The Oort Cloud

The Oort Cloud is like a giant bubble around our solar system. It is full of billions of icy objects. It is the farthest part of the solar system. No one has ever seen it directly. Scientists believe it is where long comets come from.

Where It Is

The Oort Cloud is very, very far from the Sun. It is thousands of times farther than Earth is. Sunlight is so weak there that the Sun looks like a small bright dot. It wraps around the solar system like a round shell.

An artist's picture of the Voyager spacecraft sailing through deep space.
An artist's picture of the Voyager spacecraft sailing through deep space. (NASA/JPL / Wikimedia Commons)

Home of Comets

Sometimes a piece of the Oort Cloud gets pushed toward the Sun. As it gets close, it heats up and grows a bright tail. This is a comet. Some of these comets take thousands of years to come around.

Fun Facts

  • The Oort Cloud is named after astronomer Jan Oort.
  • It may hold trillions of icy objects.
  • No spacecraft has reached it yet.

Did You Know?

It would take the fastest spaceship thousands of years to reach the Oort Cloud!