Remember that awesome image of the Kimberley Waypoint we showed you yesterday? Well, some astute observers noticed an artificial light glowing on the surface. And that's certainly what it looks like — but there's a very reasonable explanation.
I contacted Ken Kramer from Universe Today to get an explanation.
"That tiny little blip is likely a cosmic ray strike or a hot pixel," he replied. "It's not aliens." Indeed, one UFO website in particular started to make wild proclamations about an intelligent civilization living beneath the Martian surface.
Kramer also added that it's not in the corresponding left-side NAVCAM image, and he's absolutely right. Check out this GIF put together by Phil Plait of Bad Astronomy:
Cosmic rays are charged subatomic particles (like protons, electrons, and so on) zipping around in space. On Earth, our atmosphere absorbs them so they don't have much of an effect on cameras down here. But if you put a telescope in space, they are bombarded by these little beasties. When a cosmic ray slams into the electronic detector in the camera, it deposits some energy in the pixel (or pixels) where it hits. These detectors are designed to detect energy from incoming light, and they can't tell the difference between a cosmic ray hit and a photon coming from a distant star.
This isn't the first time we've seen this optical effect. "Cosmic ray strikes have appeared many times in spacecraft images," Kramer told io9.
Plait concurs, writing:
I'll note we see this kind of thing all the time, including in Curiosity images. Here's one over a rock, for example. It's not hard to find more if you peruse the Curiosity raw images archive (or the Unmanned Spaceflight forum, where space aficionados post and discuss the latest images from various missions).