Is the sun yellow (or orange)?

Ask any child to draw a picture of the sun and he will instantly reach for a yellow crayon. This is indeed how we were all taught growing up. Some have suggested this is the main reason for this myth – that you can’t draw a white sun on white paper. Another factor is the phenomenon of light scattering. The sun is normally much too bright to be viewed directly – the only time we really get a look at it is when it’s rising or setting. But during these periods the light from the sun must pass through a thick atmospheric layer that scatters the higher (bluer) wavelengths of light, leaving only the yellowish and reddish hues. Therefore, the rising or setting sun does appear yellow, but this is only an illusion.

Not all stars are white. Red giants, for example, have a surface temperature of 3,000 to 4,000 degrees Kelvin and thus emit light in the reddish part of the spectrum. Rigel, in the constellation Orion, burns at a very high 10,000 degrees, giving it a blue appearance. The sun’s temperature however, is 6,000 degrees Kelvin, which science tells us can only produce a white light. In fact, sunlight is the very definition of “white” light on earth.

But what about official NASA photographs that show a yellow- or orange-looking orb of light? These photos are generally shot in black and white, with color later added by computer. The photos can also include wavelengths invisible to the human eye, such as infrared and ultraviolet, which also have false color added, for clarity and visibility. “We often use color as a tool, whether it is to enhance an object’s detail or to visualize what ordinarily could never be seen by the human eye,” – NASA’s official Hubble website.