The Sun is White Not Yellow
Today I found out the Sun is white, not yellow. For you graphics people or web developers out there, the exact color of the sun is #fff5f2. The reason the Sun looks yellow to us on Earth is that our atmosphere scatters light from the Sun; so the apparent color of the sun changes. This same scattering effect is why the sky looks blue in the day time instead of black, like at night.
Specifically, what is going on here is the Earth’s atmosphere scatters light in the blue and violet wavelength range, so the remaining wavelengths of light appear yellow. This same effect is why the sky will also often appear yellow when the Sun is disappearing over the horizon, as well as why the sky/Sun can appear more red at times during this phase of the day.
As the sun is setting, more of the shorter wavelength blue is being scattered because of the decreased angle of the sun relative to you; thus the light has to pass through more atmosphere to get to you. This increased diffusion results in less of the blue wavelength being visible to you and thus what remains appears yellow. Similarly, if it is dusty or there are a lot of other larger particles in the air, this will filter out larger wavelengths, resulting in a red sky and red sun.
Bonus Factoids:
Light travels from the Sun to the Earth in about 8 minutes and 19 seconds.- While it only takes 8 minutes and 19 seconds for the light from the surface of the sun to reach us, it actually takes about 10,000-170,000 years for a photon to travel from the core of the sun to the surface.
- Once regarded by astronomers as a small and relatively insignificant star, the Sun is now known to be brighter than about 85% of the stars in the Milky Way.
- The Sun has an effective surface temperature of 5780 K, which is equivalent to just under 10,000 F and 5500 C.
- The core of the Sun has a density almost 150 times the density of water on Earth. The temperature at the core is close to 14 million Kelvins and Celsius degrees, or 25 million degrees F.
- About 3/4 of the Sun’s mass consists of hydrogen, with most of the rest being helium (23.8%) and about 2% remaining consisting of other elements such as iron, oxygen, carbon, neon, and a variety of others.
- The Sun generates its energy from nuclear fusion at its core fusing the hydrogen nuclei into helium. The nuclear fusion is self regulating; if the Sun’s diameter gets smaller while maintaining the same mass, the pressure at the core increases creating more nuclear fusion which in turn causes it to expand. If it expands maintaining the same mass, the pressure lessens in the core causing less nuclear fusion. So a natural equilibrium has resulted in this process with our Sun, though there are stars that can be observed going through this process of massive expansion and contraction at very steady rates.
- At the core of the Sun, nuclear fusion power produced is estimated at about 276.5 watts/m^3. Interestingly this power production is more equivalent to a reptile’s metabolic energy production than what we would think like a nuclear bomb.
- This is in contrast to the amount of energy per (W/m^2) deposited on the surface of the Earth from the Sun, which is about 1368 W/m^2.
- Each second more than four million tons of matter are converted to energy within the Suns core. At this rate, the Sun has so far converted 100 Earth masses of matter into energy. This will give the sun an effective lifetime as a main sequence star of about 10 billion years with about 5 billion years to go.
- The Sun does not have enough mass to go supernova and explode. However, in about 5 billion years it will enter a red giant phase steadily expanding until it consumes the Earth. But fear not, the Earth will already be dead in about 1 billion years due to the fact that the sun becomes about 10% brighter every billion years; so in 1 billion years the Earth’s surface temperature will be such that no liquid water will be able to exist unprotected on the surface of the Earth.
- The Sun orbits the center of the Milky Way at a distance of approximately 24,000-26,000 light years.
- The Sun completes a clockwise orbit of the Milky Way center in about 225-250 million years.
- The Sun is about 150 million km or about 93 million miles from the Earth; this is by definition one astronomical unit (1 AU).
- The Sun is almost a perfect sphere; its diameter at its poles differs from the diameter at its equator by only 10 km or 6 miles.
- The area of the sun we call the “surface” is really just the outermost layer that radiates a significant amount of light. There is actually quite a bit of the Sun above that layer.
- The Sun’s magnetic field is less than half of what it was just 22 years ago. This has shrunken the Sun’s heliosphere which helps protect the earth from cosmic radiation. Because of this, the Earth is now being struck with significantly more cosmic radiation than just a couple decades ago.
