The Oort Cloud

The Oort Cloud


The edge of our solar system is not Pluto, it is the Oort Cloud.


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The Oort Cloud is the most distant region in our solar system, and it's jaw-droppingly far away, extending perhaps one-quarter to halfway from our Sun to the next star.

To appreciate the distance to the Oort Cloud, it’s helpful to set aside miles and kilometers and instead use the astronomical unit, or AU — a unit defined as the distance between Earth and the Sun, with 1 AU being roughly 93 million miles or 150 million kilometers.

For comparison, Pluto’s more elliptical orbit carries it between about 30 and 50 astronomical units from the Sun. The inner edge of the Oort Cloud, however, is thought to be located between 2,000 and 5,000 AU from the Sun, with the outer edge being located somewhere between 10,000 and 100,000 AU from the Sun.

If those distances are difficult to visualize, you can instead use time as your ruler. At its current speed of about a million miles a day, NASA's Voyager 1 spacecraft won't enter the Oort Cloud for about 300 years. And it won’t exit the outer edge for maybe 30,000 years.
Even if you could travel at the speed of light (about 671 million miles per hour, or 1 billion kilometers per hour), a trip to the Oort Cloud would require that you pack for a lengthy expedition.


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