Ask any child to draw the sun, and they will scribble a yellow circle. Illustrations in books also show a bright yellow orb to represent our sun. The sun is not yellow. Because the sun is so important, you would expect everybody would know what color it is. However, most people do not. The reason for this is simple - it is dangerous to look at directly. A glance can cause permanent eye damage. To know the color of our sun, we need to understand what it is – a star.
Our sun is white. The reason why most people do not realize this is because the most of us see the sun from the surface of the Earth, where the air interferes with the wavelengths of light and change the color we see. The visible wavelength of light from the sun is also white, but it can be split into separate parts of the color spectrum by using a prism. This is what happens in a rainbow. The white light coming from the sun changes color due to the interaction with particles and chemicals in our atmosphere making it appear red, orange and yellow.
What we call the sun is a star, one of many billions in our galaxy. The Latin scientific name for the sun is Sol – but most texts call it the Sun. The energy our sun gives out is what allows life to exist on Earth. This energy takes the form of radiation we cannot see, such as heat, and light energy we can see. Although the sun is 92.96 million miles away from the Earth, we get just the right amount of light for life to thrive. If our planet were closer like Venus or further away like Mars, the light we received would be too much or little to support life.
Stars are grouped into different categories. These different types of stars appear to be different colors because of what they are made from, their temperature, and their ages. Most stars are classified using the letters O, B, A, F, G, K, and M, a sequence from the hottest (O) to the coolest (M). Each letter class is then given a number with zero the hottest and nine being coolest. Our sun is G2 and made from mostly hydrogen. It is these characteristics which give stars their color. Some stars have names that describe their color; red dwarfs and giants. However, most star’s color can only be determined by viewing them with scientific instruments which measure the light emitted. Colors of stars range from browny-red, yellow, white, and blue.
Light is our name for the part of the energy spectrum which we can see. Light is made from photons which travel at the speed of light (186,282 miles per second) in a straight line. Light can be reflected or refracted to change its direction of movement, which can also change the color it appears. It is the refraction of light that allows us to see the colors of the rainbow when a beam of white light travels through a prism.
There are specialist instruments and equipment which is essential for looking at the sun. The amount of energy given out by the sun is vast – the equivalent of 3.86 x 1026 watts of power, and this energy can blind you. Our eyes use a lens to focus the light reflected from what we see onto our retina. If a person were to look directly at the sun to try and see its color, this lens would focus the energy and cause permanent damage to the eyes. Using sunglasses will not help, and in fact, may cause more damage to the eye than not using them because the dark glass makes the iris dilate and lets more light into the eye.
So we know the sun is white. If we were to see it in space – using filtering glass or equipment so that we would not be blinded – it would look pure white. The reason why the sun appears to give off a yellow glow on Earth is due to the effects of our atmosphere. The earth's atmosphere is mostly composed of nitrogen. When the Sun is high in the sky, the shorter waves of energy hit the nitrogen air molecules in the upper atmosphere and scatter. This makes the sky looks blue. Enough blue light is scattered out in the Earth's atmosphere to cause the Sun to appear slightly yellow.
Although the sun appears yellow when viewed through our atmosphere, it can seem as different colors too. When the sun is low in the sky at sunrise or sunset, it can seem yellow, orange, or red. That is because the short-wavelength colors (green, blue, violet) are scattered away by the Earth's atmosphere. The thicker layer of air means only the reds, yellows, and oranges wavelengths get through the atmosphere to our eyes.
Culturally, we are all conditioned to see the sun as a yellow circle. Children’s storybooks, science fiction films, and even articles from NASA show photos and pictures of the sun as a yellow orb. The reason for this is threefold.
Other planets in our solar system have different atmospheres with different percentages of chemicals in them. It is these local conditions which change what color the sun appears to be as seen from the planet surface.
The other planets receive very little of the sun’s light or are gas giants with no place to observe the sunlight through their thick atmosphere.
Artists from the Neolithic times up to the modern day have expressed their wonder at the sun’s beauty and power through art. These artistic representations affect how people of that culture think of the sun too. For example, many young children in Japan would draw a red sun rather than a yellow one – because that is how the sun appears on their flag. However, most cultures use the color yellow to represent the sun. Many also include rays or beams coming out from the sun. We cannot see these rays, with our eyes but this shows how people have understood for thousands of years that energy is flowing as the light from the sun to us on earth.