July 27th, 2018 will feature the 21st century's longest lunar eclipse, which will include an almost two hour long 'blood moon' phase when the moon will turn a brilliant red.

Modern end times preachers have included blood moons in their apocalyptic belief structure since at least 2014, when Christian ministers John Hagee and Mark Biltz claimed that a series of four consecutive lunar eclipses--known as a 'tetrad'--would result in the end of the world. The lunar eclipses ran from April of 2014 into September of 2015, and fully failed to predict any imminent Armageddon, at least so far.

Current end times preachers are continuing this apocalyptic tradition through their particular interpretation of two quotes from scripture.

One, from the Book of Joel, states "The sun will turn into darkness, and the moon into blood, before the great and terrible day of the Lord comes."

And another, from the Book of Revelation, which says "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."

"The Bible teaches that end event is coming just ahead of us now and that will be the greatest prophetic fulfilment in the last 2,000 years," Endtime Ministries' Irvin Baxter said to UK publication The Mirror.

Baxter is perhaps best known for a string of failed end times predictions dating back to the mid-1980s.

YouTube preacher Pastor Paul Begley is another believer in the blood moon's role in predicting the upcoming apocalypse, although he also believes that the planet is currently in the midst of a period of tribulations awaiting the return of the messiah.

“These Blood Moons always happen on significant days of prophecy," Pastor Begley said in a YouTube update. “And if you study the Blood Moons of 2014 and 2015--the four Blood Moons Pastor Mark Biltz and Pastor John Hagee made everyone aware of back in 2014, in 2015--they happened on the Feast of Passover and on the Feast of Tabernacle."

“Sandwiched in between there what happened? A war broke out in Israel and many other events," he continued.

“What’s happening now? Well the Blue Blood Moon in January was showing us that something was going to happen with Jerusalem and with Israel on its 70th year."

“But what is this Blood Moon saying? Is this the sign that a peace agreement going to happen? The Covenant of Many?"

“Or is it telling us a brutal war will happen in the Middle East?"

"We don’t know yet, that’s why you watch these signs in the heavens, you watch these signs of what’s going on on Earth and you keep an eye on Biblical prophecy because we’re living in the last days,” said the YouTube pastor.

Many mainstream Christians disagree with this apocalyptic approach, citing Matthew 24:36, which says of the timing of the apocalypse that "of that day and hour knoweth no man, no, not the angels of heaven, but my Father only."

Astronomers point to the relatively commonplace occurrence and well-understood nature of blood moons as evidence for why they are not predictive of any calamity, especially since there is no indication as of yet that the world has, in fact, ended.