Don't Martians know that stone stacking is bad for the environment? NASA's Perseverance rover on Mars captured this image of what appears to be a small stone balanced atop a large rock. How odd. Or maybe not. Gizmodo reached out to NASA and heard back from planetary geologist James Rice of Arizona State University's School of Earth and Space Exploration and here's his take on it:
Balancing rocks (sometimes called Precariously Balanced Rocks PBRs) of various sizes, ranging from small rock sizes (inches) to formations hundreds of feet high, are naturally occurring and not really that unusual. Often a balancing rock is in fact connected to the larger underlying rock by a stem or pedestal. The Martian balancing rock shown is found at the Rockytop outcrop near the base of the delta and was most likely formed after extensive aeolian (wind) and/or chemical erosion carved it out from the local bedrock.
These types of features are more than just geologic curiosities; in fact they have been called "reverse seismometers" because the existence of PBRs makes it possible to measure earthquakes/marsquakes that didn't happen. If these rocks are still balanced, then the ground hasn't moved enough to knock them over. So we can use these features to learn about a region's seismic history.
