What Color Is The Sun?

The sun usually appears yellow to our eyes when it’s high in a clear blue sky. Photo: Bob King

Think of the sun. What color is it in your mind’s eye? Most of us would say yellow without hesitation. That’s how appears in a clear blue sky. I looked at it this morning and thought pale gold was also a good fit. We’ve also seen red and orange suns around sunrise and sunset, but we know that’s not the intrinsic color of our star but soupy air and dust at work.

White light or sunlight is composed of every color in the rainbow from violet to green to yellow to red. When the sun is high in the sky, all these colors reach our eye with equal intensity and the sun appears pure white. But wait – the sun doesn’t look white. It’s yellow, right?

In truth, colors aren’t created equal when it comes to Earth’s atmosphere. Each is affected differently by everything ranging from air molecules to suspended dust to volcanic aerosols.

White sunlight composed of all the rainbow colors streams through
space. When it hits Earth’s atmosphere, the oxygen and nitrogen
molecules scatter the blue and violet part of sunlight across the sky to color it blue. Credit: www.pingry.org

Air molecules scatter blue and violet rays away from the hidden rainbow of colors in white light and send them bouncing around the sky. That’s why the sky is blue. When you look up to admire a blue sky, you’re seeing the blue part of sunlight set free. Come to think of it, we’re literally inhaling blue sky every time we take a breath. And to go one step further, we spend most of our time with our heads in the sky, since our feet are the only part of us touching the ground.

This loss of blue and violet to the sky causes the sun to look look yellow or “warmer” than it should. If we could peer out the cupola windows of the space station at a sun unfiltered by the atmosphere it would appear its natural color – glaring white.

Around noon, sunlight takes a short, direct path through the atmosphere and appears pale yellow. When near the horizon around sunset and sunrise, it passes through the lower, “dirtier” part of our atmosphere the entire distance. All that extra dust, smoke, etc. effectively scatter much of the sun’s light, leaving only oranges and reds. Illustration: Bob King

The size and concentration of particles in the atmosphere like smoke, dust, pollen and pollution affect what colors we see from the sun. When the sun’s high overhead, its light takes the short path through mostly rarefied air and then through the bottom 10 miles of atmosphere where the air is thickest. No great loss of light. But at sunset and sunrise, the sun is near the horizon and has to shine horizontally through hundreds of miles of the lowest, thickest layer of Earth’s atmosphere.

A red sunrise over Lake Superior. Dust, pollen, smoke, salt and
other particulates, collectively called “aerosols”, scatter violet,
blue, green and even yellow from sunlight leaving only orange and red. Credit: Lyle Anderson

Air molecules and aerosols across that great distance scatter away not only the shorter wavelength violet and blue parts of sunlight but also the longer wavelength yellows, leaving the familiar rich oranges and reds of a beautiful sunset.

This is a weird analogy but imagine tossing a handful of rocks, some very tiny pebbles and others the size of golf balls, at a beaded curtain. The teeny-tiny rocks will be scattered back by the curtain but the big ones will sail right through. Blue light (tiny pebbles) consists of very short wavelengths easily scattered by air molecules; red light rays (big rocks) have longer wavelengths and move through the air unimpeded.

When particles are few, sunsets are a bright yellow, but when the air is laden with dust or salt (near the oceans) the sun looks like a big red ball of fire. What color will it be tonight?

A white sun in airless, black outer space seen from the International Space Station. Credit: NASA

103 Responses

  1. Edward M. Boll

    The British Astronomical Association has Comet Panstaars at Magnitude 9.5 now. It will get 11 times closer to the Sun. If this holds we could be looking at a 15-16 magnitude brightening by Perihelion.

    1. astrobob

      Sounds like a good prospect, but again I’d like to caution, that unlike planets, comets often don’t follow projections to the letter.

  2. Edward M. Boll

    I meant to say a 14-15 magnitude rise. It is performing better than expected. And it is more than 2 magnitudes brighter than originally predicted.

    1. astrobob

      That would put the comet at -5. Wow! We can only hope. Hale-Bopp, one of the brightest comets in years, only reached -1 magnitude. The brightest comet I’ve ever seen was C/2006 P1 McNaught in 2006 when it was visible through my scope in a blue sky not far from the sun. That one reached about -5. Here’s a list of some of the brightest recent comets: http://www.icq.eps.harvard.edu/brightest.html

  3. Kent Southers

    Diggin’ the pic of the sun in space.

    Likewise, diggin’ the perpendicular variance @ color between overhead and sidelighting.

