Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Announcements and News >> Discussion of CN Articles, Reviews, and Reports

Pages: 1 | 2 | 3 | 4 | (show all)
mloffland

*****

Reged: 09/03/04

Loc: Norman, Oklahoma
The Red Sirius
      #3401956 - 10/21/09 11:16 AM

The Red Sirius

Post Extras: Print Post   Remind Me!   Notify Moderator  
arpruss
Vendor: Omega Centauri Software
*****

Reged: 05/23/08

Loc: Waco, TX
Re: The Red Sirius new [Re: mloffland]
      #3402070 - 10/21/09 12:20 PM

Quite interesting! One thing to take into account is that perhaps not all of the ancient witnesses are independent. It is quite possible for one of them to write of Sirius as fiery red because he has read this description in some earlier author, without having actually looked (or maybe having looked, but not trusting his own observation).

Is there any chance that some sort of color-blindness on the part of one or two of the writers would explain the event? Or that perhaps some of the less astronomically astute might have confused it with another star?

According to wikipedia
Quote:

not all ancient observers saw Sirius as red. The 1st century AD poet Marcus Manilius described it as "sea-blue", as did the 4th century Avienus. It is the standard star for the color white in ancient China, and multiple records from the 2nd century BC up to the 7th century AD all describe Sirius as white in hue




Edited by arpruss (10/21/09 12:24 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
stevecoe
"Astronomical Tourist"
*****

Reged: 04/24/04

Loc: Arizona, USA
Re: The Red Sirius new [Re: mloffland]
      #3402079 - 10/21/09 12:24 PM

Howdy all;

I am going to bring up a discussion from the late Issac Asimov. He said that Sirius was most important when it was rising before the Sun in the morning sky. This helical rising marked the flooding of the Nile and other important religious times in the ancient Middle East.

So, we all know that a rising star is shining through a lot of dust in the air. He believed it was reddened by that dust pollution and that when it was in its most important position in the sky to the ancients it was indeed ruddy.

It is an interesting solution;
Steve Coe


Post Extras: Print Post   Remind Me!   Notify Moderator  
EJN
Carpal Tunnel
*****

Reged: 11/01/05

Loc: 53 miles west of Venus
Re: The Red Sirius new [Re: mloffland]
      #3402095 - 10/21/09 12:36 PM

The real reason Sirius looked red was because at that time
the Sirians were using a massive array of ruby lasers
to launch a lightsail starship.














(Those familiar with "The Mote in God's Eye" will get this,
otherwise nevermind)


Post Extras: Print Post   Remind Me!   Notify Moderator  
David Knisely
Postmaster
*****

Reged: 04/19/04

Loc: southeastern Nebraska
Re: The Red Sirius new [Re: mloffland]
      #3402162 - 10/21/09 01:11 PM

One point which might be made would be concerning the behavior of the star visually. When the very brightest stars are seen either when the seeing is unstable or they are closer to the horizon, they seem to be scintillating violently with radical variations in brightness and sometimes in color. This may give them the appearance of being "fiery" rather than just red in color. Sirius is particularly prone to this effect, especially during the Heliacal rising which was so important to some ancient cultures. Also, not all ancient sources describe Sirius as reddish. The 1st century writer Marcus Manilius (1 A.D) described it as "sea-blue", and so did the 4th century writer Avienus. In addition, the ancient Chinese used Sirius as a sort of "standard" for the color white, with some records in the 2nd century B.C. to the 7th century A.D. also reporting its color as white.

Another factor to consider is that *if* a red giant star was put in place of the current Sirius B white dwarf, Sirius would be much brighter than it appears today (probably in the -4 to -8 magnitude range depending on the mass of the giant), making daylight sightings more common. There should also be at least some evidence (gas or faint nebulosity) of the considerable mass loss around the star from the time before it contracted into its current white dwarf status (especially after so short a time between when it was reported as red to when Sirius was said to be bluish-white). It is an interesting idea of having Sirius-B as a red giant in ancient times, but there is also the possibility that we are misinterpreting what the ancients really meant when they described Sirius as "fiery". Clear skies to you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: The Red Sirius new [Re: mloffland]
      #3402181 - 10/21/09 01:20 PM

Great info!! Very interesting. btw, at this link if you read the last para there is an working astophysics theory that can explain this phenomenon. Very cool when the historical record points out some things we never imaged could have happened. Keeps us on our toes

Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: The Red Sirius new [Re: mloffland]
      #3402605 - 10/21/09 04:38 PM

Glorious article!

Robert Burnham Jr. in his celebrated Celestial Handbook also speculates on the ancient ruddines of Sirius. He noted a couple of other instances where things modern folks don't think of as being "reddish" were described with epithets that implied reddish hue.

For example, in the Iliad there are many references to "wine-dark sea". Wine in ancient times was normally red. Of course, there are other explanations. In ancient times there was no clear glass. Wine was drunk from opaque goblets. Pour a nice cabernet into a stoneware mug, and I can unserdstand how the inky liquid might mimick the darkend surface of a stormy Aegean.

I wonder if there's a possible explanation around air quality. Sirius is brilliant, and still relatively low in elevation in Greece and Mesopotamia. Could some combination of wood fire smoke and perhaps increased levels of volcanic activity in the Mediterranean be responsible for Sirius' fiery appearance?

On especially turbulent nights, when Sirius is near the horizon, I find that refraction causes it to briefly flash many colors other than blue-white. Perhaps some of the ancients meant "fiery" as in animated and flickering rather than "fire-colored"?

At any rate, this is one of my favorite CN articles of all time. A thousand thanks for posting it!

- Jim

Edited by jrbarnett (10/21/09 04:49 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Crossen
super member
*****

Reged: 07/14/08

Loc: Vienna
Re: The Red Sirius new [Re: stevecoe]
      #3402662 - 10/21/09 05:12 PM

Quote:

I am going to bring up a discussion from the late Issac Asimov. He said that Sirius was most important when it was rising before the Sun in the morning sky. This helical rising marked the flooding of the Nile and other important religious times in the ancient Middle East.

So, we all know that a rising star is shining through a lot of dust in the air. He believed it was reddened by that dust pollution and that when it was in its most important position in the sky to the ancients it was indeed ruddy.




This is a good point to raise because of how important heliacal risings and settings of celestial objects were in most ancient cultures. One of the replies is that no ancient author calls Canopus white even though that important star never got very far above the horizon and therefore would have been even more vulnerable to atmospheric effects than Sirius.

A couple of responses have brought up the statement of Marcus Manilius regarding Canis Major. A careful reading of the original Latin reveals that it is not Sirius that Manilius says is blue, but the "face" of the Dog. Sirius was regarded as marking the mouth of Canis Major. Manilius calls Delphinus "dark blue"--a statement certainly not applicable to any of its stars, which are too faint to reveal color to the unaided eye. Manilius seems to have used the idea of constellation color in a peculiar way--perhaps related to astrology, which was, after all, the main topic of his book.

