Scientists explain why the Moon turns red during a total eclipse

Before every total lunar eclipse, LiveScience publishes articles explaining in popular language to ordinary people why we see a Blood Moon during a total eclipse. The next total lunar eclipse is May 26, 2021.

The only total lunar eclipse this year will occur when the full moon passes through Earth’s shadow. This event is also called a Super Moon, due to the fact that the satellite is very close to Earth at this time. During a total lunar eclipse, the surface of the moon always takes on a brick red hue.

A total lunar eclipse or Fiery Moon is the most dramatic of the three types of lunar eclipses. First of all, it is during a total eclipse that the Sun, Earth, and Moon are perfectly aligned, not a single deviation. During an eclipse, from the first seconds to the last, the Moon constantly changes its visible color from amber to blood-red.

To understand why this happens, scientists suggest that a person imagine standing on the Moon and looking at the Earth during an eclipse. When the Earth is directly in front of the Sun, preventing the sun’s rays from illuminating the Moon, you will see a fiery rim surrounding the planet. This happens because the Sun’s light skirts the edges of the Earth before it reaches the surface of the Moon.

But before it does, the sun’s rays pass through Earth’s atmosphere, which filters out the short-wave blue light, leaving the red and orange colors intact, which is what reaches the moon. This is why the Moon appears red.

Atmospheric conditions can also affect the brightness of colors and differences in hues. For example, forest fires on the planet’s surface can make the Moon appear blood-red, which looks intimidating.