Kate Vate

Lunar eclipses occur when the Moon passes through the Earth’s shadow, however, for a total lunar eclipse to occur, the Moon and Earth have to be on the same orbital plane with the Sun — this is known as a syzygy. During a total lunar eclipse, the Moon travels completely into the Earth’s shadow (umbra). Even though the Moon is immersed in the Earth’s shadow, indirect sunlight will still reach the Moon. As sunlight passes through Earth’s atmosphere it gets absorbed and then radiated out (scattered). The atmosphere filters out most of the blue-colored light. What’s left over is the orange- and red-colored light. From the Moon’s perspective the Earth’s edge appears to glow bright orange or red. This red-colored light passes through our atmosphere without getting scattered, projecting indirect, reddish light onto the Moon.