Mike Brown is convinced that beyond Neptune, at the far reaches of our solar system, there's an unseen giant planet. "This is the 5th largest planet in our solar system, lurking out there ...

A team of scientists at the Institute for Advanced Study School of Natural Sciences in Princeton, New Jersey, might have found a new dwarf planet, potentially leading to more evidence of a ...

HANDOUT/University of Cambridge/AFP via Getty Scientists believe they might have discovered evidence of life on a planet 700 trillion miles away from Earth. K2-18b, a planet more than double the ...

A team of astronomers says it has identified a single, slow-moving infrared object that checks all the right boxes for it being the long-theorized ninth planet lurking beyond Neptune. The hunt for ...

Astronomers announced Thursday that they had detected the most promising "hints" of potential life on a planet beyond our solar system, though other scientists expressed skepticism. There has been ...

Astronomers announced Wednesday they have discovered a massive planet orbiting a tiny star, a bizarre pairing that has stumped scientists. Most of the stars across the Milky Way are small red ...

Discovered in 1930, Pluto was the ninth planet for over 75 years, orbiting at the chilly fringes of our solar neighborhood. But then scientists at the International Astronomical Union decided ...