Home › Solar System › Oort Cloud
Region at the edge of the Solar System
Oort Cloud
Very, very far out there is probably a giant ball of trillions of chunks of ice: the Oort Cloud. Nobody has ever seen it, but sometimes a chunk falls from there towards the Sun – then we see a comet.
Fact file
- Type
- Region at the edge of the Solar System
Interesting facts about the Oort Cloud
- Right at the edge of the Solar System, researchers suspect there is a gigantic sphere of trillions of icy chunks: the Oort Cloud.
- It may reach out to 100,000 times as far as Earth is from the Sun – almost a quarter of the way to the nearest star.
- Nobody has ever seen it: its chunks are too small and too dark. We infer that it exists because comets keep arriving from there.
Formation
The icy chunks formed close to the giant planets and were flung far out by their gravity.
Structure
On the inside the cloud is more disc-shaped (Hills cloud), on the outside spherical. Passing stars sometimes nudge chunks, which then fall towards the Sun as long-period comets – like Hale-Bopp.
Exploration
No probe has ever been there. Voyager 1 still needs about 300 years to reach the inner edge – and 30,000 years to cross it.
Importance for Earth
It is named after the Dutch astronomer Jan Oort, who predicted it in 1950.
This site is free and has no banner ads. Here is how you can support it