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rmollise
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Re: The Red Sirius new [Re: jrbarnett]
      #3410177 - 10/25/09 02:49 PM

Quote:

Here's a longshot...

How long does it take a red giant to devolve into a white dwarf?





About 400 million years or thereabouts.

I believe the aforementioned explanations, "fiery" being misinterpreted as "red" and Sirius scintillating when near the horizon more than adequately explain "red."


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Uncle Burnout
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Re: The Red Sirius new [Re: Crossen]
      #3410370 - 10/25/09 04:24 PM

The passage from Manilius which you quote speaks only to the "fiery" aspect of Sirius, whereas the passage I quoted from book I of the Astronomicon clearly describes Sirius' color as "blue". The political or literary pre-eminence of a writer on this type of topic has, at best, no weight in my estimation. Why for example would you trust a paper by an ex-president on a scientific topic more than you would trust a relative unknown's work? Either Manilius is incorporating his own observations or transmitting an alternative tradition.

I believe that if you haven't you should read the paper by R. C. Ceragioli (which I came across last night) which offers a fairly exhaustive examination of this topic and the scholarly debate. While I take issue issue with some of his interpretations (his treatment of "candor" in relation to Hyginus' description of Sirius for example), it is a solid piece of work. Here is a link:
Link to PDF

edit, to correct spellings; note I also mistyped Avienius' name in another post.

Edited by square_peg (11/03/09 01:03 PM)


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Tony Flanders
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Re: The Red Sirius new [Re: Starman1]
      #3410548 - 10/25/09 06:11 PM

Quote:


The Greeks and Romans traded extensively with the Egyptians, and many things were borrowed.




Oh yes, it's well known that the Greco/Roman tradition of astronomy was primarily adopted from other civilizations. The influence of Mesopotamia was far more profound than the influence of Egypt, but no doubt they borrowed from Egypt too. The genius of the Greeks is largely due to the fact that they were such brilliant borrowers.

When you talk about astronomy in the ancient Mediterranean and Middle East, you're really talking about a single tradition with variants or subcultures. The cultural interactions throughout the region were enormous. Even India, to a large extent, is part of the same tradition.

To give a *really* compelling argument for Sirius being red, you should cite sources from China or the Mayans. The former was largely independent of the "Western" tradition, and the latter entirely so.


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Larry Geary
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Re: The Red Sirius new [Re: Starman1]
      #3410632 - 10/25/09 07:17 PM

You probably have the right answer. The stars were more objects of astro-theological interest than astrophysical study.

BUT, the current global warming controversy demonstrates that we don't know as much as we'd like to think we do about how our climate operates, or how our own star operates.

SO, maybe at the time in question Sirius A was undergoing a period of high starspot activity. Starspots (like sunspots) are cooler than the surrounding photosphere, and therefore redder. Perhaps this changed Sirius A's color from white to more reddish.

OR perhaps it consumed a large "hot Jupiter" in very close orbit and spewed out a cloud of dust and/or hydrogen that reddened it for a few hundred years.

Just thinking out loud.


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Crossen
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Re: The Red Sirius new [Re: Tony Flanders]
      #3410720 - 10/25/09 08:13 PM

Quote:

Quote:

One of the most important aspects of the question of an ancient red Sirius is the intellectual sophistication of the ancient authorities who report Sirius as red. These were neither credulous nor gullible men. The genius of Ptolemy is beyond dispute ...




Yes, anybody who's read Ptolemy has to be aware of Ptolemy's incredible mastery of his material and his mathematical sophistication.

But not gullible? I beg to differ! Remember, Ptolemy is also the man who established the underpinnings of astrology as we now know it. And defended it by arguments that were as feeble then as they seem when repeated now.




Ptolemy did not "establish the underpinnings of astrology as we now know it." Classical astrology was derived from Babylonian astrology, the roots of which go back to the Sumerian 3rd millennium BC. We don't know a great deal about the astrology of the Sumerians; but there are a large number of Assyrio-Babylonian astrological texts from the 2nd millennium BC.

