a little help with the Oort Cloud please

[Brian W (Brian)]

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 (Peter)]

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 (Ron)]

Originally Posted by Waxing_Gibbous

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!

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
Cheers

[Rob_K]

This isn't a bad article:

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

Cheers -

[CraigS]

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 (Ron)]

Originally Posted by CraigS

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

Yes Craig I should have put hypothesised
Cheers

[CraigS]

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 (Brian)]

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]

Originally Posted by Brian W

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

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 (Brian)]

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]

Originally Posted by Brian W

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

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 (Richard Brown)]

Originally Posted by CraigS

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

Oh No! My whole scientific career is in jeopardy! I spent years developing and performing experiments to disprove hypotheses!

Richard

[CraigS]

Originally Posted by bkm2304

Oh No! My whole scientific career is in jeopardy! I spent years developing and performing experiments to disprove hypotheses!

Richard

Hi Richard;

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



Cheers

[bkm2304 (Richard Brown)]

Originally Posted by CraigS

Hi Richard;

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



Cheers

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 (Carl)]

Well despite it being hypothetical, there "Oort" to be an Oort Cloud

[CraigS]

Originally Posted by renormalised

Well despite it being hypothetical, there "Oort" to be an Oort Cloud

.. I wonder what the test criteria Oort to be for disproving it ?


Cheers

[renormalised (Carl)]

Originally Posted by CraigS

.. I wonder what the test criteria Oort to be for disproving it ?


Cheers

Well, the planetary scientist will have to have a "Jan" amongst themselves to see what "Oort" to be the criteria

[bkm2304 (Richard Brown)]

Originally Posted by renormalised

Well, the planetary scientist will have to have a "Jan" amongst themselves to see what "Oort" to be the criteria

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.

[bkm2304 (Richard Brown)]

Originally Posted by bkm2304

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.

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....

[CraigS]

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