Starship Asterisk*

by **Sputnick** » Tue Jun 24, 2008 8:16 pm

<< Quote: Another trick perpetrated in the French capital was due to the physicist Jean Perrin (who won a year later the 1926 Nobel Prize for his work on the thermal motion of molecules). Perrin mischievously packed a powerful aviation gyroscope into a suitcase, set the gyro spinning and left the suitcase at a Paris railway station. An unsuspecting porter picked up the apparently forgotten luggage, marched off with it and then made the mistake of trying to turn a corner. The case – or, rather, its contents – refused to follow. When the porter attempted to force the unwilling bag to point in the new direction he wanted to travel, it simply rotated on its handle at a bizarre angle and twisted the bewildered man's wrist. Dropping his strange load in alarm, the porter ran off yelling "Le diable soi-même doit être la dedans!" (The Devil himself must be inside!) :etouQ>>[/quote]

So that's why my head can't change direction easily .. I'm spinny!

by **henk21cm** » Tue Jun 24, 2008 8:05 pm

Qev wrote: Yes, that's correct. Angular momentum has to be conserved, and it's a vector quantity... direction counts.

There is a anecdote about a gyroscope and Jean Perrin. I read the story as a younster in a book by George Gamov. The nice illustration in Gamovs book lacks in the following quote.

<< Quote: Another trick perpetrated in the French capital was due to the physicist Jean Perrin (who won a year later the 1926 Nobel Prize for his work on the thermal motion of molecules). Perrin mischievously packed a powerful aviation gyroscope into a suitcase, set the gyro spinning and left the suitcase at a Paris railway station. An unsuspecting porter picked up the apparently forgotten luggage, marched off with it and then made the mistake of trying to turn a corner. The case – or, rather, its contents – refused to follow. When the porter attempted to force the unwilling bag to point in the new direction he wanted to travel, it simply rotated on its handle at a bizarre angle and twisted the bewildered man's wrist. Dropping his strange load in alarm, the porter ran off yelling "Le diable soi-même doit être la dedans!" (The Devil himself must be inside!) :etouQ>>

by **Sputnick** » Tue Jun 24, 2008 2:44 pm

astrolabe wrote:Hello All,

In the interest of this topic and maybe to others similar to it, there is going to be a workshop/seminar in Padova, Italy on Aug. 25-28 this year to discuss what are called "non-axisymmetrical phenomenon in galaxies".

The workshop intends to bring together ideas and the measurements of the different methods used in the past 20 years to determine rates of pattern speed and rotation of different shaped galaxies as well as dark halos.

The workshop is titled: "Tumbling, Twisting, and Winding Galaxies: Pattern Speeds Along the Hubble Sequence". I'll be interested to see what the theorists come up with.

Ahh .. I should let them know that if they were willing to pay expenses I would appear as a speaker. I've always wanted to visit Italy, and I could take my moped and camping gear, sleep out under the stars and watch the galaxies tumble .. maybe tumble with Sophia Loren .. Ahhhhh. (I hope she's still alive.)

by **Qev** » Tue Jun 24, 2008 5:10 am

Sputnick wrote:
Qev wrote:
Sputnick wrote:If I were in space, and hurled a spinnng gyroscope in such a way that I caused it to tumble as it flew, I make a guess that it's anybody's guess as to when it becomes "free falling".
I don't think it quite works like that. You can't "set a gyroscope tumbling" without applying a constant torque, unless I've completely forgotten how angular momentum works...
Do you mean to tell me that if I threw a Gyroscope it space, using my
fingers to spin the whole assembly against the spin of the wheel, that the gyroscope would not tumble?

Yes, that's correct. Angular momentum has to be conserved, and it's a vector quantity... direction counts. You can apply a force (torque, actually) to alter the orientation of a gyroscope's rotational axis, but the instant you stop applying that torque, it's going to remain in whatever its last orientation was (in addition to other effects).

by **BMAONE23** » Tue Jun 24, 2008 4:16 am

Looking at the full image for location http://antwrp.gsfc.nasa.gov/apod/ap080619.html, then the enlarged image for clarity, it appears that there is a small Hand shaped asterism at about the 11:00 position consisting of 5 small stars (the fingertips) and an ovid shape in the palm. Perhaps the ovid shape is the remnant galactic core of the canibalized galaxy. It does fall within the center of one of the star trails.

by **astrolabe** » Tue Jun 24, 2008 1:09 am

Hello All,

In the interest of this topic and maybe to others similar to it, there is going to be a workshop/seminar in Padova, Italy on Aug. 25-28 this year to discuss what are called "non-axisymmetrical phenomenon in galaxies".

