kelroshamからの質問: Explain this red moon phenomenon pls
So the “blood” red moon happens for the same reason that the sky turns red when the sun sets. Before I explain this further, lets establish some facts:
First, we consider that the only reason the moons “shines” at night is because it is reflecting light from the sun. The reason we see this reflected light as being colored white is because it is coming from all wavelengths in the spectrum (all visible colors of light mixed together make white light).
A lunar eclipse occurs when the Earth is in between the sun and the moon like so:
Now you might ask: “Because the sun’s light is blocked shouldn’t the moon be completely dark? Shouldn’t we be unable to see it at all during a lunar eclipse?” This seems like a logical assumption before earth’s atmospheric light scattering is considered. In a similar way that prisms “bend” white light and separate it into colors, so does earth’s atmosphere (this is why the sky changes colors when the sun sets, i.e. because the light travels through more of the atmosphere and begins to approximate this prism effect for different wavelengths of light).
It just so happens that red light travels out of our atmosphere at an angle so that it hits the moon and is reflected back to earth. That is why a Lunar Eclipse makes the moon seem red like this!
Thanks for the ask!