Astronomers have made a remarkable discovery on Mars that could revolutionise our understanding of the red planet's history.
NASA's Perseverance rover has identified unusual pale rocks containing a aluminum associated mineral called kaolinite.
This finding has stunned scientists because kaolinite typically forms only in warm, wet environments.
"These rocks are very different from anything we've seen on Mars before," said Professor Roger Wiens from Purdue University, who led the research team.
The pale rocks were found on the surface of the Red Planet
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The discovery suggests Mars may have once been warmer, wetter and more hospitable to life than previously thought. It came about when Professor Wiens directed the rover to shoot its laser at oddly pale rocks lying on the Martian surface.
This analysis revealed they contained unusually high aluminum associated with kaolinite. The blocky projection on top of the Perseverance rover, which resembles a quadruped's neck and head, is called SuperCam.
This instrument was developed by an international team led by Wiens before he joined Purdue University. SuperCam uses a suite of techniques to analyze the Martian surface, allowing scientists to make these groundbreaking discoveries.
Researchers had observed the small, pale pebbles in the Martian soil from the first day the rover landed.
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"On Earth, these minerals form where there is intense rainfall and a warm climate or in hydrothermal systems such as hot springs. Both environments are ideal conditions for life as we know it," Wiens explained.
The mineral kaolinite typically forms in environments that are hospitable to some forms of microbial life.
Scientists are particularly excited because this suggests Mars had conditions that could have supported life.
"It's fascinating. It's unexpected on a cold, dry planet like Mars," said Wiens. The discovery was published in Communications Earth & Environment by Wiens and his team.
This finding challenges our current understanding of Mars as a perpetually cold, dry world. The team found more than 4,000 of these white rocks and pebbles scattered across the Martian surface.
Analysis revealed they contain both kaolinite and spinel, likely aluminum spinel.
"The big questions about Mars are about water," Wiens said. "How much water was there? How long was there water?"
He added: "Given how cold and dry Mars is now, where did all that water go?"
Mars will stand out with its distinctive reddish colourGettyDr Candice Bedford, co-lead author of the research, noted that whilst the rover hasn't seen these rocks "in place" in bedrock, satellite data shows "kaolinite-rich rocks in Jezero crater's rim".
"Investigating these rocks in place will help us test our hypotheses on how the rocks formed, how they relate to Mars' ancient environment and the habitability of the planet in the past," she said.
These insights could guide scientists to the first true signs of ancient extraterrestrial life.
