red moon

A lunar eclipse from Sydney on Aug. 28, 2007. Photo courtesy of Peter Gaylard, via Wikimedia Commons

Could a series of “blood moon” events be connected to Jesus’ return? Some Christians think so.

In the wee hours of Tuesday morning, the moon slid into Earth’s shadow, casting a reddish hue on the moon. There are about two lunar eclipses per year, according to NASA, but what’s unusual this time around is that there will be four blood moons within 18 months — astronomers call that a tetrad — and all of them occur during Jewish holidays.

A string of books have been published surrounding the event, with authors referring to a Bible passage that refers to the moon turning into blood. “The sun shall be turned into darkness, and the moon into blood, before the great and terrible day of the Lord,” Joel 2:31 says.