The Oort Cloud: what little is known
Link here. This is one of the best articles on the theorized Oort Cloud, in that right off the bat the author recognizes this important fact:
We know so little about it that its very existence is theoretical — the material that makes up this cloud has never been glimpsed by even our most powerful telescopes, except when some of it breaks free.
The cloud’s existence is extrapolated from the arrival of long period comets, and seems to make sense. Yet, without any direct observations it remains a theory only, and an unproven one at that.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Link here. This is one of the best articles on the theorized Oort Cloud, in that right off the bat the author recognizes this important fact:
We know so little about it that its very existence is theoretical — the material that makes up this cloud has never been glimpsed by even our most powerful telescopes, except when some of it breaks free.
The cloud’s existence is extrapolated from the arrival of long period comets, and seems to make sense. Yet, without any direct observations it remains a theory only, and an unproven one at that.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
“Konstantin Batygin: Planet 9 and the Edge of Our Solar System”
Lex Fridman Podcast #201 (7-19-21)
https://youtu.be/tm7poMupE8k
2:39:53
As the article states, the estimate is that it will take 300 years for Voyager to reach the inner edge of the Oort Cloud. I’ve read elsewhere it would possibly take 30,000 years to fly beyond the outer edge. That boggles the mind.
The existence of the Oort Cloud seems to be entirely theoretical; no observational evidence has been reported, as far as I can tell. It was hypothecated in order to get around the problem arising from the incontrovertible fact that comets deteriorate too rapidly to support claims of “billions and billions of years” theory of the age of the universe. Again, this is as far as I can tell from a review of the literature.
Steve (retired/recovering lawyer) wrote: “The existence of the Oort Cloud seems to be entirely theoretical;”
Hypothetical, yes. It and the Kuiper Belt were hypothesized as attempts to explain comets that have very high aphelions. Some comets that come from far away are well out of the plane of the rest of the planets (hypothetically from the Oort Cloud, a spherical volume), and some that are not quite so far away seem to be close to that plane (hypothetically from the Kuiper Belt, roughly a disk). Both are volumes of space around the Sun rather than known collections of comets, asteroids, planetoids, etc.