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View Full Version here: : a little help with the Oort Cloud please


Brian W
18-02-2011, 08:58 PM
Hi all, is the O.C. truly like a balloon that encircles our solar system? And is it really out there far enough to be gravitationally affected by other star systems?
Brian

Waxing_Gibbous
19-02-2011, 12:11 AM
Though thought to be largely as you describe it I believe the Oort Cloud is still theorectical.
For the sake of argument: Its about a light year out and is the source of long-period comets. I don't know about other star sysytems, but it could conceivably be influenced by the gravitational tug of the rest of the Milky Way and possibly a close - passing star. Its grip by the Sun must be very tenuous at that distance though so possibly a larger star -system could disperse it.
It's named after a Dutch astronomer who theorised that because comets were so volatile they would not have formed in their current orbits and therfore there had to be an outside source or nursery. If memory serves he wasn't the first to bring up the idea but he definately popularised it.

It is probably made up from debris left over from the formation of the solar system that was somehow ejected, possibly by the inner planets.

The debris itself would probably comprise water and methane ice, frozen CO, ethane and possibly some very light rocky rubble. Whether it formed in one go or over a period of eons, I have no idea.
That's about all I know, or think I know about the Oort Cloud!
Chime in anyone who has better info! :)

astroron
19-02-2011, 12:39 AM
Good reply there Peter:)
Not much more to add, except it was first theorised by E Opic in 1932 and developed in about 1950 by Dutch Astronomer Jan Oort, sometimes known as the Oort-Opic cloud,there is no direct evidence for it other than the need to explain the long period comets that sometimes come into the inner Solar System:thumbsup:
Cheers

Rob_K
19-02-2011, 01:20 AM
This isn't a bad article:

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

Cheers -

CraigS
19-02-2011, 08:02 AM
Formally speaking, the Oort Cloud is still considered a Hypothesis and is not a Theory, due to a paucity of data.

As mentioned in the Wiki description, there are only four known objects which MAY belong to the hypothesised Oort Cloud. There are other hypotheses which could also explain their behaviours/origins.

Predicting a Jupiter sized planet, on the basis of it perturbing hypothetical objects which may constitute a hypothetical 'cloud', would seem to fall into a highly speculative category.

Whilst the Oort Cloud is a reasonable hypothesis, it seems reminiscent to me, of the hypothesised "Great Southern Continent", which required Captain James Cook having to spend large chunks of his life disproving. A lot of good discoveries came our way as a result however, and lives were lost.

Cook was quite vocal in expressing the frustration he felt at having to disprove a hypothesis he also spent a lot of time having to disprove the north-west passage.

Food for thought

Cheers

astroron
19-02-2011, 08:49 AM
Yes Craig I should have put hypothesised;)
Cheers

CraigS
19-02-2011, 09:11 AM
No worries Ron. Actually, I wasn't even thinking of your post when I wrote mine.
:)
It seems to me that the community, in general, is very quick to adopt speculative ideas, and frequently overlook the scientific distinctions which underpin how the information should be positioned in our thinking.

Scientific philosophy is just as significant as observational data.

Cheers

Brian W
19-02-2011, 12:08 PM
Hi Craig, he could not disprove the North west passage for the simple reason that there is one. Though he may have spent a lot of time not finding it.

Brian

CraigS
19-02-2011, 12:57 PM
Ahhh … but as I recall, immediately following Vancouver's later expedition (after Cook's), it was concluded that there was no passage south of the Bering Strait. This was also confirmed by others. Following this, there was effectively no 'useful' Northwest Passage. (No-one was interested in anything else). So, in those days, all of these explorers had disproven the (then) concept of a northwest passage.

The 'disprove' was complete against the original concepts (and boundaries), outlined by the hypothesis of the time.

Modern day interpretations exist separately from those of the original explorers .. ie: the 'hypothesis' has changed .. evidence is again sought to test it, etc, etc.

Cheers

Brian W
19-02-2011, 02:06 PM
Ok Craig, using this as a teaching tool... I agree that they disproved the postulation(?) of a usable NW passage.

However with he melting ice packs there now is a usable NW passage.

Does this mean that their -theory- postulation- hypothesis- was correct after all?

I think I am asking; can one revisit a 'dis-proven theory' with new information and show it to be true?
Brian

CraigS
19-02-2011, 02:37 PM
The disproven hypothesis should be restated, and reformulated, in modern times, in the light of additional known information. It would then become a new hypothesis, with new testing methods, possibly looking for different outcomes. The 'ice barriers' existing in Cook's time, clearly may not exist in modern times, so the situation has also changed .. many variables would cause the hypothesis to have to be re-stated, not the least of which, would be the outcomes of the original hypothesis' test results (eg: Cook's and Vancouver's maps).

