"Basically, when you look at the sun, it has enough of all the different colors in it and it’s so bright that everybody’s eyes are firing like crazy and saying, 'It’s too bright for me to tell you what color it is.' That’s why the sun looks white to us... 'Essentially, it’s a green star that looks white because it’s too bright, and it can also appear yellow, orange or red because of how our atmosphere works.... 'The sun is at its midlife, and it still has quite a lot of years before it changes colors.... It still hasn’t dimmed out one bit.... When astronomers say color, they really mean temperature.... But to anyone in the public, color just means the color you see and how you make sense of the world."
Said W. Dean Pesnell, project scientist of NASA’s Solar Dynamics Observatory, quoted in "Is the sun white or yellow? It’s a hot debate, and everyone’s wrong.
Plot twist: It’s green" (WaPo).
According to the article, some people on social media are discussing whether the sun used to be yellow and now it's gone white.
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४० टिप्पण्या:
On the Pacific, right at sunset's final moment, with calm seas, you sometimes see a 100 millisecond green flash. Delightful.
The sun's not yellow; it's chicken.
I am Laslo.
Obviously it's not yellow, it's chicken.
I've looked at the sun through various neutral filters (that reduce all frequencies intensity). It never looks green.
The human eye / visual system is simply not great at seeing green when there is a lot of energy in adjacent colors present.
It does look green looking at it through a telescope with one of those polarized lenses screwed into the eyepiece...
It looks like a red mess with floaters when you look at it through a telescope without one of those polarized lenses screwed into the eyepiece. Made that mistake once. Once...
Silly conflation of human perception with physical measurements.
The "color" is what we see and discuss in human languages. The physical properties are what we measure.
See the philosophy of perception and the notion of phenomenology :
https://plato.stanford.edu/entries/perception-problem/
Another in the long string of articles along the lines of "Why do all stars look white, yellow, orange, red, or blue?"
And the answer's always the same -- it's how our eyes work, despite them truly being any and all colors. I've been seeing articles like this for decades. Kinda fun how it's still new to so many. Guess the XKCD cartoon about "The Lucky 10,000" really is true ;-)
https://xkcd.com/1053/
A shifting frame of reference and dynamic environment means that everyone is wrong.
"'Essentially, it’s a green star that looks white because it’s too bright, "
This is ridiculous, as anyone can see for themselves. There are a lot of other stars in the sky that are not too bright for our eyes to handle. Is Arcturus green? Is Spica? Do any of them look green? NO.
There is quite a striking difference in star colors, depending on the temperature of their photosphere. Stars are white, blue, yellow, orange, and red. But there are no 'green' stars.
Take a look at 18 Scorpii (you'll need binoculars). Its brightness, age, size, and color is a very close match to our sun. Does it look green? It does not.
That's interesting, because there is often a little sliver of green when the sun sets over the ocean, just as it dips out of sight.
ISN'T man made (or woman made) global warming responsible for this?
Isn't man made (or woman made) global warming responsible for EVERYTHING?
Doesn't All evil exist because of man made (or woman made)global warming?
Doesn't ALL reality exist because of man made (or woman made) global warming?
Doesn't ALL reality exist because of man (or woman)?
That's what we're teaching today*, isn't it?
teaching today* well.. That; and that we have NO IDEA what a man (or woman) is
Blacksmiths can tell the temperature of the steel by its color.
Somewhere in my collection of material I have a true color chart of what color coincides with what temperature for a given heat. It's been valuable for heat treating in the shop.
It is the color that humans see it as.
""The sun would appear green if your eye could handle looking at it.""
No. The sun is just another star, and when you look at stars through a telescope you see that they come in reddish, white, and blueish. No green.
Sol (the name of our star commonly referred to as the Sun) is a Yellow Dwarf.
"But momma, that's where the fun is!"
@Laslo Spatula
That was almost the post title.
Somewhere in my collection of material I have a true color chart of what color coincides with what temperature for a given heat
We have those charts for watch hands and screws, too, though the only color that really matters is cornflower blue- 290 degrees C is about perfect...
"When astronomers say color, they really mean temperature"
Yes, indeedy, and the two shouldn't be confused.