The astrology that took over the decaying Roman Empire during the 3rd century AD was indeed contemptible, but a consequence of the uncertainty and instability of that time. But the astrology of Ptolemy and Manilius was ultimately founded upon Stoic monism, which simply asserted the interconnectedness of all things. The idea in fact goes back to Babylonian astrology, because an ancient text now called "A Babylonian Diviner's Manual" asserted, "The signs on earth just as those in the sky give us signals. Sky and earth both produce portents though appearing separately, they are not separate (because) sky and earth are related." (Oppenheim, Journal of Near Eastern Studies Vol. 33 p. 204.) Graeco-Babylonian astrology was a hypothesis about the nature of the physical world: it eventually was rejected by thoughtful people because, after being tested, it proved not to work. But the test was not concluded until after Ptolemy. So to blame Ptolemy for writing the "Tetrabiblos" is to fail to appreciate the state of knowledge at his time.

There was nothing irrational or even illogical about Stoic monism, providing you accepted the initial assumption of a universe presided over by a Rational and Good Supreme Being. Indeed, modern astrophysics itself is based upon the monistic belief that what happens on earth happens in the stars and between the stars.

Physics as a whole is monistic, and initially it was assumed that Newtonian physics and its associated constants were general "laws." This particular monistic belief proved false when Newtonian physics broke down on the microscopic level--hence the necessity for quantum mechanics. But it is also sheer monistic assumption to believe that Newtonian physics, which has been developed in the high-radiation, high-gravity environment of the earth's surface, applies to the low-radiation, low-gravity environment between the galaxies. As Binney and Tremaine wrote in their text "Galactic Dynamics" (p 635): "It is worth remembering that all of the discussion so far has been based on the premise that Newtonian gravity and general relativity are correct on larger scales. In fact, there is little or no direct evidence that conventional theories of gravity are correct on scales much larger than a parsec or so." Since Binney and Tremaine wrote the above, some astrophysicists have been experimenting with equations that assume that the force of gravity decreases faster than Newtonian physics states in low-gravity environments ("Modified Newtonian Dynamics"--MOND) and find that the rotation curves of several well-observed spiral galaxies can be modelled perfectly well WITHOUT appeal to the notorious "dark matter." (See the IAU Symposium No. 220, "Dark Matter in Galaxies" for extended discussions of MOND.) Thus Newtonian physics is showing some cracks on the macroscopic level as well.

The breakdown of Newtonian physics on the microscopic level should be a warning that we must not be complacent about our mathematics and physics. If Sirius was indeed red 2000 years ago, it would point to another hole in our physics. That is the ultimate importance of a "Red Sirius."

Craig Crossen


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Starman1
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Re: The Red Sirius new [Re: Crossen]
      #3410964 - 10/25/09 10:36 PM

Craig,

It is the responsibility of anyone who lends credence to the idea that somehow, in violation of physics as we know it, Sirius was red in color only a couple thousand years ago to explain HOW Sirius could have been red.

Your argument that the words of scientifically illiterate people should hold any water is as implausible as the arguments that the alignment of the planets can foretell one's personality.

It is an error in logic to assume that, because we are not all-knowledgeable on the evolution of stars and the processes contained therein that therefore anything goes. SOME things about Newtonian physics were not overturned by Einsteinian physics. SOME aspects of sub-atomic physics do not require quantum mechanics to explain.

It is unlikely that further knowledge of stellar astrophysics would lead to a physics that allows a red star to turn into a blue star in 2000 years without some form of cataclysm.

Likewise, the law of parsimony would dictate, in this case, that the classical references to a red Sirius are simply inconsistent with our knowledge of astrophysics in the 21st century, NOT that somehow or other our incomplete understanding of stellar physics admits to a physics directly contradictory to the understanding we have so laboriously acquired.

We may have an incomplete understanding of gravity on large scales, but that does not invalidate the argument that if I step off a tall building I will fall to the ground.

Thus, the argument that a red Sirius may have actually existed only a few thousand years ago I find curious. My first inclination would have been to find such classical quotes quaintly mistaken rather than to lend them any weight in physical reality. Why you argue the other side when it flies in the face of all current knowledge of stellar astrophysics may speak more to psychology than physics.


