Sorry, beacon of light in Mars photo caused by 'shiny rock' not aliens, says Nasa

Nasa has rained logic and common sense on speculation that the bright light that features in a photo from the surface of Mars taken by its Curiosity rover is some kind of luminous alien, suggesting it is "likely a glinting rock or cosmic-ray hit".

The image has been widely shared since the rover tweeted it yesterday, with people trading various optimistic theories as to what could be causing the light on Mars' horizon.

And who could blame them, when explanations like it is the light from an alien hut are far more entertaining than the reality: it's probably just some light shining off a rock.

"In the thousands of images we've received from Curiosity, we see ones with bright spots nearly every week," said Justin Maki of NASA's Jet Propulsion Laboratory, the leader of the team that built and operates the rover's Navigation Camera.

"These can be caused by cosmic-ray hits or sunlight glinting from rock surfaces, as the most likely explanations."

Nasa did admit that this particular bright spot is a little unusual however.

"The bright spots appear in images from the right-eye camera of the stereo Navcam, but not in images taken within one second of those by the left-eye camera," it stated. "Normally we can quickly identify the likely source of a bright spot in an image based on whether or not it occurs in both images of a stereo pair. In this case, it's not as straightforward because of a blocked view from the second camera on the first day."

Not the Independence Day moment many were looking for then, but if you are in need of a "Duuuuuuude" space story, here's what Earth looks like from Mars.