Researchers have reanalyzed the Lafayette meteorite, originally discovered in 1931, uncovering significant insights into the historical presence of liquid water on Mars.
The meteorite, a 5 cm glassy fragment of cosmic rock, was found in a box at Purdue University. Its origins remain unclear, but its discovery has greatly influenced the scientific community.
Recent analyses indicate that approximately 742 million years ago, liquid water existed on the Martian surface. This conclusion is supported by the meteorite's mineral composition, which interacts with liquid water during its formation.
Marissa Tremblay, a researcher from the Department of Earth, Atmospheric, and Planetary Sciences, stated that the age of the meteorite's minerals is less than a billion years. While it is believed that liquid water was scarce during this period, it may have emerged from melting subsurface ice, potentially triggered by ongoing magmatic activity on Mars.
The research team utilized changes in argon molecules found in the minerals to determine their age. They also considered heating effects from a collision 11 million years ago, as well as the meteorite's journey through space and Earth's atmosphere.
Although the exact date of the meteorite's arrival on Earth remains unknown, evidence suggests it may have fallen around 1919, based on fungal traces on its surface and anecdotal accounts of a student witnessing its descent.
Factors such as impacts and heating during its journey did not affect the age of the water-related changes in the Lafayette meteorite. This study established an effective method for determining the age of minerals in meteorites, applicable to other celestial objects.