Brains
This post first appeared on NASA’s ‘Astronomy Image of the Day’ page.
What color is the Moon? It depends on the night. Outside of the Earth’s atmosphere, the dark Moon, which shines by reflected sunlight, appears a magnificently brown-tinged gray. Viewed from inside the Earth’s atmosphere, though, the moon can appear quite different.
The featured image highlights a collection of apparent colors of the full moon documented by one astrophotographer over ten years from different locations across Italy.
A red or yellow-colored moon usually indicates a moon seen near the horizon. There, some of the blue light has been scattered away by a long path through the Earth’s atmosphere, sometimes laden with fine dust.
A blue-colored moon is rarer and can indicate a moon seen through an atmosphere carrying larger dust particles.
What created the purple moon is unclear––it may be a combination of several effects.
The last image captures the total lunar eclipse of 2018 July––where the moon, in Earth’s shadow, appeared a faint red––due to light refracted through air around the Earth.
