Closeup view of a rocky, diamond-shaped asteroid in space


Asteroids, sometimes called minor planets, are rocky, airless remnants left over from the early formation of our solar system about 4.6 billion years ago.

Most asteroids can be found orbiting the Sun between Mars and Jupiter within the main asteroid belt. Asteroids range in size from Vesta – the largest at about 329 miles (530 kilometers) in diameter – to bodies that are less than 33 feet (10 meters) across. The total mass of all the asteroids combined is less than that of Earth's Moon.

The current known asteroid count is 1,382,263. This count includes dwarf planets, and objects in the Kuiper Belt – a doughnut-shaped region of icy bodies extending far beyond the orbit of Neptune. Scientists call these worlds Kuiper Belt objects (KBOs), or trans-Neptunian objects (TNOs). Trans-Neptunian objects are objects in our solar system that have an orbit beyond Neptune. There may be millions of other icy worlds in the Kuiper Belt that were left over from the formation of our solar system.

The total mass of all the asteroids in the main asteroid belt combined is less than that of Earth's Moon.

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Featured Asteroids

NASA has sent several robotic spacecraft to encounter asteroids up close to learn more about their composition and size.

Asteroid Psyche in space. The asteroid has reddish patches and large craters.


A grainy image with a distant asteroid circled


An image of asteroid Dinkinesh, a pair of grey asteroids with a slightly jagged surface, taken from the Lucy spacecraft.

Dinkinesh and Selam

Two asteroids in space

Didymos and Dimorphos

Ida and Dactyl

Image of an asteroid in space


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