A science blog with Eric Berger

What color is the Sun?


It’s yellow, right?


Visible light wavelengths.

Visible light wavelengths.





Behold: The true color of our Sun.

Behold: The true color of our Sun.



According to NASA, here’s how to interpret the colors above:




Eric Berger

20 Responses

  1. IANVS says:

    Not to mention significant amounts of UV & IR & smaller amounts of radio waves, microwaves, X-rays, & gamma rays, all invisible to the naked human eye, after 100,000 years of bumpy rides & a smooth last 8 minutes.

    “Most of the electromagnetic radiation emitted from the sun’s surface lies in the visible band centered at 500 nm (1 nm = 10-9 meters), although the sun also emits significant energy in the ultraviolet and infrared bands, and small amounts of energy in the radio, microwave, X-ray and gamma ray bands. The total quantity of energy emitted from the sun’s surface is approximately 63,000,000 Watts per square meter (W/m2 or Wm-2).”

    “It takes a photon approximately 100,000 years or about 1025 absorptions and re-emissions to make the journey from the core to the sun’s surface. The trip from the sun’s surface to the Earth takes about 8 minutes.”

    The Encyclopedia of Earth

  2. Morris says:

    “Particles with longer wavelengths” — does that mean light particles?

    I had thought that the relative intensity of the sun’s light peaked in the green area of the spectrum, and that is why the sky is blue rather than violet. So I understand that all wavelengths of visible light are represented, but isn’t there a distribution curve of intensity?

    • ScientistMike says:

      The sky is blue because the contents of the Earth’s atmosphere scatter the shorter (blue and violet) wavelengths more than the others.

      Yes, the sun emits a distribution of wavelengths and only part in the visible region. This diagram shows that. The intensity scale is logarithmic, so the visible spectrum is far greater intensity than the very short or very long wavelengths.

    • StanleyS says:

      There is such a distribution curve, and one could argue that the color of the Sun, rather than being white, is the color at which that distribution curve peaks.

    • JohnD says:

      One of my astronomy professors was fond of saying that the Sun was green, just like the explosion from a hydrogen bomb.

      There is a peak in the curve near green but given the total number of photons and the relatively small decrease in intensity across the visible spectrum saying that it is white is close enough.

    • Eric Berger says:

      This blog is like horseshoes and hand grenades — close enough counts!

    • IANVS says:

      … & atomic bombs.

  3. ScientistMike says:

    Well, it’s YELLOW. Ask any kid who colors a picture of the sun! :)

  4. craig says:

    This topic calls to mind the old question “If a tree falls in the forest does it make a sound?”. Same perspective. Does the interpreter of any event or phenomenon have any bearing on what actually is happening as far as ultimate truth? You make the call. : )

  5. Kay says:

    I was wondering if the scientist used different color lens, what does that do to this analysis?

    • ScientistMike says:

      @Kay, if you look at the video above, where images are displayed in different colors, that in essence is what happened. They are views of the sun through different filters, but not just colors (visible light), also wavelengths outside the visible spectrum.

      If that is what you are asking.

      The other thing not mentioned here yet is a feature called “color temperature”, a big factor in photographic applications. For example take a photo indoors under incandescent lighting and it may look somewhat yellow, because the color temperature is in the 2500 to 3000 Kelvin degrees range. But with electronic flash colors look normal because the color temperature is in the 5000 to 6000 degrees range.

      Our sun is close to an ideal “black-body radiator” and its color temperature (its surface temperature) is about 5800 Kelvin, and that generally is defined as “white light”. Spectroscopically it may have a bit more green than the other rainbow colors, but colors are relative and we define that as “white”.

      On a cloudless day with the sun high our world is illuminated by the mix of wavelengths that make up that white light. But if it is early morning, or cloudy, or in the deep shade of a tree, the color temperature could be anywhere from about 2000 to about 10,000 Kelvin. The temperature of the sun hasn’t changed but the different conditions change the distribution of wavelengths and the light is what you would get from an ideal black-body radiator at those temperatures.

      Back to photography, most modern digital cameras in the “AUTO” mode use automatic color-balancing so you get fairly realistic color no matter what the color temperature of the light. But back in the days of color film photography, indoor available light photos had a color cast, depending on whether the light source was incandescent or fluorescent. Accomplished photographers often used a colored filter over the lens to compensate and get better color balance, plus printing of color negatives could further improve the color.

      So “white” light is far from being a simple concept.

  6. IANVS says:

    re: “But it’s not really yellow.”

    A poll of prolific pollinators on the wing worldwide would likely see things quite differently from merely grandstanding humans.

    “What colors creatures see has long interested scientists, and aside from us, more is known about what colors bees see than any other living thing. Like us, bees are trichromatic (have three photoreceptors within the eye). Whereas we base our color combinations on red, blue, and green, bees base all their colors on UV, blue , and green. Just as color blind people do not see red or green, and therefore experience the world of color differently, bees also perceive the world in colors entirely different from ours. Bees do not see red and have a hard time distinguishing it from surrounding green leaf backgrounds. Bees that frequent red flowers are either perceive them in color they can see, or the red flower is not being lost against a green background. Even though bees don’t see red, they can see other reddish wavelengths such as orange and yellow.”

    Colors Bees See

    • IANVS says:

      re: “How do you know!”

      OK, Ed, we’ll play.

      So how do you know that your mother’s face is the same your father or siblings see?

      How do you know that the Statue of Liberty or the Washington Monument or Old Glory are visually the same liberty icons that appear to JohnD’s sentience?

      & how do you know that a basketball is spheroidal, or an egg ovoid, or a box 3-dimensional, or an inch an inch? Or that spheroidal is spheroidal, or ovoid is ovoid, or that 3-D is 3-D?

      How likely is it that, viewed in good lighting from identical POV (& sober), you & your father can not distinguish your mother’s visage from a stranger, or what you peg a statue JohnD regards a flag, or that you’re dribbling cubes & cracking bananas & your inch to us is his cm or our mile?

      From a casual observation, apparent gaps in your perception may be mere gapes** in your explanations.

      [**XXX WARNING: Do NOT google Urban Dictionary.]

  7. Ed C says:

    I often wonder if everyone sees the same color of anything. How can you tell if what I see as blue is seen by others as blue? What if you see my yellow or green?