    Can you expand on how the “short path” scatters more blue than the “long path” does? I was taught that the angle of entry relative to the wavelengths that passed through was responsible for the color that was allowed to come through the atmosphere?

    Can you compare/contrast this?


    1. astrobob

      Hi Kent,
      The sideways (sunrise / sunset) path scatters the most light because sunlight travels through hundreds of miles of the lowest, dustiest, most water-saturated part of the atmosphere. Light from an overhead sun passes through a few hundred miles of very rarefied air and then through only about 10 miles of the low, dense, dusty layer. That angle makes a big difference in how much dense air vs. thin air sunlight passes through.

  4. rl

    The answer that the “true” color of the sun is white makes no sense given that its that its spectral class is G2.I say that any star as powerful as the sun and as close to earth would appear white!

    1. astrobob

      You’re certainly correct about that. Add in classes O,B and A too. The blog’s intent was simply to make a distinction between how the sun appears when viewed through our atmosphere (which scatters away blue light) and from airless space.

  5. ThinkerTixer

    The sun is BLUE! That’s why the sky is blue!

    If you look at the sun a short wild and look on a white paper the daze-spot will appear yellow. And as many of you discovered, the eye compensates for one color with it’s opposite on the colordiagram if you stare at something. (ex – photo negative)
    Therefor, if you later close your eyes after have looked at the sun, the daze-spot will appear blue.

    1. astrobob

      The sky is blue because air molecules scatter the shorter-wavelength blue light from the sun more than the other colors, not because the sun itself is blue. You’re right about the after-image of the sun appearing yellow, but it’s not an indicator of the sun’s actual color. Because air removes some of the blue light, the sun really appears slightly yellow.

  6. rl

    The sun looks yellow when I project its image onto white paper using binoculars,fitting its spectral class,but in space it looks white betraying its spectral class.Why is the latter “actual color” and not the former?

    1. astrobob

      Dear rl,
      It looks white to the eye because it’s also emitting a large amount of light in the red, blue and green part of the spectrum too. Taken together, that makes for a white sun. Down here on Earth, the “blue end” of sunlight is scattered by our atmosphere – goes to make the blue sky. With blue removed the sun’s color is a pale yellow

  7. rl

    Again,why is the suns “actual color” white? It seems to me that the atmosphere acts as a kind of correcting agent allowing us to see it in its true spectral glory. It may be an issue of definition,but to proclaim that the sun is “actually” white and those who see it as yellow are all wrong is not only unreasonably arbitrary,but flies in the face of the stellar classification system.
    Deneb,Altair,and Vega in the summer night sky are all white stars according to class.Why dont they look yellow like Capella and
    Alpha Centauri,both G class stars like the sun when viewed here on Earth? Surely their blue light is scattered too!
    If the Sun and Altair were next to each other in the sky as first magnitude stars,would you suggest that they would look identical?
    If you would,then I would say that the stellar classification system is meaningless,at least as regards to what we lay observers regard as star colors!

    1. astrobob

      It is a fact that the atmosphere removes violet and blue from sunlight so the sun must necessarily appear warmer in color from the ground compared to staring at it through the window of the space station. That doesn’t mean we’re seeing its true color any more than seeing a red sun at sunset. The sun appears white to the eye from above the atmosphere because its light output is overwhelming across the entire visible spectrum even though it peaks in green. Add those colors up and you get white. You pose an interesting question about Deneb, Vega and other white stars. It may be true that their light is scattered as well, with the atmosphere giving them a slightly yellower tint than they’d otherwise have, but set against the dark night sky in a telescope, we can’t detect the slight color difference. I’ll see if I can get an answer to that.

      We should’t forget there’s a subjective factor in all this. Most stars appear white to the naked eye because they’re simply too faint to excite the cones in our retinas responsible for color vision. Also, on a very clear day, the sun looks white to my eyes and not yellow. And try as I might, Capella looks white to me. Antares on the other hand looks distinctly reddish because it’s cool enough to emit a significant portion of its light at longer wavelengths than the sun.

  8. rl

    Thanks for your reply Bob!

    cant see yellow in Capella? Take a pair of binoculars and pan back and forth between it and Sirius and you will not be able to miss it!
    Truly Bob,star colors are really just pale tints,not vivid colors like traffic lights or Christmas tree bulbs;they do not produce monochromatic light.I know that you are not saying this but many reason in a way
    that tacitly assumes this.
    I guess my beef if is not with you but with those who have taken this arrogant stance of “ha ha you dummies all thought that the Sun is yellow but I know that it is really white!”