The workshop intends to bring together ideas and the measurements of the different methods used in the past 20 years to determine rates of pattern speed and rotation of different shaped galaxies as well as dark halos.

The workshop is titled: "Tumbling, Twisting, and Winding Galaxies: Pattern Speeds Along the Hubble Sequence". I'll be interested to see what the theorists come up with.

by **Sputnick** » Mon Jun 23, 2008 11:02 pm

iampete wrote:
Sputnick wrote:Since we're talking nonsense ..
My 2 cents on "nonsense".

Pejorative labels are unhelpful in any discussion.

I believe that the consensus is that there exists a mechanism to account for the streams and that mechanism is a companion galaxy. Manifestations of similar streams around other galaxies and companions are supportive evidence. Possible angular momentum changes caused by the ingestion of a companion galaxy may be further evidence, although no one else has signed up for that one yet. Possible explanations as to why a companion galaxy is not visible in this view appear to have reasonable basis, although they are certainly not inarguable. To call this "nonsense" is unwarranted.

Your belief of stream creation by the galaxy itself without a companion galaxy has not been refuted as being impossible by any mechanism we know about. However, to this point, there does not seem to be any evidence of which I am aware that supports this. Nevertheless, until someone is able to rule it out, calling your belief "nonsense" is also unwarranted.

In matters of opinion and conjecture, especially on a forum like this, words like "nonsense" should be reserved for statements (EDIT: that) have been or can be unequivocally debunked as false, e.g., a flat earth, a geocentric solar system, and similar thoughts. Use of descriptors such as possible, likely (highly, more, less, un-), supported/unsupported by evidence, etc., etc. will result in this forum being more about discussions than confrontations.

My apologies for sounding preachy.

Exactly, nonsense is nonsense, and I apologized, and I think it's nonsense that the offense was further furthered (just speaking nonsense here .. whimsical humour, nonsensical.)

However, I take exception to ignoring of the statements which make the total vanishing act of the supposed companion galaxies, shall we say, extremely perplexing, unexplainable, highly suspect. I cannot provide any quotes, but they are there. There is and seems to always have been among scientists an acceptance and promotion of the easy explanation which leads to lack of serious pursuit of less attractive options .. partly because we as humans enjoy the companionship of our peers, and we don't want to be ejected for rocking the boat. This is a sad situation, and were it not reinforced, our flat earth might not have become surrounded by an orbiting garbage dump resulting from our attempts to reach and understand space. Ye are not the only preacher here, Iampete.

by **iampete** » Mon Jun 23, 2008 10:40 pm

Sputnick wrote:Since we're talking nonsense ..

My 2 cents on "nonsense".

Pejorative labels are unhelpful in any discussion.

I believe that the consensus is that there exists a mechanism to account for the streams and that mechanism is a companion galaxy. Manifestations of similar streams around other galaxies and companions are supportive evidence. Possible angular momentum changes caused by the ingestion of a companion galaxy may be further evidence, although no one else has signed up for that one yet. Possible explanations as to why a companion galaxy is not visible in this view appear to have reasonable basis, although they are certainly not inarguable. To call this "nonsense" is unwarranted.

Your belief of stream creation by the galaxy itself without a companion galaxy has not been refuted as being impossible by any mechanism we know about. However, to this point, there does not seem to be any evidence of which I am aware that supports this. Nevertheless, until someone is able to rule it out, calling your belief "nonsense" is also unwarranted.

In matters of opinion and conjecture, especially on a forum like this, words like "nonsense" should be reserved for statements (EDIT: that) have been or can be unequivocally debunked as false, e.g., a flat earth, a geocentric solar system, and similar thoughts. Use of descriptors such as possible, likely (highly, more, less, un-), supported/unsupported by evidence, etc., etc. will result in this forum being more about discussions than confrontations.

My apologies for sounding preachy.

by **Sputnick** » Mon Jun 23, 2008 9:39 pm

bystander wrote:APOD: 2008 June 19 - The Star Streams of NGC 5907

bystander wrote:The evidence of the missing galaxies is the tidal streams of stars which were the point of the apod.

