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Oort cloud

Adapted from Wikipedia · Explorer experience

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The Oort Cloud

The Oort Cloud is a huge, distant area around our Sun. It is filled with billions of icy objects. This cloud was first suggested by a Dutch astronomer named Jan Oort in 1950. He thought it could be the source of long-period comets that sometimes visit the inner parts of our Solar System.

The Oort Cloud stretches very far from the Sun, from about 2,000 to 200,000 astronomical units away. It is much farther than where the planets are. Scientists think the Oort Cloud has two parts: an inner part shaped like a disk and an outer part that is round. Both parts are far beyond where the Sun’s influence ends, floating in the space between stars.

Even though we cannot see the Oort Cloud directly with our telescopes, it is very important. When the gravity of passing stars or our galaxy nudges these icy objects, some may fall toward the Sun. This is how we sometimes see comets in our night sky.

The Oort Cloud is believed to be made of material that once formed closer to the Sun. The gravity of giant planets pushed these objects far out into space. Today, the Oort Cloud may be the main source of many comets that enter the inner Solar System.

Images

An artist's illustration showing the distances in our solar system and the journey of NASA's Voyager 1 spacecraft as it travels into interstellar space.
An artist's illustration showing the Voyager spacecraft traveling through space.
A stunning view of Earth rising over the Moon, captured by astronauts during the Apollo 8 mission in 1968.
A visual guide to the major objects in our Solar System, showing the relative sizes of planets and the Sun.
A stunning view of our planet Earth from space, showing Africa, Antarctica, and the Arabian Peninsula.
A colorful image of Ceres, a dwarf planet, showing bright craters like Haulani and Oxo on its surface.
A colorful image of the planet Pluto showing its icy surface and the bright 'heart' region known as Sputnik Planitia, taken by NASA's New Horizons spacecraft.
A stunning photograph of Comet Hyakutake, a bright comet visible from Earth in 1996, showing its tail and stars in the background.
A stunning image of comet 67P captured by the Rosetta spacecraft from its mission to study this icy visitor from space.
An artist's impression of HE 1523-0901, one of the oldest known stars in our Galaxy, located about 7,500 light-years from Earth.

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Gravity

This article is a child-friendly adaptation of the Wikipedia article on Oort cloud, available under CC BY-SA 4.0.

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