For those of us who grew up learning about the solar system‘s nine planets, there may be nothing that can fill that Pluto-shaped hole in our hearts. However, astronomers recently announced the potential discovery of a new planet in our solar system, bringing the total planet count once again back up to nine. Nearly the size of Neptune, the as-of-yet unnamed planet lurks beyond Pluto in the far reaches of the solar system. From this distance, “Planet X” slowly circles the sun, completing one orbit every 15,000 years.
The quest to find a planet beyond Pluto has confounded astronomers for centuries. Any breakthrough would understandably yield skepticism. Researchers Konstantin Batygin and Mike Brown of the California Institute of Technology (Caltech), who discovered the new planet have a simple response. “Why is this [time] different? This is different because this time we’re right,” says Brown. Batygin and Brown determined the presence of a planet by an abnormal bunching of six other bodies known to orbit near Neptune. This indicates the gravitational pull of a planet, one with the mass of 10 Earths. The researchers say there is only a 0.007 percent chance, or about one in 15,000, this bunching is a coincidence.
If “Planet X” does exist, its gravitational pull should make it easier for scientists to discover new small objects in that part of space. However, the new ninth planet can not be added to textbooks and planetarium shows until it can be confirmed through a telescope. “Until there’s a direct detection, it’s a hypothesis—even a potentially very good hypothesis,” says Brown. Brown and Batygin are using a powerful telescope in Hawaii to search for their planet and they encourage other astronomers to join the hunt. Brown’s new job as planet hunter offers him some redemption from his previous role as “Pluto slayer”. In 2005, Brown’s discovery of Eris, an icy world similar to Pluto in size and location, demonstrated that Pluto was just one of several dwarf planets in the Kuiper belt. For Brown, Pluto’s demotion pales in contrast to his new pursuit. He says, “Killing Pluto was fun, but this is head and shoulders above everything else.”
Via Science Magazine