If you ever had to watch the sunrise or sunset of a night luminary, then surely at this moment your unusual color and size attracted your attention. Why is the moon red and large when it is near the horizon? If the size can somehow be explained by the optical illusion associated with the refraction of light, then what about a bright orange hue? In olden times, when people were still not so literate as to understand why the Moon was red at certain points in time, an unusual color was regarded as a gloomy omen of terrible events. But how in our time do scientists explain this phenomenon?
Color metamorphosis
If you look at the Earth’s satellite from space (you don’t need to strain your imagination - the astronauts have already taken its pictures), then we will see a light gray ball, perfectly illuminated by the Sun. Astronauts do not puzzle over why the moon is red, since the color of the satellite changes only if you look at it from the earth's surface. When the night star is just beginning to rise above the horizon, it looks like a big orange circle. Our planet makes a revolution around its axis. The moon rises higher above the horizon, while its color changes. At first, the orange hue turns into yellow, and after some time - into white and yellow. When the moon takes a position above the observer’s head, it practically becomes light gray. Naturally, in reality, the satellite of the Earth does not change its color. The whole secret is that we look at it shining through the atmosphere, and it is like looking at something through a veil.
Why is the moon red in the morning?
Before the light reflected from the satellite reaches our eyes, it will have to go through the air, consisting of nitrogen, oxygen, and other gases. Together with the smallest particles of dust, smoke and other pollution, they inevitably change the spectral composition of light, noticeably shifting it to the red side. That is why the moon is red in the early hours of the day. This effect is especially noticeable in windy, sultry weather or during fires, when microscopic soil particles are carried away upstream and, not having time to settle, hang in the atmosphere for hours. There is another explanation for why the moon is red. It consists in the fact that the short-wave rays of the solar spectrum are scattered upon reaching the Earth, and the long-wave rays pass through the atmosphere and are reflected from the Earth’s satellite. It is they who give the night star a red tint.
Why does the moon sometimes seem huge?
In some photographs, you can see that the Earth’s satellite, being above the horizon, looks incredibly large. Sometimes this phenomenon can be noticed by yourself, and therefore it is not necessary to say that the size of the moon is oversized in the images. There are several explanations for this fact. Firstly, this optical illusion is associated with an interesting feature of the human eye - irradiation: bright light figures on a dark background always seem larger than their actual size. Secondly, according to the theory proposed back in the 60s. By James Rock and Lloyd Kaufmanov, for some reason our brain “believes” that the shape of the heavenly dome is not correct, but as if flattened by a hemisphere. For this reason, objects on the horizon seem larger than those at their zenith. And despite the fact that the eye observes the constant angular size of the Moon (approximately 0.5 degrees), the brain automatically makes a correction for the distance, and we get an enlarged image of the observed object. However, so far, scientists have not decided which of the proposed versions is the most plausible.
