Astronomy and "controlled scientific tests"

[astro_uk]

Dark matter cannot be lab tested in controlled conditions, so we have no idea of any of the "properties" that astronomers assign to dark matter are valid, and there is no possibility of testing anything.

Not strictly true, if the DM particle is one of the postulated weakly interacting particles then it is is extremely difficult but not impossible to detect in the lab. Plus there are possible decay routes for some of these particles that would mean you can expect to find line emission from their decays in dense regions, detectors to look for this kind of thing are just beginning to get off the drawing board.

Anyway there are plenty of particles that are difficult to detect and (neutrinos being the obvious example) yet no one really doubts their existence now.

[Nereid]

If astronomers don't have a bottle of 'nebula material' to test, in their labs, how can they be sure it's composed of O, H, S, etc?

I can see unique spectral lines that can be reproduced in tests of various elements on earth. I have no reason to believe atoms behave differently at a distance or that distant atoms would emit light any differently than they emit here on earth. I therefore have no problem with the concept.

Which is, of course, not an answer to the question asked.

The logic - or assumptions - are, no doubt, common ("I have no reason to believe otherwise, therefore the nebula is composed of O, H, S, etc").

And, in some loose sense, it is also consistent with the nature of science - theories as the engine, viable alternative theories (and tests thereof) are how progress is made.

Although this takes us away from what this thread is about, it is encouraging to see that, at least in this loose sense, consistency with the nature of science*.

It's how the concept gets used as it relates to determining solar composition I object to, mainly because it is based on the assumption that plasmas do not mass separate on the sun. I see no evidence that this particular assumption is valid.

Interesting ... perhaps we could examine this in another thread?

The relevant spectra - emission or absorption - of H, O, or S (in any appropriate state of ionisation) are indeed quite distinct.

And because the emission wavelengths are unique to various elements, we can indeed link specific wavelength to specific elements.

But without a bottle of 'nebula material' in your hand (or you lab), how can you be sure - really sure - that what you see through your telescope was indeed emitted (or absorbed) by H, O, or S?

Why would we have any reason to believe that atoms behave differently at a distance than they behave here on earth as it relates to which wavelengths of light they tend to emit?

Or, going down a level: the spectra of H, O, and S (in any appropriate ionisation state, or any other element, or even compound) can be understood in terms of a 20th century theory in physics.

If you decide - ignore for now how you decided - that the 'nebula material' does indeed include H, O, and S, to what extent is your decision equivalent to a statement (or belief?) about the universality* of that particular 20th century theory of physics?

Hmm. I would not call it a pure statement of 'faith' in the sense that the spectral connection to various elements is fully reproduceable and lab testable any time any one wishes to test the idea.

Here's a good place to introduce something important - let's call it 'extrapolation' - as it is common in astronomy.

There are many spectral lines, seen in astronomical objects, that have not been produced in labs here on Earth.

Further, if we examine the spectra in greater detail - looking at relative line strengths, line profiles, etc - earthly labs fall even more short, in terms of being able to produce what astronomers regularly observe.

And the reason is very simple: earthly labs cannot produce the conditions in which spectra that correspond to what astronomers observe would (should) be seen.

So all you have to do, to get an inconsistency between 'can be produced in labs here on Earth' and astronomical spectra is go down one level in detail (relative line strengths, line profiles, etc).

Of course, this is not a problem, in modern astronomy, because the underlying (quantum) theory very nicely accounts for what astronomer observe ... and so, turning this around, astronomers use the relative line strengths, line profiles, etc to estimate the physical conditions of (in) the nebula, photosphere, etc from which the photons come.

However, it would seem to be a considerable problem for the Michael Mozina (non-standard) variety of astronomy. Is it?

On the other hand there are aspects of astronomy that cannot be tested or falsified.

In this particular example you cited if we have any doubts about the relationship between wavelengths and various atoms, we can certainly test these ideas right there on earth, right now. No actual leaps of faith are required.

[snip]

Actually, there are ... as I just explained ... let's explore this some more ...

I'm sure you'd agree that we cannot test, in any earthly lab, how a system of three compact objects, of masses ~10^30, ~10^27, and ~10^26 kg, separated by distances of ~10^12 m, behaves, under their mutual gravitational influence. Similarly, we cannot test, in any earthly lab, how such a system of compact objects behaves under their mutual magnetic, electrical, nuclear (weak or strong), ... influence either.