More Tidal Streams

APOD: 2008 February 7 - NGC 4013 and the Tidal Stream
APOD: 2007 November 4 - The Closest Galaxy: Canis Major Dwarf
APOD: 2005 May 29 - The Sagittarius Dwarf Tidal Stream

Sputnick wrote:Sorry to have to use the word 'nonsense' Bystander .. but most contributors have said the companion galaxies are speculation, their disappearance being a huge question mark.
I think "most contributors" would take exception to that statement. The currently accepted explanation for tidal streams is that they are the remnant of galaxies that are being (or have been) ripped apart and absorbed by a larger, more massive, galaxy. See the above links. The only "nonsense" is calling the considered opinion of mainstream astrophysicists "nonsense".

Here's another: APOD: 2002 October 17 - Centaurus A: Young Blue Star Stream

Since we're talking nonsense .. (and I apologize for my rudeness, but I've been under the stresses of the universes tugging at my heart in every direction and anti-direction) no more talking nonsense .. we are not talking about tidal streams other than the tidal streams we are talking about .. the streams in this particular photograph which shows to rare phenomenon pictured together .. the streams which contributors here have said may be (and I stress 'may be') from companion galaxies, but that supporting evidence for the missing galaxies does not seem to exist. And while someone may say they may be hiding behind or in the pictured galaxy, I say they are/were pure fiction, never having existed, and that the pictured galaxy created the trails, and that the trails are the missing bulk of the pictured galaxy. Period. End of response except to say thank you for not being as rude to me as I was to you.

by **henk21cm** » Mon Jun 23, 2008 9:07 pm

Alietr wrote:Does anyone know what the blurred object in the upper right-hand corner is? It could be "just" another galaxy, but it doesn't look like it would be one.

On first sight, yes, galaxy, since it is not shaped as a point. On second thought, the shape is rather weird. It resembles a shoe, seen from the long side. The right back end of the trail is thicker than the left upper end, which curls upwards.

When compared with other non circular shapes, e.g. near the tidal stream itself, at the right side, close to the extremely bright star right below, these objects are more regularly shaped.

Since the image is taken in Draco, it is unlikely to be an astroid, which moved during the exposure with respect to the stars.

by **bystander** » Mon Jun 23, 2008 8:35 pm

APOD: 2008 June 19 - The Star Streams of NGC 5907

bystander wrote:The evidence of the missing galaxies is the tidal streams of stars which were the point of the apod.

More Tidal Streams

APOD: 2008 February 7 - NGC 4013 and the Tidal Stream
APOD: 2007 November 4 - The Closest Galaxy: Canis Major Dwarf
APOD: 2005 May 29 - The Sagittarius Dwarf Tidal Stream

Sputnick wrote:Sorry to have to use the word 'nonsense' Bystander .. but most contributors have said the companion galaxies are speculation, their disappearance being a huge question mark.

I think "most contributors" would take exception to that statement. The currently accepted explanation for tidal streams is that they are the remnant of galaxies that are being (or have been) ripped apart and absorbed by a larger, more massive, galaxy. See the above links. The only "nonsense" is calling the considered opinion of mainstream astrophysicists "nonsense".

Here's another: APOD: 2002 October 17 - Centaurus A: Young Blue Star Stream

by **Sputnick** » Mon Jun 23, 2008 7:45 pm

bystander wrote:
Sputnick wrote:What's missing is why the 'missing' companion galaxies are so accepted as having been there in the first place. The 'evidence' is pure speculation, but I am disappointed that the 'missing' galaxies are so present in the minds of most of you as to disallow any real speculation of the possiblility that the existing galaxy created the trails. However, I am satisfied that my initial observation of the possibility of a tumbling galaxy has been credited as being at least possible .. although I am certain it is a fact.
The evidence of the missing galaxies is the tidal streams of stars which were the point of the apod.

Sorry to have to use the word 'nonsense' Bystander .. but most contributors have said the companion galaxies are speculation,
their disappearance being a huge question mark.

More Tidal Streams

APOD: 2008 February 7 - NGC 4013 and the Tidal Stream
APOD: 2007 November 4 - The Closest Galaxy: Canis Major Dwarf
APOD: 2005 May 29 - The Sagittarius Dwarf Tidal Stream

Sputnick wrote:Would a scientist here please explain the scientific meaning of "working hypothesis"? Please and thank you.
Hypothesis - A tentative conjecture explaining an observation, phenomenon, or scientific problem that can be tested by further observation, investigation, and/or experimentation.

