Starship Asterisk*

neufer wrote:

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APOD Robot wrote:our yellow-appearing Sun

zbvhs wrote:1. Why are some broad lines fuzzed out at the edges?
2. Are some lines weak and barely visible because of low abundance of the elements producing them? Or, are they resonances of some sort?
3. Why no transmission lines (i.e., white ones)?

drhr wrote:I have to concur with the brick wall theory. But I also think the use of a prism is a 2-dimensional manner of analyzing the energy from the Sun. The prism decompresses the visible light, but does not make non-visible colors visible, they pass through and remain undetected.

Does the test here take into account the gases which the light has to pass through within our own atmosphere? Have we looked at it from space? I'd like to see if there is a difference.

Chris Peterson wrote:

drhr wrote:Does the test here take into account the gases which the light has to pass through within our own atmosphere? Have we looked at it from space? I'd like to see if there is a difference.

Yes to both (although this particular telescope obviously hasn't been used in space). When spectrograms of astronomical objects are analyzed, they are compensated for atmospheric absorption lines and band.

http://www.atoptics.co.uk/atoptics/gf15.htm wrote:
<<Some textbooks and most web pages say that the green flash is produced by refraction under ordinary atmospheric conditions. That is not true, if it was then we would see flashes much more often.

A standard stable atmosphere gets cooler with increasing height and the air density falls smoothly and monotonically. The lower and denser portion acts as a giant lens bending rays from the setting sun towards the earth. As a result, the rays appear to be coming from a point higher in the sky and the sun appears to be raised up. Green light is refracted more strongly than red and so different coloured images of the sun become very slightly vertically separated. As the sun sinks it develops a green** upper edge and a red lower one. But the effect is small usually only visible in binoculars - do not ever look without full eye protection, even for an instant.

To make a green flash these tiny refraction effects need somehow to be considerably magnified. We need a mirage ...
..............................................................................................
Why a green edge, why not blue? Why are green flashes green? Blue light is refracted more strongly than green or red and the sun's upper edge might be expected to be rimmed with blue outside a band of green. This rarely happens because so little blue light remains in the rays of the setting sun. Blue light is strongly scattered by air molecules, small dust and aerosol particles out of the direct rays. There is a further effect: traces of ozone absorb the orange light makes the contrast between the red sun and green flashes more pronounced.>>

APOD Robot wrote:
our yellow-appearing Sun

The above spectrum was created at the McMath-Pierce Solar Observatory and shows, first off, that although our yellow-appearing Sun emits light of nearly every color,...

...it does indeed appear brightest in yellow-green light.

o_0 wrote:I just figured it out why they had this spectrum today... it's Gay Pride Day.

• Gay Pride Day: 2 rainbow spectra vs 13 other APODs (1995-2009)
  Non-Gay Pride Day: 0 rainbow spectra vs ~5460 other APODs
  
  Fisher's Exact Test
  http://www.langsrud.com/fisher.htm
  ------------------------------------------
  TABLE = [ 2 , 13 , 0 , 5460 ]
  Left : p-value = 1
  Right : p-value = 0.0000070069719370384826
  2-Tail : p-value = 0.0000070069719370384826
  ------------------------------------------

http://en.wikipedia.org/wiki/Rainbow_flag_%28LGBT_movement%29 wrote:
<<The original gay-pride flag was hand-dyed by Gilbert Baker with his boyfriend Jomar Teng. It flew in the San Francisco Gay Freedom Day Parade on June 25, 1978. It has been suggested that Baker was inspired by Judy Garland's singing "Over The Rainbow". The flag consisted of eight stripes; Baker assigned specific meaning to each of the colours:

hot pink: sexuality
red: life
orange: healing
yellow: sunlight
green: nature
turquoise: magic/art
indigo: serenity/harmony
violet: spirit

After the November 27, 1978 assassination of openly gay San Francisco City Supervisor Harvey Milk, demand for the rainbow flag greatly increased. To meet demand, the Paramount Flag Company began selling a version of the flag using stock rainbow fabric consisting of seven stripes of red, orange, yellow, green, turquoise, blue, and violet. As Baker ramped up production of his version of the flag, he too dropped the hot pink stripe because of the unavailability of hot-pink fabric. Also, San Francisco-based Paramount Flag Co. began selling a surplus stock of Rainbow Girls flags from its retail store on the southwest corner of Polk and Post, at which Gilbert Baker was an employee.

In 1979 the flag was modified again. When hung vertically from the lamp posts of San Francisco's Market Street, the center stripe was obscured by the post itself. Changing the flag design to one with an even number of stripes was the easiest way to rectify this, so the turquoise stripe was dropped, which resulted in a six stripe version of the flag - red, orange, yellow, green, blue, and violet.>>

Ann wrote:Let's hope that neither the gay flag nor the solar spectrum will be burned by people who feel that their own heterosexuality has been offended!

neufer wrote:magic/Art

owlice wrote:

neufer wrote:magic/Art

A fitting pair!

http://en.wikipedia.org/wiki/Clarke%E2%80%99s_three_laws wrote:
<<Arthur C. Clarke formulated the following three "laws" of prediction:

• 1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right.
  When he states that something is impossible, he is probably wrong.
  
  2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
  
  3. Any sufficiently advanced technology is indistinguishable from magic.

The first of the three laws, previously termed Clarke's Law, was proposed by Arthur C. Clarke in the essay "Hazards of Prophecy: The Failure of Imagination", in Profiles of the Future (1962). The second law is offered as a simple observation in the same essay; its status as Clarke's Second Law was conferred on it by others.

In a 1973 revision of his compendium of essays, Profiles of the Future, Clarke acknowledged the Second Law and proposed the Third in order to round out the number, adding "As three laws were good enough for Newton, I have modestly decided to stop there." Of the three, the Third Law is the best known and most widely cited. It may be an echo of a statement in a 1942 story by Leigh Brackett: “Witchcraft to the ignorant, …. Simple science to the learned.”

Clarke's Third Law codifies perhaps the most significant of Clarke's unique contributions to speculative fiction. A model to other writers of hard science fiction, Clarke postulates advanced technologies without resorting to flawed engineering concepts (as Jules Verne sometimes did) or explanations grounded in incorrect science or engineering (a hallmark of "bad" science fiction), or taking cues from trends in research and engineering (which dates some of Larry Niven's novels). Accordingly, the powers of any future superintelligence or hyper-intelligence which Clarke often described would seem astonishing.

But in novels such as The City and the Stars and the story "The Sentinel" (upon which 2001: A Space Odyssey was based) Clarke goes further; he presents us with ultra-advanced technologies developed by hyperintelligences limited only by fundamental science. In Against the Fall of Night the human race has mysteriously regressed after a full billion years of civilization. Humanity is faced with the remnants of its past glories: for example, a network of roads and sidewalks that flow like rivers. Although physically possible, it is inexplicable from their perspective. Clarke's Third Law explains the source of our amazement as our limitation, rather than the impossibility of the technology.

In his 1999 revision of Profiles of the Future, published in London by Indigo, Clarke added his Fourth Law:
"For every expert there is an equal and opposite expert."
This is similar to Gibson's law, which holds that "For every PhD there is an equal and opposite PhD.">>

neufer wrote:

• 3. Any sufficiently advanced technology is indistinguishable from magic.