A striking feature of the ancient testimony to the redness of Sirius are the variety of authorities who report it. Both Ptolemy and Geminos were clearly men intimately familiar with the night sky and not likely to make an error on such an important point. Germanicus was a field general in the Roman Army who would have seen the star under a variety of conditions. Columella was a practising agriculturalist. It is inconceivable that such a group of highly intelligent men whose knowledge of the heavens came from such a variety of experiences would have simply repeated the same mistake.

Craig Crossen


Post Extras: Print Post   Remind Me!   Notify Moderator  
turtle86
Pooh-Bah Everywhere Else
*****

Reged: 10/09/06

Re: The Red Sirius new [Re: Crossen]
      #3402711 - 10/21/09 05:33 PM

Thanks for the great article. The ensuing thread has been pretty great too. The actual color of Sirius during ancient times is surely one of the more interesting mysteries in the history of astronomy. It is too bad we can't go back in time to see for ourselves whether the Dog used to be red...

Quote:

Quote:

I am going to bring up a discussion from the late Issac Asimov. He said that Sirius was most important when it was rising before the Sun in the morning sky. This helical rising marked the flooding of the Nile and other important religious times in the ancient Middle East.

So, we all know that a rising star is shining through a lot of dust in the air. He believed it was reddened by that dust pollution and that when it was in its most important position in the sky to the ancients it was indeed ruddy.




This is a good point to raise because of how important heliacal risings and settings of celestial objects were in most ancient cultures. One of the replies is that no ancient author calls Canopus white even though that important star never got very far above the horizon and therefore would have been even more vulnerable to atmospheric effects than Sirius.

A couple of responses have brought up the statement of Marcus Manilius regarding Canis Major. A careful reading of the original Latin reveals that it is not Sirius that Manilius says is blue, but the "face" of the Dog. Sirius was regarded as marking the mouth of Canis Major. Manilius calls Delphinus "dark blue"--a statement certainly not applicable to any of its stars, which are too faint to reveal color to the unaided eye. Manilius seems to have used the idea of constellation color in a peculiar way--perhaps related to astrology, which was, after all, the main topic of his book.

A striking feature of the ancient testimony to the redness of Sirius are the variety of authorities who report it. Both Ptolemy and Geminos were clearly men intimately familiar with the night sky and not likely to make an error on such an important point. Germanicus was a field general in the Roman Army who would have seen the star under a variety of conditions. Columella was a practising agriculturalist. It is inconceivable that such a group of highly intelligent men whose knowledge of the heavens came from such a variety of experiences would have simply repeated the same mistake.

Craig Crossen




Post Extras: Print Post   Remind Me!   Notify Moderator  
deSitter
Still in Old School


Reged: 12/09/04

Re: The Red Sirius new [Re: turtle86]
      #3403659 - 10/22/09 03:32 AM

Interesting, but there is really no possibility that Sirius was actually red. I think it's much more likely the authors are referring to the colorful scintillations we've all seen when Sirius is in clear air on a cold night, or close to the horizon. Sometimes Vega does this as well - so it would be interesting to see what the old authors said about that star. And for comparison, Rigel, Antares, Arcturus, and Capella.

A red giant at 8.6 light years would be a spectacular sight, much less a nova at that distance - so I don't think there is any hope of explaining a ruddy Sirius as being due to Sirius-B in an earlier life. Antares and Betelgeuse are resp. ~600 and ~500 light years distant. So 100-fold change in distance for them would increase their brightness 10,000 times or 10 magnitudes, to near that of the full Moon!

Nice to see this sort of article!

-drl


Post Extras: Print Post   Remind Me!   Notify Moderator  
-=BB=-
only get better


Reged: 07/25/08

Loc: Connecticut, US
Re: The Red Sirius new [Re: deSitter]
      #3403715 - 10/22/09 06:01 AM

If there was a color shift, you would think that someone would have noticed and remarked on it. Even if they didn't witness the actual "event", the change in color of such a significant star would certainly have been something worth noting - even as a portent of some sort.

Excellent article and discussion. Very interesting. Thank you!


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: The Red Sirius new [Re: -=BB=-]
      #3404062 - 10/22/09 12:02 PM

Here's a longshot...

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

Is it possible that Sirius B made the transition from red giant to white dwarf over the span of a couple of thousands of Earth year?

Were the Sirius system composed differently a few thousand years ago, consisting of a brilliant blue-white star and a contracting red giant, the apparent color of the combined light of the system that *could* have been actually red.

Of course, the theory of stellar evolution for red giants into white dwarfs predicts a billion+ year transition (often with a planetary nebular phase during the early part of transition).

Another somewhat far fetched possibility is a change in human ocular physiology in the intervening millennia. What if the human eye perceived certain colors differently? Alternately, what if ancient populations had a much higher incidence of male color blindness than do modern populations? I note that the sources quoted are all males, likely due to the patriarchical social structures of those cultures being sampled.

Are there any surviving female accounts of the color of Sirius? I wonder if any of Sappho's lost works mentioned Sirius?

This is a great, thought-provoking article.

Regards,

Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
Crossen
super member
*****

Reged: 07/14/08

Loc: Vienna
Re: The Red Sirius new [Re: -=BB=-]
      #3404126 - 10/22/09 12:51 PM

Quote:

If there was a color shift, you would think that someone would have noticed and remarked on it. Even if they didn't witness the actual "event", the change in color of such a significant star would certainly have been something worth noting - even as a portent of some sort.




This is a good point. The problem was that as early as the 3rd century AD Europe was beginning to slip into the Dark Ages. In effect astrology had completely displaced astronomy by the 4th century and very few people were really looking at the stars any more, just repeating what earlier astrological writers like Manilius--and Ptolemy himself in his "Tetrabiblos," which is work on astrology--had said. By then social, political, and economic conditions were terrible, and virtually nobody had the will or leisure to do real astronomy anyway.

During the depths of the Dark Ages 'star-gazing' was associated with astrology, which was under interdiction by the Church. Any real astronomy that was done in the centuries around 1000 AD was being done by Near Eastern astronomers writing in Arabic; but their contributions to Classical Ptolemaic astronomy was negligible. The most "scientific" of these medieval Arabian astronomers seem to have been Al-Sufi of the 10th century and Al-Buruni of the 11th century. The stars Al-Sufi (903-986) mentions as red are Aldebaran, Arcturus, Antares, Betelgeuse, Pollux, and, strange to say, Alphard and Algol. He says nothing specifically about the color of Sirius, but does relate an Arabian myth in which Sirius and Canopus appear as sisters, implying a similar color. Al-Sufi thus gives strong, but not conclusive, evidence that Sirius had changed in color by the 10th century.

Craig Crossen


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: The Red Sirius new [Re: Crossen]
      #3404653 - 10/22/09 05:20 PM

While there are Chinese accounts from the 7th Century describing Sirius as "white" there are also at least one 6th Century European account describing Sirius as reddish. Gregory of Tours in a writing directed at monks nicknamed Sirius as "Rubela" meaning reddish.