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Uncle Burnout
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Re: The Red Sirius new [Re: Starman1]
      #3411064 - 10/25/09 11:36 PM

From the article:
Germanicus, in a rather freer rendering of the passage, nevertheless uses the term rutilis[sic], and says that the Dog¡¯s mouth (marked by Sirius) ¡°vomits flame¡±.

Apparently, the line that employed "rutilus" is no longer considered genuine and possibly did not refer to Sirius in the first place (Ceragolio, note #58). I don't have any edition of Germanicus' translation, much less a critical one, but the one I found online did not include any form of rutilus in the description of Canis (the constellation). This seems to be the location cited by Crossen:

talis ei custos aderit canis ore timendo.
ore vomit flammam, membris contemptior ignis.
Sirion hunc Grai proprio sub nomine dicunt. 335
cum tetigit solis radios, accenditur aestas,
discernitque ortu longe sata, vivida firmat,
at quibus adfectae frondes aut languida radix,
exanimat. nullo gaudet maiusve minusve
agricola et sidus primo speculatur ab ortu. 340
Auritum leporem sequitur canis et fugit ille,
sic utrumque oritur, sic occidit in freta sidus.

I also found a quotation from Avienus' translation in Ceragolio's notes (#79):

Sed primaeva Meton exordia sumpsit ab anno
torreret ruti locum Phoebus sidere Cancrum,
cingula cum veheret pelagus procul Orionis
et cum caeruleo flagraret Sirius astro

I'm only typing this in (risking errors) because I haven't found an edition of the text online to view the quote and thought others might want to see it as well, for what its worth.


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Tony Flanders
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Re: The Red Sirius new [Re: Starman1]
      #3411353 - 10/26/09 07:20 AM

Quote:


It is the responsibility of anyone who lends credence to the idea that somehow, in violation of physics as we know it, Sirius was red in color only a couple thousand years ago to explain HOW Sirius could have been red.

Your argument that the words of scientifically illiterate people should hold any water ...




Now wait just one minute! I think that Craig is giving far too much weight to the classical descriptions of Sirius as red (or perhaps fiery), but this is going way overboard in the opposite direction. Calling Ptolemy scientifically illiterate is preposterous. On the contrary, he was probably the most knowledgeable and certainly the most influential scientist in the Western tradition prior to Galileo. There is a reason that his book is called not by its proper name but by its Arabic nickname: The Greatest.

As for the laws of physics, we have only the vaguest idea how stars work. Our "knowledge" is based on theoretical models that are well-known to be gross oversimplifications. Much of the behavior of the Sun -- the only star that we can study in detail -- is still a mystery.

Stars are constantly surprising us. Nobody expected Delta Scorpii to flare up after remaining at a constant magnitude for the entire telescopic era, but it did.


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deSitter
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Re: The Red Sirius new [Re: Tony Flanders]
      #3411740 - 10/26/09 11:32 AM

While I don't think Sirius was ever red, I totally agree here - a lot of stellar astrophysics is known, but not everything, and the jury is still way out on neutrinos, not only in the Sun, but in general (the weak interaction is still poorly understood and relies on a mechanism whose main actor is still missing).

And yes Ptolemy was surely as towering a figure as even Newton. One should also be careful when denigrating astrology. Not only astronomy, but also in a very strange way, psychology, emerged from it, much as chemistry emerged from alchemy. Without astrology and alchemy there might very well be no science at all.

It's also interesting to note that Newton was a tireless alchemist and filled volumes upon volumes with his private researches, while Kepler made at least part of his living doing people's horoscopes, from a position of faith in the results.

-drl

Quote:

Quote:


It is the responsibility of anyone who lends credence to the idea that somehow, in violation of physics as we know it, Sirius was red in color only a couple thousand years ago to explain HOW Sirius could have been red.

Your argument that the words of scientifically illiterate people should hold any water ...




Now wait just one minute! I think that Craig is giving far too much weight to the classical descriptions of Sirius as red (or perhaps fiery), but this is going way overboard in the opposite direction. Calling Ptolemy scientifically illiterate is preposterous. On the contrary, he was probably the most knowledgeable and certainly the most influential scientist in the Western tradition prior to Galileo. There is a reason that his book is called not by its proper name but by its Arabic nickname: The Greatest.

