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ianindy t1_jefbmwd wrote

All of it Nobody has seen it. They don't have proof that it is really there.

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[deleted] t1_jefcj9a wrote

[deleted]

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VeryFarDown t1_jefeaat wrote

Actually, the person you replied to is correct. The Oort Cloud is still a hypothesis. This is from Universe Today:

>For thousands of years, astronomers have watched comets travel close to Earth and light up the night sky. In time, these observations led to a number of paradoxes. For instance, where were these comets all coming from? And if their surface material vaporizes as they approach the Sun (thus forming their famous halos), they must formed farther away, where they would have existed there for most of their lifespans.
>
>In time, these observations led to the theory that far beyond the Sun and planets, there exists a large cloud of icy material and rock where most of these comets come from. This existence of this cloud, which is known as the Oort Cloud (after its principal theoretical founder), remains unproven. But from the many short and long-period comets that are believed to have come from there, astronomers have learned a great deal about it structure and composition.

Voyager 1 will reach it in about 300 years, but unfortunately, it won't have the ability/power to report its findings back to us.

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ianindy t1_jefheoz wrote

Here is the description from Wikipedia:

>First described in 1950 by the Dutch astronomer Jan Oort, is a theoretical concept of a cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from 2,000 to 200,000 AU (0.03 to 3.2 light-years).

https://en.wikipedia.org/wiki/Oort_cloud

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