On the night of January 20-21, the full moon will coincide with a total lunar eclipse, which will cause Earth's satellite to take on an eerie red glow in an effect that's come to be known as the Blood Moon. At the same time, the moon will sit at the closest point to Earth in its orbit, when it will appear massive in the night sky. It will make for a striking combination of both a supermoon and the Blood Moon, and marks the last total lunar eclipse we'll see until 2021.