Ergo, a 'leap of faith' is required.

Or maybe not ... would you be so kind as to tell us how this works, in your view of astronomy (as a science)?

*kovil's post, and many of harry's posts, are a good foil in this regard - even this basis seems to be absent.

[Maddad]

Nereid
I have not been ignoring you. I have been in the hospital for the last three days. Before I went in, I had been composing a response. That information is on my flash drive, which is attached to my home computer. I came here for a check-up, and the daggone doctor said, "We're keeping you."

http://www.thespaceport.us/forum/index. ... opic=17162
I do not have the stamina for a lot of writing. I talked about being offline a bit at this other board that I've been a member of for the last three years. There are two posts of mine, one at the beginning and the other at the end. The others posted only quick get well comments. They're all good people.

I'll get home this afternoon and compose a response to you. May not post it till tomorrow, but I have not forgotten you.

[Nereid]

chuckles, , and the fun begins.

I would hope that at least one serious aspect of this thread is a better appreciation, by those reading the posts in it, of the nature of modern astronomy as a science.

And, as a bonus, some insight into how, and where, those who've expressed strong feelings about some of the important results, in modern astronomy, are basing those feelings (logically) on foundations that are a-scientific (or even anti-science), or have serious consistency issues within the non-standard bases of their stated 'science', or both.

[Maddad]

a-scientific. Let's not go there before we have a post to evaluate, Ok? Ok. I'm home. 25 minutes ago. I'll take this one at a time.

What really draws me though is exploring how the intense gravity of a black hole bends the shape of distance and time. . .

I see perhaps five frames of reference, maybe six. All discussion on the subject uses only one of them, the outside observer, with only the most superficial treatment of two more - approaching and being at the event horizon.

Yes, but ... there is no other way that I know of to address this, observationally.

Yanno, a month ago I would have agreed with you. Actually, I argued your point vigorously with a member on another board. Then the book Einstein that just came out flummoxed me. The man thinks from almost a purely deductive point of view, whereas I argued from an inductive one. In part, it was his ability to come at problems from this other direction that enabled him to make the advances that he did, specifically those four papers he turned loose in 1905.

Now, you asked for insight as opposed to emotion, an excellent request. In this case, my insight is that intense gravity can result in at least five frames of reference, each one equally valid, and each one seeing the passage of time radically different from the other frames. From the outside in, those frames are 1) the outside observer, 2) the inbound traveler just outside the event horizon, 3) the inbound traveler at the event horizon, 4) the inbound traveler just inside the event horizon, and 6) the inbound traveler at the center of the black hole. There may be case five between the fourth and sixth, but I have not yet considered it.

We say that time slows as you approach the event horizon. We are speaking from the first frame of reference about the second. From the second frame of reference, there is no ability to perceive change in the passage of two’s time. However, to be consistent with one, two must see one’s time quickly advancing. From two’s point of view, one must move forward into two’s future.

Let us consider this part of the first insight before moving on to the next part, which will be the way one and three perceive each other’s flow of time.

[nikki]

I have a question or two!
What would hapen to gravitational oscillator, which is falling into BH?
Are there solutions for gravitational waves under event horizon?
Singularity; it knows for the rest of the universe & universe knows of it thru gravitation. Why not to comunicate with singularty with gravitational radiation?
What about tidal forces on BH? Are they deform BHs?

[Maddad]

I am going to assume that you are speaking of how the two frams of reference, one and two, see this oscillator. The outside observer, 1, will see the inbound traveler near the outside of the event horizon, 2, as having a slowing oscillator. Two will think his oscillator is running normally.

If you are going to communicate with the black hole, you are communicating from one of the first three frames of reference with the others. One difficulty is that gravity passes through space at the speed of light, and gravity would have to exceed this speed to cross that boundary. Measurements of the speed of gravity says that it only goes at the speed of light, and therefore would not be able to carry communication across that event horizong boundary.

Tidal forces are a separate issue. They are interesting, and may or may not be detectable depending on the mass of the black hole and wihch frame of reference is watching which, but that is a good discussion for another time.

