An asteroid is a rocky or metallic body orbiting the Sun, too small to count as a planet and lacking the ice-driven tail of a comet. Most travel in the main belt between Mars and Jupiter, though many follow paths that cross Earth's orbit. They are leftover building material from the formation of the solar system, never assembled into a planet because Jupiter's gravity kept stirring the region. Missions such as OSIRIS-REx and Hayabusa2 have brought samples home, and DART showed that a spacecraft impact can measurably shift an asteroid's orbit.
Space Exploration · NASA · Asteroids
We can never drill to the center of the Earth. So NASA sent a spacecraft to the next best thing: 16 Psyche, a metal asteroid that may be the naked, ex...
Space Exploration · Planetary Defense · NASA
On September 26, 2022, a 610-kilogram spacecraft slammed into a 160-meter asteroid at 22,000 kilometers per hour. The goal was to nudge its orbit by 7...
Cosmology · Astrobiology · Asteroids
Fifteen of the twenty amino acids life uses. All five DNA and RNA bases. Ribose. Glucose. And a polymer never seen anywhere else in space. NASA opened...