What if red things were actually hot

Why is the banana yellow?

A banana is yellow, not because it gives off yellow light. It's not a flashlight. The banana is yellow because it keeps purple. The white light of the sun consists of many rainbow colors. When these colors hit the bananas and are reflected again without violet, this mixture appears yellow. The color of non-luminous objects (banana) is the phenomenon of subtractive color mixing.

The leaves are green because of the many colors of white light they absorb the red. The rest is reflected and appears green when mixed. The bike is blue because it absorbs the yellow.

The subtractive color mixture

The colors that we perceive are linked to objects - they are called material or body colors. Here, parts of the light waves of daylight or parts of an artificial light source are absorbed or reflected. The color we see is the mixture of all the reflected colors.

Black objects absorb everything, reflect nothing - hence black. (Black is not a color).

White objects don't absorb anything, reflect everything - hence white (white is a color).

It's about the complementary colors. White-black, yellow-purple, red-green etc.

In the case of a yellow banana, purple is absorbed as a complementary color - the opposite color on the color wheel.

Further examples:

Leaves are green, not because they glow green like a green lamp. It is green because it absorbs red (complementary color of green) from white sunlight. The reflected rest appears green.

A person who blushes appears red, not because he is glowing red, like a red flashlight. It appears red because it absorbs green from the colors of the white light (complementary color to red), the reflected rest appears in its mixed color red.

Subtractive color mixing. With pigment colors that you brush or print somewhere.

Amazingly, you can produce all body colors with three basic colors: magenta, cyan, yellow. Depending on how you mix them, a certain color will appear. If you mix them all together in the same way, as the children like to do with the watercolors, it turns black. Black is a color. This is the case with printing inks, with body colors, with all colors of objects that do not shine themselves.

Additive color mixing

This is now about glowing flashlights of a certain color. Here is really: if it lights up yellow, it lights up light with the wavelength that corresponds to "yellow".

Here are the three basic colors red (R), green (G) and blue (B). If everything lights up, it is white. If nothing lights up, it is black. We speak of the RGB color space - which occurs, for example, in monitors.

These are glowing flashlights.

Embedding in current research

Only the blue components of the many colors of sunlight scratch the curve so strongly that they hit our eyes.

We can determine quite well which atoms and molecules are in what quantity in our atmosphere by analyzing sunlight. It should actually be white, made up of all the colors of the rainbow. A spectral splitting by a prism, a raindrop, etc. shows the mixture nicely. Certain atoms and molecules in the atmosphere absorb certain “matching” wavelengths (colors). These are absent when they reach the earth or are reduced. In spectral analysis, these wavelengths are no longer available or only available to a reduced extent. The mixture no longer appears white to our eyes when the effect is great.

And why is the sky blue?

It is actually black - on the moon, for example, if you are not looking directly into a star or the sun. If we look at the sky on earth, where there is no sun, it should also be black. Obviously something there deflects the sunlight into our eyes, like small mirrors. That is what the air molecules do. They “scatter” the light of the sun around the curve into our eyes, and they do this particularly well with blue light. In the evening, the path of sunlight through the atmosphere is so long that all the blue light is gone, and the red parts remain. Sunset!