[nikki]

I have only one observer in mind- the outside observer. If the oscillator is increasing frequency (like pair of neutron stars or BHs), the outside observer will see in some cases constant frequency of gravitational radiation. In other cases the frequency will stil increase! The question is can gravitational waves (space-time distorsions) deform event horizon?

[Maddad]

Yes they can, because those gravitational waves in a sense define the exact limit of the event horizon. Those distortions at a distance, like Earth is away from a nearby star, becme so tiny though that we are still struggling to even be able to see them at all. Near the black hole they might be pretty big though. Haven't thought much about it yet.

[nikki]

In other cases the frequency will stil increase!

It s energy paradoxon. Eternal radiation at event horizon with increasing frequency?! Probably I am wrong. But why not! 8)
Just do not forget, that there are other kind of radiations (we have four forces) in universe than electromagnetic radiation! The picture of cosmos only in electromagnetic radiation is not complete.

[Maddad]

Nikki, there may well be value in what you are saying. Right now though I am working on the relationship between time and gravity with different frames of reference.

[Nereid]

a-scientific. Let's not go there before we have a post to evaluate, Ok? Ok. I'm home. 25 minutes ago. I'll take this one at a time.

What really draws me though is exploring how the intense gravity of a black hole bends the shape of distance and time. . .

I see perhaps five frames of reference, maybe six. All discussion on the subject uses only one of them, the outside observer, with only the most superficial treatment of two more - approaching and being at the event horizon.

Yes, but ... there is no other way that I know of to address this, observationally.

Yanno, a month ago I would have agreed with you. Actually, I argued your point vigorously with a member on another board. Then the book Einstein that just came out flummoxed me. The man thinks from almost a purely deductive point of view, whereas I argued from an inductive one. In part, it was his ability to come at problems from this other direction that enabled him to make the advances that he did, specifically those four papers he turned loose in 1905.

Now, you asked for insight as opposed to emotion, an excellent request. In this case, my insight is that intense gravity can result in at least five frames of reference, each one equally valid, and each one seeing the passage of time radically different from the other frames. From the outside in, those frames are 1) the outside observer, 2) the inbound traveler just outside the event horizon, 3) the inbound traveler at the event horizon, 4) the inbound traveler just inside the event horizon, and 6) the inbound traveler at the center of the black hole. There may be case five between the fourth and sixth, but I have not yet considered it.

We say that time slows as you approach the event horizon. We are speaking from the first frame of reference about the second. From the second frame of reference, there is no ability to perceive change in the passage of two’s time. However, to be consistent with one, two must see one’s time quickly advancing. From two’s point of view, one must move forward into two’s future.

Let us consider this part of the first insight before moving on to the next part, which will be the way one and three perceive each other’s flow of time.

Maddad, how could you test the reality, or existence, of any of the frames of reference, other than the outside observer (us), way out in a weak field region?

In particular, what role would astronomy have in any tests?

[Nereid]

Here's a good place to introduce something important - let's call it 'extrapolation' - as it is common in astronomy.

There are many spectral lines, seen in astronomical objects, that have not been produced in labs here on Earth.

Ok, so we can't "extrapolate" a lot about those spectral lines (though I'm curious which ones you refer to specifically), but the ones we can recognize, we can identify.

Google on 'forbidden lines': example one, example two.

The lines themselves are well-understood, because we have a highly successful theory of atoms (quantum theory) that can account for them.

However, many have not been, and probably cannot be, produced in earthly labs.

Further, if we examine the spectra in greater detail - looking at relative line strengths, line profiles, etc - earthly labs fall even more short, in terms of being able to produce what astronomers regularly observe.

I'd like you to identify these observations specifically.

Kinematics of the Nuclear Ionized Gas in the Radio Galaxy M84 (NGC 4374) contains some nice examples (if you know of any lab which can produce these spectra, do tell us).

More commonly, check out the P-Cygni profile (or lines), and this nice white dwarf + M dwarf binary. Indeed, almost any white dwarf spectrum would serve to make my point, as would almost any spectroscopic binary spectrum.

Closer to home, have you seen any reports of a lab spectrum which reproduces the solar spectrum, line intensities, line profiles, and all?