Your point that Sirius and Canopus were regarded as "sisters" in 10th Century Arabic astronomical writings is very interesting. To me Canopus is white. Perhaps a little yellowish tinged, but certainly not red. I could call Sirius white as well, perhaps with a little tinge of blue.

If the Gregory of Tours lead is correct (6th Century), that would suggest that the color change might have occurred between the 6th and 7th Centuries (i.e., Chinese observers in the 7th Century call Sirius white; a European writer in the 6th Century calls it "Rubela").

Are there any post-6th-Century accounts of a red Sirius? How about pre-6th-Century accounts of a "white" Sirius? Are any of these accounts scientifically credible? For example, can we be sure that the authors weren't simply repeating color attributions from earlier writings rather than basing their color attributions on first-hand observations?

- Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
hoof
Carpal Tunnel
*****

Reged: 04/07/05

Loc: Redmond, WA
Re: The Red Sirius new [Re: jrbarnett]
      #3405027 - 10/22/09 08:53 PM

Through all this, we assume that the star the ancients were talking about is the *same* star, and not another bright star in the same vicinity.

If there was a brighter star in the vicinity (thus referred to as the brightest star in that area of the sky), and it dimmed substantially in the last 2000 years, could we not mistaken their references to the red star as Sirius simply because that's the brightest star *we* see in that region of the sky? How can we be so certain that there wasn't another brighter star?

Just like the constellations have altered in brightness (and configuration a bit) in recent times (which is why we see different asterism than the people who named the constelations on most nights), we might also have evidence here that there was another *brighter* star in the vicinity of Sirius. So far, I haven't seen any evidence either way as to whether the star we call Sirius is indeed the same star that the ancients referred to.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Matt Lindsey
sage
*****

Reged: 06/06/08

Loc: Baltimore, MD, U.S.A.
Re: The Red Sirius new [Re: mloffland]
      #3405051 - 10/22/09 09:10 PM

Maybe the Dogon people know something about this...
But seriously, interesting article. Would love to see more similar to this.


Post Extras: Print Post   Remind Me!   Notify Moderator  
star drop
Snowed In
*****

Reged: 02/02/08

Loc: Snow Plop, WNY
Re: The Red Sirius new [Re: hoof]
      #3405067 - 10/22/09 09:21 PM

Could it be possible that there was a cloud of perhaps carbon surrounding the system that slowly dissipated? Or could there have been a line of sight background star that was in its red giant phase at the time?

Post Extras: Print Post   Remind Me!   Notify Moderator  
rookie
Good Night Nurse
*****

Reged: 01/14/06

Loc: St. Petersburg, FL
Re: The Red Sirius new [Re: hoof]
      #3405190 - 10/22/09 10:22 PM

The history of astronomy is remarkable because it ties us the knowledge of the men of old. For what is ancient to mankind is just a cosmic twinkle. We share the essentially same sky. A red Sirius is a facinating puzzle.

If it's red appearance applies the heliacal rising, then why are not other white stars such Rigel also described?

It's possiblity of being misidentified is doubtful since the entire Egyptian calendar was based on Sirius = Sothis. The expectation of the annual Nile flooding was based on the morning rising of Sothis. Babylonians named and described it as the arrow of a bow and arrow constellation. It was identity was common knowledge and was an object of worship of many civilizations.

I really enjoyed reading this fine article, and the discussion it has generated.

I'm looking forward to the rest of the book!


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: The Red Sirius new [Re: rookie]
      #3405379 - 10/23/09 12:21 AM

Because several of the bright stars are noticeably red, a certain "importance" tot the color red would be a given.
Since Sirius is so bright, the description of Sirius as "red" could be as much a cultural identification as a spectral one. After all, many kings through the middle ages are described as tall and stately when their coffins indicate they were barely 5 feet tall--short even in the middle ages.
So it would be wise to take such ancient writings with a grain of salt. They may not have been describing an empirical observation. Remember the scholarly debate about the number of teeth in the horse's mouth? Empiricism was not a phenomenon of the Roman Era or even what followed.
Ascribing literalist interpretations to ancient writings is fraught with danger.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Crossen
super member
*****

Reged: 07/14/08

Loc: Vienna
Re: The Red Sirius new [Re: Starman1]
      #3405580 - 10/23/09 04:04 AM

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, and it is clear that he was not a merely a "desk astronomer" but an active observer (working from Alexandria, Egypt, the intellectual capital of the eastern Mediterranean at that time).

Cicero, Germanicus, and Seneca, all of whom report Sirius to be red, were deeply involved in the snake-pit of Roman politics of the 1st centuries BC and AD. Cicero, one of the geniuses of Latin literature and deeply read in all aspects of Greek philosophy, held the consulship--the highest post in the Roman Republic--in 63 BC, and later used his influence to attempt a reconcilation between Pompey and Julius Caesar. Modern American law claims decent from Roman Republican law, one of the chief interpreters of which was Cicero.

Germanicus was a member of the Julio-Claudian family, from which derived the Roman Emperors from Augustus to the notorius Nero. He was nephew of Tiberius and such a capable field general that there were those who said Germanius, not Tiberius, should be Emperor. During the reign of Augustus a Roman force had been ambushed in the forests of Germany and lost three legionary standards--a great disgrace. Germanicus had the difficult and unenviable task of crossing the Rhine and avenging this defeat. He died at a young age (rumors had it that he was poisoned on orders of Tiberius) but his son Caligula followed Tiberius as Emperor.

Finally Seneca was a Stoic philosopher who also wrote for the Roman theater. He was the tutor of the future Emperor Nero, who, when he first assumed the purple, began well. But Nero was too weak to resist the hedonistic possibilities of his position. He knew the Stoics, several of whom were also prominent senators, disapproved of him on both political and moral grounds. This put Seneca in a very delicate position, and he retired from public life to devote himself to his studies and writing. He did not want to end up like Germanicus, so he took such precautions as eating fruit only from his own garden. Eventually, however, Nero "suggested" that it was time for Seneca to commit suicide.

I go into some detail on these men's lives to make the point that they were hard minded and sophisticated--well-travelled, widely-read, and experienced in life-and-death matters in a complicated political setting. Not the kind of men easily duped or quick to take anybody's word for anything. None of them 'bought into' the Paganism of their time: Cicero was a self-avowed agnostic with Stoic leanings; and Seneca, as a Stoic, was a Deist. And they took great pride in their writing and intellectual accomplishments. In those days such things were taken much more seriously than they are in present Western culture, and Cicero, Germanicus, Julius Caesar, and Seneca did not write carelessly, or just to fill in idle time, but knew that their historical value would be judged as much by their intellectual as their political accomplishments.