    1. rl

      This is a coninuation of my previous remarks.
      What is THE DEFINITION of a stars natural color?Why should it be the view from space rather than the view from Earth? In space we are at a disadvantage in accessing the Suns “natural color” due to reasons that you have already pointed out; the same disadvantage that I face in the outfield on a sunny baseball day.A pair of sun glasses works just fine! Is my improved view of the ball a false view? It sure looks real to me!

      1. astrobob

        Star colors are described scientifically by passing their light through three calibrated filters to determine how much red or blue excess there is. This also gives us an idea of a star’s temperature. Star temperature (and color) are also determined precisely using a spectrograph to examine the star’s spectrum in detail. Based on the spectrum, each star is assigned a spectral class. I know you’re already familiar with those classes but for the sake of other readers, those classes are arranged by temperature (which also directly relates to a star’s color). O,B and A star classes appear white to the eye; F and G slightly yellow and K and M mildly orange and red respectively. What color it appears to your eye and how saturated the color is can be quite subjective. For instance a red star can appear redder in a small telescope compared to the view in a larger scope. That’s because the large scope gathers more light, making the star brighter and colors less saturated. That’s why true star colors – the ones astronomers use – are determined spectroscopically or using multiple filters – no need to go into outer space. By the way, I’m enjoying this discussion.

    2. astrobob

      I’ll give it try sometime with Capella Sirius. It’s true that one of the best ways to see color is by contrast.

  9. rl

    Hi Bob, and the rest of you too! To continue my star color rant (when a guy’s on a roll,what are you goin to do?) do this little experiment: take a pair of binoculars and project the suns image onto various colored cloths.In particular project one lens onto green and the other lens onto blue.I was blown away! I cant explain the result! Also do the “grand tour” at night:Castor,Pollux,Capella,Sirius.
    Just fun; no big point to make.
    Move the glasses rapidly in a circuit.
    It may be late in the season now though!

    1. astrobob

      Hi Rl,
      Did the green one look brighter than the others? That would be my guess. We’ve lost Sirius now in Duluth but still have the other stars.

      1. rl

        The image all colored cloth showed yellow including white cloth.On green it showed VERY yellow;but when I used green and blue,two dots appeared,one bright yellow and the other pure white! I just dont get it.

  10. rl

    Hi again Bob! Question : if stars display colors,and they apparently do,where does this color come from? The disks of the stars are not colored;Hubble proved this with its image of Betelgeuse,glaring white just like the sun! But when I look at it in the sky it looks pale red;and Rigel looks blue.Most certainly the disk of Rigel is glaring white too.So where the heck does the blue tint come from?

    1. astrobob

      Most stars emit strongly across the entire visual spectrum as opposed to radio, X-rays, etc. Hotter stars like Rigel emit more of their light toward the blue end of the spectrum and have a slight bluish tint. Others like Betelgeuse radiate more light toward red end of the spectrum, giving the star a red hue to the eye. Stars can look virtually any color in photos depending on exposure time and what filters were used. Again, true color and star temperature are found by the filtration and spectroscopy methods I described earlier. Check out this website to get a better visual representation of why different temperature stars show different colors: http://hyperphysics.phy-astr.gsu.edu/hbase/wien.html

      1. rl

        I dont think I put the question clearly.I fully understand blackbody theory as it pertains to star light.What I dont understand is “where” is this blue light that I see when I look at Rigel. If I were close enough to see its disk,I doubt that it would be seen as blue.Could it be that there is some kind of halo around stars that fits their spectral class that is only visible at “stellar distances”?

        1. astrobob

          Yes, I’m sure Rigel would look glaring white seen up close. The blue you see is the blue excess that the star is emitting – that’s what gives it that tint. More blue photons are coming your way than yellow or red. Does that help?

          1. rl

            Thanks Bob;yes that helps immensely! Now I am off to the University of Michigan astronomy library to look up blackbody curves of the brightest stars in each stellar class so that I can better understand their visual light output.Learning to interpret these light curves is going to be a challenge,for they are only approximately blackbody,but it will be fun!

  11. rl

    Hi Bob!Been doin some astro library research without much success on perceived star colors vs spectral class.It appears pro astronomers dont give a hoot about this issue.
    However,I have found that determining the color of a hypothetical star is not as simple as saying that its light curve “peaks in the blue-green part of the spectrum at 500nm,so its color is white”.
    The Sun has a light curve that differs markedly from the “classic” blackbody curve;it looks an M with two peaks,one at blue-green and another at yellow-green with spur at a lower,but still high pure yellow.I dont know if this is why astronomers give it a G status or not,but there has to be a reason for G and not F.

