Nature of astrophysics (I) - between theory and observation

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Nereid
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Nature of astrophysics (I) - between theory and observation

Unread post by Nereid » Sun Dec 05, 2010 8:20 am

This is the first of a series of threads I hope to post, on specific aspects of the nature of physics and astronomy ('physics and astronomy' is too long for a thread title, so I shortened it to 'astrophysics').

My motivation for these comes from some of the discussions I've been engaged in, here in this Thunderbolts Forum; specifically, it seems to me that I have a different - possibly quite radically different - view of things like the relationship between experiment and theory (in physics and astronomy), the relationship between observation and theory (ditto), and the relationship between experiment and observation (ditto). Here are two threads containing examples: TPOD 19 OCT 2010, Relativity and Cosmology in Crisis—Again!.

Given the clearly stated scope of this forum, I'm also interested in what "electromagnetism" is, the extent to which it is (or should be) special (within physics and astronomy), and the relationships among theory, observation, and experiment with respect to electromagnetism.

To start I'd like to look at some 'timing gaps'; periods in the history of physics and astronomy where theory was ahead of observation or experiment, and vice versa.

The discovery of Neptune

Many years of records of observation of the planets - especially Uranus - were analysed, independently, by a couple of people in the year or so leading up to 1846. Their analyses lead to predictions of the existence of a new planet, and of its current position; one such prediction was almost immediately followed up, and the new planet observed quite close to where it was predicted to be.

In this case a theory of physics (Newton's law of universal gravitation) had been used to analyse observations, leading to a prediction, which was verified (by observation) very quickly.

The non-discovery of Vulcan

Around the same time as the discovery of Neptune, Le Verrier, one of the people who predicted the new planet, also analysed observations of Mercury. These analyses lead him to predict (in 1859) the existence of a new planet, given the name Vulcan.

No such planet was ever observed, and in 1915 Einstein proposed a new theory of gravity, which accounted for the 'anomalous' observations of Mercury.

Birkeland and the solar wind

In the early years of the 20th century, Birkeland conducted a series of experiments and made extensive observations of the aurorae and associated geophysical phenomena. On the basis of these experimental results and observations, he proposed models (as we'd call them today) of the rings of Saturn, aurorae, and more.

In 1958 some of the first artificial satellites discovered (or confirmed) the existence of belts of trapped charged particles near the Earth; later space probes discovered (or confirmed) the existence of the solar wind and the Earth's magnetosphere.

Neutrinos

In the early years of the 20th century, the newly discovered phenomenon of radioactive decay was exensively researched. One type of decay - beta decay - was observed, in experiments, to apparently violate the law of the conservation of energy.

In 1931 Pauli proposed that an as yet undiscovered particle was being emitted in beta decay, carrying off energy (and so re-establishing the validity of the law).

In 1957 Cowan and Reines announced the direct detection of the neutrino, with properties just as predicted (Reines was awarded the 1995 Nobel Prize for his work; Pauli had died in 1958, and Cowan in 1974).

Nebulium

In 1864 an intense green emission line was observed in the spectrum of a planetary nebula. In the following years and decades several other emission lines were observed in such astronomical objects (and the initial green line was found to be a doublet). In these decades a great many experiments (or observations) were made, using spectroscopy, of the emission lines given off by every element (and many ions) then known. None of the experimentally verified lines matched any of the nebular ones. A new element was proposed as being responsible for these lines, nebulium.

In 1928 Bowen proposed that the nebulium lines were due to 'forbidden' electronic transitions in ions of oxygen and nitrogen (and later others were proposed, e.g. neon). His proposal was based on a theory that did not exist in 1864 (quantum mechanics), and assumptions about the density of the gas (or plasma) in planetary nebulae, the intensity and spectral distribution of light emitted by the star at the centre of such nebulae, and so on. None (or very few) of these emission lines has ever been observed in the laboratory. (Source)

Status in the gaps

Did Neptune exist between when it was proposed and when it was observed?

