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Bookmark or Share- Has the Oort cloud moved? - Astronomy Stack ExchangeThe Oort Cloud lies far beyond Pluto and the most distant edges of the Kuiper Belt. While the planets of our solar system orbit in a flat plane, the Oort Cloud is believed to be a giant spherical shell surrounding the Sun, planets and Kuiper Belt Objects. It's like a big, thick bubble around our solar system, made of icy, comet-like objects.
- Why is the Oort cloud presumed to be spherical?The Oort cloud is simply a concept that can explain why long-period comets appear to come from random directions. With the current instruments, we are not able to detect any of these comets "at the source".
- Do other stars have Oort clouds? - Astronomy Stack ExchangeIf we use our Oort cloud as a model, and, warning, these estimates are enormously ballpark, but, a trillion Oort cloud objects 1 KM or larger and the Oort cloud extends between 100,000 and 200,000 AU (lets say 150,000 as a middle estimate), that works out to one 1 KM or larger object per cubic region of space about 15 AU across. That's 3/4ths ...
- Do all stars have an Oort cloud or is it a rare occurence?Oort-cloud objects are 2,000 - 50,000 (or more) AU away-- so these objects, to us in the same solar system, have an apparent magnitude much fainter than 11. The point of that poorly-explained interlude is that these objects are faint. Very faint. And objects in Oort Clouds around other stars would appear even fainter.
- Why can't we observe the Oort cloud with a telescope?The detection of Oort cloud objects is simply a question of detecting the (unresolved) reflected light in exactly the same way that one detects a faint (unresolved) star. Confirmation of the Oort cloud nature of the object would then come by observing at intervals over a year or so and obtaining a very large ($>2$ arcseconds) parallax.
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