This weekend, the combination of a supermoon and a "blood moon" has some people freaked out about the possible end of the world.
The event, which will happen overnight Sunday, is basically the convergence of two astronomical phenomena: A supermoon, which happens when the moon reaches its closest point to Earth, and a lunar eclipse, which takes place when the earth moves in between the moon and the sun. With direct sunlight blocked, the moon appears to take on a reddish hue, hence the phrase "blood moon."
The last time this combination of events happened was in 1982.
A lot of people are seeing these phenomena as a sign of the end of times.
The idea is that the blood moons are the fulfillment of prophecy from the New Testament, with Revelations 6:12 among the oft-cited passages:
And I beheld when he had opened the sixth seal, and, lo, there was a great earthquake; and the sun became black as sackcloth of hair, and the moon became as blood.
When there is a series of four blood moons within two years, it's called a "tetrad." Saturday's blood moon will complete a tetrad, having followed previous lunar eclipses in April and October of 2014, as well as April of this year.
Each of the recent blood moons have also happened on Jewish feast days, which believers see as significant.
Pastor John Hagee is one of the highest profile figures connecting the upcoming blood moon to prophecy and, potentially, disaster. Hagee is the author of the 2013 book Four Blood Moons, and in a promotional video for the book he predicted a "world shaking event that will happen between April 2014 and October 2015."
In an interview posted online earlier this week, Hagee further suggested war involving Iran was "guaranteed."
"The day we validate this Iran nuclear deal as signed, sealed, and delivered will be the day we stick our finger in the eye of God," Hagee said.
Others from various factions of both Christianity and Judaism have connected to the blood moon to an array of other events from natural disasters to the return of the Messiah.
Anxiety about the blood moon is driving sales of emergency supplies.
The apocalypse bug has apparently hit many Mormons as well. The Salt Lake Tribune reported that emergency kits are flying off the shelves in Utah, with one salesman describing "a sense of urgency" and people "mentioning things about September."
Another salesman, for the company Emergency Essentials, told the Tribune many customers think "this is the month it will all happen — with a 'blood moon' and a currency collapse and everything."
The company has a lengthy infographic on its website explaining blood moons and tetrads, and concludes that now is the time to "get prepared."
It's difficult to tell how widespread fear of an apocalyptic event is in Utah and Mormonism.
The Associated Press reported that most Mormons "probably haven't even heard of this latest theory tied to the blood moon," and an unscientific survey of friends of this reporter, who is Mormon, showed that most were only vaguely aware of the theory, if at all.
Still, speculation was rife enough that the church issued a statement — which was provided to BuzzFeed News Friday — reminding members to "avoid being caught up in extreme efforts to anticipate catastrophic events."
The statement also noted that members of the church are encouraged to have emergency supplies of food and water to cope with "disasters and the normal hardships that are part of life, including illness, injury or unemployment."