A new dwarf planet, discovered beyond Neptune and described as Pluto's 'cousin,' could void the hypothesis of a Planet X in ...

A small team led by Sihao Cheng, Martin A. and Helen Chooljian Member in the Institute for Advanced Study's School of Natural ...

In a thrilling development that challenges long-held assumptions about the outer reaches of our solar system, astronomers ...

DOES Pluto have a wayward cousin lurking in the inner solar system? The dwarf planet Ceres – and other icy chunks – may have been born in the same realm as Pluto, but travelled all the way to ...

and five times better than the best images of Pluto's cousin Triton, Neptune's large moon, obtained by Voyager 2 in 1989. Mission scientists expect more imagery from this set over the next several ...

“Meanwhile, its perihelion—the closest point on its orbit to the Sun—is 44.5 times that of the Earth’s orbit, similar to Pluto's orbit.” This extreme orbit, which takes the object ...