Excerpted from The Universe in 100 Colours: Bizarre and Wondrous Colours from Science and Nature by Tyler Thrasher and Terry Mudge. September 24, 2024, Sasquatch Books. Printed with permission.
The crimson of a blood moon is the right instance of how two separate our bodies can have a drastic but short-term impact on each other. A couple of issues need to line up excellent for people to benefit from the colourful show of a blood moon, beginning with the truth that Earth is fortunately simply massive sufficient to forged the moon fully in its shadow underneath the best situations, often known as a full lunar eclipse. The second needed part is our environment. A blood moon is the results of Rayleigh scattering, a phenomenon additionally liable for our sunrises and sunsets. When daylight passes via Earth’s environment, particles within the air take in sure wavelengths of sunshine, leaving solely yellows, oranges, and reds.
When a complete lunar eclipse happens, glowing remnants from Earth’s environment stretch via area and land on the floor of the moon. As the sunshine stretches farther away from us, the wavelengths additionally lengthen, giving that mild a crimson look. The standard of our environment may also work to change the looks of a blood moon, corresponding to volcanic eruptions deepening the crimson.
In case you’d wish to learn extra from The Universe in 100 Colours: Bizarre and Wondrous Colours from Science and Nature, try Animals solely see in black and white and 5 different colour myths.