    1. astrobob

      Not sure what solar radiance curve you looking at but the sun’s peak emission is around 500 nm very much in the blue-green, not yellow. While it also emits yellow (and every other color)the overall appearance to our eyes without an atmosphere is still white. The sun is a G-class star. F class stars are not only larger (generally) but also hotter.

      1. rl

        Bob,yes I know that the Sun appears white in space;but there are those who insist that white is the “true color” of the Sun as a result of this observation! I say that this is presumptuous.I have even had a local astronomer tell me this.
        I don’t believe this because the stellar color classification system makes no sense if a star as cool as the Sun can be labeled white along with A class stars.http://www.google.co

        1. astrobob

          I think you’re missing the point here. Stars of several spectral classes appear white to the eye. That’s their appearance only and doesn’t mean they’re members of that class. The actual spectrum and other factors like size must be taken into account to classify a star as F, A, etc.

          1. rl

            can you give me a short list of stars that appear white but are not F class or higher? Be sure to check out Jim Kaler on this.
            Also, thanks for putting up with my disagreeableness .

          2. astrobob

            Hah! And I thought I was the argumentative one. I can’t give you a list of K and M stars that appear white because those classifications emit enough light in the cooler regions of the spectrum to appear warm yellow, orange and red to the eye. Perhaps I should have clarified an earlier comment – most stars appear white to the eye because they’re too faint to stimulate our eyes’ color receptors unless you pump up their light with a telescope.

  12. rl

    Bob I tried to send you a link to the irradiance curve that I have been studying. I am a complete amatuer at this,so I could have it all wrong!Here goes.I think I know why the Sun is classified as G yellow and not even high F white,let alone A.You cant be misled by the peak at 500nm!The entire curve must be considered.There are many peaks,almost all of which occur considerably to the right of 500nm.It drops off intensity almost to infinity to left of 500nm,but drops off very gradually to the right,ie towards longer wavelengths.it has peaks in yellow while falling vertically to the left of 500nm.Next: area under the curve.

    1. astrobob

      You’re absolutely correct there are other peaks but max overall emission (tallest peak) is around 500 nm. Those other peaks and “plateaus” contribute to the overall white appearance of the sun to the eye.

      1. rl

        The Sun looks yellow here on Earth according to most people as far as I can tell;and we evolved and live on Earth,not in space!So the color of the stars must be considered with this in mind.Take a pair of binoculars and project the Suns image onto a black piece of paper and you will see that it is not white!Yessss I know the atmosphere scatters blah blah blah…..So what!It also scatters the light of Sirius and it doesn’t look yellow.

  13. Also worth mentioning: The peak of a broad spectrum has little meaning, as it is different in frequency space compared to in wavelength space. The solar spectrum peaks in the violet in wavelength space according to the ASTM Terrestrial Reference Spectra, and peaks in the infrared in frequency space. To complicate things, if you use a fitted blackbody model instead of actual data (like astronomers like to do), the solar spectrum peaks in the green. As this all makes clear, giving special status to the peak of a broad spectrum is misleading. The sun is white. In fact, all stars are white. When astronomers classify stars by color, they are saying more about the star’s temperature and less about what the star actually looks like. No star is a monochromatic source like a laser.

    1. astrobob

      Hi Christopher,
      Thanks for your comments on the sun color topic however I have to disagree a bit with your point about all stars appearing white. Those in classifications like F and hotter certainly appear white, but Mira variables, carbon stars and red dwarfs clearly have a red cast or tint. Since red dwarfs comprise the vast majority of stars, one might even say that most stars are warm or red-hued.

  14. rl

    All stars are white? Who told you this? Apparently you have never taken a night to observe the heavens! Stars dont produce monochromatic light like lasers? Wow,thats a revelation.Sorry for the sarcasm,but pontification upsets me.

    I am no expert,but the observational evidence dating back to Galileo all the way to the astronauts and cosmonauts aboard the space station give testimony to the fact that star colors,from red through orange,yellow,white,to blue are real! No amount of technical bombardment can change that!