Craig Crossen


Post Extras: Print Post   Remind Me!   Notify Moderator  
David Knisely
Postmaster
*****

Reged: 04/19/04

Loc: southeastern Nebraska
Re: The Red Sirius new [Re: Crossen]
      #3405608 - 10/23/09 05:19 AM

Yes, this is all very nice, but the question is; are we interpreting what they wrote properly and accurately? Do we really know exactly what they meant? There appears to be some question here as to whether they really meant that Sirius was red all the time no matter where it was in the sky or just behaved in a "fiery" manner due to scintillation. From an astrophysical point of view, there is no evidence that Sirius-B was a red giant in historic times. There is also some contradictory evidence from other writers or observers that Sirius was reported as white rather than red:

http://shc2000.sjtu.edu.cn/031207/sirius.htm

So we are left in something of a quandary. At this point, I think that there just isn't quite enough evidence to point to Sirius being much different than it is now. Clear skies to you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
deSitter
Still in Old School


Reged: 12/09/04

Re: The Red Sirius new [Re: David Knisely]
      #3405658 - 10/23/09 06:43 AM

Again I would point out the simple calculation of the apparent brightness of say Betelgeuse or Antares at the distance of Sirius, roughly 100 times closer than either. The laws of light propagation show that the surface brightness does not change with distance - now something that is 100 times closer will have 100^2 or 10,000 times the area as something of the same physical size at the original distance - assuming that each part of the star shines with the same brightness (more or less, discounting fall-off at the limb) then moving a star 100 times closer means making it 10,000 times brighter - now 5 magnitudes is a factor of 100, so we're talking about a magnitude difference of 10 - Betelgeuse at the distance of Sirius would be magnitude -10 roughly, more than 100 times brighter than Venus - it would cast shadows at night and be visible in daylight without any effort. So there is not really any possibility that Sirius-B or any other nearby star was a red giant in historical time.

-drl


Post Extras: Print Post   Remind Me!   Notify Moderator  
hfjacinto
I think he's got it!
*****

Reged: 01/12/09

Loc: Land of clouds and LP
Re: The Red Sirius new [Re: deSitter]
      #3406145 - 10/23/09 12:22 PM

I have to say I like reading smart pondering on what the ancients wrote.

I for one can agree with most of what was written. But I have a question can Sirius B have been in front of Sirius A in line of sight to Earth?

Could red Sirius been an usually bright Sirius B being illuminated by Sirius A?

The magnitude would have been minimal in increase.


Post Extras: Print Post   Remind Me!   Notify Moderator  
David Knisely
Postmaster
*****

Reged: 04/19/04

Loc: southeastern Nebraska
Re: The Red Sirius new [Re: deSitter]
      #3406326 - 10/23/09 01:56 PM

Quote:

Again I would point out the simple calculation of the apparent brightness of say Betelgeuse or Antares at the distance of Sirius, roughly 100 times closer than either. The laws of light propagation show that the surface brightness does not change with distance - now something that is 100 times closer will have 100^2 or 10,000 times the area as something of the same physical size at the original distance - assuming that each part of the star shines with the same brightness (more or less, discounting fall-off at the limb) then moving a star 100 times closer means making it 10,000 times brighter - now 5 magnitudes is a factor of 100, so we're talking about a magnitude difference of 10 - Betelgeuse at the distance of Sirius would be magnitude -10 roughly, more than 100 times brighter than Venus - it would cast shadows at night and be visible in daylight without any effort. So there is not really any possibility that Sirius-B or any other nearby star was a red giant in historical time.

-drl




The current mass of the Sirius-B white dwarf is on the order of one solar mass. This points to an original mass of around five solar masses for the star prior to its white dwarf stage, so any red giant phase star would not have had nearly the intrinsic brightness of red giants like Betelgeuse (at least 18 solar masses) or Antares (15 to 18 solar masses). The absolute magnitude of a five solar mass red giant would probably be in the -3 to -4 range depending on exactly where the star was in its red giant stage. At the distance of Sirius, that would make the giant a visual magnitude of between roughly -7.6 and -8.6 even without including the contribution of Sirius A itself. It would shine far brighter than Venus does and might be roughly comparable to the brightness of a first-quarter moon. Clear skies to you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Uncle Burnout
super member


Reged: 08/06/03

Loc: California (Bay Area)
Re: The Red Sirius new [Re: mloffland]
      #3406431 - 10/23/09 02:40 PM

Taking a look at (my complete though very ancient) Lidell and Scott, "hypokirros" (assuming this is the word you transliterate as hypocirros) has only "somewhat yellow" as the definition and a scant 2 references, neither to Ptolemy. "Kirros" (of which the word in question is a compount) is defined as "tawny, orange-tawny, between purros and xsanthos". There is definitely a yellow component implied, in my opinion. Perhaps there are newer and better definitions available?

Rutilus, according to the OLD (Oxford Latin Dictionary) is often taken to mean glowing red, but also can be taken as "golden" or "orange" and definitely has associations with fire and the rising sun, but also to the hair color of ancient Germans (yellow or reddish blond, pehaps?), the color of metallic gold, etc. It may be in the secondary sense that rutilus is considered a proper translation, i.e., warm and brilliant.

As far as I'm concerned, the fact that Cicero and the others translated a word probably meaning "somewhat yellow" with a word maybe meaning "red" or "golden" or even "tawny" probably means nothing, except that they understood more about the ancient conceptions of color than we do. Try reading Isidore's classification on the different colors of horses, for a nice demonstration on just how seriously the ancients took these things at times.

Unfortunately, all of the Roman authors you cite are in fact little more than translators (or perhaps re-organizers) when it comes to scholarly works on natural science, though their importance to history is great, as you say. Which is to say that they probably translated to the best of their considerable abilities, but most likely never bothered to verify the material. In this case, the "redness" of rutilus (the translation) is far more convincing than the original term, but far from unambiguous.

Anyway, I don't agree that Sirius must necessarily have been percieved by the Greek and Latin sources cited as "red", but I did enjoy your article immensely and want to stress that this is just my understanding and an attempt to further the conversation.


Post Extras: Print Post   Remind Me!   Notify Moderator  
sp.
journeyman


Reged: 10/10/08

Loc: Budapest
Re: The Red Sirius new [Re: Uncle Burnout]
      #3406535 - 10/23/09 03:41 PM

Very interesting. Maybe the lifecycle is totally different of a star which has a close neighbourhood, the A . Maybe, thats why B can not became a real red giant or nova. Maybe, that neighbour steal/blow the mass. I think the story must be different, if a star is alone or they are together.
sp.
(but maybe im stupid)


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: The Red Sirius new [Re: David Knisely]
      #3406794 - 10/23/09 05:52 PM

I suppose that certain of the references *could* be subject to interpretations where the adjective being used to infre "redness" has alternative meanings that might imply "fiery" or "golden", but there seems to be a fairly large volume of material from widely different sources spanning a couple of thousand years where writers use a variety of different adjectives that imply redness. Even after you factor in that certain of the writers were not astronomers, and may have been basing their color attribution on earlier writings, I find it more probable that those authors with first-hand observing experience said "red" because that is what they saw.

