Good day, student of introductory astronomy!

Since you were interested enough to inquire, I have decided to pass along the following to you. This is in regards to why we can still see the Moon during a total lunar eclipse. And why is it red?

Well, if the Earth had no atmosphere, the Moon would enter the Earth's broad umbral shadow and then....lights out! The Moon would simply disappear from view as all sunlight would be blocked by the opaque Earth. However, the Earth is surrounded by a thin layer of atmosphere that acts as a lens that refracts (bends) sunlight toward a focus in the direction of the Moon. Most of the light is blocked by the Earth, and the Moon becomes very dim indeed. But those rays from the Sun that pass through the Earth's atmosphere are bent towards the Moon, illuminating it faintly. The reason the Moon appears a ruddy or coppery red color has to do with the same reason our Sun appears similarly at sunrise and sunset. Molecules of air, as well as very small solid particulates (called aerosols) scatter short wavelength (blue) light preferentially (making our sky blue), leaving mainly longer wavelength (red) light to pass through. An astronaut standing on the Moon watching the eclipse of the Sun would see a red ring of ``sunset'' surrounding the dark Earth.

thanks for your interest,

Professor Korista