This highlights the need for very specific, (as unambiguous as is possible), formal wording of any hypothesis and succesful outcomes/testing criteria to be established, before one sets out to test it. Ever notice that NASA projects all set out with a definition of a successful mission statement? This is kind of the analogy of the scientific process.

Mind you, the practical side of me acknowledges that I don't think I've ever seen a modern hypotheses stated as clearly as I'm making out .. and in Cook's time, we'd have to rely on his written orders and the act of Parliament which led to the reward being posted .. after all .. none of this philosophical definitional stuff existed then ! ;)
:)
Cheers

bkm2304
19-02-2011, 03:30 PM
Oh No! My whole scientific career is in jeopardy! I spent years developing and performing experiments to disprove hypotheses! :eyepop:

Richard

CraigS
19-02-2011, 03:38 PM
Hi Richard;

So why would that put your scientific career in jeopardy ??
Cook became a famous 'scientist' why can't you ?

:)

Cheers

bkm2304
19-02-2011, 03:46 PM
It doesn't and won't. It was a play on the foundations of the scientific method - design your experiments to disprove the hypothesis under question. Maybe a little too subtle I guess......

renormalised
19-02-2011, 03:48 PM
Well despite it being hypothetical, there "Oort" to be an Oort Cloud :):P

CraigS
19-02-2011, 03:54 PM
.. I wonder what the test criteria Oort to be for disproving it ?
:):P:)

Cheers

renormalised
19-02-2011, 04:02 PM
Well, the planetary scientist will have to have a "Jan" amongst themselves to see what "Oort" to be the criteria:D:D:P:P

bkm2304
19-02-2011, 04:15 PM
The Oort Cloud question will be solved by rigidly adhering to the principles and structure of scientific method; namely, the postgrad will discover the answer by accident one night when she/he is looking at something entirely unrelated - you know, the usual way these things are settled. Then the Prof will say "I knew it all along" and everyone within Cooee will get their name on the paper to Nature. :thumbsup:

bkm2304
19-02-2011, 04:20 PM
Oh, forgot to add; The postgrad will get an acknowledgment in the reference section for technical support - an authorship is just not right for them at this stage of their career....:confuse3:

CraigS
19-02-2011, 04:35 PM
Richard;

Point taken and accepted. As I mentioned, the practical side of me is with you on this.

As with any process, it needs to be managed. Your comments relate to the management of the scientific process and I, for one, am not aware of too many scientists renowned for their management prowess.

This however, I also see changing, with new up-and-comers.

(I'll bet there'll be hell for me to pay, after that comment, too. ;) )

Cheers

astroron
19-02-2011, 04:53 PM
Craig, Can you in all your wisdom come up with anything other than an Oort Cloud :question: I would be interested to hear your Hypothesis :D
Please advise accordingly :thanx:
Cheers

CraigS
19-02-2011, 05:20 PM
:lol::rofl::rofl::lol:

Now .. why would I do that ?
I have no intentions of fallin' for that one, Ron.
:)
Cheers

bkm2304
19-02-2011, 05:38 PM
You're pulling my leg, right?:rofl:
Florey (managed Sir william Dunn School of Path, Oxford)
Fenner (John Curtin)
Nossl (WEHI)
Watson (Cold Spring Harbour, Nat Centre for Human Genome Research)
Oppenheimer (Manhattan Project)
Braggs (Cavendish)
Watson (AAT)
Clunies - Ross (CSIRO)
Pasteur (Institut Pasteur)
Koch (Koch Institute)
Hale (Yerkes, Mt Wilson, Palomar, CalTech)
Burnet (WEHI)
Edison (All he surveyed)
etc etc etc

renormalised
19-02-2011, 05:40 PM
I agree with you wholeheartedly there, Craig.

renormalised
19-02-2011, 05:43 PM
But most were more interested in the research and left the real management to underlings and others. They got all the kudos and the headlines, the others did the shoveling of the proverbial fecal matter.

bkm2304
19-02-2011, 05:55 PM
Which ones, in particular?

renormalised
19-02-2011, 06:11 PM
All of them....they make great front men to these institutions, act as the guide and inspiration to move the research along, oversee the "big picture" organisation and planning, go to all the important meetings with politicians etc, and get all the credit when things go wonderfully great...but most of the groundwork is done by middle management. All the hard yards and nitty gritty is done by them. The big boys just look in every now and then to make sure things are running smoothly and how they want them to. Then get all the credit for the successes.

