Oort Cloud

Oort Cloud - NASA.gov (public domain)

What is the Oort Cloud?

In the far reaches of the solar system, past Pluto and the Kuiper Belt, lies the Oort Cloud: a spherical bubble of icy bodies that surrounds our solar system. Over a trillion pieces of icy debris comprise this cloud; when nudged out of orbit, some of them can fall towards the sun as comets. Most planets that we know of have a flat, elliptical orbit around our sun. The Oort Cloud, however, has a spherical, shell-like orbit. As of now, we do not think that it can support life.

A Comet Nursery

The Oort Cloud is named after Dutch astronomer Jan Oort, who proposed its existence in order to explain the origin of long-period comets. Most comets that reach our inner solar system are known as short-period comets. The ones that take thousands of years to reach our sun are known as long-period comets, and most of them have only been observed once in their recorded history. Once they approach the sun, gaining an atmosphere called a coma as they do so, these long-period comets take over 200 years to orbit it. Once their orbit carries them farther away from the sun, their atmosphere collapses.

Learning More About the Oort Cloud

Members of NASA are currently trying to study the Oort Cloud in order to learn more about the particles contained within it and to study long-period comets. NASA launched a spacecraft called Voyager 1 in 1977, aiming to study the outer reaches of our solar system. As of now, Voyager 1 has traveled farther than any other man-made object, and has collected significant data about planets and celestial bodies that are distant from Earth. It will take Voyager 1 at least another 300 years to reach the Oort Cloud, and at least 30,000 years to get to the other side of it. Until NASA is actually able to send a probe to the Oort Cloud and send data back to Earth, we can only study the predictions made in the past and look forward to more clarity on this large spherical bubble in the future.