I would also like you to note that even though we may not be able to identify the specific atom that released each and every single photon, we can identify some photon sources by their signature wavelengths. While we may not have a perfect understanding of some emissions, we cannot ignore the things we can identify either.

And the reason is very simple: earthly labs cannot produce the conditions in which spectra that correspond to what astronomers observe would (should) be seen.

I'm not talking about conditions yet, only the correlation between certain wavelengths of light and certain atoms.

Michael, you can't have it both ways ... either you are sure, absolutely sure, of what is causing the observed (line or band) emission (or absorption) in a spectrum, or you are not.

If you are sure, then it is legitimate to ask about relative intensities and line profiles ... and if you can't account for these aspects, from your lab spectra, then you're already on the slippery slope that takes you right into dark matter and dark energy.

So all you have to do, to get an inconsistency between 'can be produced in labs here on Earth' and astronomical spectra is go down one level in detail (relative line strengths, line profiles, etc).

I'm assuming here that you are describing supernova like events? You will concede that we have created plasma up to billions of degrees here on earth, correct?

You assumed wrong (see above), but supernovae also provide spectra that have not, AFAIK, ever been reproduced, in detail, in any earthly lab.

Of course, this is not a problem, in modern astronomy, because the underlying (quantum) theory very nicely accounts for what astronomer observe ... and so, turning this around, astronomers use the relative line strengths, line profiles, etc to estimate the physical conditions of (in) the nebula, photosphere, etc from which the photons come.

Here however things are already starting to get get a bit murky. We are "assuming" what we believe conditions might be like, but we can't really be sure these are the exact mechanisms that are responsible for these specific photons. In other words, we are doing more now than simply noting the spectrum relationship between specific atoms and specific wavelengths of light, we are also making some assumptions about the mechanisms responsible for these emissions. We are assuming a cause and effect relationship now that may or may not be true. The photons could come from a specific atoms, but not be related to our theory about why these emissions are taking place.

Er, no.

As I have already pointed out (several times), the "noting the spectrum relationship between specific atoms and specific wavelengths of light" only works if you are prepared to have a very loose standard ... even quite mild quantitative precision takes you into spectral details where your approach surely fails. Or, remaining satisfied with only such weak constraints prevents you from being able to test a great many interesting hypotheses, and condemns any science based on this approach to little more than word salad explanations.

However, it would seem to be a considerable problem for the Michael Mozina (non-standard) variety of astronomy. Is it?

It's not really a problem for me at this stage, but we'll get into emissions mechanism theory that might be a problem for me.

Actually, there are ... as I just explained ... let's explore this some more ...

I'm sure you'd agree that we cannot test, in any earthly lab, how a system of three compact objects, of masses ~10^30, ~10^27, and ~10^26 kg, separated by distances of ~10^12 m, behaves, under their mutual gravitational influence.

Well, some theoretical aspects will certainly not be "lab testable" as in here on earth. On the other hand, as long as you don't whip out anything on that metaphysical bad boy list I cited earlier, I'll be happy to let you theorize all you like.

Similarly, we cannot test, in any earthly lab, how such a system of compact objects behaves under their mutual magnetic, electrical, nuclear (weak or strong), ... influence either.

That's true. In fact that's one of the problems with current solar theory IMO. We cannot test the theory that elements stay "mixed" in the sun, so we can't actually "assume" that they do.

Ergo, a 'leap of faith' is required.

Well, I'll be the first to admit that some leaps of faith may be required, but they should be short leaps whenever and wherever possible. As long as you aren't trying to create new fields of nature however, I don't really see much of a problem.

[snip]

'leap of faith' is all I need ... once you abandon an insistence that everything in astrophysics be reproduced in an earthly lab before it can be accepted, and accept a cosmological principle (crudely, 'if the spectrum has H, O, and S lines in it, then the distant object contains H, O, and S'), the only place you have to run - as far as I can see - is the denial that quantitative detail in astronomical data can provide a legitimate constraint on any theory whose domain of applicability includes the objects under study.

Welcome to degenerate matter, to black holes, to dark matter, to dark energy, ...

Welcome to astronomy.

[makc]

...the only place you have to run - as far as I can see - is the denial that quantitative detail in astronomical data can provide a legitimate constraint on any theory whose domain of applicability includes the objects under study.

