What is the Oort Cloud?
A vast spherical shell of frozen debris at the edge of our solar system.
The answer
The Oort Cloud is a hypothesized spherical shell of icy objects surrounding our solar system at distances of 2,000 to 200,000 astronomical units (up to 3.2 light-years from the Sun - nearly halfway to the nearest star). It is believed to contain billions of cometary nuclei left over from the solar system's formation. Long-period comets that visit the inner solar system are thought to originate here, knocked inward by gravitational perturbations from passing stars. No spacecraft has ever reached the Oort Cloud, and it has never been directly observed.
Source: NASA Solar System Exploration
- Oort Cloud
- comets
- solar system
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