As for the laws of physics, we have only the vaguest idea how stars work. Our "knowledge" is based on theoretical models that are well-known to be gross oversimplifications. Much of the behavior of the Sun -- the only star that we can study in detail -- is still a mystery.

Stars are constantly surprising us. Nobody expected Delta Scorpii to flare up after remaining at a constant magnitude for the entire telescopic era, but it did.




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Starman1
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Re: The Red Sirius new [Re: Tony Flanders]
      #3412351 - 10/26/09 04:00 PM

Quote:

Quote:


It is the responsibility of anyone who lends credence to the idea that somehow, in violation of physics as we know it, Sirius was red in color only a couple thousand years ago to explain HOW Sirius could have been red.

Your argument that the words of scientifically illiterate people should hold any water ...




Now wait just one minute! I think that Craig is giving far too much weight to the classical descriptions of Sirius as red (or perhaps fiery), but this is going way overboard in the opposite direction. Calling Ptolemy scientifically illiterate is preposterous. On the contrary, he was probably the most knowledgeable and certainly the most influential scientist in the Western tradition prior to Galileo. There is a reason that his book is called not by its proper name but by its Arabic nickname: The Greatest.





Correct, in a way. The most knowledgeable and influential "scientist" of his time was, by today's standards, scientifically illiterate.
He had no knowledge of molecules, atoms, cells, or most things found today in introductory texts on ANY scientific subject.
He had only the most primitive of tools with which to investigate his universe because the technology wasn't yet there.
Almost by definition, ALL humans alive in his time were scientifically illiterate.

It's remarkable how much they did understand (or at least a few people, not most), but his understanding of the Universe was that of Humanity's pre-scientific millenia.

Today, we recognize there are huge gaps in our knowledge, but we have come a long way in our understanding. It's a journey without end, but let's understand that the span between us and Ptolemy is a vast gulf.


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David Knisely
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Re: The Red Sirius new [Re: Starman1]
      #3412507 - 10/26/09 05:26 PM

The main point here is that there is doubt about the historical record concerning the color of Sirius. If every single record or account that mentioned star color had Sirius clearly stated as being a red color, then it might be worthy to give the reports a little more weight. However, as reported, this was not the case. Some of the reports merely indicated a possible reddish hue, while others in the same period (the Chinese for example) did not. The current astronomical and astrophysical facts behind red color for stars do not support the idea of Sirius being reddish any time within the historical record time period. This, plus the less than conclusive descriptive record, must point to the likelyhood that Sirius has not been red anytime in the past few thousand years or so. I think that is where the facts leave us. Clear skies to you.

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Uncle Burnout
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Re: The Red Sirius new [Re: David Knisely]
      #3412996 - 10/26/09 09:39 PM

From the article:
Cicero, in his translation of Phaenomena 326-34, writes, rutilo cum lumine claret fervidus ille Canis, ¡°with ruddy light fervidly glows that dog.¡±

I don't know how I missed this before. Here "rutilus" (translated above as "ruddy") does not refer to the the color of Sirius alone; it refers to the light of the constellation Canis, i.e., multiple stars. This is particularly clear if you add the rest of the sentence from Cicero: "stellarum luce refulgens", "flashing with the light of stars" (plural). There seems something similar could be going on in Aratus' original, where "poikilos" could make sense with its normal definition if it refers to the constellation.

Anyway, my initial excitement at seeing this article join two of my favorite interests has long subsided. I've only continued this long out of irritation. I think the author does not read Latin or Greek except in translation.


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arpruss
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Re: The Red Sirius new [Re: Starman1]
      #3413764 - 10/27/09 10:15 AM

Quote:

It is the responsibility of anyone who lends credence to the idea that somehow, in violation of physics as we know it, Sirius was red in color only a couple thousand years ago to explain HOW Sirius could have been red.

Your argument that the words of scientifically illiterate people should hold any water is as implausible as the arguments that the alignment of the planets can foretell one's personality.




