Colour of Sun,Moon and Stars

Discuss the differences in colour between the sun, the moon and the stars.

We know that sun has its own light. Its light is inherited by the moon and stars. As moon reflects sunlight and does not have an atmosphere so the colour of the moon and the sun should have been same. We also know that the sun radiates at a surface temp of about 5780K. This means its light is white. Although it looks yellow from here on Earth, the light of the Sun would actually look very white from space. But if blue is scattered in the atmosphere it will be scattered for both sunlight and moonlight. The moon is slightly yellowish at night. And on the other hand moon light is usually white.

The moon is yellow at night because if were to pin the colour output to a spectrometer we'd see it yellow. But there are two more things that make it appear different from the daytime sun: a) the colour is more diffuse through scattering of the surface on the dusty moon and our atmosphere b) our eye have very poor colour perception in dim lighting or from dim lighted sources. So if we combine diffuse light with poor perception of dim light sources, it’s not that much of a stretch to see that our eyes perceive it to be less than yellow in colour. During the daytime though, if the moon appears white, it has more to do with the combination of blue sky that overwhelms any perception of the dim, diffuse yellow that the moon might be reflecting.

At first glance, the stars may appear to all be white, but if we look at them from dark skies for any amount of time, we will see they are a diverse variety of colours which are red, yellow, white, and blue. Stars are such of these different colors depending on how hot they are that means on its surface temperature. Star work in the same way as a fire does. The coolest part of the fire is the top where the flames are red. It is hotter in the middle where it glows yellow while the hottest part is near the fuel where it glows blue. Therefore some of the hottest stars are blue and are called Blue Giants. The biggest known stars are called Supergiants. Rigel is blue Supergiant which is over 100 times bigger than the sun. Yellow stars like the sun are a bit cooler, and are called Yellow Dwarfs. Red Dwarf stars are smaller and cooler than the sun.