Scientists have detected a striking heat anomaly buried deep within the planet Mars.
The data suggest that the southern interior may be hundreds of degrees hotter than the northern half.
Some of the material at that depth could even be partially molten, behaving more like thick, hot liquid than solid rock.
This lopsided distribution of heat was not what researchers had expected from a planet often assumed to be geologically quiet.
The finding forces scientists to rethink what is happening beneath the Martian surface today.
It also offers fresh clues about how the planet formed and evolved over billions of years.
Understanding this internal heat could explain past volcanic activity and even the movement of the crust.
Once again, a distant world is proving far more dynamic than its calm surface suggests.