1. One of the defining features of science is its answering to empirical observations. While some observations require sophisticated instruments, there are also observations--and in particular the observations of the visual color of bright stars--that do not require sophisticated instruments. To throw out observation reports because they do not fit the theory is not good scientific procedure. It is not necessary for the observer to have a theory to explain his or her observations. And if we required observations to be compatible with existing theory, we would stop much scientific progress.

2. Our knowledge of stellar evolution rests on observations of stars at different stages, combined with a good dollop of theory. On the theory side, it is certainly not the case that the stellar evolution predictions are derived from the most basic laws of physics (not that we know what these are, either). Rather, various approximations are made, computer simulations of simplified models are done, and so on. I suspect--I do not know in this case--that significant parts of the models are derived not from fundamental laws, but are "phenomenological", simply a best fit to the observational data.

3. One of the limitations of the observational data we have is that while we are fortunate enough to observe objects of different ages, we are rarely able to observe the very same object at significantly different ages in its own evolution. Potentially, ancient astronomical observations are a way of supplying for that defect in our data. Such observations potentially provide data that we did not have available when we created the current theories of stellar evolution, and it is not scientifically responsible to discount it.

4. As for the scientific illiteracy of the observers, they were smart people. Greek mathematics was sophisticated. Just pick up Euclid, and see how quickly you can fill in all the proofs yourself. :-) Sure, many of them had astrological beliefs. But while it would be irrational for you or me to believe that the positions of the planets at birth affect us in significant and predictable ways, it is far from clear that it was irrational at the time to believe it. What is and is not rational to believe is dependent on the evidence or data available. Given the evidence Newton had, believing in General Relativity would probably have been irrational. Given the evidence we have, believing classical physics to be true (not merely as an approximation) is irrational. This is not a relativism, of course--I am not saying that Newton and Ptolemy are just as right as we are. We do, after all, have more data than they did. But while our scientific theories are closer to the truth than those of Newton and Ptolemy, we would be unjustified in saying that our present scientists are more rational than Newton and Ptolemy were.

5. All that said, I do wonder--as a previous commenter said--about the extent to which the perception of color can be affected by how one thinks of the stars. If one thinks of the stars as flaming, then one might see them as redder than they are. Probably not to the extent of seeing Sirius as red, though, except low on the horizon. And it is also true that some, though not all (presumably not Ptolemy), of the ancients were more likely to look at what their predecessors wrote than at what is up in the sky.

Edited by arpruss (10/27/09 10:16 AM)


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deSitter
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Re: The Red Sirius new [Re: Uncle Burnout]
      #3413773 - 10/27/09 10:18 AM

I was just reading Allen ("Star Names") and he mentions in a paragraph on p. 127 that an astronomer named See in the late 19th century concluded that Sirius was in fact red, and that on the contrary Schiaperelli concluded that it was not. Here then is a letter to the periodical "The Observatory" by Prof. Lynn, referring to this matter (look to the bottom and click "Send PDF" to get the article):

http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1902Obs....25..130L&classic=YES

and here is a summary of the matter from 1984

Google Books link

I will try to find more.

-drl


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Tony Flanders
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Re: The Red Sirius new [Re: David Knisely]
      #3413972 - 10/27/09 12:16 PM

Quote:

The main point here is that there is doubt about the historical record concerning the color of Sirius. If every single record or account that mentioned star color had Sirius clearly stated as being a red color, then it might be worthy to give the reports a little more weight. However, as reported, this was not the case. Some of the reports merely indicated a possible reddish hue, while others in the same period (the Chinese for example) did not. The current astronomical and astrophysical facts behind red color for stars do not support the idea of Sirius being reddish any time within the historical record time period. This, plus the less than conclusive descriptive record, must point to the likelyhood that Sirius has not been red anytime in the past few thousand years or so. I think that is where the facts leave us. Clear skies to you.




Pretty much sums it up. The evidence isn't conclusive either way, but as things stand, the most economical explanation is that the current theories of stars are right and the ancient observers who said that Sirius was red were wrong -- or misinterpreted.

Although the Greeks were dazzling thinkers, respect for empirical data -- especially data that ran counter to their theories -- was *not* one of their strong points.


