An analysis of the rocks that Perseverance sampled suggests that the Jezero crater had long been watered.
If you now look at the pictures Perseverance took in the Jezero crater on Mars, it may be difficult to imagine that life once existed here. And yet this is the place where NASA, after careful consideration, has decided to look for traces of (decayed) life. Mars must once have been much warmer and more humid than it is today. And judging by an ancient delta area found in Jezero Crater, researchers believe that rivers at that time carried water into the crater, creating a veritable crater lake there. And with that, the crater had one of the most important ingredients for life as we know it: liquid water.
However, it was unclear how long the crater had liquid water available. An analysis of the rocks Perseverance has sampled to date is now encouraging. “It appears that our first stones testify to a potentially habitable area that lasted for a long time,” said researcher Ken Farley. “It is very important that the water was there for a long time.” Because the origin of life (as we know it) requires not only water, but also time.
It was certainly not obvious that the lake in the Jezero crater lasted for a long time. Until recently, researchers could not rule out the possibility that the crater only filled with water during floods and then dried up again in a short time. But the first rocks that Perseverance has examined paint a different picture. It’s not just about Rochette – the foundation stone Perseverance successfully sampled twice earlier this month. But also to sample the stone that the robber tried – without success – in August. The extent to which both rocks have been affected by water points to the long-term presence of groundwater. How long exactly is still unclear, but based on what the researchers have seen, they are now more convinced that life may have originated in this area.
But the rocks do not only testify to the long-term presence of water. Salts have also been found in the rocks. And that too is good news. The salts may have formed when groundwater moved through the rocks and modified the minerals in these rocks. Another very real possibility is that they can be traced to the evaporation of liquid water. When this water evaporated, the salts were left behind. And from research on Earth, we know that these salt minerals are very capable of preserving any traces of life. The salt minerals in the first two cores may also contain tiny bubbles of Martian water, which can act as time capsules and provide even more insight into the past climate and habitability of Mars.
Researchers can’t wait to analyze the samples collected by Perseverance. However, some patience is in order; the samples are not expected to be brought to Earth until the beginning of the next decade.
Even more monsters
In the coming years, Perseverance will first sample many more – at various stones located in the Jezero crater -. And of course researchers hope to find traces of life in the process. In addition, however, the different rocks – with different ages – can also be used to draw up a timeline that provides more insight into how the climate in this crater changed over time and what impact those changes had on possible life.
With two samples in his pocket, Perseverance now searches for new rocks to sample and explore. NASA is targeting an area 200 meters away that has been christened South Séitah. The rocks in this area are probably older than the rocks Perseverance sampled or attempted to sample earlier. It could be a while before Perseverance also drills into rocks in South Séitah. Of course, the rover has to drive there first. In addition, all Mars missions will be halted in early October due to the conjunction of Mars. Mars – seen from Earth – is behind the sun. That makes communication a bit more difficult and so all missions are shut down for a few weeks as a precaution. Perseverance is expected to resume drilling after that.
Although Perseverance’s mission has only just begun and it is still completely unclear whether the rover will find what it is looking for (namely: traces of life), the first results are promising. In any case, the rover seems to have landed in a place where life may have originated and the traces of that possible life may also have been preserved.