Earth has a newly-discovered neighbor in the solar system. But the heavenly body – possibly a dwarf planet à la Pluto – isn't a frequent visitor. Located beyond Neptune, its extreme orbit ...

Once the quirky underdog of our solar system, Pluto held planetary status until 2006, when it got a cosmic demotion that still stings space fans. Discovered in 1930, Pluto was the ninth planet for ...

For the first time since Pluto was demoted, the idea of a true ninth planet is edging from speculation toward something testable. Instead of restoring Pluto, researchers are closing in on a different, ...

Why Can't We Find Planet 9? Deep in the outer reaches of our solar system, far beyond Neptune and Pluto, something massive is ...

A recent research paper suggests that a planet may exist far beyond Neptune — less than 20 years after the previous ninth planet, Pluto, was demoted. That research paper, accepted last month for ...

Pluto sits far out in the Solar System, small and dim, moving at a pace that barely fits human timelines. It was found in ...

1. What is a planet? -- 2. Seven perfect planets made of aether -- 3. The Earth becomes a planet -- 4. Sixteen planets -- 5. Not everything that orbits the Sun is a planet -- 6. Uranus! -- 7. The ...

"Orbiting at the edge of the outer Solar System, Pluto is an intriguing object in astronomy. Since the fascinating events surrounding its discovery, it has helped increase our understanding of the ...