The project is similar to Zooniverse’s Planet Hunters project, in which participants look for exoplanets by studying the dimming of stars’ light that could be caused by a transiting planet.
For the new Backyard Worlds project, citizen scientists are asked to study data from NASA’s Wide-field Infrared Survey Explorer (WISE) telescope to distinguish points of light moving against background stars from artifacts, which are false positives caused by system errors.
The movement of these points of light against the field of background stars indicates these objects are relatively close to Earth, much closer than other star systems.
According to Zooniverse, the method citizen scientists will use in this project is much like that used by Pluto discoverer Clyde Tombaugh in 1930. Tombaugh captured images of the sky on photographic plates, then used a blink comparator to find objects that moved against background stars from one frame to the next.
Between Pluto and Proxima Centauri, the nearest star at four light years from Earth, sit both the Kuiper Belt, a region of numerous cold, icy objects including comets and a few small planets, and the Oort Cloud, a much larger sphere, also filled with icy objects.
Several scientists at the California Institute of Technology believe a large, Neptune-sized gas giant is lurking in one of these regions and may even be visible with today’s telescopes once astronomers know where to look.
Alternately, the undiscovered object could be a brown dwarf, a sub-stellar object more massive than gas giants, that emits infrared radiation.
“Because there’s so little sunlight, even large objects in that region barely shine in visible light,” explained Marc Kuchner of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
WISE searches the sky in the infrared, allowing it to detect objects too dim to emit visible light. Between 2009 and 2010, it scanned the whole sky and discovered brown dwarfs, black holes, and remote galaxies.
The hypothesized outer solar system planet is referred to by some scientists as “Planet 9” and by others as “Planet X.” The latter is the conventional term used to refer to theorized but undiscovered objects and is preferred by those who consider dwarf planets to be a subclass of planets, giving the solar system a minimum of 13 planets and counting.
Anyone interested in participating in the search, which is jointly organized by Zooniverse, NASA, UC Berkeley, the American Museum of Natural History in New York, Arizona State University, and the Space Telescope Science Institute in Baltimore is encouraged to visit the project’s website.