“The sun shall be turned to darkness, and the moon to blood, before the great and awesome day of the LORD comes.” (Joel 2:31)
This passage from Joel (quoted in Acts 2:20, and alluded to in Rev. 6:12) is believed by many to refer to the astronomical phenomena of the “Blood Moon,” an eclipse-like event where the earth casts a red shadow on the moon.
Such an event happened last night, and is being interpreted by some as a preparatory sign of the second coming of Christ.