    1. astrobob

      (rl’s comment is a response to this comment by Christopher Baird):
      “Also worth mentioning: The peak of a broad spectrum has little meaning, as it is different in frequency space compared to in wavelength space. The solar spectrum peaks in the violet in wavelength space according to the ASTM Terrestrial Reference Spectra, and peaks in the infrared in frequency space. To complicate things, if you use a fitted blackbody model instead of actual data (like astronomers like to do), the solar spectrum peaks in the green. As this all makes clear, giving special status to the peak of a broad spectrum is misleading. The sun is white. In fact, all stars are white. When astronomers classify stars by color, they are saying more about the star’s temperature and less about what the star actually looks like. No star is a monochromatic source like a laser.”

  15. rl

    Hi Bob! Been a while.My apologies to Christopher for flaring at him.It must be my disappointment with the weather here in Ann Arbor,ie no Perseids tonight!But really Bob, check out these words from Australia Telescope Outreach and Education:
    The Colour of Stars

    Astronomy is full of colour references; white dwarfs, black holes and red giants for example. If you look up into the night sky you may be able to see a few thousand stars from a dark site. As the stars are all so distant they appear as points in the sky. Most appear white but a few stars such as Antares and Betelgeuse have an orange or reddish hue to them. Others such as Rigel suggest a bluer colour. The colours of stars, however, are not obvious in most stars for several reasons discussed below. Colour is nonetheless an important and useful property of stars. In this page we will look at how it is defined, measured and used in astronomy.
    Bob,these are not the words of amateur cranks like me!

  16. rl

    The colour that we see is usually an additive combination of the
    emissions from each wavelength. Hot stars appear blue because most energy is emitted in the bluer parts of the spectrum. There is little emission in the blue parts of the spectrum for cool stars – they appear red. Even though the Sun’s peak emission wavelength (Wien’s Law) corresponds to the green part of the spectrum, its colour appears pale yellow due to the relative contributions of the different parts of its Planck curve to the overall colour. The table below shows the approximate colour and temperature range for stars.
    Bob,this expresses exactly what I have been trying to say all along,that the Sun is NOT A WHITE STAR despite the fact that it peaks in the blue-green part of the spectrum!

    1. astrobob

      Thanks for your thoughts on the color of the sun and reference.Technically you’re right, it peaks in green but receives contributions from many different wavelengths making it a pale yellow star spectroscopically, however the apparent pale yellow hue we see on the ground results from Earth’s atmosphere selectively scattering away the blue and violet. Above Earth’s atmosphere in outer space the sun APPEARS white to the eye because it’s overwhelmingly brilliant across the visible spectrum; short wavelength blue and violet light, unscattered by Earth’s atmosphere, contributes to its white APPEARANCE. Again, the point of the article about the sun’s color was to show how our atmosphere plays a part in the altering it.

      1. rl

        Bob,Australia Telescope makes clear that the Sun is yellow visually,not just spectroscopically; of course the atmosphere scatters…,; color is an appearance! Is the Sun’s yellow color an aberration created by the atmosphere, and yet the color of all the other stars “true” to spectroscopic class? Here are two good questions for you Bob, being a far northerner: what color is merak (the bottom pointer),what color is Dubhe

        Bob,take a look at the online HST pictures of Alberio.Two beautiful stars,one blue,the other gold, the gold one being very close to the Sun both spectroscopically and visually(dont know for sure but must be!)This shot taken from space must be how the Sun would look in the gold star’s place; not a blue star and a white star! That would not be the Alberio we astro folks know and love! Of course the HST image processing team could have blown it,but it is my impression that they are superb at rendering “natural colors”!
        I suggested a while back panning back and forth between Capella and Sirius to detect color in Capella.Try Dubhe and Merak instead;they are much more close together in the sky.


        1. astrobob

          I’ll compare the two Pointer stars tonight, but I know that Beta UMi (Kochab), a similar 2nd magnitude star, looks orangish. Albireo looks golden and pale bluish-white to my eye through the telescope. Other people see the colors differently. You can’t fully trust photos – HST and others – since color depth depends on exposure and processing. The gold-colored Albireo A is a very different star from the sun both physically and spectroscopically. It’s a K giant star 950 times the sun’s diameter so I would expect it to appear yellow or warmer-toned compared to the sun. The sun would not look at all like Albireo A seen from outer space.
          Just take a look at photos of Alpha Centauri, which is also a G2 star – it’s white in the photos I’ve seen. I’ve also viewed it in a telescope several times and it appeared white to my eye.

