Alien fans have finally been given a scientific explanation for the mysterious "spire" they spotted on the moon.
NASA scientist, Dr. Noah Edward Petro, told the Huffington Post US why UFO enthusiasts were wrong to assume that intelligent life was responsible for the structure.
UFO Sightings Daily, a website dedicated to extraterrestrial sightings, claimed the discovery "was probably built to accommodate a very large vessel so that it could dock safely without landing."
YouTube user, MexicoGeek, spotted the crater using Google Moon and posted a collage of the images in a video.
Scott C. Waring of UFO Sightings Daily later added: "The spire looks to be coming out of the center of a crater, but these are not craters, but many small white shiny structures."
However, Petro, deputy project scientist for Lunar Reconnaissance Orbiter Camera (LROC) mission, stated: "That's no spire! What is going on is that there is a small crater that formed on the rim, after the larger crater, Mersenius E."
He added: "The sun is so low on the horizon such that the dimple in the crater wall casts a shadow on the eastern wall of the crater.
"There is a dark cascade of material falling down into the larger crater, likely caused by material falling into the crater floor.
"No spire there, so yes, it's an optical illusion."
So, nothing to see here. Let's keep calm for now, at least until the next optical illusion comes along.