Conjecture - A statement likely to be true based on available evidence, but which has not been formally proven.

A working hypothesis is simply the hypothesis under scrutiny, or being tested. It is not "pure speculation" but a reasoned observation based upon the evidence available. Hypotheses must be testable (refutable, falsifiable). See Scientific Method.

Thank you .. the language says the same thing .. possibilities.

by **Sputnick** » Mon Jun 23, 2008 7:38 pm

Qev wrote:
Sputnick wrote:If I were in space, and hurled a spinnng gyroscope in such a way that I caused it to tumble as it flew, I make a guess that it's anybody's guess as to when it becomes "free falling".
I don't think it quite works like that. You can't "set a gyroscope tumbling" without applying a constant torque, unless I've completely forgotten how angular momentum works...

Do you mean to tell me that if I threw a Gyroscope it space, using my
fingers to spin the whole assembly against the spin of the wheel, that the gyroscope would not tumble? the Physics of space must be totally different then the physics in our atmosphere. I'm not talking about an eternal tumble here .. just for the length of time physics would set. Everything comes to an end .. even time "There shall be time no more" - Revelation.

by **bystander** » Mon Jun 23, 2008 1:50 pm

Sputnick wrote:What's missing is why the 'missing' companion galaxies are so accepted as having been there in the first place. The 'evidence' is pure speculation, but I am disappointed that the 'missing' galaxies are so present in the minds of most of you as to disallow any real speculation of the possiblility that the existing galaxy created the trails. However, I am satisfied that my initial observation of the possibility of a tumbling galaxy has been credited as being at least possible .. although I am certain it is a fact.

The evidence of the missing galaxies is the tidal streams of stars which were the point of the apod.

More Tidal Streams

APOD: 2008 February 7 - NGC 4013 and the Tidal Stream
APOD: 2007 November 4 - The Closest Galaxy: Canis Major Dwarf
APOD: 2005 May 29 - The Sagittarius Dwarf Tidal Stream

Sputnick wrote:Would a scientist here please explain the scientific meaning of "working hypothesis"? Please and thank you.

Hypothesis - A tentative conjecture explaining an observation, phenomenon, or scientific problem that can be tested by further observation, investigation, and/or experimentation.

Conjecture - A statement likely to be true based on available evidence, but which has not been formally proven.

A working hypothesis is simply the hypothesis under scrutiny, or being tested. It is not "pure speculation" but a reasoned observation based upon the evidence available. Hypotheses must be testable (refutable, falsifiable). See Scientific Method.

by **Alietr** » Mon Jun 23, 2008 12:50 pm

Does anyone know what the blurred object in the upper right-hand corner is? It could be "just" another galaxy, but it doesn't look like it would be one.

by **Qev** » Mon Jun 23, 2008 1:46 am

Sputnick wrote:If I were in space, and hurled a spinnng gyroscope in such a way that I caused it to tumble as it flew, I make a guess that it's anybody's guess as to when it becomes "free falling".

I don't think it quite works like that. You can't "set a gyroscope tumbling" without applying a constant torque, unless I've completely forgotten how angular momentum works...

by **Sputnick** » Mon Jun 23, 2008 12:08 am

iampete wrote:My thoughts from a layman's perspective:

..... The change in direction of the AM vector is likely to have been the result of the combination of the AMs of the original (massive) galaxy and the apparently ingested small galaxy. However, this change in direction of the AM vector is a "single" small change ("single" but of mega- or giga-year duration), not a continuous change which would cause a "tumble".

Bottom line: galaxies with a persistent "tumble" should not be possible.

Does this make sense, or am I missing something?

What's missing is why the 'missing' companion galaxies are so accepted as having been there in the first place. The 'evidence' is pure speculation,
but I am disappointed that the 'missing' galaxies are so present in the minds of most of you as to disallow any real speculation of the possiblility that the existing galaxy created the trails. However, I am satisfied that my initial observation of the possibility of a tumbling galaxy has been credited as being at least possible .. although I am certain it is a fact.

by **iampete** » Sun Jun 22, 2008 9:22 pm

My thoughts from a layman's perspective:

The shape of the galaxy under discussion in this thread suggests that the angular momentum (AM) vector is pretty much perpendicular to the galactic plane. Since the galaxy is not a single solid object, for it to be "tumbling" (i.e., a non-trivial component of this vector being parallel to the galactic plane), should result (over time) in the change of the galaxy's shape such that the vector is again perpendicular to the galactic plane. Therefore, any "tumble" would not persist unless a constant torque were to continually change the net AM vector.