Did Vulcan exist between when it was proposed and when Einstein published his paper?

Did the solar wind exist in the early years of the 20th century?

Before the discovery of belts of trapped charged particles, what was the status of Bireland's aurorae predictions? of his Saturn rings prediction?

What was the status of the law of the conservation of energy between the discovery of beta decay and Pauli's proposal? Between his proposal and Cowan and Reines' experiments (or observations)?

Must we wait for obsersations of 'nebulium' emission lines in Earthly labs before we can say for sure that they are due to certain electronic transitions of oxygen ions (etc)?

What to you think?

MosaicDave
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Theory and observation

Unread post by MosaicDave » Mon Dec 06, 2010 9:08 am

Well, I think this is a great topic, so Nereid thank you for starting this thread. I have some "possibly quite radically different" views of my own; maybe this will get very interesting...

To your list of questions, I might add one or two of my own:
Did Neptune exist between when it was proposed and when it was observed?
First of all, of course, what about the period before it was proposed?

Is it possible, that previous to anyone proposing or looking for Neptune, that it neither existed, nor did not exist?

What is the role of consensus, in shaping "reality"?

To add an example to your list, if I may, there are many people (I among them) who believe they have observed anomalous forces on highly electrically polarized dielectrics. There are others (of course many times more) who are equally convinced that this is nothing but pseudoscientific bunk.

What role does the attitude of an experimenter have, in the shaping of a phenomenon that is being observed? Is it possible that in some cases, an outcome isn't determined until an observation is made? Is it possible for two different observers, to observe two different versions of reality? I'm not talking about selective bias in collecting observations of an external objective reality, nor about "mind over matter", but rather something more like the shaping of one's own reality through intention.

I once participated in what amounted to a profound healing by the laying of hands. Which I think is related somehow to all of this, though it's also very different in certain ways.

--dc

Nereid
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Re: Nature of astrophysics (I) - between theory and observation

Unread post by Nereid » Mon Dec 06, 2010 9:51 am

You, dear reader, may have noticed that there is a certain ambiguity in my use of 'observation' and 'experiment'.

For example, on Birkeland I wrote that he "conducted a series of experiments", but on nebulium, I wrote about certain emission lines not having "been observed in the laboratory".

So what's an observation, and what's an experiment? If it's done in a laboratory, isn't it an experiment, by definition? And if it's not, isn't it an observation, by definition? I don't think it's quite so simple.

Consider radioactivity.

Suppose you go out into 'the field' (as geologists and biologists are wont to say), with a super-duper detector, and note its outputs as you walk/ride/fly over some rocky terrain. That's a set of observations, right?

Suppose you pick up some of the rocks, and bring them back to your lab, where you photograph them, put them in chambers which are even more capable of detecting gammas, betas, and alphas, etc ... but you do not in any way disturb the integrity of the rock. Is that an observation? or an experiment?

Suppose you slice one of the rocks with a diamond saw, making a thin 'section'; you also collect the dust. Those too go into yet more superer-duperer detectors.

Then you dissolve some of the rock in acid; bombard parts of the thin section with high energy electrons, neutrons, etc; heat some bits you broke off until they melt, and then boil; etc ... followed by yet more detections by yet more detectors.

With the exception of the neutron bombardment, you have not (you hope!) in any way altered any nuclei of any atoms in the rock; they behave just like they did when they were sitting on the ground out in the field. On the other hand, you have certainly broken quite a few chemical bonds, destroyed many a crystalline lattice, shaken up magnetic domains (if there were any), etc.

Next you ask your colleagues in the physics department (or perhaps the Medical School) to produce some F-18 for you, so you can study beta+ decay (do you know why the Med School would have some?). Having got your hands on some (well, figuratively), you then repeat many of the tests you did with stuff you'd produced - by mechanical or other means - from that hapless rock. This time the nuclei were not found 'in nature', but rather produced, by some fellow humans, in what you choose to call 'a lab'. Does the fact that the object of your tests came from a lab make them 'experiments'? Or does the fact that your tests were done in a lab make them such?