          1. rl

            Bob,I suspect that your vision is relatively color insensitive as you can’t see the yellow color of Capella, and I will send you and your favorite other out to dinner at the best restaurant in Duluth if you can find on the internet a seasoned observer who describes it as white! As far as Alberio A is concerned you are right.That was a poor choice on my part; but Capella isn’t. It is a G star with a color index very close to that of the Sun and a temperature as well; and size and mass are not key factors in determining the color of a star or anything else for that matter.Temperature is what really matters according to thermodynamics!

          2. astrobob

            Love that dinner possibility! Anyway, Capella may indeed look pale yellow to my eyes once it’s up high enough to make a good comparison. I just haven’t done that in a long time. Last night for instance when it was about 15 degrees high it looked sparkling white by itself. In the end, we are both correct in my opinion. You are right – the sun is spectroscopically yellow, at an appropriate distance to tone down it incredible brilliance and especially doing a comparison with a similar A star, it would look slightly yellow. My article sought to drive home the fact that the yellowy color we see here on Earth has much more to do with the Earth’s atmosphere than the sun’s spectral classification. Seen from Earth orbit, it would appear blindingly white. I think at this point we should just out to dinner together. Beer’s on me.

  17. rl

    OOPS! The above quote about the Sun’s color vs it’ spectral peak also came from Australia Telescope Outreach and Education.Sorry about that!

  18. rl

    Truce! Hey Bob,my wife and I are thinking of driving through Duluth on our way to California along our favorite highway ,route 2 pnext summer.Perhaps we could meet at a nice restaurant for lunch and swap astronomy stories!
    How did the Perseids look up there?

    1. astrobob

      Sounds like a great idea. Let me know when you’re passing through and if we can work it out, that would be nice. The Perseids were and continue to be a wonderful shower. We’ve had five clear nights in a row and counting. My daughter and I saw 60 on the date of max. Even last night they were flying all over. How about you?

      1. rl

        As you know, I am fascinated by G class stars.Why are there so few among the top brightest 100 stars? Is this a bad sign for life elsewhere?


        1. astrobob

          I would say brightness isn’t everything. G class stars are not particularly large or luminous compared to the supergiants, A, O and B stars

          1. astrobob

            I’d say there are few G stars in the Top 100 brightest because G stars are moderately sized and not particularly hot unlike the larger, hotter A, O and B (and monster M) stars.

    1. astrobob

      Seen from above Earth’s atmosphere, the sun is blindingly white because it emits light all across the visual spectrum from red to violet. Together these make white. Seen from the ground, the air scatters away some of the blue and violet but there’s still some blue and violet getting through plus plenty of green, yellow, orange. Without as much contribution from blue and violet the sun takes on an overall yellow color.

  19. rl

    If this is so, then doesn’t this this mean that we are in a part of the Universe that is different in some respects ?

          1. astrobob

            I understand now, thanks 🙂 G class stars are relatively common – more so than any of the hotter classes (F,A,B,O) – but less common than cooler spectral types like K and M. They make up 7.5% of stars in the sun’s neighborhood, which is defined by some as 10,000 cubic parsecs. The vast majority (76%) of stars near the sun are M class red dwarfs. Nature finds it easier to make little stars compared to big ones. I don’t know that 22% for G class in the Top 100 brightest stars is a fixed percentage. It depends on where you live in the galaxy. Aliens living on a planet orbiting Rigel would see a different assortment. Does that help to answer your question?

    1. astrobob

      Since Rigel’s 773 light years away, Rigelians see a different sky and a slightly different part of the galaxy. Hence someone there would likely see a different proportion of “brightest stars” in the sky. I don’t think anyone’s worked out the Top 100 brightest stars as seen from Rigel.

        1. astrobob

          I wish. Just an example of a faraway but familiar star that would have a sky different from what we see here in our galactic nook.

          1. rl

            Has there been a study by PROFESSIONAL astronomers that show what the distribution of stars is according to class out to various distances? My 22% idea is based on Jim Kaler’s table and is quite unscientific and the information provided in the link shows this,if is correct.


          2. astrobob

            I know there’s another study with similar results but I’m unable to find it just now. Overall the percentages are accurate because it’s well known that the larger stars – A, O, B and M supergiants – are far rarer than G types, which in turn are rare compared to M dwarfs. Nature makes very few large stars and very many small ones. You’ll find numerous references to M dwarfs as being by far the most common star out there at least in the solar neighborhood and an equal number of references pointing out how rare large stars are.
            Since we’ve been on this topic a while, could you refresh me again on what you’re driving at?

