Solar System · Shell of icy bodies around the Sun
Oort Cloud
Starts ~2,000 AU from the Sun · Light crosses it in 3.2 years
- Across
- 3.16 light-years
- Vs Earth
- 3.16 light-years across
Open Oort Cloud in Cosmic Scale
About
The Oort Cloud is a vast shell of icy bodies surrounding the Solar System, so far out that passing stars can nudge its members loose. Nobody has ever seen it directly — we infer it from the comets that fall inward from every direction.
Where long-period comets come from — its outer edge is a third of the way to the nearest star.
At a glance
| Inner edge | About 2,000 AU |
|---|---|
| Outer edge | 50,000–100,000 AU |
| Proposed | 1950, Jan Oort |
| Members | Perhaps trillions |
Did you know
- Its outer edge is roughly a third of the way to Proxima Centauri.
- A comet falling in from there can take millions of years to reach the inner Solar System.
- Voyager 1 will need about 300 years just to reach the inner edge.