And so on.

At the other end of the scale, perhaps you got some time on the Hubble Space Telescope, and used its ACS to acquire some data on a small section of a spiral galaxy with an "M" designation. Did you 'make an observation'? or did you 'conduct an experiment'?

Or you worked, over several decades, on a laser-guided adaptive optics system on one of the VLTs, where the project started with simple deconvolution data reduction programs (applied to the raw data from the CCDs in the camera attached to the prime focus), became a primitive (by today's standards) tilt-tip mirror, then a flexible secondary with actuators and 'wavefront sensors' (but you could only use this very close to a bright star), to the final laser-based system. The whole thing involved a huge number of trials and errors, engineering plans, software simulations, mock-ups, some champagne but many tears - in short a very great deal of experimentation (based heavily on theory) - to be used to 'tame' the atmospheric 'seeing' so you could 'take images' of astronomical objects with close to the 'theoretical limit' of the telescope's 'resolution'.

What do you think?

omni-tom
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Re: Nature of astrophysics (I) - between theory and observation

Unread post by omni-tom » Mon Dec 06, 2010 10:23 pm

well, here's the way I see it, as a mere "reader", no physics training just an enthusiastic observer.
Suppose you go out into 'the field' (as geologists and biologists are wont to say), with a super-duper detector, and note its outputs as you walk/ride/fly over some rocky terrain. That's a set of observations, right?
yes, an observation
Suppose you pick up some of the rocks, and bring them back to your lab, where you photograph them, put them in chambers which are even more capable of detecting gammas, betas, and alphas, etc ... but you do not in any way disturb the integrity of the rock. Is that an observation? or an experiment?
also an observation
Suppose you slice one of the rocks with a diamond saw, making a thin 'section'; you also collect the dust. Those too go into yet more superer-duperer detectors.

Then you dissolve some of the rock in acid; bombard parts of the thin section with high energy electrons, neutrons, etc; heat some bits you broke off until they melt, and then boil; etc ... followed by yet more detections by yet more detectors.
here you have physically manipulated the objects, an experiment seems the only logical conclusion
At the other end of the scale, perhaps you got some time on the Hubble Space Telescope, and used its ACS to acquire some data on a small section of a spiral galaxy with an "M" designation. Did you 'make an observation'? or did you 'conduct an experiment'?
an observation of the galaxy using a very expensive experiment
Or you worked, over several decades, on a laser-guided adaptive optics system on one of the VLTs, where the project started with simple deconvolution data reduction programs (applied to the raw data from the CCDs in the camera attached to the prime focus), became a primitive (by today's standards) tilt-tip mirror, then a flexible secondary with actuators and 'wavefront sensors' (but you could only use this very close to a bright star), to the final laser-based system. The whole thing involved a huge number of trials and errors, engineering plans, software simulations, mock-ups, some champagne but many tears - in short a very great deal of experimentation (based heavily on theory) - to be used to 'tame' the atmospheric 'seeing' so you could 'take images' of astronomical objects with close to the 'theoretical limit' of the telescope's 'resolution'.
this is most certainly an experiment of engineering the technology itself,the end result of acquiring an observation of the subject.

I may be way off base here, but to me this seems related to a dark matter/energy discussion. The examples you presented, Neptune, the aurora, neutrinos etc were postulated as consequences of known physical laws. Thats not to say that what is known is all we'll ever have to work with, but the observation of an anomaly within physics is by no means a license to introduce new forces/exotic matter until ALL avenues of known physics are thoroughly exhausted. Can you honestly say that they have in this case? Is our technology sufficient to rule out all other options besides new matter/forces?

Nereid
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Re: Theory and observation

Unread post by Nereid » Tue Dec 07, 2010 3:27 am

MosaicDave wrote:Well, I think this is a great topic, so Nereid thank you for starting this thread. I have some "possibly quite radically different" views of my own; maybe this will get very interesting...
I didn't notice that you'd posted this, before I posted my second in this thread (I usually prepare offline).
To your list of questions, I might add one or two of my own:
Did Neptune exist between when it was proposed and when it was observed?
First of all, of course, what about the period before it was proposed?

