Small Bodies of the Solar System

The small bodies in the solar system include comets, asteroids, the objects in the Kuiper Belt and the Oort cloud, small planetary satellites, Triton, Pluto, Charon, and interplanetary dust. As some of these objects are believed to be minimally altered from their state in the young solar nebula from which the planets formed, they may provide insight into the formation and evolution of the solar system.

small bodies of the solar system

Asteroids, Comets, and Meteors

Asteroids, comets, and meteors are chunks of rock, ice, and metal left over from the formation of our solar system 4.6 billion years ago. They are a lot like a fossil record of our early solar system. There are about 1.3 million known asteroids, and more than 3,800 known comets.

Learn More About Asteroids, Comets, and Meteors

A close up view of diamond-shaped Asteroid Bennu. The asteroid appears gray in this image. Rocks and craters are visible.

This mosaic image of asteroid Bennu is composed of 12 PolyCam images collected on Dec. 2, 2019, by the OSIRIS-REx spacecraft from a range of 15 miles (24 kilometers).

NASA/Goddard/University of Arizona

small bodies of the solar system

The Kuiper Belt

The Kuiper Belt is a doughnut-shaped region of icy objects beyond the orbit of Neptune. It is the home to Pluto, most of the known dwarf planets, and some comets. It may hold the best available record of the original interstellar materials that formed the solar nebula, and it is the most likely birthplace of short-period comets.

Learn More About the Kuiper Belt

Artists concept of Kuiper Belt Object far from the Sun

Artist's impression of the view from a KBO. The four giant planets appear as bright dots, but inner planets are too close to the Sun to be seen.

NASA, ESA, and G. Bacon (STScI)

small bodies of the solar system

The Oort Cloud

The Oort Cloud is the most distant region of our solar system, believed to be a giant spherical shell surrounding the rest of the solar system. It is like a big, thick-walled bubble made of billions or trillions of icy pieces of space debris the sizes of mountains and larger. It is thought to be the home of long-period comets.

Learn More About the Oort Cloud

This image shows comet C/2018 Y1 Iwamoto as imaged in multiple exposures of infrared light by NASA's Near-Earth Object Wide-field Survey Explorer (NEOWISE) space telescope.

Comet C/2018 Y1 Iwamoto as imaged in multiple exposures of infrared light by the NEOWISE space telescope. The infrared images were taken on Feb. 25, 2019, when the comet was about 56 million miles, or 90 million kilometers, from Earth. C/2018 Y1 Iwamoto is a long-period comet originally from the Oort Cloud and coming in near the Sun for the first time in over 1,000 years. Appearing as a string of red dots, this comet can be seen in a series of exposures captured by the spacecraft. Infrared light detected by the 3.4-micron channel is mapped to blue and green, while light from the 4.6-micron channel is mapped to red. In this image, stars show up as blue because they are hotter, whereas the cooler dust around the comet - with a temperature near the freezing point of water - glows red. Movie available at https://photojournal.jpl.nasa.gov/catalog/PIA23165

Keep Exploring

Discover More Topics From NASA

Solar System Exploration

Asteroids, Comets & Meteors

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

Moon

Kids