked to look through data collected by NASA's Wide-field Infrared Survey Explorer (WISE) and help to separate real objects from system artifacts that can look like real objects (false positives). Citizen scientists will look for spots of light that move across the sky, signaling that those points of light are objects relatively close to Earth compared to the background stars. [The Evidence for 'Planet Nine' in Images (Gallery)]
Like all of the Zooniverse projects, Backyard Worlds is asking citizen scientists to do a job that can't be done by a computer.
"While it's possible to process the data to find moving points of light, we can't get rid of all the noise," according to the Zooniverse website. "Spiky images of stars, especially variable stars, are everywhere. Worse, are the optical ghosts, blurry blobs of light that have been scattered around inside WISE's instruments. These can hop back and forth, or even change color. These artifacts can easily fool our image processing software.
"But with your powerful human eyes, you can help us recognize real objects of interest that move among these artifacts," the description reads. "You'll be able to tell what objects are real by the way they move around differently from the artifacts."
The website compares the method used in Backyard Worlds to the approach taken by Clyde Tombaugh, who discovered Pluto in 1930. Tombaugh used photographic plates and a device called a blink comparator to look for moving objects in the night sky.
Beyond the orbit of Neptune lies a belt of cold, icy objects called the Kuiper Belt; beyond that is a sphere of similar objects called the Oort Cloud. There are a few dwarf planets in addition to Pluto that lie in this region. Between Neptune and the nearest star to the sun, Proxima Centauri, there may be a planet about the size of Neptune, according to some recent predictions by a group of scientists at the California Institute of Technology. The research team also says the object is very likely visible with modern telescopes and could be discovered in the next year.
"There are just over four light-years between Neptune and Proxima Centauri, the nearest star, and much of this vast territory is unexplored," Marc Kuchner, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement from NASA.
"Because there's so little sunlight, even large objects in that region barely shine in visible light," Kuchner said. But WISE searches for infrared light, which can be emitted by objects that are too cool to emit visible light. (Even human bodies radiate infrared light.)
The WISE mission scanned the entire sky in 2009 and 2010, uncovering distant galaxies, black holes and objects called brown dwarfs, which are larger than Jupiter but smaller than dwarf stars. There may be a hidden population of brown dwarfs in the region just outside the solar system, according to the Zooniverse website. The WISE spacecraft was also used to search for near-Earth asteroids.
"Backyard Worlds: Planet 9 has the potential to unlock once-in-a-century discoveries, and it's exciting to think they could be spotted first by a citizen scientist," Aaron Meisner, a postdoctoral researcher at the University of California, Berkeley, who specializes in analyzing WISE images, said in the statement.
Backyard Worlds: Planet 9 is a collaboration among NASA, UC Berkeley, the American Museum of Natural History in New York, Arizona State University, the Space Telescope Science Institute in Baltimore, and Zooniverse, according to the statement from NASA.