I also find the "misidentification" argument (i.e., the writers said "Sirius" but actually meant another, truly red, bright star") to be far fetched. If you buy that, perhaps also we should concerned that ancient literary references to "cows" actually refer to "sparrows". In fact, in a world devoid of television, radio, rapid modes of transportation, etc., folks had much more time to be outside and to look up. I would wager that the average Joe on the street in ancient times was far more knowledgeable about star names, locations and the like than the average mass-media-innundated modern person.

Regards,

Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
Uncle Burnout
super member


Reged: 08/06/03

Loc: California (Bay Area)
Re: The Red Sirius new [Re: jrbarnett]
      #3407112 - 10/23/09 09:26 PM

Here's a passage from Manilius' Astronomicon bk. I (1st century AD), clearly describing the star as "blue". Surely there are others.

subsequitur rapido contenta Canicula cursu,
qua nullum terris violentius advenit astrum
nec gravius cedit; nunc horrida frigore surgit,
nunc vacuum soli fulgentem deserit orbem:
sic in utrumque movet mundum et contraria reddit.
hanc qui surgentem, primo cum redditur ortu,
montis ab excelso speculantur vertice Tauri,
eventus frugum varios et tempora dicunt,
quaeque valetudo veniat, concordia quanta;
bella facit pacemque refert varieque revertens
sic movet, ut vidit mundum, vultuque gubernat.
magna fides hoc posse color cursusque micantis
in radios: vix sole minor, nisi quod procul haerens
frigida caeruleo contorquet lumina vultu.
cetera vincuntur specie, nec clarius astrum
tinguitur oceano caelumve revisit ab undis.


Post Extras: Print Post   Remind Me!   Notify Moderator  
David Knisely
Postmaster
*****

Reged: 04/19/04

Loc: southeastern Nebraska
Re: The Red Sirius new [Re: sp.]
      #3407531 - 10/24/09 01:25 AM

Quote:

Very interesting. Maybe the lifecycle is totally different of a star which has a close neighbourhood, the A . Maybe, thats why B can not became a real red giant or nova. Maybe, that neighbour steal/blow the mass. I think the story must be different, if a star is alone or they are together.
sp.
(but maybe im stupid)




No, the two stars never approach each other closely enough to exchange a significant amount of mass, so a nova is not possible with the Sirius system (periastron of about 8.1 A.U.). The B component very probably *was* once a red giant in the distant past, but that was probably several million years ago at the latest (and probably a lot earlier than that). It is now a one solar mass white dwarf. Clear skies to you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Dave Mitsky
Postmaster
*****

Reged: 04/08/02

Loc: PA, USA, Planet Earth
Re: The Red Sirius new [Re: David Knisely]
      #3407627 - 10/24/09 03:50 AM

As far as the possibility of Sirius being red in the not-too-distant past, I'll put my money on astrophysics.

Dave Mitsky


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: The Red Sirius new [Re: Uncle Burnout]
      #3408037 - 10/24/09 11:33 AM

Marcus Manilius is an interesting figure, not so much for his surviving astrological poem, but for the fact that no one seems to know anything at all about him. There's no certainty even as to his name. In the early books of Astronomica he remains nameless, adopting the name "Manilius" on in later books. No other ancient author quotes from or even mentions Manilius. He uses distinctive (and odd) grammatical construction.

None of this discounts what you've quoted, of course. He clearly does use adjectives and other descriptors that mean "blue" (if I read the passage correctly - not a given since I haven't translated any Latin in 25 years ). Unfortunately Manilius is obscure enough that I could not find any free, online English translations of the work. The references I see are "caeruleo" and "clarius astrum
tinguitur oceano". Cerulean blue and tinted like the sea.

I would be interested to know whether Manilius describes any other bright stars of known color elsewhere in the work, and if so whether he correctly attributes color to those stars?

I'm interested enough to order a copy of the Loeb translation in fact (I figure that the Creech translation would be in Elizabethan English anyway, and almost as hard (for me) to read as the Latin text.)

One other interesting point - Manilius calls the Dog Star blue. Meticulous Chinese astronomers, on the other hand, called it white. Granted that both blue and white are closer to what we see today, but it is interesting that the Chinese sources do not attribute any blueness.

Lastly, I agree that it would be great to find other early sources that refer to Sirius as something other than ruddy. Given that is one of the "Behenian fixed stars" used in astrology, I would expect there to be other ancient and medieval references to Sirius and its color.

Nice find, by the way.

- Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
Uncle Burnout
super member


Reged: 08/06/03

Loc: California (Bay Area)
Re: The Red Sirius new [Re: jrbarnett]
      #3408366 - 10/24/09 03:02 PM

I think your Latin is good and doubt you even need the Loeb for Manilius (if that's his real name)! I will see what I can dig up with other stars, as you raise a good point. Being somewhat indifferent to color myself, blue seems reasonable, but I wonder if the description "lumina frigida" doesn't imply a cool, "whitish" cast.

I also ran across references to a 4th century (?) passage by Avenius, who is even less known to me, but haven't had a chance to look it up.

I'm still frankly stumped by the Seneca passage: "Rubor" is about as red as it gets, but there seems to be a possibility that the passage is implying a color imparted by atmospheric conditions more than an inherent color of the star. I'm also uncertain about Gregory's "rubeola", since it would be typical of someone at that time period to simply pass along what he thought understood from an earlier text, but that is not a satisfying explanation to me, either.

Otherwise, I'm almost certain the term Ptolemy used is (incorrectly) translated by "fiery red" simply because most of the other stars he names fit that description. Terms that translate as simply "fiery" or "burning" don't convince me of a perceived red tint either, as fire would have been a common referent for brightness and light sources in those days, along with the sun and a very few other things. There is also the then common perception that Sirius caused excessive heat and dryness (the "dog days"), making fire metaphors almost unavoidable.


Post Extras: Print Post   Remind Me!   Notify Moderator  
deSitter
Still in Old School


Reged: 12/09/04

Re: The Red Sirius new [Re: David Knisely]
      #3408404 - 10/24/09 03:21 PM

Excellent point!

-drl

Quote:

Quote:

Again I would point out the simple calculation of the apparent brightness of say Betelgeuse or Antares at the distance of Sirius, roughly 100 times closer than either. The laws of light propagation show that the surface brightness does not change with distance - now something that is 100 times closer will have 100^2 or 10,000 times the area as something of the same physical size at the original distance - assuming that each part of the star shines with the same brightness (more or less, discounting fall-off at the limb) then moving a star 100 times closer means making it 10,000 times brighter - now 5 magnitudes is a factor of 100, so we're talking about a magnitude difference of 10 - Betelgeuse at the distance of Sirius would be magnitude -10 roughly, more than 100 times brighter than Venus - it would cast shadows at night and be visible in daylight without any effort. So there is not really any possibility that Sirius-B or any other nearby star was a red giant in historical time.

