A new study has proposed the existence of Planet Y, an alternative Planet Nine candidate that is smaller and closer to Earth than the hypothetical Planet X, which astronomers have been hunting for ...

Pluto, the king of the underworld, was the ancient Romans' embodiment of death itself. Known as Hades in Greek mythology, ...

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 ...

Astronomers have identified a small but significant possibility that a Neptune-sized planet is quietly orbiting within the ...

Recently, astronomers detected the presence of a relatively new quasi-moon called 2025 PN7, which appears to orbit our planet ...

(Correction: An earlier version of this story misstated how far Pluto is from the sun. The correct number is 3.7 billion miles.) What was discovered in Flagstaff, Arizona, and killed off in Prague? If ...

In 2006, updated research led to Pluto being controversially demoted to dwarf planet status by the International Astronomical Union. The reasoning was that Pluto's location in the far-flung ...

Pluto's unusual eccentricity and tilt is likely due to its interactions with neighboring Neptune and other giant planets, ...

Exoplanet hunters Christopher Watson and Annelies Mortier explain the long search for a 'twin Earth' capable of sustaining ...

The planet Neptune wobbled in its orbit around the Sun. That could only mean one thing, astronomers said: There was a ninth planet out there, somewhere, lurking in the fringes of the solar system.

From the column: "Just 0.3% of the world’s land area would need to be covered with solar panels to meet all energy needs." ...

Clyde Tombaugh noticed a speck of light that was Pluto in 1930. — -- Clyde Tombaugh is finally getting to visit the speck of light he spotted at the edge of the solar system in 1930. New Horizons ...