Is it possible, that previous to anyone proposing or looking for Neptune, that it neither existed, nor did not exist?
In this case, the question is capable of being answered, to a high degree of confidence: there are historical records, pre-dating the discovery observation, among which Neptune should be found (and so it turned out to be, IIRC).

This frequently happens with newly discovered asteroids; there are hundreds of thousands of astronomical observations in the form of glass plates (covered in photographic emulsion), going back almost a century (to give just one example).
What is the role of consensus, in shaping "reality"?

To add an example to your list, if I may, there are many people (I among them) who believe they have observed anomalous forces on highly electrically polarized dielectrics. There are others (of course many times more) who are equally convinced that this is nothing but pseudoscientific bunk.
If we stick with physics and astronomy, as I would like to do in all my threads here, then this sort of thing should be relatively easy to address, at least in principle.

For example:
* write down the hypothesis to be tested
* discuss it until a reasonable number of competent people agree that the hypothesis is clearly and unambiguously stated, and that it could be objectively addressed
* design an experiment to test this hypothesis, paying particular attention to the protocol for ensuring objectivity
* conduct the experiment
* publish the results, which would include all the raw data
* if necessary, repeat twice (once with a different team using the same protocol, and once starting entirely from scratch)
What role does the attitude of an experimenter have, in the shaping of a phenomenon that is being observed?
If there is any, then what's being studied is unlikely to be physics (and surely couldn't be astronomy!)

In studying medicine and human physiology, for example, I should imagine it is a particularly troublesome issue (e.g. the placebo effect).
Is it possible that in some cases, an outcome isn't determined until an observation is made? Is it possible for two different observers, to observe two different versions of reality? I'm not talking about selective bias in collecting observations of an external objective reality, nor about "mind over matter", but rather something more like the shaping of one's own reality through intention.
Not in physics or astronomy, surely!

Nereid
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Re: Nature of astrophysics (I) - between theory and observation

Unread post by Nereid » Tue Dec 07, 2010 9:00 am

omni-tom wrote:well, here's the way I see it, as a mere "reader", no physics training just an enthusiastic observer.
All are welcome to comment and respond! :)
Suppose you slice one of the rocks with a diamond saw, making a thin 'section'; you also collect the dust. Those too go into yet more superer-duperer detectors.

Then you dissolve some of the rock in acid; bombard parts of the thin section with high energy electrons, neutrons, etc; heat some bits you broke off until they melt, and then boil; etc ... followed by yet more detections by yet more detectors.
here you have physically manipulated the objects, an experiment seems the only logical conclusion
Question: does picking up the rock mean you have "physically manipulated" it?

And in this case, where you were studying radioactivity, your physical manipulation did not disturb the nuclei (except, as I said, in the case of neutron bombardment).

What do you think makes for physical manipulation? And could there be cases where it is unclear if any such thing took place? Or, perhaps, where it's physical manipulation in one case, but not in another - even though it's the same physical actions (perhaps removing the rock from its environment changed the amount of water it held, in the first few mm of its bottom surface?)?
I may be way off base here, but to me this seems related to a dark matter/energy discussion. The examples you presented, Neptune, the aurora, neutrinos etc were postulated as consequences of known physical laws.
But were they?

Neptune certainly, but at the time (and this is key, I think), why was it expected that Newton's law of universal gravitation was, indeed, universal?

After all, Vulcan was postulated as a consequence of exactly the same law, yet it took more than a half century, and the postulation of a different physical law, to account for the observations.

Birkeland and aurorae present a similar puzzle; his observations (in the field) plus his experiments (in the lab) plus his knowledge of the then known physical laws enabled him to postulate an explanation for (a 'model', in today's terms) aurorae, Saturn's rings (and much more). Yet his aurorae model turned out to be only partly right, and his Saturn's rings one completely wrong (in fact, had he known of some astronomical observations going back as far as several decades earlier, he would likely have not published this particular model!).