For you graphics and web developers out there, here are some more stars and their associated hex colors:
Sources:
- Science Made Simple
- What Colour is the Sun?
- Sun
- Star Color (image source)
“the exact color of the sun is #fff5f2″ that’s quite a generous way of using the term “exact”. I sincerely doubt the exact color of the sun is limited by a 32-bit color representation :/
Shut up, nerd.
Here’s another fact:
Sun worship can be found in thousands of corporate logos, products, pop culture references, TV shows, songs, pro wrestling, Family Guy, websites, video games, bowling alleys, shopping malls, fast food restaurants.
It’s everywhere. Why? What kind of mad cult is this?
Well, as this article says, the sun will devour the Earth with heat in about 1 billion years. So, sun worship is subliminal, subconscious death worship, just like the skull and bones logos that are so fashionable. It’s a way of making people feel weak and dependent, and not know why. It keeps you in line, to the same effect as the pyramid logo found everywhere, including the dollar bill.
We are living in infinity, and certain people (cough Bush, cough Kerry, cough Skull & Bones secret society) want to control you from cradle to grave. Even if you’re smart on this, look at the general public. They are drunk with hubris, with no ability to even think of the powers that fight for control of their minds.
Actually, the sun exhibits a phenomenon known as black-body radiation. Yes it shines the entire spectrum, however due in part to its temperature, that radiation is most highly concentrated in the YELLOW portion of the wavelength spectrum. It also shines wavelengths all the way from radio to gamma waves.
Well, it might be limited by a 32-bit representation, but #fff5f2 is not even a single bit as precise as that…
ff-ff-ff, or 255-255-255 : 24-bits… That’s way less precise!
Vincent
Not to mention, every single artist in the world is also ON the world, subject to the atmosphere. Useless information is informative but useless! What artist would want to represent the sun in a way that they’ve never seen, and their audience will never understand?
Daniel, while I agree with you, count your bits – there are only 24 there.
No, the sun’s light is white, but the sun is yellow.
“it actually takes about 10,000-170,000 years for a photon to travel from the core of the sun to the surface.” — Our sun’s radius is not 10000-17000 light years… Other things are probably invalid too.
hey Daniel, STFU fag. k thx
I think sun is basically white.. I think
I beg to differ. If you have ever taken an astronomy/astrophysics course you will see that many stars in our visible ranges can only be picked up by a few pixels on a ccd telescope. The color that you get is usually the highest “density” of a particular light frequency. In that case, the color of the star looks uniform because our sample is so small. So from afar, without a telescope, I’d say it would be safe to say that the exact color of a star can be represented by 32 bits for the sake of a game.
“This is in contrast to the amount of energy per (W/m^2) deposited on the surface of the Earth from the Sun, which is about 1368 W/m^2.”
What is the lumenous efficacy(lumens/watts) of this measurement? so basically I want to know how many lumens hit a cubic meter.
@qwerty: What you are failing to consider is that the process of a photon making it’s way through the extremely dense plasma in the sun, particularly near the core where most all the energy is created, doesn’t happen at light speed. In fact, it happens pretty slowly. For more information on this process, check out the sources or just grab a cosmology book (where I first learned about this back in college).
Just as important, the name of The Sun is Sol.
qwerty, you are using the speed of light in a vacuum, but the centre of the sun is not a vacuum. Think of it as an extraordinarily high refractive index.
The sun looks white, not yellow anyways, you’re insane
Do you know why we arbitrarily divide the continuous spectrum of the Sun’s light into only three colors, red, green, and blue? Because that’s how our eyes work.
Do you know what color the Sun is? It’s white. Know why? Because we’re the descendants of life that has evolved on this planet for 3.8 billion years. We see the Sun as being white because, not so coincidentally, the exact spectrum it’s putting out is what our entire visual system has spent millions of years optimizing for.
If we ran into aliens who live around a two Solar mass star, they’d see their own star as white, even though it would look decidedly blueish to us. If they looked at Sol, they would say it was red (or whatever their equivalent word for “longer than the median visible wavelength” is).
Isn’t a FACTOID something false that is presented as a fact?