-drl




The current mass of the Sirius-B white dwarf is on the order of one solar mass. This points to an original mass of around five solar masses for the star prior to its white dwarf stage, so any red giant phase star would not have had nearly the intrinsic brightness of red giants like Betelgeuse (at least 18 solar masses) or Antares (15 to 18 solar masses). The absolute magnitude of a five solar mass red giant would probably be in the -3 to -4 range depending on exactly where the star was in its red giant stage. At the distance of Sirius, that would make the giant a visual magnitude of between roughly -7.6 and -8.6 even without including the contribution of Sirius A itself. It would shine far brighter than Venus does and might be roughly comparable to the brightness of a first-quarter moon. Clear skies to you.




Post Extras: Print Post   Remind Me!   Notify Moderator  
Hipparchus
member


Reged: 07/26/09

Loc: San Francisco, CA
Re: The Red Sirius new [Re: deSitter]
      #3408547 - 10/24/09 04:54 PM

Interesting discussion.

During this time period, are there any references outside the Mediterranean to Sirius being red? Seems significant.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Crossen
super member
*****

Reged: 07/14/08

Loc: Vienna
Re: The Red Sirius new [Re: Hipparchus]
      #3409385 - 10/25/09 05:01 AM

Marcus Manilius and his "Astronomicon" have been mentioned in several recent posts. I decided not to use him for a couple reasons, one being exactly what Jim mentioned: Manilius is a rather shadowy figure about whom little is known, so it is hard to judge whether or not he was an active observer.

The relevant passage in Manilius about the redness of Sirius is in Book V, lines 207-8:

Exoriturque Canis, latratque Canicula flammens,/ Et rabit igne suo, geminatque incendia Solis.

This speaks of the rising Dog as "flaming vehemently, raging in its fire, and duplicating the fires of the Sun." Since this is explicitly about the rising Sirius, it cannot be taken as necessarily the star's color when it is well above the horizon.

A letter discussing the original Latin of Manilius' statements regarding the color of Sirius was published in "The Observatory" magazine in 1989 (vol. 109, p.58f.) It can be most easily found by simply Googling "Manilius Sirius."

One later Roman astrological writer, Maternus Julius Firmicus of the early 4th century BC, seems to have been familiar with Manilius' "Astronomicon," though he mentions neither explicitly. In "Matheseseos" VIII 12, 3f, Firmicus states that the constellation of Haedus ("Goat Kid"), rises simultaneously with Libra. This repeats "Astronomicon" V 311f, which is the only other place in Classical astrological or astronomical literature where the constellation "Haedus" is mentioned. (It's not merely a confusion for the Haedi, "Goat Kids," of Auriga, which did not then, and do not today, rise anywhere nearly simultaneously with Libra.)

In response to Hipparchus' question: The only possible ancient references to the color of Sirius outside of the Graeco-Roman world of which I am aware are those from Mesopotamia I mention in the article, which can be doubted on the basis of the fact that they are metaphors more than direct statements. However, the ancient Mesopotamians were careful and consistent about their religious metaphors. Red was the color of the war-god and the stage of Nebuchadnezzar's ziggurat dedicated to the planet of the war-god was faced with red-glazed baked bricks. It's easy to underestimate the ancient Mesopotamians given how fragmentary our information about them really is. The fact we find the Pythagorean Theorem used on an Old Babylonian tablet of about 1700 BC hints at their intellectual discipline.

Craig Crossen


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tony Flanders
Postmaster
*****

Reged: 05/18/06

Loc: Cambridge, MA, USA
Re: The Red Sirius new [Re: Crossen]
      #3409468 - 10/25/09 07:57 AM

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.

I still think that cultural conformity is overwhelmingly the most likely explanation of Sirius's redness. Ptolemy, being tapped into the astronomical tradition root and branch, is the *most* likely person to have taken such traditions for granted.

Expectations have an overwhelming influence on observations. History is rife with examples of blatantly incorrect observations that were passed down unquestioned for centuries. Nobody can escape the assumptions of the surrounding society. We are *all* gullible -- it's part of human nature.

So I'd say that odds are easily 10 to 1 that modern astrophysics is right and those ancient descriptions were wrong. But yes, that lingering 1-out-of-10 doubt is bound to remain.

Edited by Tony Flanders (10/25/09 08:01 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
deSitter
Still in Old School


Reged: 12/09/04

Re: The Red Sirius new [Re: Tony Flanders]
      #3409476 - 10/25/09 08:08 AM

I have another theory. These folks had one source of man-made illumination - fire. They had no white light other than sunlight to compare anything to. Using the word "fiery" could have been literal - they no doubt assumed that the light was coming from some sort of cosmic fire, which could very well sway their description and even their perception of it. (Who was it who called the Sun "a fiery rock as big as the Peloponnessus"?)

-drl


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: The Red Sirius new [Re: deSitter]
      #3409718 - 10/25/09 11:15 AM

And, of course, we know that the descriptions of antiquity were wrong, because there is no physical way they could have been right.

Because any insinuation that their descriptions were physically true suffer from an inability to explain any rational physical process whereby they would be true.

Having studied ancient cultures extensively (I have a degree in Anthropology), I would simply state that the explanation for the descriptions about which the discussion pivots is not in physical reality. We are merely looking for cultural and intellectual reasons why they might have used the words they used to describe a star which was a Class A star even then.


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: The Red Sirius new [Re: Crossen]
      #3409848 - 10/25/09 12:20 PM

The interesting part (to me at least) isn't that the ancient accounts were wrong,but rather trying to figure out whether there is a common source or cause for them being wrong. I'm wondering if Sirius wasn't red "by tradition". I'll explain.

I'm wondering in particular about Egyptian texts. After all, Sirius played a central role in Egyptian religious life (and agriculture). The "Sothic Cycle" was measured by priestly abservations of the heliacal rising of Sirius (that is the rising of Sirius immediately prior to the sunrise). In fact, I recall reading somewhere that different predictions for the coming year were based on the star's apparent color at the helical rising. Red foretold war in the coming year.

Is it possible that the tradition of a red Sirius is really a concept imported into Western Hellenic culture via imported traditions from ancient Egypt? That is, knowing that associations of red with the star were "important" to more ancient cultures, but losing the context (heliacal rising) in the mists of time.

Many of our modern "sayings" come about this way. The original context long forgotten, but the saying itself remains, taking on a more literal application.

Regards,

Jim

Edited by jrbarnett (10/25/09 12:24 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: The Red Sirius new [Re: jrbarnett]
      #3410058 - 10/25/09 02:07 PM

To back up Jim, Sirius is referred to as "The Dog Star" and the hottest days of summer, the "Dog Days" of summer, occur in early July, when Sirius is rising in the east at dawn. This also corresponded to the time of the annual flooding of the Nile, so people living in low areas would pack up and head for higher ground.
The Greeks and Romans traded extensively with the Egyptians, and many things were borrowed. After all, Ptolemy was an Egyptian.