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Uncle Burnout
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Re: The Red Sirius new [Re: deSitter]
      #3414253 - 10/27/09 02:58 PM

Did you read the Ceragioli paper I cited earlier? R.C. Ceragioli JHA xxvi, (1995): "The Debate Concerning the 'Red' Sirius". There's a link to the .PDF in a post above. Even if we concede that Ptolemy catalogs the star as "reddish" (a possible rendering of "hypokirros", but more appropriate to the Latin translation of Ptolemy, "subrussa"), there is no reason to believe that the ancients saw Sirius as a red star, certainly not "fiery red". Ceragioli thoroughly examines the debate and a great number of passages in detail, some of which seem initially to support the theory of a red Sirius in antiquity. As I said in an earlier post, I don't agree with C.'s every interpretation, but his method is careful and scholarly, and his conclusion reasonable.

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jrbarnett
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Re: The Red Sirius new [Re: Uncle Burnout]
      #3414316 - 10/27/09 03:30 PM

More Hoisin sauce on the fire...

Link

Pardon the Babelfish translation, but the article has nice data regarding several different ancient Chinese records spanning several hundred years of Sirius' color (white).

Regards,

Jim



Edited by square_peg (11/03/09 01:01 PM)


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Uncle Burnout
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Re: The Red Sirius new [Re: jrbarnett]
      #3414420 - 10/27/09 04:29 PM

Good find -- I happen to enjoy the Babelfish touch:). I'm especially interested in the "yellow" reference to Sirius, as Ptolemy's "hypokirros" may tell us more about Ptolemy than the color of the star. It seems that the Chinese also used the color of Sirius upon rising, as is likely the case in the Near East and West.

The 'red Sirius' really is an interesting question, but more a cultural and philological one than astrophysical. By trying to prove that Sirius was 'red' in Western antiquity, I think we're losing an opportunity to learn a great deal about ancient observations, terms used technically (not to mention poetically), and analytical techniques. The fact that we have to force meanings on words and ignore and contort quotes to prove what is almost ceratinly an astrophysical impossibility speaks volumes.


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Crossen
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Re: The Red Sirius new [Re: Tony Flanders]
      #3414686 - 10/27/09 06:52 PM

Quote:

The evidence isn't conclusive either way, but as things stand, the most economical explanation is that the current theories of stars are right and the ancient observers who said that Sirius was red were wrong -- or misinterpreted.

Although the Greeks were dazzling thinkers, respect for empirical data -- especially data that ran counter to their theories -- was *not* one of their strong points.




Your summary of things--especially the phrase "economical explanation"--is, I think, right on the mark. Precedence must be given to modern astronomical theories of stellar evolution while keeping in mind that here we have a body of ancient data that has, since it was noticed by Thomas Barker in 1760, been difficult to explain--or explain away.

Most of the statements about a red Sirius are from Romans or Greeks who worked during the height of Roman civilization (1st cent. BC to 2nd cent AD). Though the Greeks of the Hellenic age indeed seem to have been more inclined to the desk than to the field, the Romans were not. Concerning the Roman Epicurean philosopher Lucretius (a contemporary of Cicero), the American Classicist Tenney Frank wrote,

"Lucretius also responded to Roman tempermental inclinations when he stressed the importance of observation and inductive logic in philosophy. The Romans of the Republic disliked mysticism and were ripe for a cosmology that substituted sense perception for vague mystery. They were also impatient of abstractions, and made little progress with such deductive sciences as mathematics. . . . Democritus [whom you will remember was the 'inventor' of the atom] had long ago proposed the hypothesis of natural creation, and Lucretius accepted the theory from Epicurus. What Lucretius himself saw was the need of emphasizing to the Romans the method the approach by induction from observable data . . . Beneath every statement [in an argument in Lucretius' first book] there lies a mass of careful observation, tested by what John Stuart Mill calls the method of "agreement and difference," and these valid conclusions are in turn used for the final induction . . ." ("Life and Literature in the Roman Republic" Chapter VIII)

Educated Romans tended to ally themselves with either the Stoics or the Epicureans; thus the ideas of Lucretius had a wide hearing. Thus observation in the modern scientific sense WAS part of Roman culture.

