New ice world raises ‘Planet Nine’ hopes
Astronomers have discovered a dwarf planet at the very outer reaches of our solar system—a find that may point the way to a long-hypothesized ninth large planet lurking somewhere far beyond Pluto. Nicknamed the Goblin, the roughly 200-mile-wide dwarf planet follows an extremely elongated orbit, reports The New York Times. Right now the ice world is as close as it gets to the sun, some 7.4 billion miles away, or about 2.5 times farther than Pluto. At the most distant end of its 40,000-year orbit, the Goblin will be more than 200 billion miles from the sun. Because the Goblin is beyond the gravitational pull of the solar system’s giants—Jupiter, Saturn, Uranus, and Neptune—scientists believe that something else must have shaped its unusual orbit. That is where the elusive Planet Nine comes in: The Goblin is the third small planet of its kind to have been discovered in the outer solar system, and the orbits of all three appear to be clustered together. That suggests the distant worlds are being shepherded by a massive, undiscovered object—possibly our solar system’s ninth large planet. Astronomer Scott Sheppard, of the Carnegie Institution for Science, says the Goblin’s discovery isn’t a “slam dunk” for Planet Nine believers, but it makes the mysterious planet’s existence look “more likely than not.” ■
The Goblin: Signpost to the ninth planet?
October 12, 2018 THE WEEK