All objects emit a spectrum of electromagnetic radiation. The higher the temperature of the body, the more high frequency radiation that is emitted. We can't see anything below the boundary of visible light (hence the name) and most radiation emitted by living bodies is in that "infrared" range. Fires will give you a lot of higher frequency red and orange. The sun is hot enough to radiate all the colors and more, but fortunately, most of the ultraviolet is filtered out by the atmosphere. The sun's spectrum peaks in the green but it includes lots of the other colors. This is unlike a green piece of paper, which absorbs most of the non-green light and predominantly reflects the green.
There's a nice animation where you can change the temperature and see how the spectrum changes (it's in wavelengths; higher frequencies mean lower wavelengths).
“not yellow, it's chicken”
It’s trans yellow. Now don’t be chicken; SAY IT: trans yellows are yellows!!!
Sirius, the brightest star in the sky, is a beautiful star to observe. When it is low in the sky and especially when the atmosphere is turbulent (what is called poor "seeing" by astronomers) it "twinkles" strongly, giving off flashes of all of the "colors in the rainbow", including green. That's because green is in the spectrum of light emitted by Sirius. But so are blue and red and everything else, which is why Sirius looks white under more normal conditions.
Even teh Sun!?!
White Supremacy!
The sun is not green, it is an unregulated dirty nuclear fission reactor that is not controlled by any government. The UN should obtain an injunction to have it shut down.
Green colored light in the sun is produced by iron fe3. Iron produced from silicon is the last stage of the reactions of the sun as it takes more energy to convert silicon to iron than is produced by the reaction. There will be a low level of iron in the sun until the useful elements are converted. Some stars will go nova, but our sun will just shrivel up and die. So the sun is now just slightly green.
“ To scientists, though, the different wavelengths of light in the corona give them information about what is going on there. An international team of astrophysicists observed eclipses in 2006, 2008 (above) and 2009; they presented their findings at this week's American Astronomical Society meeting. The red, blue and green colors in their corona images represent wavelengths of light produced by iron ions. Though scientists have known that the ions were in the corona, this is the first time that they have mapped their distribution. This mapping could lead to more insight into the corona and how the sun's behavior affects Earth.”
NASA is welfare for engineers.
just to be clear...
This "scientist" is saying:
NOTHING good is white*.. Our sun is good..
THEREFORE: our sun is NOT white; it MUST be a sun of color (maybe green?)
white* white is EVIL!!!
"'Essentially, it’s a green star that looks white because it’s too bright, "
Bollocks.
When the sun is high in the sky — minimizing blue scattering — clouds are white. Why? Because the sun, the sole light source the clouds are reflecting — is white.
The green flash is indeed wonderful to see, though sadly rare. It demonstrates my previous point: the green IS visible when It is isolated by atmospheric refraction, but not otherwise.
I've seen it clearly four times. Best was from the bluffs on the coast road to Lahaina.
Doesn't scientific consensus decide what things are and are not? If 97 percent of scientists (what field? Doesn't matter because science) say it's white, then based on current theory, it's white. I'm pretty sure that you'd get a less than 3 percent saying it's green (as such, they are clearly wrong).
To correct, the sun is a fusion reactor, not fission.
If we’re to take full responsibility for the catastrophic environmental consequences of our actions upon the earth, the sun must be greener than the Green Lantern.
Color is just a look. However it looks, that's the color.
Having seen many sunrises, I can tell you, at sunrise, the sun is usually orange. But it's sometimes red and sometimes yellow. It's when the sun is higher that it looks white.
"Doesn't the sun look green today" -- Jefferson Airplane, "The Ballad of You and Me and Pooneil"
“Color is just a look. However it looks, that's the color.”
The theory behind rose-colored glasses.
Speaking of whiteness, the guy giving us this info is a middle-age white guy.
I will only believe an affirmative-action diversity hire.
how would sun look if sun shone? on sun?
It occurs to me, that merely saying "NASA is welfare for engineers", every time some clown employed by NASA earns his living, by making some asinine, woke pronouncement, stops short of conveying my meaning. It is not merely that the NASA program has devolved into a make-work operation for people with advanced degrees in the supposedly "hard" sciences. It is also that they are fully as incompetent and useless as we expect people on welfare to be. There was a time when NASA hired competent people, and set them to doing useless "work". Faking a Moon Landing, for instance. But at this point, NASA is merely a mechanism by which the Fake Science scam that has taken over science can provide sinecures for the Fake Scientists the modern academy turns out in profusion. GI, GO.