But these are just words. Where is the evidence that the Romans actually practised observation and inductive reasoning on any scale? That evidence is in fact all over southern Europe and the Mediterranean. It is Roman architecture. For what are architecture and engineering but applied physics? The Roman buildings that still stand in whole or large part prove that the Romans had mastered that branch of physics called statics. They understood the effects of gravity. They understood thrust and the principle that "every reaction has an equal and opposite reaction." They knew how to channel thrust through the weight-bearing walls and pillars of a structure. Think of the Pantheon in Rome, a domed structure that has stood whole for nearly two millennia in an earthquake zone! The number of Roman archs that survive around the Mediterranean are literally uncountable. By contrast, the Interstate 35W bridge just upriver from my alma mater stood just 40 years--and it didn't have to face earthquakes and wars.

Some of Roman knowledge about architecture has survived in Vitruvius' "On Architecture," a work not superceded until the Renaissance. But the Romans were not people of the desk: they'd rather be doing than writing. I've known a lot of tech-men who are that way. But when they did write, most of them were careful about what they said. In the early books of his "History," Livy again and again warns readers that what he is narrating is only legend, but the only information about the early centuries of Rome that survived. However, excavations on the Capitoline and Palatine and under the Forum have confirmed the substance of Livy's account. A Danish excavation in the 1980s reconfirmed the Livian date of about 490 BC for the founding of the Temple of Castor. . . .

. . . but Roman archaeology is one of my favorite subjects, so I'd better stop before I run on worse than I have. The point is that educated Romans were alert and careful observers of the world around them and knew how to apply observational knowledge in numerous fields of human endeavor--including astronomy.

Craig Crossen


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Michael A. Earl
vendor- Canadian Satellite Tracking and Orbit Research


Reged: 11/17/08

Loc: Brockville, Ontario, Canada
Re: The Red Sirius new [Re: Crossen]
      #3414777 - 10/27/09 07:35 PM

I am surprised that nobody mentioned the obvious. Are there accounts of the colors of other stars nearby the declination of Sirius (keeping in mind precession over 2000 years)?

Today, there are not many stars near the same declination of Sirius. The obvious, Rigel is white, just like Sirius. Is Rigel also described as being red? No? Then Sirius had to be red while Rigel was not, suggesting an astrophysical reason.

I find it hard to believe that every seasoned astronomer of that era viewed the sky through flames and smoke. They would have known (as we do now) that the sky is much better viewed from outside fire's influence.

Does anyone mention Fomalaut, Canopus, Spica or Antares? If all of them are described as "red" or "ruddish" then there is certainly an atmospheric connection somewhere. With the exception of Antares, all are clearly white or nearly so.

Procyon is a good example of a star that has some issues with respect to the observer. Many would see it as white, but seasoned observers know that it has a slight orange or red quality.

I can't see Sirius b as an explanation. No one in history commented on how Sirius became progressively whiter over time. You would think that someone would have noticed, Sirius being such a bright star and all! If Sirius is indeed getting whiter, spectroscopic analysis would have revealed that; even today. In the past 100 years, no one has commented on Sirius' spectral lines changing.

We can see Sirius as red or orange today, especially those who live on the eastern seaboard of the U.S. On a very humid night in September, go see Sirius just before dawn. I am sure that you would see red too. If humidity levels were high at the venues, Sirius could be red. However, if the humidity levels became low again, Sirius would once again appear white.

On the outside, the only event I can possibly think of is absorbing dust in between Sirius and the Earth. However, if the dust is heavy enough to turn Sirius red, it would have also greatly diminished its apparent brightness, thus removing it from the altar of ancient worship.

However, there is another angle. It is possible that the area of observation was polluted with volcanic activity. The Mediterranean has both Mount Etna and Mount Vesuvius. This might explain how the Greeks called Sirius red and the Chinese did not. Volcanoes would also diminish the apparent brightness of the stars and would have turned them all red.

Unless we can go back in time and ask them and see Sirius for ourselves, it will be a mystery for many years to come.


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