Many End Time theorists believe a celestial event, known as the Blood Moons or blood moon tetrad, coincide with periods of great change affecting not only Israel, but also the world. The three places in Scripture when the moon turns the color red is in Joel 2:31, Acts 2:20 which specifically quotes Joel and also Revelation 6:12. A lunar eclipse is the obscuring of the moon’s light, a reflection of the sun’s rays hitting it, due to the earth passing between it and the sun. A solar eclipse on the other hand is the obscuring of the sun’s light due to the moon passing between it and the earth. A tetrad is a series of four consecutive total eclipses of the lunar surface. Tetrads are very rare occurrences. While none of these occurred from 1582 to 1908, seventeen are to take place from 1909 to 2156.