During a Total Lunar Eclipse the Sun, Earth, and Moon form a straight line. As the Moon comes into alignment it enters the shadow created by the Earth called the Umbra. Even though the Earth blocks direct sunlight from reaching the surface of the Moon, the Moon is still visible to the naked eye, and actually turn’s red creating the legendary Blood Moon. This is caused by the Earth’s atmosphere which refracts the sunlight, bending particular wave lengths at different angles (like when rain refracts light to create a rainbow). The red light casts on the surface of the Moon, making it appear red.