SUN - THE YELLOW STAR but THE LIGHT FROM IT IS WHITE!

 

We must understand that the Sun is not really yellow. It's actually white.

As in, the color of snow, milk, and marshmallows.

The Sun emits light across all the visible colors in the electromagnetic spectrum fairly evenly.

When these come together united in sunlight, the Sun appears white. This is useful because if this balance was thrown off, colors less favored would be difficult to see.

Imagine a world where everything looks blue or red. How boring would that be?

We see the Sun as yellow mainly due to our atmosphere. The atmosphere acts as a kind of light filter that scatters some colors more than others.

The short wavelengths (blue) of light from the Sun are scattered by the atmosphere (which is why the sky appears to be blue), leaving behind the longer (yellow-red) wavelengths.

The Sun is a yellow star, but the Earth's atmosphere makes the Sun look more yellow than it appears than if you were to observe it from space where it would appear more white than yellow.

But you don't have to leave Earth to see that the Sun is really less yellow than it appears.

If you are in the Rocky Mountains at 11,000 ft elevation, the Sun looks less yellow and more white than it does at sea level. There are fewer air molecules at this elevation to filter the Sun's other colors.

Also, when you are able to look at the Sun where you live, it's morning or late afternoon. It's easier to look at the Sun for a few seconds than it is at noon.

The Sun appears more yellow at those times than it would if you were to observe it at noon (12 PM) when Sun is highest in the sky for the day; it's at its brightest and whitest - hard to look at.

Because of the Sun's high position at noon, the sunlight has less air to travel through. Less air means less filtering of other colors.

Remember: Light appears white because all colors are equally reaching your eyes. So, at noon the Sun appears to be more white, less yellow - closer to the way it really is. (Don't try to make this observation without hi-tech eye protection) .

Its not just the atmosphere.

You see, The Sun's surface temperature (5,500 degrees C) produces a range of visible light (red to blue) in which yellow is the most plentiful, but not much more than other colors it produces.

If the Sun were cooler, say 2,500 degrees C, it would look red, like the stars Antares and Betelgeuse.

Or if the Sun were hotter, say 15,000 degrees C, it would look blue, like the star Rigel. The color of a glowing object depends on its temperature.

The Sun is a G-type main-sequence star (G2V), informally called a yellow dwarf star, though its light is actually white.

It formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud.

It is a massive hot ball of plasma, inflated and heated by nuclear fusion reactions at its core. Part of this internal energy is emitted from the Sun's surface as light, ultraviolet, and infrared radiation, providing most of the energy for life on Earth.