NASA photo of strange light on Mars has UFO buffs talking

This image taken by NASA's Curiosity Mars rover on April 3 includes a bright spot, in the upper left, which has yet to be explained. This image taken by NASA's Curiosity Mars rover on April 3 includes a bright spot, in the upper left, which has yet to be explained. Photo: Associated Press Photo: Associated Press Image 1 of / 10 Caption Close NASA photo of strange light on Mars has UFO buffs talking 1 / 10 Back to Gallery

Microbes, faces and rusted cars have all appeared as images on the surface of Mars, and now an official NASA photograph shows a bright light shining from the Martian surface.

It has - as they say - gone viral.

UFO buffs claim the light could be proof that some form of "intelligent life" is living underground and uses light "just as we do."

But scientists at the Jet Propulsion Laboratory in Pasadena, who have discovered evidence that ancient streams of water once flowed across the slopes of a vast Martian crater, are suggesting more prosaic explanations for the light.

A NASA spokesman said the bright spot appears in two images taken April 2 and 3 by the specialized Navigation Camera on the Curiosity rover, which has been exploring the planet's surface for nearly two years.

The image was picked up from NASA and posted by Scott C. Waring, who maintains a website called UFO Sightings Daily with the motto "The Truth Is Within Our Grasp."

In his blog, Waring said the light seems to be shining upward from the Martian ground and appears flat at the bottom.

"This could indicate there is intelligent life below the ground and uses light as we do," Waring wrote. "This is not a glare from the sun, nor is it an artifact of the photo process."

Rover mission spokesman Guy Webster told The Chronicle in an e-mail that "among the thousands of images received from Curiosity, ones with bright spots show up nearly every week."

The bright light appears in two images taken by the "right eye" of the Rover's stereoscopic camera, but not in its left one. Both lens systems, Webster said, are focused on the same spot of what appears to be the top of a nearby ridge, but is actually at ground level in front of a crater rim on the horizon.

"One possibility," Webster said, "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.

"The rover science team is also looking at the possibility that the bright spots could be caused by cosmic rays striking the camera's detector," he said.

NASA has sent six unmanned missions to the surface of Mars since 1976, when the two Viking spacecraft landed there seeking chemical evidence of living organisms but finding none.

The six-wheeled Curiosity rover, weighing more than a ton, landed inside Gale Crater on Mars on Aug. 6, 2012.