This is useful for space games, art, or anything that would have one’s perspective outside the Earth’s atmosphere. If one were on a different planet, the color perceived would of course change based on the planet’s atmosphere or even if you were somehow inside a nebula or anything that affects light. The light could even appeared warped due to gravitational lensing depending on the viewer’s relative location in space. There are all sorts of things one can quibble over, although, I personally say, let the artists have liberty to make things visually look “good”–accuracy isn’t always important for all applications. Still, some interesting info regardless. It all reminds me of how small we are in the universe as we know it and it makes me want to watch some Carl Sagan Cosmos videos on Netflix
Is not most art based on perception not necessarily reality? If the sun appears yellow from my vantage point the within the confines of my mind the sun is indeed yellow. If you fly me out to space then I guess that perception would change.
I’m glad you asked. That is a common misconception. See here: http://www.todayifoundout.com/index.php/2010/02/the-difference-between-a-fact-and-a-factoid/
Vincent, the last 8 bits are for alpha. 8 bits of each color and then 8 bits of transparency.
Mr Dylan says that the sun isn’t yellow, it’s chicken.
So if you are in space is the sun white?
How can the sun orbit the milky way in a particular direction? It would depend on which side you are observing it from.
Space is so interesting. It’s amazing to think there are 100 million stars in our galaxy and 100 billion different galaxies out there.
Dear Davon
A mistake I often see in printed media is the incorrect use of the word factoid. A factoid is a false or incorrect statement. According to Wicapedia a factoid is defined as ” a questionable or spurious—unverified, incorrect, or fabricated—statement formed and asserted as a fact, but with no veracity.” Language is always changing and evolving maybe some day it will refer to a little known fact but for now it still is defined as stated above.
Thanks
Misleading- there are already stars classified as white, and our sun is certainly not in that category.
Thanks for the feedback. However, the definition has already more or less changed or rather been modified thanks to certain news agencies out there. Wikipedia is behind the times there; check Websters for a more up to date definition or just read my post here on the subject
I thought that agreed number of stars in the Milky Way was around 400 billion.
Given this is a general estimate im sure (and not an actual set number), and given the estimate of galaxies in the known universe (google’d at 170 billion), the number of stars in existence is mind boggling. (simple math, 400,000,000,000 * 170,000,000,000 = 68,000,000,000,000,000,000,000. Whats the name for that place? 68 sextillion stars?)
This article is not entirely correct. All stars are mostly white. But they do have color, whether viewed from Earth or from space.
The reason it is considered a yellow star is because yellow is it’s most predominant non-white color index (which is due to it’s temperature). It can only be viewed as yellow when put through a heavy non-polarized filter to block out the majority of the light. If you look directly at it, it will appear completely white because it will oversaturate the cones in your eyes.
A correct statement would be that the Sun is mostly white with a tinge of yellow. Also, the Earths atmosphere does affect the Sun’s apparent color, but that’s not to say that it doesn’t still have a predominant yellow color when viewed from space.
The sun is technically centered in the green portion of the spectrum, aka we live under a green star. You will never see this, even without the atmospheric effects. The eye is not equipped to deal with this much light, or this portion of the spectrum.
http://blogs.discovermagazine.com/badastronomy/2008/07/29/why-are-there-no-green-stars/
Great blog topic!!!
Daniel: I agree, any computer model spitting out a color code will be limited for many reasons. I think it is only fitting that the “pinkish peach” result is what they found. Is the Sun a girl star? I think not! Lol
physics: The sun is close to a blackbody radiator, but not quite. There are a number of peak energy wavelengths and temperatures that can be discussed and are used by solar physicists:
1) Planck (blackbody) temperature. If you superimpose a ~ 5850K blackbody spectrum over the Sun, it will be a reasonably close match, especially in the red end of the spectrum. The peak wavelength at this temperature is 495.4 nm (4954 Angrstroms). This is more of cyan color (greenish blue), though the color will likely vary for different observers.
2) Effective temperature. At ~ 5777K, an object will radiate the same amount of net energy per unit area as the Sun. The peak wavelength for this temp. is 501.6 nm (5016 Angstroms). This is a green color for most people, I think.
3) Spectral Irradiance peak. Sp. irr. data from space observatories demonstrate peaks that vary from 450.5 nm (near violet) as found in the Wehrli ’85 data set to about 495 nm (near green). These peaks, however, are all very close to the same energy level, so they are more like pimples than peaks.
