There are a number of explanations for it, depending upon the answer you want. In Wiccan, Druidry or other early religions, blood on the moon was a time for sacrifice, celebrating the harvest.
Astronimically, blood on the moon is a total lunar eclipse, which often makes the moon appear red.
In some religious circles, this raises the question of "Will Jesus Christ return to Earth in the year 2015?"
And can studying NASA's website provide evidence for such a scenario?
A minister who promotes the Old Testament roots of Christianity suggests a rare string of lunar and solar eclipses said to fall on God's annual holy days seven years from now could herald what's come to be known as the "Second Coming" of Jesus.
"God wants us to look at the biblical calendar," says Mark Biltz, pastor of El Shaddai Ministries in Bonney Lake, Wash. "The reason we need to be watching is [because] He will signal His appearance. But we have to know what to be watching as well. So we need to be watching the biblical holidays."
In a video interview on the Prophecy in the News website, Biltz said he's been studying prophecies that focus on the sun and moon, even going back to the book of Genesis where it states the lights in the sky would be "be for signs, and for seasons."
"It means a signal, kind of like 'one if by land, two if by sea.' It's like God wants to signal us," he said. "The Hebrew word implies ... not only is it a signal, but it's a signal for coming or His appearing."