NASA: 'UFO' Light on Mars May be a Shiny Rock - Video

Scientists are throwing cold water on yet another purported "alien" sighting by NASA's Mars rover Curiosity.

Though UFO enthusiasts may beg to differ, mission team members say bright flashes of light visible in Mars photos taken by the Curiosity rover on April 2 and April 3 almost certainly have a perfectly ordinary explanation.

"One possibility is that the light is the glint from a rock surface reflecting the sun. 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," Justin Maki, the lead for Curiosity's engineering cameras, told reporters.

"The rover science team is also looking at the possibility that the bright spots could be sunlight reaching the camera's CCD [charge-coupled device] 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," added Maki, who is based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We think it's either a vent-hole light leak or a glinty rock."

It's also possible that the flashes resulted from the impact of fast-moving cosmic rays with the camera, Maki said in a statement released by NASA today (April 8). Whatever the cause, the phenomenon is far from rare.

"In the thousands of images we've received from Curiosity, we see ones with bright spots nearly every week," Maki said in the NASA statement.