Neutrinos are, perhaps, very much an analogue of (cold, non-baryonic) dark matter (CDM). To keep a well-established physical law (conservation of energy), something new was postulated (neutrinos), and it took several decades for the newly postulated thing to be observed.

Similarly with CDM; to keep a well-established physical law (General Relativity in this case, but even Newton's law too!), something new has been postulated; who's to say how long it might take for CDM particles to be detected? And who's to say that CDM may not turn out to be more like Vulcan?

More to the point, in one of these 'timing gaps', how do you - nay, how can you - decide what the resolution will (eventually) be?
Thats not to say that what is known is all we'll ever have to work with, but the observation of an anomaly within physics is by no means a license to introduce new forces/exotic matter until ALL avenues of known physics are thoroughly exhausted.
I think a clear-eyed review of the history of physics and astronomy would show you that that has never been the way it works, at least since the time of Galileo.

Of course, the histories we most commonly read rarely recount the often huge number of alternatives that were pursued at the time; they mostly tell of how the one which became accepted came to be accepted.

Mind you, when something quite new comes along, one of the first things you see happening is a lot of work to show it's exactly what you say (i.e. an example of known forces/particles/processes/etc at work), after the independent confirmations of course. "Dark energy" provides a good example: there were a lot of papers published after the two 'high-redshift supernovae' teams reported their results, carefully looking at whether those results might be due to 'grey dust' (for example), or that Type Ia supernovae may be a heterogeneous class of object (much like the Cepheids initially used to estimate extra-galactic distances turned out to be heterogeneous), or ...
Can you honestly say that they have in this case? Is our technology sufficient to rule out all other options besides new matter/forces?
No, and I don't think any physicist or astronomer would say "our technology sufficient to rule out all other options besides new matter/forces" (or similar); it's more that no one has come up with any such option, so far (at least, none that also account, quantitatively, for all the other, relevant, observational and experimental results).

mharratsc
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Re: Nature of astrophysics (I) - between theory and observation

Unread post by mharratsc » Tue Dec 07, 2010 12:41 pm

Nereid said:
No, and I don't think any physicist or astronomer would say "our technology sufficient to rule out all other options besides new matter/forces" (or similar); it's more that no one has come up with any such option, so far (at least, none that also account, quantitatively, for all the other, relevant, observational and experimental results).
One of the major complaints that I've seen, since becoming a member of Thunderbolts here, is that 'Mainstream' doesn't exactly go out of its way to be courteous and helpful to anyone actually pursuing 'alternatives', as it were, insofar as many modern plasma physicists have documented. Or even from inside the astrophysical community itself, judging from the treatment of Halton Arp. Everything Einstein ever stated seems to have become doctrinal- if not downright dogmatic- in Physics.

Why so closed-minded? I know that no one wants to be wrong about anything, but 'Science' is always portrayed as a group of individuals with childlike curiousity who don't give a crap if some new discovery 'busts the balloon' of current understanding- it's the discovery that matters! But why doesn't this seem to be the case anymore?

In truth, Nereid- you seem to be one of the most open-minded of 'Mainstreamists' (if you will please forgive the label) that I've really ever had a good opportunity to dialogue with. Previous arguments seem to indicate that-in mainstream circles- the arguments are all concluded, the verdicts are in- 'Relativity Rules!'... even with the known, admitted, and sometimes glaring gaps in knowledge there. Experiment is allowed, but only after some level of homage is paid to Einstein (by stating what aspect of General or Special Relativity that Experiment XYZ is going to investigate).

I can't imagine why EU/PC has received such dubious responses, while experiments based up 10-dimensional 'branes' and 'strings' gets millions...? Verifiable physics vs... what? Infalsifiable thought experiments consorting with some 'elegant' mathematical symbology?

