Hi everyone,

This was part of a discussion on another listserv, but I thought it might be of interest in relation to some of the things we've discussed.
Cheers,
Todd
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From: "Todd Duncan" <duncan@scienceintegration.org>
To: COSMOGEN@LISTSERV.TEMPLE.EDU
Subject: Re: Oort cloud?
Date: Mon, Jan 17, 2000, 12:52 AM

Dear Donald and Ron and others,

The recent discussion by Donald and Ron related to the Oort Cloud brought to mind a couple of questions/observations that seem to come up often, in some form, in discussions of scientific cosmology.

1) The "remoteness" of astronomy requires a relatively long chain of reasoning to get from immediate experience to claims of fact. Often these claims of fact are based on very solid evidence, but because there are many steps that make up the chain of evidence, anyone not familiar with the steps is quite rightly skeptical of the apparent leap from immediate experience to mind-stretching conclusions. To use an example from one of Donald's earlier postings, there *is* very good evidence that light is bent by gravity: This evidence includes observations of the shift in apparent position of stars very near the sun (seen during an eclipse), as well as recent images of distant quasars that are gravitationally distorted by galaxies nearer to us (The gravity of the galaxy distorts the image from distant object much as a familiar lens would). But to understand the evidence takes a fair amount of background knowledge and experience. And in our immediate experience, we certainly do not see light being bent by gravity (because distances are too small and gravity is too weak).

Such leaps are not unique to astronomy, however. We make them all the time in other contexts. For example, when watching a CNN reporter in London, we conclude that the dots on the screen and the sounds emanating from the speaker of our TV set really are a direct representation of what a real person is saying from London. But we're comfortable making that leap because it's familiar, and because we have as part of our awareness all the little pieces in between that make it perfectly plausible that this is really what is going on. For those who don't work with astronomical data on a regular basis, many such in-between pieces are missing, so equivalent leaps seem much more far-fetched than they really are. I'm not sure exactly what we can do about this, it's just an observation.

2) Aside from points of fact, there is also a question of attitude. In comments such as Donald's (and similar statements I've discussed with other people), it seems that there is something more going on than just disagreement about the facts. (Donald wrote: "It seems to me scientists are even wilder storytellers then the people who wrote the bible. Just what flimsy evidence do physicists have to validate the existence of the black hole - the big bang - worm holes, etc. I hope it is more then Einstein's Principle of Equivalence. Einstein had a few good ideas but most are a crock!") There is a sense that perhaps we *don't like* something about the picture of the universe that Einstein and more modern cosmologists are giving us. I wonder if we might try to articulate what makes us *want* Einstein's and related ideas to be wrong? What is it about a universe in which these ideas are correct that we think we don_t like? If we could identify these things more clearly, we might be in a better position to make progress in interpreting those "facts" for which there is pretty good evidence.

Best to all,
Todd

>From: Ron Olowin <rpolowin@stmarys-ca.edu>
>To: COSMOGEN@LISTSERV.TEMPLE.EDU
>Subject: Re: Oort cloud?
>Date: Thu, Jan 13, 2000, 12:13 PM
>
> Dear Donald,
>
> Thank you for your note. Let me explore the Oort hypothesis with you and
> perhaps clarify the model.
>
> The orbits of periodic comets are elliptical and hence follow the
> gravitational pull of the sun as their main influence. Since ellipticalorbits
> (a natural consequence of how gravity works as an inverse-square law) have a
> common focus, all periodic (elliptical) comet orbits must have the sun at one of
> the elliptical focii. But the oribit of these objects are at randon
> ellipticities and orientations to the plane of the solar system, so that their
> outer envelope must be at some external common radius from the Sun, hence the
> "cloud." Since Jan Oort postulated the existance of such an area, we call it
> the "Oort Cloud" of cometary material.
> It is pretty certain that a substantial mass of volitile (icey) materials exist
> at the periphery of the solar system and this is where the comets appear to come
> from. Surely, a long tail of deduction, but it is supported by a host of
> evidence that eliminates most of competing explanations.
>
> The same story goes for the halo of stars and objects that surround the Milkh
> Way in the Halo population of stars. From the orbits of globular clusters of
> stars studied by Harlow Shapley in the early part of this century, we have
> mapped a similar cloud of objects surrounding the disk of the galaxy. This is
> just using a gravitational model which seems to explain much of what we see.
>
> As for Black Holes and the like, we use the "Duck Theory." If it looks like a
> duck, walks like a duck, talks like a duck and is seen in the comapany of ducks,
> chances are it IS a duck. So, likewise with black holes. High energy
> astrophysical phenomena (evidence of dark collapsed objects, copious X-ray
> emission, and other effects {in particular on companion stars in binary
> systems}) lead us to the conclusion that nothing other that we know of can
> produce these artifacts than what we call a "Black Hole." True, the ultimate
> understanding of these objects is elusive, but at the moment, they're the only
> game in town, and their physics is beginning to be understood, as we begin to
> understand General Relativity. One must accept that these are "models" of the
> universe... but they appear to be consistent to an incredible number of details
> to the extent that we call the theory "robust." A robust theory... like the
> Atomic Theory... survives countless tests of it's validity and is accepted as an
> "accurate" description of the world, eg. most scientists today believe in the
> existence of atoms and their species (the chemical elements) and that belief has
> entered the culture and provided new scientific insights and technological and
> even biological growth.
>
> So, I wouldn't be so quick to call these interpretations "flimsy" or a "crock"
> however you mean these terms. Please understand that they are models of the
> world established with the deepest integrity and have the support of
> observational evidence as the arbiter of their truths, albeit special kinds of
> truths.
>
> With best wishes,
>
> -- Ron
>
> DONALD L HAMILTONE wrote:
>
>> What evidence is there that the "Oort clould even exists? It seems to me
>> scientists are even wilder storytellers then the people who wrote the bible.
>> Just what flimsy evidence do physicists have to validate the existence of
>> the black hole - the big bang - worm holes, etc. I hope it is more then
>> Einstein's
>> Principle of Equivalence. Einstein had a few good ideas but most are a
>> crock!
>> Well I guess they are fun to talk about anyway.
>> Have a good day -
>> Don Hamilton http://novan.com/weight.htm http://novan.com/space.htm