Sourced from The universe in 100 colors: Strange and wonderful colors from science and nature by Tyler Thrasher and Terry Mudge. September 24, 2024, Sasquatch Books. Published with permission.
The red of a blood moon is the perfect example of how two separate bodies can have a drastic but temporary effect on each other. A few things have to fit together just right for people to enjoy the colorful display of a blood moon, starting with the fact that Earth is fortunately just big enough to cast the moon completely in its shadow under the right conditions, aka known as a full moon. lunar eclipse. The second necessary component is our atmosphere. A blood moon is the result of Rayleigh scattering, a phenomenon that is also responsible for our sunrises and sunsets. When sunlight passes through Earth’s atmosphere, particles in the air absorb certain wavelengths of light, leaving only the yellow, orange and red hues.
During a lunar eclipse, the moon moves toward the center of this circle and red wavelengths cover its surface. Image: Courtesy of Sasquatch Books
When a total lunar eclipse occurs, glowing remnants of Earth’s atmosphere extend through space and land on the moon’s surface. As light extends further away from us, the wavelengths also become longer, giving that light a red appearance. The quality of our atmosphere can also change the appearance of a blood moon, such as volcanic eruptions deepening the red.
If you want to read more from The universe in 100 colors: Strange and wonderful colors from science and naturesee Animals Only See in Black and White and 5 Other Color Myths.