NASA has an office, well-staffed, whose mission is to make sure that every NASA program, however obscure, has at least one component manufactured in each of the 435 American Congressional Districts. If you want NASA to fund your NEA-approved plan to blast terrariums made by third-graders into orbit to "study" how spiders weave webs in Zero Gee, that's great! We love it! But it needs to have at least 435 hi-tech moving parts. Maybe you could include a remote-controlled webcam? Oh, and also, there needs to be a pervert factor. Yeah, that's new. We like to get a pervert factor, plus, also, a Muslim factor. I realize, that's a bit tricky, given how Muslims and perverts feel about each other. But hey, there's money involved. A lot of it, actually. Muzzies, Muxxies, whatever. Everybody has his/her/their/xis/xer price.
The article leaves out probably the most important part of the discussion which is the difference in speed that varying light wavelengths travel. Adhering to the correct terms the article uses, the brighter, thus hotter wavelengths travel much faster than the cooler, slower ones. So the blues hit our eyes faster than the reds. When I image deep sky objects, say the Great Orion Nebula, a very short exposure time of 30 seconds or less will produce a bright bluish white image. If I take out as long as 4 minutes, then the pinks and reds will emerge. Note for this I’m just talking single image exposures on the very short side with no light, dark, etc exposures or any stacking of multiple images; with stacking and and all the reference frames, many of the hotter/faster/brighter colors will be much more subdued, giving a much truer representation of the object *as our brain interprets the data*.
Correctly mentioned in the article is the atmospheric filtering taking place where the light from the Sun high in the sky travels through a narrower layer of atmosphere v on the horizon at sunset where the layer is considerably thicker and denser. The green at Sunset over water is a combination of the light bouncing off the surface of the Earth, reflection of the various particles in the layer of atmosphere and filtration by those same particles in the atmosphere. A very simple observation exercise at sunset illustrates the filtration aspect in that the Sun and the planets are the only objects you can view (unaided) at the horizon while as you look higher in the sky other stars become visible to the eye. You can also find brighter objects during the day if you know where to look. Jupiter is easily visible during daylight if you know the exact spot in the sky. Next Wednesday, in fact, the waxing crescent moon will occult Jupiter in the early morning and you will be able to see it naked eye IF you can see the Moon; binoculars or other optics will make this extremely easy.
I’m not totally buying “green”, however. I’ll defer to the expertise cited but I think the answer is considerably more complicated than what is stated in the article. There is no mention of whether green emerges because it is the most prevalent wavelength(s) visible outside of any filtering, such as what is observed by orbiting observatories or if it is the aggregate of wavelengths (blue mixed with yellow makes green). It’s a “who ya gonna believe, the experts or your lyin’ eyes”, which in this case likely favors the experts but not enough information is provided. The only time I get green through my telescope is when I view through O III and/or neutral density filters, which help to enhance structure in many nebulas I’ve looked at at the expense of some if the colors that make them worth observing/imaging in the first place.
Regardless on all that, it’s obviously global warming causing any color and temperature shifts of our home star…
Meade said...
“not yellow, it's chicken”
"It’s trans yellow. Now don’t be chicken; SAY IT: trans yellows are yellows!!!"
Does Perdue know about this?
Original Mike,
Sirius is a binary system and you are correct, a very beautiful star(s) to observe especially when “split” via magnification using a medium sized telescope. Sirius itself is a main sequence, spectral class A1 V star (our Sun is main sequence G2 V for reference); Sirius B is a white dwarf, the first ever discovered and the first binary I managed to split. Once I got the hang of it, I’ve split dozens since.
I generally observe through an 8” Dobsonian (Orion XT8) for casual night sky viewing, but I also have a 130mm refractor (Celestron 130 EQ) and a 14” Dob with tracking (Orion XX14G). I can’t really image on the big Dob as it’s alt/az tracking. I do some Camera prime imaging on an iOptron tracking platform mounted on a tripod and can hold accuracy for up to 4 minutes exposure.
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