I don't get it. I really don't. And I really don't think that the majority of the 'mainstream' is quite as open-minded to 'alternative interpretation' as you seem to suggest, either. Not based upon most of the articles that I've read, and conversations on some boards that I've seen, at any rate. And I think that in itself should be a cause of concern in the scientific community, as well. :\

Sorry that this is off-track with 'Experiment vs Theory'... I just needed to get this off my chest- I'm all better now! :oops:
Mike H.

"I have no fear to shout out my ignorance and let the Wise correct me, for every instance of such narrows the gulf between them and me." -- Michael A. Harrington

Nereid
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Re: Nature of astrophysics (I) - between theory and observation

Unread post by Nereid » Wed Dec 08, 2010 3:23 am

I welcome your response, mharratsc, even if much of it is rather beyond the scope of this particular thread; it touches on several themes that I would like to explore in future threads on the nature of physics and astronomy (with particular emphasis on electromagnetism and plasmas), so I may quote from this post of yours, possibly extensively, later (I hope you won't mind).

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Re: Nature of astrophysics (I) - between theory and observation

Unread post by D_Archer » Wed Dec 08, 2010 8:58 am

Nereid wrote:
Yet his aurorae model turned out to be only partly right, and his Saturn's rings one completely wrong (in fact, had he known of some astronomical observations going back as far as several decades earlier, he would likely have not published this particular model!).
Could you please explain where his aurora model was partly right and where it was partly wrong?

Could you please explain where/how his Saturn's rings model was as you state 'completely wrong'?

Kind regards,
Daniel
- Shoot Forth Thunder -

Nereid
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Re: Nature of astrophysics (I) - between theory and observation

Unread post by Nereid » Wed Dec 08, 2010 9:31 am

D_Archer wrote:Could you please explain where his aurora model was partly right and where it was partly wrong?
Sure.

As I understand it, aurorae, in Birkeland's model, are due to electrons emitted by the Sun being accelerated towards the Earth by a strong electrical field (I think in a later, tweaked, version he added what we'd today call protons, or ions). That the aurorae are due to energetic charged particles which come from the Sun is the part that's right. However, the role of the Earth's magnetosphere in trapping, and accelerating, the particles (from the Sun) are not in his model.

Also, if I recall correctly, his estimates of the energies of the particles (electrons) as they hit the Earth's upper atmosphere were quite wrong (a fact he himself recognised!).
Could you please explain where/how his Saturn's rings model was as you state 'completely wrong'?
In his model, Saturn's rings (the ones known to astronomers of the day) are self-luminous (shine by their own light); recall that at the time such a concept would be restricted to visible light and perhaps a bit of the UV (Birkeland used photographic film whose emulsions were quite sensitive to UV and blue light). However, it was already known (to astronomers) - even several decades earlier - that Saturn's rings shine by reflected sunlight (these conclusions came from careful observations during more than one 'ring crossing', where the rings turn 'edge-on' to us, and where, for a few days, the unilluminated side of the rings is what we see).

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JaJa
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Re: Nature of astrophysics (I) - between theory and observation

Unread post by JaJa » Wed Dec 08, 2010 2:04 pm

Hi Nereid

Sorry to have to drag this thread into elementary realms of understanding but I do have some questions;

The following is from Sir Roger Penrose:
"Time and space had a finite beginning that corresponded to the origin of matter and energy. The singularity didn't appear in space; rather, space began inside of the singularity. Prior to the singularity, nothing existed, not space, time, matter, or energy – nothing”
My first question is simple. What is nothing and has it ever been observed or measured either directly or indirectly?

My second question is; why is Time defined as a dimension when it seems to be a man-made concept used to measure change brought about by Motion. Without Motion - how could I define time?

My third question relates to the "space" between atoms. Is it empty in the literal sense?

Thanx

JJ
Omnia in numeris sita sunt

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webolife
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Re: Nature of astrophysics (I) - between theory and observation

Unread post by webolife » Wed Dec 08, 2010 3:47 pm

Nereid's Question: does picking up the rock mean you have "physically manipulated" it?