That would be quite easy to do:

.....8) <--------------- <--------------------------------
Michael..........Something that................................An object
......................changes quantitative details...........under study
......................but is not itself an object
......................under study

[Nereid]

[snip]

And the reason is very simple: earthly labs cannot produce the conditions in which spectra that correspond to what astronomers observe would (should) be seen.

I'm not talking about conditions yet, only the correlation between certain wavelengths of light and certain atoms.

[snip]

I forgot to mention: you can't ignore the conditions!

To take an obvious, if somewhat absurd, example.

We know that a fish is composed of H, O, N, C, S, Na, Cl, K, and much more.

However, if we were to put a fish, in a fishtank or not, at the entrance slit of any astronomical spectrograph, we most certainly would not get an emission (or absorption) spectrum with H, O, N, C, ... lines.

[Nereid]

[snip] I'm not talking about conditions yet, only the correlation between certain wavelengths of light and certain atoms.

[snip]

I forgot to mention: you can't ignore the conditions!

To take an obvious, if somewhat absurd, example.

We know that a fish is composed of H, O, N, C, S, Na, Cl, K, and much more.

However, if we were to put a fish, in a fishtank or not, at the entrance slit of any astronomical spectrograph, we most certainly would not get an emission (or absorption) spectrum with H, O, N, C, ... lines.

Funny you should mention this. IMO that is exactly what you are trying to do with spectral emissions of a mass separated sun.

Where, as in - in which country/town/lab - can one go to observe the (observed) spectrum of the Sun created from an object (in this lab) called "a mass separated sun"?

[Nereid]

'leap of faith' is all I need ...

I'll tackle the rest of your post as I get time today, but this comment deserves a response of it's own. No, it's not all you need. You can't use any of those metaphysical entities I mentioned earlier until you can demonstrate they actually exist in nature. I'll let you takes leaps of faith as it relates to *KNOWN* possible physical causes, but you can't take leaps of faith in unicorns, and elves and start assigning properties to them in an ad hoc manner and then try to use them to explain the movements of the universe!

Sorry Michael, the genie is out of the bottle ...

once you abandon an insistence that everything in astrophysics be reproduced in an earthly lab before it can be accepted, and accept a cosmological principle (crudely, 'if the spectrum has H, O, and S lines in it, then the distant object contains H, O, and S'),

I do accept we can't test all scientific ideas.

Which is, as I'm pretty sure you are very well aware, not a paraphrase of what I wrote ...

As I said earlier, once you let the genie out of the bottle (e.g. you cannot reproduce the observed spectrum of the Sun, in any earthly lab), you must - logically - declare all astronomy (beyond the solar system, closer to the Sun than any Mariner probe went, etc) a-scientific ... or develop different (scientific) criteria ... or adopt multi-tiered science (e.g. 'the only thing we can say - scientifically - is that {nebula} may contain H, O, and S, in some form'; however, 'this fish contains H, C, O, N, ...').

And since this forum is about astronomy (especially that beyond the solar system), it would seem there's little in the way of any meaningful (science-based) communication we could possibly have, is there?

the only place you have to run - as far as I can see - is the denial that quantitative detail in astronomical data can provide a legitimate constraint on any theory whose domain of applicability includes the objects under study.

I'd be happy to let you use that technique to decide between competing theories that are grounded in known physics and known laws of physics.

What constitutes "known physics"?

What are the "known laws of physics"?

How are these established?

Is the theory of General Relativity (GR) "known physics"? Is it a "known law of physics"?

How about the Standard Model (of particle physics)?

What you can't do however is simply invent things like invisible unicorns, assign physical properties to invisible unicorns, create a bunch of math related to unicorn theory, and then try to use those distant measurements to tell if your unicorn theory is valid!

What's the difference between one unicorn ('that nebula contains H, O, and S') and another ('that galaxy cluster contains 10^n sols of dark matter')?

Remember that you need at least some unicorns (a.k.a. 'a leap of faith'), if only because you can't reproduce the spectrum in your lab.

Welcome to degenerate matter,

Maybe.

[snip]

Hmm ... you do realise, don't you, that your PC requires degenerate matter to run properly?