A total lunar eclipse will make the moon appear red across the Western Hemisphere during the "Blood Worm Moon" this week.

Earth’s shadow will block most of the light that illuminates the lunar surface, creating what is known as a blood moon.

Lunar eclipses are often called "blood moons" because a red hue can be produced when the Earth's shadow covers the moon. The coloration happens because any sunlight not blocked by Earth is filtered through a thick slice of Earth’s atmosphere as it approaches the lunar surface, according to NASA.