A NASA picture of a mysterious bright light on Mars has sparked the interest of UFO believers.
"One possibility is that the light is the glint from a rock surface reflecting the sun," said Justin Maki from NASA's Jet Propulsion Laboratory.
Maki explained that the bright spots appear in single images taken by the Navigation Camera on NASA's Curiosity Mars rover's right-eye but not its left.
In the right-eye images, the spot is in different locations and is seen at the ground surface level in front of a crater rim on the horizon.
"When these images were taken each day, the sun was in the same direction as the bright spot, west-northwest from the rover, and relatively low in the sky," said Maki.
"The rover science team is also looking at the possibility that the bright spots could be sunlight reaching the camera's CCD directly through a vent hole in the camera housing, which has happened previously on other cameras on Curiosity and other Mars rovers when the geometry of the incoming sunlight relative to the camera is precisely aligned."
The picture was captured on April 3 by the right-hand navigation camera on NASA's Mars Curiosity rover.
"We think it's either a vent-hole light leak or a glinty rock."