This is an illustration of what the Oort cloud might be like.
Click on image for full size
Where do comets come from?
Mathematical theory suggests that most comets may come to the solar system from very far away. In this picture, the solar system is buried deep within the cloud.
An AU is the distance from the earth to the sun and is about 100,000,000 miles. Mars is 1.5 AU from the sun, Jupiter is 5 AU from the sun, and Pluto is 39 AU from the sun. So comets come from very far away indeed.
Comets come in to the solar system from all directions.
But some comets may come to the solar system from closer in.
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