Operators of the Perseverance rover have found that the bedrock on which the rover moves is composed of frozen magma, that is, formed by flows of volcanic lava. In addition, the rocks found in the crater have repeatedly interacted with water over many geological eras, and some of them contain organic molecules.
Earlier discoveries in the Jezero Crater
Mars today is cold and dry, but observations from rovers and orbiters show that its climate was milder in the past, and liquid water existed on the planet’s surface. To better understand exactly when it was, and whether Mars was inhabited at that time, NASA sent a new rover to the planet – Perseverance. It has been operating since February this year in the 45-kilometer Jezero crater.
Previously, it was assumed that there was a system of open lakes in the Jezero crater, but now the researchers came to the conclusion that Lake Jezero was closed (without rivers flowing out of it on a permanent basis), and the water level in it was lower than previously thought. All this new data came from the Perseverance rover and its sediment analysis.
Based on the results, scientists reported that a river flowed into the lake, which gradually formed sediments in the delta region. In addition, the history of the lake has had repeated episodes of flooding of varying intensity, which could have been caused by heavy rainfall or events of the rapid melting of snow or ice.
During floods, streams flowing at a speed of up to 9 meters per second along the river bed could move very large and heavy boulders from the edges of the crater to the bottom of the lake.
Thus, the crater bottom, as the former lake bottom, is of interest from the point of view of searching for organic matter or biosignatures. And Perseverance did not disappoint – in a new announcement, scientists reported that the rover discovered organic molecules in the crater.
Perseverance finds organic molecules in the Jezero Crater
The new discovery was made with the help of the PIXL (Planetary Instrument for X-Ray Lithochemistry) instrument – a planetary instrument for X-ray lithochemistry, an X-ray fluorescence spectrometer for accurately determining the elemental composition of materials from the surface of Mars, and mapping rocks encountered along the path of the rover.
The Perseverance mission team found that the rocks in the crater in ancient times were in contact with liquid water. This suggested that Jezero was once a lake. The analysis also showed that some of the Martian rocks contain organic molecules.
These are the substances that were found when analyzing the rocks and dust that the rover found in the crater. By the way, one of the stones found, as determined by scientists, was formed in ancient times from a red-hot magma splashed out onto the surface.
Organic molecules on Mars: what does it mean?
The organic molecules in the Jezero Crater were identified using the SHERLOC instrument. It is designed for scanning the environment using the Raman scattering method. The luminescence method is used directly to search for organic and chemical substances. The latter helped determine that carbon-containing molecules are not only found inside the rocky rocks analyzed by the SHERLOC instrument, but also in the dust.
Confirmation of organic matter is not confirmation that life once existed in Jezero Crater, the researchers note. The fact is that such a biosignature can also be created by non-biological mechanisms that create organic matter. At the same time, the discovered molecules, according to scientists, were quite capable of serving as “building blocks of life.”
The discovery of organic molecules inside ancient rocks, regardless of their origin, is in any case a breakthrough discovery. The very fact of this suggests that potential biosignatures, that is, signs of life, could be preserved not only in the Gale and Jezero craters but also in other regions of Mars.
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Sources:
• Crane, L. (2021, December 16). Perseverance mars rover uncovers the watery history of Jezero crater. New Scientist.
• Mangold, N. (n.d.). Perseverance rover reveals an ancient delta-lake system and flood deposits at Jezero crater, Mars. Science.
• NASA. (n.d.). NASA’s Perseverance Mars rover makes surprising discoveries.
• Wall, M. (2021, December 16). NASA’s perseverance rover finds organic chemicals on Mars. Space.com.