In my opinion, the very slight "S"-shape of the galaxy in the edge-on view may be the result of a long-ago change in the original angular momentum vector, with the structures at the greatest distance from the galactic center having not quite finished with their re-alignment (although I'd prefer someone with a better feel for the physics to comment on that). The change in direction of the AM vector is likely to have been the result of the combination of the AMs of the original (massive) galaxy and the apparently ingested small galaxy. However, this change in direction of the AM vector is a "single" small change ("single" but of mega- or giga-year duration), not a continuous change which would cause a "tumble".

Bottom line: galaxies with a persistent "tumble" should not be possible.

Does this make sense, or am I missing something?

by **astrolabe** » Sun Jun 22, 2008 7:09 pm

Hello All,

I'm assuming, of course, that tumbling is being used as an additional possible motion characteristic of a galaxy (or anything else for that matter), something other than just rotation. My first thought is, yes, galaxies rotate and tumble, but only with outside influence. A bicycle spinning in a vertical plane could be considered tumbling but I think the spirit of the word is to mean motion that is perhaps not inherently natural for an object.

If a galaxy was to be tumbling one would think that the trail would have more of a modulated appearance like waves and troughs as the object tumbled from face on to flat, again and again, until an outside influence or eventually dark matter slowed or stopped it. Is dark matter considered static or fluid? That being said, maybe they all started out tumbling!

One last comment: nothing says tumbling would be perfect in it's geometry were it to happen. The axis could be anywhere across the galactic plane for example with two thirds of the object on one side of the axis and a third on the other with the galaxy sort of "lobing" along with what would look like a hop in the trajectory followed by a kind of hi/lo alternating tail behind it. Ya' THINK

P.S. Welcome to the new members

by **Sputnick** » Sun Jun 22, 2008 6:42 pm

Sputnick wrote:My response: I played with a small but substantial, steel gyroscope as a boy .. and while the spin prevented the gyroscope from tipping off it's pointed pedestal, if the gyroscope were set spinning and then thrown through the air it certainly would tumble.

Qev - I'm pretty certain a free-falling gyroscope isn't going to tumble, unless an outside force is acting on it.[/quote]

You're right, Qev, with the point being 'an outside force acting on it'. If generally accepted theorem is correct, something outside of the galaxies set them in motion. If I were in space, and hurled a spinnng gyroscope in such a way that I caused it to tumble as it flew, I make a guess that it's anybody's guess as to when it becomes "free falling". In the case of this galaxy, I think that outside force is a Black Hole which captured the galaxy so suddenly, that as its forward direction was altered suddenly and drastically, it began to tumble, as it shows in the simulation.

by **Qev** » Sun Jun 22, 2008 5:55 pm

henk21cm wrote:I just wonder, whether such a trail of stars is also (faintly) visible around our galaxy, caused by the two Magellanic clouds. As you were proffering, the plane of the orbiting system must be right, the angle of view, etc. These are all parameters we can not influence. Not in the least the abundant presence of stars in our own galaxy, allowing the stars in the trail to hide between these stars.

There's also the Sagittarius Dwarf Tidal Stream...

Sputnick wrote:My response: I played with a small but substantial, steel gyroscope as a boy .. and while the spin prevented the gyroscope from tipping off it's pointed pedestal, if the gyroscope were set spinning and then thrown through the air it certainly would tumble.

I'm pretty certain a free-falling gyroscope isn't going to tumble, unless an outside force is acting on it.

by **Sputnick** » Sun Jun 22, 2008 4:25 pm

Would a scientist here please explain the scientific meaning of "working hypothesis"? Please and thank you.

by **Sputnick** » Sun Jun 22, 2008 4:22 pm

henk21cm wrote:
starnut wrote: The Magellanic Stream was detected in the 1970s.
http://apod.nasa.gov/apod/ap980826.html
http://en.wikipedia.org/wiki/Magellanic_Stream
Nice to see that NGC5907 is not one of a kind. Nevertheless two of a kind is not a huge number in astronomical sense.