Picking up a rock manipulates it if you are testing the effect of its gravitational potential energy. Also, are you replacing it where it was originally or into a new medium such as water? Did you pick it up by hand, in which case you may have removed a small amount of its surface mass, or changing its temperature through conduction? Or did you pick it up with some sort of mechanical device, imparting to it some piezoelectric effects? Perhaps the rock had some radioactive properties that changed its new locale/environment measurably, or removing it from its previous location changed the radioactivity levels in that locale? Did you rotate the rock in any way relative to a local light source so that its luster/reflectivity was guaged, or so that certain included cleavage planes or crystal patterns were revealed? Did you drop the rock after picking it up, inducing all sorts of energy transformations upon impact? Did you pick it up to look at it through any colored filters or polarizing apparatus, or subject it to UV using a black light? For that matter, was the rock outside exposed to weathering elements before you picked it up, affecting changes in the long term processes acting on the rock?
Truth extends beyond the border of self-limiting science. Free discourse among opposing viewpoints draws the open-minded away from the darkness of inevitable bias and nearer to the light of universal reality.

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Re: Nature of astrophysics (I) - between theory and observation

Unread post by Nereid » Wed Dec 08, 2010 9:34 pm

JaJa wrote:Hi Nereid

Sorry to have to drag this thread into elementary realms of understanding but I do have some questions;
Hi JaJa,

If you don't mind, I'd rather keep this thread on the topic set out in its beginning.

I think your questions are interesting ones, but why not start a separate thread on them, so discussion of them would be more focussed?
The following is from Sir Roger Penrose:
Where does it come from, may I ask?

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JaJa
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Re: Nature of astrophysics (I) - between theory and observation

Unread post by JaJa » Thu Dec 09, 2010 2:03 am

Hi Nereid

Sorry, I thought from the title "nature of astrophysics - between theory and observation" that I would be able to pose such questions. Of course I will start another thread - I hope you'll contribute :D

With reference to the Penrose quote; I find this most unusual because that quote WAS at the link below up until a few weeks ago because it was used, spoken about and referenced in a university presentation given by myself... now it seems to have been edited out of existence.

http://en.wikipedia.org/wiki/Nothing

The section on Wikipedia I used went like this;
In mathematics, “nothing” does not have a technical meaning. The number zero is often used interchangeably with the term. It could also be said that a set contains “nothing” if and only if it is the empty set, in which case its cardinality (or size) is zero...

In physics, the word nothing is not used in any technical sense either. A region of space is called a vacuum if it does not contain any matter...

"Time and space had a finite beginning that corresponded to the origin of matter and energy. The singularity didn’t appear in space; rather, space began inside of the singularity. Prior to the singularity, nothing existed, not space, time, matter, or energy – nothing" (Roger Penrose
To which I wrote in my presentation...

"I’m not setting out to criticize a man of Penrose’ stature – but isn’t this kind of thinking in conflict with common sense..."

It seems the above was replaced by this...
In physics, the word nothing is not used in any technical sense either. A region of space is called a vacuum if it does not contain any matter, though it can contain physical fields. In fact, it is practically impossible to construct a region of space that contains no matter or fields, since gravity cannot be blocked and all objects at a non-zero temperature radiate electromagnetically. However, even if such a region existed, it could still not be referred to as "nothing", since it has properties and a measurable existence as part of the quantum-mechanical vacuum.
Does this mean I will have to re-write my project :o

JJ
Omnia in numeris sita sunt

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MrAmsterdam
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Re: Nature of astrophysics (I) - between theory and observation

Unread post by MrAmsterdam » Thu Dec 09, 2010 2:58 am

What would the scientists say about their models and theories if we could teleport them from the 18th, 19th and 20th century to nowadays?
Let's take Mr Einstein as example. Would he look at the data acquired by the modern spaceprobes and build a theory or vica versa?

The difference between astrophysics in the 19th century and astrophysics nowadays is the amount of new data we have acquired via spaceprobes. Would this have any influence on the 'nature of astrophysics' ?
Today's scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality. -Nikola Tesla -1934

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