An eclipse happens when Earth or the Moon moves into the other's shadow. In a solar eclipse the Moon's shadow falls on Earth, at new Moon. In a lunar eclipse Earth's shadow falls on the Moon, at full Moon. Eclipses do not happen every month because the Moon's orbit is tilted about 5 degrees, so its shadow usually misses. The same lamp-and-ball model that explained the phases explains eclipses. Eclipses are modeled indoors in this course, and the Sun is never looked at.