  20. rl

    Bob,you are right.I have been meandering a bit. This what got me going ;I am an argumentative kind of guy : you keep placing at the top of this thread that “the Sun is intrinsically white” Please ditch this misinformation. The Sun is not “intrinsically white” according to spectral theory and you have an intellectual obligation to inform your readers of this fact!

    1. astrobob

      I never said the sun was “intrinsically white” only that it appears glaringly white when viewed from above the Earth’s atmosphere vs. pale yellow from the ground. The original blog was about the sun’s color as we see it with our eyes, not about its spectral classification. Yes, I could have taken the additional step to describe its spectral color, but at the time, I felt it was beyond the scope of the article. I believe we agree that when viewed from a distance of light years and especially when seen in comparison to an A class star, the sun would look pale yellow. When seen nearby, for instance from Earth orbit, it would appear pure blinding white, not yellow, due to the overwhelming amount of light it pours out across the entire visual spectrum.
      By the way, some studies show the sun might be slightly peach-colored, others that it’s really white. Spectral classification is one thing but how it looks to the eye can be quite another.

      1. rl

        Ok Bob,the Sun is peach or white or whatever.Do a little work and go out with a pair of binoculars and project its image onto a dark blue sheet of paper vs a black piece of paper and then tell me that the Sun is “really” peach!


          1. rl


            NASA describes the Sun as having a yellow color along with that of Alpha Centori.NASA wont convince you? Then I am sure that I have no hope.You will not be hearing from me again.



          2. astrobob

            There’s spectral classification and then there’s human color perception. I’ve agreed with you that the sun is a yellow star spectrally, so I don’t see an issue here. Seen above the atmosphere the sun is white to the eye, and you’ll find numerous references to that (here’s one: http://www.universetoday.com/18689/color-of-the-sun/). Does Betelgeuse, which is an M-class RED supergiant look red? Not on close inspection. We call it red but that term covers a lot of ground. Take a closer look at it and it’s more pinkish-orange, and if you view it through a telescope it’s closer to a deep yellow-orange. Many red dwarfs are likewise not red like a fire hydrant despite their spectral classification. Take a look at the RED dwarf in the Castor system through a telescope or the 61 Cygni pair – they’re closer to pale pink than red. The 61 Cyg twins also show orange hues mixed with pink. These are just a couple examples of visual impressions of stars. Others will see them differently from me depending on their set of eyes and the instrument they’re using to look at the star. If we were to take the argument that the sun should look the color of its greatest spectral emission then it would appear green to the eye. It doesn’t because of the contribution from so many other wavelengths across the visual spectrum. So again, we’re talking two different things: spectral class vs. how the human eye perceives color. I don’t understand your resistance to allowing for the difference.

  21. I need someone to tell me the real color of the sun if you know please tell me I want to know what it is from space without the light to bright that it shows up white on camera. Please please please please please please please please please please please please please please please please please tell me!!!!!

    1. astrobob

      It would look pure white to your eye from anywhere in space in or near the solar system. From light years away, when viewed through a small telescope, my hunch is it would look pale yellow especially if compared to a spectrally white star like Vega. Keep in mind that colors are not hard and fast when it comes to our eyes. Some people see shades and colors more (or less) intensely than others. Color saturation also depends upon how bright the star appears. Stars below 4th magnitude all look white because they don’t fire up our eyes’ color receptor cells. A very bright red star looks less red than a fainter red star if you placed them side by side. Many variables!

  22. supurna

    Is the white sun seen in outer space captured by a camera or the human eye?
    The yellow sun that we see from the earth is seen with our eyes. Just
    wanted to eliminate effects coming from differences in the detection process.

    1. astrobob

      The yellowish sun seen from the ground is that color because the air has removed (by scattering) blue and purple light from the sun. Seen with the eye above the atmosphere the sun appears pure white – so say the astronauts.

      1. supurna

        Thanks for the prompt answer. Since the astronauts have seen it
        with their own eyes the sun must be appearing white to the
        human eye in outer space.

  23. Brendon Corder

    The sun is actually black thus it absorbs heat it doesnt reflect it it absorbs the heat it is what absorbs lots of heat from space but gives it to every planet cus its the center I also believe that blackholes are time portals and that one day antimatter and matter will form another bigbang recreating everything

    1. astrobob

      The sun neither reflects nor absorbs heat. Heat is created in the center of the sun through the process of nuclear fusion – it then radiates outward to the surface and into space where it warms the planets.

