Scientists have found the oldest direct evidence of hot water activity on Mars, providing new insights into the planet's potential for habitability.

Researchers from Curtin University analyzed a 4.45-billion-year-old zircon grain from NWA 7034, the Martian meteorite also known as "Black Beauty," discovered in the Sahara Desert in 2011. The findings, published in "Science Advances" on Saturday, show that Mars had hydrothermal conditions during its early crustal formation which could potentially support life.

Using high-resolution microscopy and geochemical analysis at the nanoscale, researchers identified chemical zoning patterns and magnetite inclusions within the zircon grain. These features are consistent with minerals formed in the presence of water-rich fluids, indicating that Mars' crust interacted with hydrous fluids during the Pre-Noachian period, over 4.1 billion years ago. Hydrothermal systems provide heat and nutrients and are crucial for life, suggesting that ancient Mars could have supported habitable conditions.

Aaron Cavosie from Curtin University explained that their research detected signs of hot water on Mars 4.45 billion years ago. Despite meteorite impacts in Mars' early history, the presence of water could have created environments that support life. 

The study also found that these hydrothermal systems were linked to strong remnant magnetization in the Martian crust, showing evidence of a geodynamo during Mars' early history. These systems are crucial for insights into the surface hydrology and deep structure of the planet.

The zircon grain's features resemble those of terrestrial zircons formed with water, suggesting Mars' crust hosted wet, dynamic conditions early in its history. This discovery adds to previous observations of river-like landforms and clay minerals in the Noachian crust, extending the evidence of water activity back to the planet's primary crust formation. It implies that Mars may have had habitable conditions earlier than Earth.