Post Extras: Print Post   Remind Me!   Notify Moderator  
rmollise
Postmaster
*****

Reged: 07/06/07

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."


Post Extras: Print Post   Remind Me!   Notify Moderator  
Uncle Burnout
super member


Reged: 08/06/03

Loc: California (Bay Area)
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)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tony Flanders
Postmaster
*****

Reged: 05/18/06

Loc: Cambridge, MA, USA
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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Larry Geary
Carpal Tunnel
*****

Reged: 09/24/06

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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Crossen
super member
*****

Reged: 07/14/08

Loc: Vienna
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


Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Uncle Burnout
super member


Reged: 08/06/03

Loc: California (Bay Area)
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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tony Flanders
Postmaster
*****

Reged: 05/18/06

Loc: Cambridge, MA, USA
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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
deSitter
Still in Old School


Reged: 12/09/04

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.




Post Extras: Print Post   Remind Me!   Notify Moderator  
Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
David Knisely
Postmaster
*****

Reged: 04/19/04

Loc: southeastern Nebraska
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.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Uncle Burnout
super member


Reged: 08/06/03

Loc: California (Bay Area)
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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
arpruss
Vendor: Omega Centauri Software
*****

Reged: 05/23/08

Loc: Waco, TX
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)


Post Extras: Print Post   Remind Me!   Notify Moderator  
deSitter
Still in Old School


Reged: 12/09/04

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


Post Extras: Print Post   Remind Me!   Notify Moderator  
Tony Flanders
Postmaster
*****

Reged: 05/18/06

Loc: Cambridge, MA, USA
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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Uncle Burnout
super member


Reged: 08/06/03

Loc: California (Bay Area)
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.

Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
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)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Uncle Burnout
super member


Reged: 08/06/03

Loc: California (Bay Area)
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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Crossen
super member
*****

Reged: 07/14/08

Loc: Vienna
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


Post Extras: Print Post   Remind Me!   Notify Moderator  
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.


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: The Red Sirius new [Re: Michael A. Earl]
      #3415941 - 10/28/09 11:56 AM

I think we're examining the problem of "red Sirius" accounts from ancient Western sources too much through our modern lens. Careful examination of the thread, both in favor of Sirius being red and against, reveals a common set of assumptions regarding the motivations and context of the ancients when making observations.

In the the Hellenic world, there was no distinct beast called "science". Fields we today classify as "metaphysics", "astrology/mysticism", "astronomy and physics," "mathematics", etc., were not distinct in ancient times. Ergo, the purpose of an ancient observer in conducting observations is unlikely to have been the same as our purpose for conduction similar observations today.

Now for some speculation. While observing bright stars like Sirius at the moment of their rising and setting at different times of the year is not the most common context of observation today, in the Ancient near east and Mediterranean it was likely the predominant context for such observations. Descriptions of "flaming" or "fiery" Sirius seem particularly apt for a Sirius just risen, viewed through miles of turbulent atmosphere. Perhaps earlier observations describing low elevation observations of Sirius as "like fire" were perpetuated by later writers.

In any case, I think that it is crucially important to recognize that what the ancients thought they saw when they looked at the night sky is not what you and I think we see. To understand the "what" of what they saw, I think you have to mindful of the "why" as in why were they observing in the first place. In my view, the later learned records by non-observers like Cicero were likely based on the records of earlier observers like Ptolemy. Ptolemy, on the other hand, was as much a meta-physicist and mystic as astro-physicist. I wouldn't be surprised to learn that his observations of Sirius were conducted near the horizion, often at or near sunrise or sunset, and that his purpose was not simply self-indulgent "scientific curiosity" in making the observations.

Regards,

Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
Uncle Burnout
super member


Reged: 08/06/03

Loc: California (Bay Area)
Re: The Red Sirius new [Re: jrbarnett]
      #3416400 - 10/28/09 03:56 PM

You are spot on in your thinking -- the question is not really "was Sirius red in antiquity", but rather "did Sirius sometimes appear or was described as red (or other color) in antiquity, and what did that mean".

We have a quote from Hephaestion of Thebes (Ceragioli, note 72 has the Greek text) describing how if the star's color upon rising was inspected as an omen. Curiously, he menitions that the star is "white" ("leukos"). This agrees with Hyginus' description of Sirius as being remarkable for its "candor", which is usually from the context interpretted as "brightness", but almost certainly implies a white tint. Add to these, Manilius and Avienus, who explicitly describe the star Sirius as "blue" or perhaps "blue-white".

Given this type of interpretation, we can perhaps understand the truly unambiguous references to Sirius' color as red (not its fierieness or the color of Canis the constellation), which actually only seem to occur a few times: In Seneca, where we're told the celestial bodies have not inherent color, but acquire it through atmospheric effects (passage cited by Crossen, although not in full context), and in Horace where he refers to Sirius as "rubra"(not cited in Crossen) in the context of extreme heat.

Since we can see that there was an awareness and assumed meaning in the color seen in Sirius, perhaps Ptolemy's characterization of the star as "hypokirros" is a guess at the star's "actual" color, since we don't know if he shared an assumption with Seneca that celestial bodies have no inherent color. There is very little context to make a guess, although several astronomers (most notably See, whom Crossen seems to follow) took up the task and piled up dubious citations leading ultimately to the conclusion that the ancients saw Sirius as a "fiery red" star all the time.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Thomas44
super member


Reged: 10/26/09

Re: The Red Sirius new [Re: Crossen]
      #3417327 - 10/28/09 11:31 PM

The article was a bit long but anyhow it's worth the read. Pretty interesting actually.

Post Extras: Print Post   Remind Me!   Notify Moderator  
7331Peg
Sirius Observer
*****

Reged: 09/01/08

Loc: North coast of Oregon
Re: The Red Sirius new [Re: Uncle Burnout]
      #3417484 - 10/29/09 01:06 AM

I've really enjoyed the discussions on this topic, and I hesitate to jump in here because I think most everything that can be said has been said.
One thing that does intrigue me, though, is the possibility of seeing Sirius just as it appears over the horizon. I'm not referring to it simply being ten or twenty degrees above the horizon, but just a few degrees above it. In this day and age that would be unlikely in most of the world, but in the period of time that is being discussed here, it would seem like it might be possible due to the lack of pollutants in the air.
If you were out in the middle of an empty plain - or on the Mediterranean with a clear view of the eastern horizon - back in that era, and if you could actually catch Sirius a couple of degrees above the horizon - especially on a warm August morning - chances are pretty darn good it would be red.

