A total lunar eclipse occurs when the moon and the sun are on exact opposite sides of Earth. Although the moon is in Earth's shadow, some sunlight reaches the moon. The sunlight passes through Earth's atmosphere, which filters out most of the blue light, causing the moon to appear red to people on Earth.

Join us on Facebook Live for a broadcast of the total lunar eclipse! 
facebook.com/exploratorium/
January 20, 2019
7:30 p.m. PDT