My response: Two of a kind is rare, and I think it signifigant that the trails are also rare .. and when you have the rare, thin galaxy occuring with the rare trails, I see as probable that the two are connected .. that the trails contain the bulk of what was a normal galaxy, thinned by the process of trail extraction.

sputnick wrote:Do we agree that the 'companion galaxies' are speculation?
Henck: As iampete points out, the companion(s) might be temporary hiding in our line of sight, obscured in the plane of the 'main' galaxy. The existence of a companion now or earlier is rather a working hypothesis than speculation.

My response: In my understanding of the English language 'Hypothesis' is connected in meaning with 'hypothetical' - 'speculation' is another word for both.

sputnick wrote:The galaxy as it is in the photo appears to have lost most of the momentum of tumbling, and is now tumbling at a greatly reduced speed.

The only tumbling i see in the simulation is that of the companion galaxy, leaving a trail of stars or matter.

My response: I apologize for wording my post in a way in which someone could misunderstand my meaning. I did not mean I saw the large galaxy in the simulation, I understood that the simulation was of a companion galaxy; however, as I do not believe there were compaion galaxies, I think the large galaxy could be substituted as the galaxy in the simulation. I will repeat that while the favoured view of the trails are from small galaxies orbiting the large galaxy, my opinion is that the large galaxy was captured by and is orbiting an invisible mass, perhaps a huge black hole.

Henck: Finally: the law of conservation of inpulse moment. That is my error, due to a wrong translation. In English it is called 'angular momentum'. See (if needed).
Conservation of angular momentum is responsible for Keplers second law. Similarly it prevents e.g. gyroscopes and cyclists from tumbling.

My response: I played with a small but substantial, steel gyroscope as a boy .. and while the spin prevented the gyroscope from tipping off it's pointed pedestal, if the gyroscope were set spinning and then thrown through the air it certainly would tumble.

by **henk21cm** » Sun Jun 22, 2008 11:07 am

starnut wrote: The Magellanic Stream was detected in the 1970s.
http://apod.nasa.gov/apod/ap980826.html
http://en.wikipedia.org/wiki/Magellanic_Stream

Nice to see that NGC5907 is not one of a kind. Nevertheless two of a kind is not a huge number in astronomical sense. Combined with a slight warping as observed in both galaxies, in our galaxy's case two companion galaxies, and the simulation jgabany has brought to our attention, a brittle conceptual model emerges.

sputnick wrote:Do we agree that the 'companion galaxies' are speculation?

As iampete points out, the companion(s) might be temporary hiding in our line of sight, obscured in the plane of the 'main' galaxy. The existence of a companion now or earlier is rather a working hypothesis than speculation. Another threat is that we do not see a lot of these star streams. We are dealing until now with 'isolated observations' and you know what the consequences are: generalization based on a few observations leads to weird conclusions. (As an example, Jacob Bronovsky told an amusing story that an alien space ship lands in the polar regions of northern Canada. These aliens come to the conclusion that our world is inhabited by polar bears and seals only.)

sputnick wrote:The galaxy as it is in the photo appears to have lost most of the momentum of tumbling, and is now tumbling at a greatly reduced speed.

The only tumbling i see in the simulation is that of the companion galaxy, leaving a trail of stars or matter. I came to that conclusion since the galaxy shown in the animation orbits around a massive center of gravity, which is not shown (and for which i assume it is the main galaxy). As pointed out earlier it is very unlikely that the main galaxy is tumbling, because of the law of conservation of angular momentum.

Finally: the law of conservation of inpulse moment. That is my error, due to a wrong translation. In English it is called 'angular momentum'. See (if needed).
Conservation of angular momentum is responsible for Keplers second law. Similarly it prevents e.g. gyroscopes and cyclists from tumbling.

by **iampete** » Sun Jun 22, 2008 10:14 am

starnut wrote: . . .

The Magellanic Stream was detected in the 1970s.

http://apod.nasa.gov/apod/ap980826.html

http://en.wikipedia.org/wiki/Magellanic_Stream

The caption for the APOD indicates that this stream is a gas cloud, while the wiki article could be interpreted to imply, but does not explicitly state, the the stream contains stars/star formation regions. From wiki: "Observations of individual stars gave us the star formation history.", but I can't tell if that's referring to stars in the Magellanic Clouds, or in the stream.

Is this Magellanic stream similar to the streams (which include stars) that you and jgabany mentioned earlier, or is it just gas and dust?

Starship Asterisk*

APOD: The Star Streams of NGC 5907 (2008 Jun 19)

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