Edward Witten, an influential physicist who developed M-theory, recently started thinking about how to scan the solar system for a primordial black hole.
A telescope looking for dark matter discovered 139 new minor planets lurking beyond Neptune's orbit, which could help scientists look for hidden planets in the outer solar system.
This alternate explanation for 'Planet Nine,' proposed by scientists in a new paper, poses some fundamental questions like: Should we visit it?
'Planet Nine' is thought to be 10 times larger than Earth, but what if it wasn't a planet at all?
Nicknamed “Farout,” the world is 120 times farther from the Sun than Earth.
The world called 'Goblin' orbits about two times farther from the Sun than Pluto—and that's at its nearest point.
Crowdsourcing the search for the hypothetical Neptune-sized world at the edge of the solar system.