Originally posted by Aramis:
[QB] Actually, Bill, Lochaber is reflecting upon one of the biggest criticisms of planetology, one I happen to share
You're over-inflating your cause. This isn't "one of the biggest criticisms of planetology" at all, it's one shared by a small minority of people (yourself included) who insist that their beliefs are more valid than scientific data. Most people are well aware of the limitations of knowledge, but very few would claim that these invalidate the whole field - if that was the case then a lot of science would have to be tossed out of the window.
So far, the number of systems observed similar to our own =1; to wit, our own. The number of systems provably NOT like our own: more than 100, and counting. The number of undocumented systems more than can be represented usefully.
That's an entirely meaningless statement though. How do you mean "similar to our own"? All the systems we've seen have a central star and planets of various size and in various orbits around them, just like our own. There are IIRC a few known systems that have the gas giants further in vaguely circular orbits and more than a few AU from the star too, which are arguably "similar to our own". And while we haven't discovered the earth-size and smaller planets yet, there's no reason to assume that they're not out there, huddled close to their stars just like in our own system. Certainly, some stars will not have rocky planets, others may have a lot more than ours. But our knowledge and models show that rocky planets are certainly likely and possible around many other stars.
Extrapolating from the Sol System is NOT science per se, even though it is based in science and the scientific method; the data set is too small. (Mind you, a 4 point study is interesting, and can be indicative, it's NOT reliable. Something most people publishing in education need to realize to cure their own cranio-rectal insertion.)
Incorrect again. Once more, you're touting flawed assumptions (which you still hold despite all the evidence against them) as fact when they're not.
Your key problem is that you overlook the fact that it's
basic physics that we're talking about here, not "extrapolation from a limited, statistically insignificant study". And the physics that applies in our own solar system is exactly the same as elsewhere in the universe - a fact borne out by observations of stars and galaxies far beyond our own. Even early in the universe/far away from us, the general physics remains the same even if the specifics (eg star masses, metallicities etc) are different.
The general processes at work here (planetesimal accumulation forming planets, nuclear fusion inside stars, gravity binding systems together etc) are the same processes that work elsewhere - and those processes are very well understood and modelled. There are obviously gaps in the knowledge (being filled all the time with new data), but most of the time changing the starting conditions and the details of the model can produce results that agree with observed reality. Knowing that, we can say a hell of a lot about other planetary systems and how they form.
Your argument that we only know about our own solar system and therefore can't say anything meaningful about others is therefore flawed and incorrect.
Likewise, to paraphrase some physicist on TV recently: simulations that show unexpected results don't prove the universe has hidden matter; it proves that the formulae match that theory that does suggest that.
That's a great reference, "some physicist on TV". Must be true, I guess.
Besides, simulations aren't what show the universe has hidden matter - observations are what's showing that. Gravitational lensing and orbital analyses show that a lot of galaxies have more mass in them than is visible.
It is a fundamental issue with planetology as extrapolation: None of it is valid YET other than there are a large fraction of main sequence stars with large, hot GG's inside the supposed GG formation limit, and that we have a small set of observed detailed data, which further local observation keeps revising, often with surprises.
That's no reason at all to claim that "none of planetology is valid". Sure, the hot jupiters caught us off guard, but we didn't have to radically change our theories of planetary formation to account for them - we just realised that forces like gas drag and tidal interactions in the protoplanetary nebula are more significant than we initially assumed. Believe it or not, most scientists are acutely aware that there are limitations to their models and theories - most of the time they can't be helped until extra computational power comes along to help account for the extra factors that scientists
know must be there but can't actually include in the models because then it'd take forever to run them.
The bottom line though about the Hot Jupiters is "Get Over It!". We know they're there now, and while we don't have all the answers we've successfully accounted for them in planetary formation theories. So they're not a problem any more. I'm sure that when we find small rocky planets there'll be a surprise there too, but I don't think it'll be as big as the hot jupiters. But I'm also sure that any rocky surprises can be accommodated easily within existing planetary formation theories, just as the hot jupiters were.
We know that, of the known systems, ours is NOT a good model for them.
Incorrect. We know that our system is not a typical one in terms of its
layout. All it means in terms of planetary formation models is that the same processes apply in all systems, but that some processes didn't go so far in our own system (for whatever reason - not enough dust/gas to spiral the GGs in by a lot, a ferocious T Tauri stage in our sun, or something else) as they did in others. In fact, after examining the orbits of the Hilda asteroids in the 3:2 resonance with Jupiter it looks like Jupiter moved about 0.5 AU inwards from its original position, so there apparently was
some migration in our system.
Of course, we can't yet find the systems that would be like our own.
Did
55 Cancri pass you by?
This is not meant to diminish the efforts to collect the needed data. I applaud the efforts to get the needed data. I suggest, however, that extrapolations are not yet useful nor reliable, because those people are in the early stages of their work.
You can "suggest" all you like, but that doesn't mean your suggestions are correct or valid. If you want to carry on believing that we know less about the universe than we actually do, or if you want to believe that scientists and educators are suffering from 'cranio-rectal insertion' because they don't accept your beliefs then go right ahead... but you're still wrong either way.
If anyone finds that my tone is "abrasive" then sorry, but my sole concern is to correct the misinterpretations and fallacies spread by people about science and astronomy here. And all I know is that time and time again I've had the same arguments with the same people, and thrown the same verifiable facts at them that contradict their claims, and yet
still they carry on insisting that their flawed assumptions are correct when they're not.
All I'd really like to see is for people who don't know much (or even anything at all) about a given subject to just
not say anything about it when people ask questions about it (or at least, add a caveat that they're just guessing), and for them to defer to those that do know. There's nothing egotistical about that - it just means that the people who know most about a subject can get the correct information to those who ask, and people won't be confused. And that applies for anything, whether it's planetary science, astronomy, materials, economics, OTU history or anything else.
