Planets

New simulations suggest that a 9-mile-thick layer of solid diamonds may lurk deep below the surface of Mercury. The gems almost certainly can't be mined for bling — but they may help solve some of the planet's biggest mysteries.

Vivid clouds swirl across Jupiter's skies like colorful brushstrokes in a new photo from NASA's Juno spacecraft.

A peculiar leopard-spotted rock, found beside an ancient, dried-out river in Mars' Jezero crater, contains some tantalizing clues of ancient life, NASA said.

NASA's Curiosity rover revealed an 'oasis' of rare elemental sulfur on Mars after accidentally crushing a rock with its tires. The yellow crystals have never been spotted on the Red Planet before.

Astronomers are proposing a new, more quantitative definition of what makes a planet. The new definition looks more directly at the object's mass — but it would still leave Pluto out of the running.

Four volunteers exited a mock Mars habitat at NASA's Johnson Space Center on July 6, bringing the agency's first year-long simulated Red Planet mission to an end.

Located 50 light-years from Earth, the beady-eyed exoplanet LHS 1140 b could be a perfect candidate for discovering liquid water outside the solar system, new research suggests.

The James Webb Space Telescope revealed that the hot Jupiter exoplanet HD 189733 b, located just 64 light-years from Earth, has an atmosphere full of hydrogen sulfide, meaning it likely smells of rotten eggs.

Slovakian artist Martin Vargic's spectacular new infographics artistically portray, visualize and compare more than 1,600 planets in other star systems.

New photos from the European Space Agency's Mars Express orbiter give us our best look yet at a giant ravine on the Red Planet. The dark "scar" was likely birthed by a gigantic blob of magma hidden beneath a massive nearby volcano millions of years ago.