Starship Asterisk*

The visible blue light has a wavelength of about 475 nm.

Ann wrote:By showing invisible ultraviolet light as blue and visible blue light as green, the Hubble picture of NGC 273 has been "shifted to the green and away from the blue", compared with what the human eye would see, if our eyes were sensitive enough to extremely faint light.

Ann wrote:Adam Block's image is, I repeat, more "true" to what our eyes would see, if they were sensitive enough to very faint light.

songwriterz wrote:Looking at the APOD (not the original photo) can anyone tell me what that blue structure is in the lower left corner?

cssbll wrote:And the blue blob also to the left of the larger galaxy, which looks the same?

Ann wrote:This is a splendid galaxy pair. The larger galaxy displays such an intricate spiral shape that it indeed resembles a rose. That is how Arp 273 is described on Hubblesite, as a "rose" of galaxies. The smaller galaxy would be the "stem", I guess!
(snip)
Ann

geckzilla wrote:

cssbll wrote:And the blue blob also to the left of the larger galaxy, which looks the same?

And that one looks like a distant background galaxy. The funny thing about these pictures is that a lot of the time all the stuff in the background doesn't even have a label or name. I like the red galaxy nestled mid-right between the two arms of the larger foreground galaxy.

cssbll wrote:

geckzilla wrote:

cssbll wrote:And the blue blob also to the left of the larger galaxy, which looks the same?

And that one looks like a distant background galaxy. The funny thing about these pictures is that a lot of the time all the stuff in the background doesn't even have a label or name. I like the red galaxy nestled mid-right between the two arms of the larger foreground galaxy.

but if it were, it should be red-shifted more. Doesn't have any discernable red-shift at all.

A possible mini-spiral may be visible in the spiral arms of UGC 1810 to the upper right. It is noticeable how the outermost spiral arm changes character as it passes this third galaxy, from smooth with lots of old stars (reddish in color) on one side to clumpy and extremely blue on the other. The fairly regular spacing of the blue star-forming knots fits with what is seen in the spiral arms of other galaxies and is predictable based on instabilities in the gas contained within the arm.

Visitor wrote:Thanks, Ann, for understanding our need to bring science down to a human scale for better understanding and appreciation. I cannot explain why I would rather see the image in visible light colors other than the fact that I am not a bee. Assigned colors are OK as long as they are labeled as such. Thank you to Hubble for bringing it in such glorious detail.

geckzilla wrote:You can see a galaxy every night in visible light colors if you travel to a dark enough place on a clear, cloudless night. Personally, I would slighted if science was always "brought down" to whatever arbitrary common denominator for the sake of reducing confusion. Besides, if they suddenly started releasing nothing but visible light spectrum photos, Ann wouldn't have anything left to post about. :wink:

geckzilla wrote:
Did anyone notice the "mini spiral" in the upper right?

http://heritage.stsci.edu/2011/11/caption.html wrote:
A possible mini-spiral may be visible in the spiral arms of UGC 1810 to the upper right. It is noticeable how the outermost spiral arm changes character as it passes this third galaxy, from smooth with lots of old stars (reddish in color) on one side to clumpy and extremely blue on the other. The fairly regular spacing of the blue star-forming knots fits with what is seen in the spiral arms of other galaxies and is predictable based on instabilities in the gas contained within the arm.

http://wonderingminstrels.blogspot.com/2001/05/big-whorls-have-little-whorls-lewis-f.html wrote:

• " Big whorls have little whorls
  That feed on their velocity,
  And little whorls have lesser whorls
  And so on to viscosity."
  
  -- Lewis F Richardson

I first encountered this wonderful verselet in James Gleick's 'Chaos'
(highly recommended, incidentally - a very understandable and well-written
introduction to the topic), and was instantly captivated. The poem works on
two levels - both as a delightfully well-done parody of DeMorgan's famous
paraphrase of Swift, and as as nice a summation of the fractal nature of
turbulence as any I've seen. - martin

Biography:

Richardson, Lewis Fry
b. Oct. 11, 1881, Newcastle upon Tyne, Northumberland, Eng.
d. Sept. 30, 1953, Kilmun, Argyll, Scot.

British physicist and psychologist who was the first to apply mathematical
techniques to predict the weather accurately.

Richardson made major contributions to methods of solving certain types of
problems in physics, and from 1913 to 1922 he applied his ideas to
meteorology. His work, published in Weather Prediction by Numerical
Process (1922), was not entirely successful at first. The main drawback to
his mathematical technique for systematically forecasting the weather was
the time necessary to produce such a forecast. It generally took him three
months to predict the weather for the next 24 hours. With the advent of
electronic computers after World War II, his method of weather prediction,
somewhat altered and improved, became practical. The Richardson number,
a fundamental quantity involving the gradients (change over a distance)
of temperature and wind velocity, is named after him.
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http://en.wikipedia.org/wiki/Ad_infinitum wrote:
The 17th century writer Jonathan Swift mocked the idea of self-similarity in natural philosophy with the following lines in his poem 'On Poetry: A Rhapsody':

• "So nat'ralists observe, a flea
  Hath smaller fleas that on him prey,
  And these have smaller fleas that bite 'em,
  And so proceed ad infinitum."

The Victorian era mathematician Augustus De Morgan expanded on this with a similar verse:

• "Great fleas have little fleas upon their backs to bite 'em,
  And little fleas have lesser fleas, and so ad infinitum.
  And the great fleas themselves, in turn, have greater fleas to go on,
  While these again have greater still, and greater still, and so on."

songwriterz wrote:Looking at the APOD (not the original photo) can anyone tell me what that blue structure is in the lower left corner?

kshiarella wrote:

songwriterz wrote:Looking at the APOD (not the original photo) can anyone tell me what that blue structure is in the lower left corner?

I had the same question as well. Looking closely, there is faint yellow halo around the dense blue (ultraviolet?) core of the object in the lower left. I was guessing that it was an orbiting irregular galaxy. If it is a huge star cluster that has been cast out, is it a possible method of formation of irregular satellite galaxies that they represent a population of stars that were flung from a mother galaxy while in the process of interacting with a third?

BMAONE23 wrote:Here is a link to the original Hi-res Hubble image (35 meg)

owlice wrote:
Except our eyes aren't "sensitive enough to very faint light." Adam's images are wonderful, but they aren't any more "true" than Hubble images, which show us "what our eyes would see, if they were sensitive enough to" ultraviolet light, because our eyes can't see either the "very faint light" nor the ultraviolet light.

geckzilla wrote:You can see a galaxy every night in visible light colors if you travel to a dark enough place on a clear, cloudless night. Personally, I would slighted if science was always "brought down" to whatever arbitrary common denominator for the sake of reducing confusion. Besides, if they suddenly started releasing nothing but visible light spectrum photos, Ann wouldn't have anything left to post about.

Chris Peterson wrote:[Even images taken only in visible light are often better displayed using synthetic palettes. Our eyes did not adapt for looking at galaxies, and we can often learn more about such objects by transforming their natural spectral output into artificial color spaces that allow us to extract much more information visually. In general, unless the intent is purely aesthetic, "natural" colors are usually not the best choice for astronomical objects.