• Key Information

  • Oort Cloud

  • Type
    Cloud of icy planetesimals
  • Diameter
    4,000 to 400,000 AU
  • Mass
    5 earths
  • Sections
    Inner (Hills) Cloud, Outer Cloud
  • Other Names
    Öpik–Oort Cloud
  • Learning Point
  • The Oort Cloud is a region of space from beyond the outer most minor planets we know about, that extends right up to the edge of the Sun's gravitational influence, and is likely made up of billions of comets and small rocky asteroids.
  • Project
  • What areas exist in our Solar System beyond the orbit of Neptune?
  • Location
  • Located in
    Our Solar System
  • Fun Facts
  • Perhaps one or two percent of the objects in the Oort Cloud are asteroids, with the remainder being icy comets.
  • As stars pass close to our Solar System, they interfere with the comets in orbit in the Oort Cloud, triggering some to fall inward towards the sun.
  • Long-period comets (they take a long time to orbit the sun) are thought to have come from the Oort Cloud.
  • The star Gliese 710 is set to pass within the Oort Cloud in around 10 million years, which would likely cause a burst of comets arriving in the inner Solar System.