Depth 16 · Comet reservoir

Oort Cloud

The Oort Cloud is a vast shell of icy bodies thought to surround the solar system far beyond Pluto and the Kuiper Belt. It has never been directly observed; astronomers infer it mainly from long-period comets that fall inward from every direction.

Fact sheet

Type

Theoretical comet reservoir

Distance

Thought to begin about 2,000 to 5,000 AU from the Sun

Size

Thought to reach out to about 10,000 to 100,000 AU, a thick shell around the whole Solar System

Discovered

Proposed 1950 by Jan Oort (never directly observed)

On the voyage

Depth 16, in the Outer Sol section of the route, between Voyager 1 and Alpha Centauri

Things to know

• Astronomer Jan Oort proposed the cloud in 1950 to explain where long-period comets come from and why they arrive from all directions. NASA
• It may hold hundreds of billions, possibly trillions, of icy objects. NASA
• NASA has no direct images of the Oort Cloud because it is so far away. NASA
• Sunlight would need up to about a year and a half to reach the cloud's outer edge. NASA
• Voyager 1 is not expected to enter the Oort Cloud for about 300 years and could take about 30,000 years to pass beyond it. NASA

Sources

• NASA – Oort Cloud Facts
• NASA – Oort Cloud