John


Post Extras: Print Post   Remind Me!   Notify Moderator  
Crossen
super member
*****

Reged: 07/14/08

Loc: Vienna
Re: The Red Sirius new [Re: 7331Peg]
      #3417700 - 10/29/09 07:20 AM

John,

I lived and worked on our family farm until I was 39 years old (with a 5-year exile in Minneapolis to attend the U of MN), and during the last ten years of that period was an active observer--as well as frequently outside during evenings doing normal farm work. Our farm was two miles from the nearest village out under extremely dark skies. During that decade I had the opportunity to observe Sirius rising or setting dozens of times under a wide variety of atmosphere conditions. When the atmosphere was thick with dust or humidity the star was too dimmed to have much color: when it got a few degrees above the horizon one might have described it as a sort of "dull ruddy", which quickly faded into a pale yellow and then off-white. But under average conditions the star appeared as a scintillating gem best described by Aratos' "many-colored" (poikilos). Red, yellow, and blue-white predominated, alternating almost too quickly to be sure you really saw them. It was like looking at the star through a fractured piece of glass and impossible under those circumstances to judge the star's "rest color". It's always been clear to me that Aratos was describing the rising or setting Sirius, not the Sirius ten or twenty degrees above the horizon.

Craig Crossen


Post Extras: Print Post   Remind Me!   Notify Moderator  
Uncle Burnout
super member


Reged: 08/06/03

Loc: California (Bay Area)
Re: The Red Sirius new [Re: Crossen]
      #3418451 - 10/29/09 03:02 PM

Craig,
That observation of yours convinces me that you must be sincere in your aims, although (sorry) a little weak in Greek and Latin. Please consider re-examining this topic before publishing your book -- there is much still in the topic that should interest observers without posing the stumblingblock of an actual change in Sirius' color. At least read Ceragioli and consult Greek and Latin scholars for review.


Post Extras: Print Post   Remind Me!   Notify Moderator  
tatarjj
Carpal Tunnel
*****

Reged: 04/20/04

Loc: Austin, TX
Re: The Red Sirius new [Re: Uncle Burnout]
      #3422610 - 10/31/09 08:42 PM

Maybe some ancients reported Sirius as being red because the Sirians were launching a red laser-powered light sail our way that crashed in Roswell in 1947! No, I don't believe that, but it would make a good conspiracy theory


Edited by tatarjj (10/31/09 08:44 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
arpruss
Vendor: Omega Centauri Software
*****

Reged: 05/23/08

Loc: Waco, TX
Re: The Red Sirius new [Re: Michael A. Earl]
      #3673233 - 03/10/10 08:34 PM

For what it's worth, I just did a little experiment. I pointed out Sirius, in a pretty bright sky (bright enough that it was hard to see anything else in Canis Major), about 30 degrees up, to my almost five-year-old color-blind son, and asked him the color. He confidently replied: "Whitish red." He has a mild to moderate red-green color-blindness, but knows color words very well.

It looked whitish blue to me.


Post Extras: Print Post   Remind Me!   Notify Moderator  
astrologia
journeyman


Reged: 04/01/12

Re: The Red Sirius new [Re: arpruss]
      #5153151 - 04/02/12 12:22 PM

I've posted my experience here:

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5153147/page/0/view/collapsed/sb/5/o/all/fpart/1


Post Extras: Print Post   Remind Me!   Notify Moderator  
RogerC
member


Reged: 04/06/09

Re: The Red Sirius new [Re: Uncle Burnout]
      #5157663 - 04/05/12 01:21 PM

Hi, Friends.

If you enjoyed my Journal for the History of Astronomy articles from 1995, you might even more enjoy my Ph.D. dissertation in Ancient Greek and Latin for Harvard University: "Feruidus Ille Canis: The Lore and Poetry of the Dog Star in Antiquity" (1992). It's fun to endlessly speculate on this topic, and feel free to continue! For myself, after rather exhausively surveying the ancient Greek and Latin evidence, texts and coinage (!), my conclusion in the dissertation (reflecting a fuller investigation than that of the articles) was that the complex of texts suggesting a reddish coloration in Sirius while reflecting the meteorological fact that at heliacal rising Sirius can appear reddish, mainly reflects a basis in folklore and mythology. That is, cultural anthropology. There's no reason to think that Sirius (A or B) has literally undergone a drastic astrophysical change in a mere 2000 years, as far as I can tell.

Different cultures (us too) always find it nearly impossible to understand one another except through the agency of stories comprehensible in their own (limited) intellectual framework.

Cheers and all the best,
Roger C. Ceragioli


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: The Red Sirius new [Re: RogerC]
      #5157908 - 04/05/12 04:13 PM

Thanks Roger.

I think you're probably correct. Sirius is bright and with a healthy dose of atmospheric refraction thrown in near the horizon, flashes fiery red and can manifest a ruddy limb.

Another thing folks sometimes point at to suggest color perceptions were different in antiquity are Homeric references to "wine-dark sea". I think the problem isn't with changes in optical physiology or perception, but rather the fact that we moderns tend to think of wine in our own material context.

What do we drink wine from? Clear stemware. The color of the liquid is unmistakable in such a vessel. During the Mycenaean period, drinking vessels were opaque stoneware or pottery. Red wine would have been inky-dark in a stoneware mug, just as the Mediterranean is inky dark when seen from the rail of a ship.

Wine-dark is literally correct in that material culture context, and I don't think implied "redness".

- Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
Crossen
super member
*****

Reged: 07/14/08

Loc: Vienna
Re: The Red Sirius new [Re: jrbarnett]
      #5182729 - 04/21/12 05:52 AM

I was rather surprised to see this thread pop up to page 1 of this forum after a hiatus of over two years. As far as I know, no new astrophysical or historical information has come to light that can´resolve the problem of "The Red Sirius." It is inconceivable to me that our astrophysics could be so wrong that Sirius (A or B) could actually have been a red star a mere 2000 years ago. On the other hand, I for one am reluctant to believe that so many ancient authorities--and authorities whose information on so many other points has proven to be accurate--could be so wrong. The modern knee-jerk reaction is to disbelieve the ancient authorities. Up to the beginning of the 20th century there was an excessive tendency to accept the ancient authorities; but during the 20th century the pendulum swung the opposite way--and clearly too far the opposite way: in my work as an academic editor I have come across far too many statements in scholarly articles and monographs about the Classical world and its authorities which are not merely incorrect, but just plain stupid. (The Anthropologists are the worst offenders in this respect.) The study of the Classics should be renewed in universities. Even when I was an undergrad the University of Minnesota's Classic Department had a bad conscience about itself: it felt itself out-of-date.

I can add one thing to the article that did occur to me during the past two years. The argument that the ancient authorities were referring to Sirius only as it rises and sets cannot solve the mystery because the ancients clearly would have observed the star when it was higher in the sky, and if it was bluish-white when higher, that fact certainly would have been remarked upon by an authority like Ptolemy. All the stars described by Ptolemy as red are not only reddish while rising, but also reddish while culminating (except for Pollux, which is yellow). Given the fact that in the best ancient philosophies the heavens were considered the realm of the Immutable and the Changeless (meteors and comets were regarded as sub-lunar phenomena), the fact that the brightest fixed star changes from red to white would certainly have created some concern and come in for some comment!

Craig Crossen


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | (show all)


Extra information
0 registered and 9 anonymous users are browsing this forum.

Moderator:  iceblaze 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 11303

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics