A video shot on the International Space Station has been claimed as evidence that UFOs have visited Earth.
The clip shows what looks like large, white objects moving with unfeasible speed above the planet.
Posted two weeks ago, it has gained more than 400,000 views. It's not clear when the footage itself was filmed - some appears to be older than two weeks - but many of the commenters appear convinced.
Others have suggested it's space debris or meteorites streaking across the atmosphere.
Rather fewer have pointed out the irony that the ISS itself - our awesome, actually-real space station - doesn't appear to count as a space ship in the eyes of the conspiracy theorists...
Take a look - what do you think? Real or fake?
Lights moving rapidly, slowly and changing directions -- Jan. 2013
This video appears to show UFOs moving across the surface of the moon, slowing down and changing directions.
Several UFOs approach the moon -- April 2012
This video shows what looks like a group of UFOs approaching the moon on April 7, 2012.
UFOs seem to be leaving the moon -- Sept. 2012
In this video, posted by the same individual from the previous video, a large group of UFOs seems to be heading away from the moon toward outer space.
Triangle-shaped UFOs near the moon -- Dec. 2011
Shot with a camera on a tripod, this poster says the video shows triangle-shaped UFOs appearing to orbit the moon.