CraigS
19-02-2011, 06:25 PM
Yes .. Richard;

Its a fine balancing act .. there are minds I've encountered who are brilliant at managing process and then there are minds brilliant at maneuvering around technical scientific issues.

There are two disciplines and two mindsets required .. and there's nothing to say that a scientist can't be a good manager, (of the process), or a good manager can't make for a good scientist. The two areas are both very tall however, and to be good at both would be quite an extraordinary find.

Come to think of it, why would you look for it all in one person, anyway ?

Isn't this why entire organisations exist, to produce the overall scientific 'goods' ?

Cheers

bkm2304
19-02-2011, 06:28 PM
Oh. I thought they got to where they were by hard work and used their experience to manage their respective institutes. Frank Fenner for instance. Rids the world of smallpox, and ran the John Curtin. Fenner, by the way, considered Florey as even more modest and unassuming than himself - which is saying something. Till the day he died last year, he was and still is an inspiration to many current and former students of immunology in Australia, myself included. Known to all as one of the most modest, humble, wise and insightful scientists the nation has ever produced. To say that this man was a credit - seeking, big boy, looking in on things every now and then is, well, I think I'll sign off on this thread now.

renormalised
19-02-2011, 06:37 PM
I didn't say they went seeking the credit, only that they got the credit for the lot when things went well. They wouldn't have been given their positions of leadership if they didn't get there by hard work and excellence in their fields. But to assume they were the ones who did all the work in managing their respective organisations and that others weren't just as responsible for the successes and shortcomings is a little short of the mark. However, where does all the credit go when something major works out...to the guys running the projects/organisations. Despite the fact that it was most likely the actual teams working on the problems that figured everything out, you hardly hear of the people in those teams. They're usually referred to as "the team/s".

None of these guys could've done what they did if they didn't have others to help them, even with the research. No one is an island of genius or anything else. In any case, what good is a genius if they can't get their ideas from theory to practice. Especially in those sciences where the theory can be put into practical use.

You're starting to treat this a little too personal and that's where stupid arguments will start to breakout. In any case, this is way off topic.

astroron
19-02-2011, 06:42 PM
QUOTE
It seems to me that the community, in general, is very quick to adopt speculative ideas, and frequently overlook the scientific distinctions which underpin how the information should be positioned in our thinking.

Scientific philosophy is just as significant as observational data.

Craig, I would have thought nearly eighty years for this hypothesis to hang around was a reasonable time for it to fall out of favour:shrug:

Craig, surely you can give us an inkling of an idea that we can build on as to what else could be out there.
It is alright to knock the wall down but you should have some thing to put up in it's place ;)
Cheers

CraigS
19-02-2011, 06:55 PM
Ron .. elapsed time doesn't disprove a hypothesis. Technology improvements may or other theories may make make advances, thus obviating the need for the original hypothesis. In the other thread (about the hypothesised hot Jupiter in the Oort Cloud) …



.. a perfect example of what I'm saying. It just hasn't happened in the case of the Oort Cloud .. so it persists … which is fine .. I have no problems with its existence (nor have I said this, as best I can recall …)



I'm not aware of any walls I've knocked down, Ron .. could you please elaborate ?

And I have no desire to hypothesise about anything at the moment.

Whilst I appreciate your request, I respectfully decline your invitation.
:)
Cheers & Regards.

CraigS
20-02-2011, 10:15 AM
Just for the sake of completeness, the purpose of my not undertaking speculation leading to a hypothesis, is purely to emphasise that the absence of an alternative hypothesis does not prove or disprove, add to or diminish from, the weight of an existing hypothesis.

There are other means for classifying outer solar system objects which co-exist alongside of, and overlap with, the Oort Cloud concept. The classification of objects described as 'The Scattered disc (http://en.wikipedia.org/wiki/Scattered_disc)', attempts to encompass a broader scope of objects (including some elliptical orbit objects), and has the science based potential to supersede the need for the Oort Cloud (via a means along the same lines as the Nemesis example, cited in my previous post).

It may not, also.

I can speculate along with the best of them, but my interest (in this Forum) will always be to strive to maintain as clear a focus as I am able, on the fine line between speculation, and the physical nature of the real world.

(And that's also not saying that I'm alone in doing so )

:)

Cheers