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Pilbara chert the key to life on Mars

 

The search for life on Mars has taken a huge step forward, with NASA’s Mars rover Perseverance touching down on the red planet.

 

On board the rover were 22 samples of earth from all corners of the world – including one chosen from Australia’s own Pilbara region by three lucky geologists.

Back in 2015, Associate Professor Patrice Rey, Professor Nicolas Coltice, and then PhD candidate Claire Mallard chose a sample that best represented what NASA hopes to find on Mars – a piece of red chert.

Of the 22 samples, 19 were synthetic, while the Pilbara red chert was one of three natural samples.

Rey, from the school of Geosciences at the University of Sydney, said they didn’t hear anything about the sample for another five years after sending it off, forgetting about it and expecting nothing from the matter.

“The advice was don’t spend too much time on new samples, you have a very small chance that one of the samples will find its way to Mars,” he said.

But the professor said he and his team were pleased to hear their chosen sample had been shortlisted last year.

“That little piece of rock we sent to Mars is a perfect analogue to what we expect to find,” Rey said. “It means that all the ingredients at the molecular and atomic level are all there trapped in our little sample.

“We couldn’t have sent a more perfect sample for the Perseverance mission and we were really excited that they chose ours.”

If Perseverance finds that the Martian surface matches the Pilbara chert, then NASA will have taken another step in confirming life once existed on Mars.

Professor Rey said he is expecting positive results from the mission to the red planet.

“I’ll be really surprised if we don’t discover [any positive results],” he said.

“The fact it is red is very significant. The red colour in that chert came from a few percent of hematite which is an oxidised form of iron hydroxide. And this shows that free oxygen was available to produce the hematite.”

Rey is currently working on projects looking at the relationship between landscapes and biodiversity on Earth.