The Perseverance Rover: Discovering potential signs of life on Mars
For the 21st time, the Mars Perseverance Rover has sampled a rock on Mars, and this occasion is particularly special. The initial analysis cautiously implies that this 21st sample holds what scientists have been hoping to find. To put it simply, this is the type of rock we were hoping to find,” says Ken Farley, a project scientist linked to the Perseverance mission.
Excitement over the findings
The reason scientists are so excited about this rock can be easily explained. An initial analysis of the rock’s interior revealed that it must have been in contact with water for a long period in the ancient past. “Almost all the minerals in the rock we just sampled were formed in water,” Farley explains. This is a significant finding because water is a crucial requirement for the emergence and maintenance of life as we know it on Earth. Therefore, this rock confirms what researchers suspected for a long time: there was conditions on Mars were once favourable for life due to the longstanding presence of liquid water.
Traces of Life
But there’s more. What particularly sets this sample apart is its potential to carry traces of life – if it has indeed existed on Mars. This is connected to the minerals making up the sample, each formed in the presence of water, Farley elucidated. Similar minerals found on Earth have been known to hold and preserve very ancient organic material and old biosignatures (chemical or physical phenomena likely resulting from life). To translate, if life once existed on Mars, this sample could be our best chance at finding traces of it.
The rock sample: Bunsen Peak
The sample was taken from a rock that NASA – the owner of Perseverance – has nicknamed ‘Bunsen Peak’. The rock is located on the edge of Jezero Crater, a 49-kilometre-wide crater in Mars’ northern hemisphere where Perseverance has been exploring since 2021. The rock instantly stood out due to its size – about 1.7 by 1 meter – and a somewhat unusual texture on one side. This presence prompted Perseverance to inspect and sample it. Before the rover drilled into Bunsen Peak, it scanned the rock with its SuperCam and PIXL X-ray spectrometer.
The composition: promising
The initial analysis of the data collected suggests that the rock comprises approximately 75% carbonate grains consolidated by almost pure silicon dioxide. “The silicon dioxide and parts of the carbonate seem to have a microscopically fine structure, making them extremely capable of capturing and preserving traces of microbial life that may have once existed in this environment,” says researcher Sandra Siljeström. This makes the sample ideal for studying biosignatures if returned to Earth. Furthermore, this sample may be among the older cores Perseverance has gathered to date, which is important given that Mars appears to have been most habitable early in its history.
The excitement about the sample collected by Perseverance is huge; however, for now, researchers can do little with it. The sample first needs to be brought back to Earth, which could still be about ten years away. In the meantime, Perseverance continues its hard work; the rover is currently moving further towards Jezero Crater’s edge. Here, researchers believe, older rock formations await further investigation. Once they’ve been studied closely, scientists plan to guide Perseverance up to the rim of the crater.
