As much as you probably wanted to believe that the weird substance found last summer by China’s Yutu 2 rover (part of the Chang’e 4 mission) was lunar slime, a closer look at the blob on the Moon’s far side has possibly demystified it.
Whatever was discovered by Yutu 2 did look sort of gelatinous. When the rover first landed on the moon, the image of a silvery glob in Von Kármán Crater that it beamed back basically made the internet explode with #GelGate. What exactly was this thing at the bottom of a crater? It is now almost certain that while it may appear slimy or glittery to the eye, you’re probably looking at black glass created by either ancient volcanic activity or the intense heat of a meteor impact.
It didn’t help that initially, Yutu 2 first viewed the mass with its obstacle-avoidance camera, which is anything but hi-res. This also explains why there were splotches of color in the original image that are now being blamed on the rover’s instruments.
NASA Goddard geologist Dan Moriarty created four enhanced versions of the image (in the tweet below) by adjusting brightness, contrast, and other elements that may reveal what the substance could be. Even with the absence of a scale bar JPEG compression getting in the way, he was able to figure out that the material was just rock that had probably been melted into glass by a meteorite impact. It was probably no different from the surrounding regolith before.
It’s not like this kind of space glass is rare on the moon. Residue left behind by meteorite impacts or spewed out by volcanoes is believed by scientists to be everywhere. Astronauts on the Apollo 17 mission unearthed orange soil that was really the aftermath of a volcanic eruption three billion years ago.
"I think the most reliable information here is that the material is relatively dark,” Moriarty told Space.com. “It appears to have brighter material embedded within the larger, darker regions, although there is a chance that is light glinting off a smooth surface."
Moriarty’s image modification goes even further than that to suggest that the impact which created the crater where the stuff was found could have hit so hard that it threw buried material to the surface. There is also the possibility of it being a breccia, a kind of heterogeneous rock made out of fragments that have fused together. If this is what it is, it may contain glass, crust, and the aftermath of ancient eruptions that are now found in volcanic seas, or mare, that have long since dried up.
If there is one thing we now know for sure, what was masquerading as a blob is actually a rock. Sorry to anyone who wanted to believe.