The Solar System

Planetary Systems

How large is our solar system?

Our solar system reaches well past the orbit of the most distant planet, Neptune, which is about three billion miles (five billion kilometers) away from the Sun. Beyond Neptune is the Kuiper Belt, a thick, doughnut-shaped cloud of small, icy bodies that extends to about eight billion miles (twelve billion kilometers). Far beyond that still is the Oort Cloud, which is a huge, thick, spherical shell thought to contain trillions of comets and comet-like bodies. The Oort Cloud may extend as far as a light-year, nearly six trillion miles, out from the Sun.


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