4) Spectral Photon flux. It is likely best to convert the spectral energy distribution into a photon flux distribution because it is a better way to model the responsiveness of our eyes. This produces an almost flat distribution across the visible spectrum. Ironically, there is a tiny peak (pimple) in the narrow yellow band, but no one peak makes a continent, and no one wavelength determines a net color observed. A flat photon flux distribution produces a white result.
Gonzobot, I see no reason to always represent the Sun in a color it is not. Further, most of the time the Sun appears as white or yellowish white since its time along the horizon is so short. I hope artists take their liberties and license and keep giving us their colorful versions, but occasionally it would be nice to see a few present it accurately, especially if it is a depiction of the Sun as seen from space.
James, the Sun Ain’t Yeller: Here is a fun and lengthy explanation:
http://www.scientificblogging.com/solar_fun_of_the_heliochromologist/the_color_of_the_sun_revelation
I suspect we are victims of using the yellow crayon in coloring the Sun, which may have left an indelible impression upon us from our youth. There are a number of ideas on this.
Daven and qwerty. The time it take an initial photon to make its way to the surface (photosphere), known as the random walk, seems to be much closer to the 170,000 years. The 10,000 year figure seems to be the time based on a more isotropic model where the Sun’s density was held constant. I vaguely recall a result of 18,000 years for the one paper I saw. I’m no expert, but I suspect I’m right on this.
Skd, the 1368 W/m^2 (The Solar Constant) is the energy per unit area that exists at one A.U., which is the Earth’s orbital radius. The net energy that reaches the surface is about 1000 watts/m^2 for direct sunlight at one atmosphere (AM1, directly overhead).
Cyde Weys. I suspect your evolutionary model is essentially correct, but there is wiggle room in this view, too. Evolution applies to all species and there is an enormous range in vision among species. White tail deer only have two color cones with one the seems to allow them some visibility in the UV range, possible best for avoiding early morning predators and maybe deer hunters climbing into blinds that the hunters think deer can not see their activity. Many birds have 4 color cones. I’d love to see what they see!
Justin & Dan. You raise a good point. For me, the “true color of the Sun” needs some definition to it. I take it to be the color observed if one were to see it from space and at a level that is comfortable for the eye, perhaps around 10 candela/m^2 or so. Astronauts have reported the Sun to appear as a very bright white star, but one all our color cones are maxed-out, then white is the result, regardless if it would look red or blue at a normal intensity level. [I see mac has addressed the oversaturation issue of our color cones.]
Solecize. Ah, you’ve been reading textbooks. That’s a problem. The Sun is classified as a dwarf star (G2V). Often it is stated to be a yellow dwarf star and most of the H-R diagrams will show it as a yellow star, though there is some that have changed this to a white color. The vast majority of textbooks and magazines will show the sun as other than white, even if the textbook tells you that the Sun is a white star, which it is.
Now that we know it is white, think about the problem this presents if we use white as the adjective for the official dwarf star classificiation. Yikes!!! The fun continues…
mac, I doubt that if you were to go in space and look at the Sun that you would see any hint of yellow even on the Solar limb. Solar projections through unfiltered telescopes do not show yellowish coloring on the disk. Since our atmosphere removes predominantly, though only partially, the colors at the blue end of the spectrum, adding these colors back into the white Solar projected disk will not cause a yellowish appearance. But would it give it a hint of blue in the hotter central region. Perhaps it will, but I wouldn’t bet much on it.
Shwan Garbett. Surprisingly, I got interested in this topic years ago when I read an east-coast astronomers very nice magazine 2 or 3 page article explaining why the Sun is a green star. This surprised me greatly and when even the Bad Astronomer (Phil Plait) was unclear on a definitive answer, I knew it might be fun to do my amateur research into this field of study, which is now known as heliochromology – the study of the color of the Sun. [Though it is a tongue-n-cheek term, it is still scientific. It’s fun in the Sun!]
Here, again, is a better story on the Sun’s color…
http://www.scientificblogging.com/solar_fun_of_the_heliochromologist/the_color_of_the_sun_revelation
George, your friendy neighborhood heliochromologist
The rest of us already knew this.
qwerty,
Nice catch on the “10,000-170,000 years for a photon to travel from the core of the sun to the surface” point. Lots of interesting comments in this one.