The sun is a yellow star…not

Eric Rasmussen studies the colors of objects as they warm up. The light given off slowly shifts from infrared light to visible red light. Warmer still objects become white. Crank the temperature all the way up, and objects glow blue.

by Eric Rasmussen

We see this all the time. In drawings, animated shows, web content, educational books. Almost anywhere we turn, our sun always is portrayed as yellow.

In reality, stars can be one of three colors: red, white and blue. Now, this is not because the universe is insanely patriotic, but because the color of stars is directly related to their surface temperature due to a physics phenomenon known as black-body radiation.

Black-body radiation describes the relationship between the color of an object and its surface temperature. Cool objects shed heat in the infrared portion of the light spectrum. Humans represent one such object, which is why our bodies glow like light bulbs when on infrared cameras.

As objects warm up, the light given off slowly shifts from infrared light to visible red light. Warmer still objects become white. Crank the temperature all the way up, and objects glow blue.

A star’s surface temperature is dependent on how massive it is. Small stars have low surface temperatures; whereas the largest stars have the highest surface temperatures. Our sun is on the smaller side with a surface temperature of 10,000 degrees Fahrenheit. This results in its white coloration.

But let’s not put the yellow Crayola’s away. Yellow is a happy color.