  24. DrDave

    The apparent color also has to do with the proximity of the peaks in the spectrum, as well as how the cones interpret the light. A cooler star looks red in part because the edge of the black body curve is closer to blue. Green colors also trigger the other cones, so even though the sun has peaks in the green area, we don’t see it as green.

  25. Alan

    Hi Bob, I’ve been admiring the sun for more than 25 years and for the first 14 years or so the sun was always yellow and classified as a yellow star, but 11 years ago I saw it and still can clearly see it is white, is there a specific date discovered by astronomers on when exactly it became white and what’s the scientific explanation behind this sudden change?

    1. astrobob

      Hi Alan,
      I think you, me and others have been conditioned to think of it as yellow. And indeed it does appear every so slightly yellowish because the atmosphere scatters blue from its light to create the blue sky. Scattering when the sun is lower is in the sky before sunset makes it appear very yellow as well as orange and red at time. But though it’s classified as a yellow dwarf, it does appear white to our eyes especially when seen from above the atmosphere in orbit or high in the sky when the atmosphere is very transparent. It has not undergone any color change in our lifetimes.

      1. Alan

        This website: http://www.grantchronicles.com/astro73.htm mentioned the change and I’m absolutely positive it was yellow as seen from space, but now it’s white even at sunset it’s barely yellowish. When the sun is high it’s clearly white but again it wasn’t always this way, weather channels still draw it yellow for that’s how it always was, and alot of people excluding the new generation agree with me that it was yellow even from space and yellow when it’s high in the sky. Yellow just like regular fire. If you ask or have any old picture showing the sun from space 13-14 years ago you’ll clearly see the difference and that it did change and admit that scientists simply have no explanation of this therefor they say it didn’t change colors. I’m not confused my eyes can tell the difference between colors and my memory serves me well. Again I’m not talking about how the atmosphere plays role in changing it’s color. I’m saying from the same position high in the sky now it’s white but it was yellow before. If it didin’t change why wasn’t classified as a white star instead of yellow. The answer is most never really look into the sun when it’s too bright in day time but I do and many others and we can tell its true color we don’t need to analyze it.

        1. astrobob

          If the sun changed color, it be one of the most spectacular astronomical events of all time. Scientists the world over would be doing research, debating the issue and churning out paper after paper about this momentous discovery. That isn’t happening. If the sun turned from yellow to white in ~30 years, it would immediately become incredibly hotter on Earth. Forget about global warming – we’re talking immediate, catastrophic climate change with a sudden VERY MUCH hotter Earth for everyone. That’s not happening either.
          Color perception can be very subjective. It depends on time of day, transparency of the atmosphere and even memory. That also applies to pictures – not only time of day but exposure and film type (back in the day) are variables. I don’t know about you but I’ve personally witnessed many “red ball” and yellowy-orange suns over the past few years. Finally, astronomers understand the evolution of stars like the sun very well. When the hydrogen in its core is exhausted, the sun will shrink a bit and ignite a shell of hydrogen surrounding the core. Heat from shell burning will cause it to expand, cool and redden. It will leave the main sequence and become a red giant star. Extra ‘whitening’ of the sun is not in the cards for billions of years.

          PS. The sun’s peak output is in the yellow-green region of the spectrum, but it appears subjectively white because it also emits light of every other color as well. You’ll remember that light of every color taken together makes ‘white’.

  26. Usher Jedidiah

    The sun defined it self on earth as affected by molecules. The sun is clearly white hence it takes any form of the seven rainbow colors in appearing to our natural eyes. Since it can’t be seen as white without indepth study,one would easily conclude the sun is yellow. Yellow would hardly change to any of the seven rainbow colors.

  27. John Pombrio

    You have to laugh. I especially like the comment that you cannot “see” the white color of the sun without a “in depth study.” What color is the full Moon? Exactly what lights up the Moon, the yellow sun? What color are sunlit clouds and fields of freshly fallen snow in bright sunlight? Shouldn’t they be yellow, or blue, or red or something? Clouds and snow are mostly translucent and gather up all the colors of the sunlight that are scattered by the atmosphere. You put all of these colors back together and you get the true color of our Sun just by looking at clouds, snow, or the Moon. No real effort, let alone a study, is needed.

    1. astrobob

      Depends. The sun radiates in all those colors and so appears white to the eye especially above our atmosphere from orbit say. On the ground it’s slightly yellowish because air molecules scatter the sun’s blue light – the reason the sky is blue. Even though the sun pours out all colors, it’s peak radiation is in the yellow-green region of the spectrum, so it’s classified as a G2 yellow dwarf.

Comments are closed.