There is a reason why Perseverance landed where it did and that reason goes back at least 3.5 billion years.
It is believed that early Mars was similar to Earth before solar radiation and other cosmic forces killed its atmosphere. This explains why the rover that has now gone viral on Twitterverse and almost everywhere else touched in Jezero Crater, which is once thought to be a huge lake that could also have crawled alive. microbial. Scientists have now found evidence that Mars went through the same phase as Earth before both planets reached their atmosphere – something that has not been proven so far.
“Low greenhouse gases such as methane (CH4) and hydrogen (H2) may be the only sustainable solution to explain the warming of the ancient Martian climate, but there was no direct geological evidence that a reduced atmosphere existed on Mars.” , said Jiancheng Liu. , which led a study recently published in Nature Astronomy.
The timing of this discovery was correct. Perseverance began to look on the Red Planet for any potential signs of life and that life – if it were something like this as we know it – would need an atmosphere. But wait. Before you realize when Mars started to get an atmosphere and what it was like with an atmosphere (kind of hard to imagine looking at what is now a space desert), you need to back it up before it does. to even oxidize the atmosphere. There is a time when things did not rust on Earth or Mars because there was not enough oxygen in the atmosphere to interact with iron-rich substances.
Instead of an oxidized atmosphere, both Earth and Mars once had a reduced atmosphere. This is not the same as the massive reduction in the atmosphere that the Red Planet experienced after most of its atmosphere was decimated by solar winds and other cosmic forces. A reduced atmosphere is made up of largely reduced gases, such as methane, ammonia, and hydrogen sulfide, which are richer in hydrogen than rich in oxygen. People would not have been able to cope with the breath of this poisoning. However, there are microorganisms that are fed methane right here on our planet, so it would not be impossible for Mars.
What once made Mars habitable was its own greenhouse effect. While greenhouse gases have been demonized on Earth because too much carbon dioxide and other types have been released into the atmosphere due to human pollution, the right amount of these atmospheric gases is needed to heat a planet sufficiently for the forms of life to prosper.
Previous studies had assumed that on Mars, this phenomenon occurred with reduced gases instead of CO2, which means that the planet must have had a reduced atmosphere. Evidence of this was eventually found by Liu and his team when they investigated spacecraft data from degraded Martian rocks that showed signs of being exposed to such an atmosphere.
“The separation of Fe from Al into Martian paleosols, which is comparable to the trends observed in paleosols before the great oxidation event on Earth, suggests that the ancient Martian surface was chemically subjected to a reducing greenhouse atmosphere,” Liu said.
An orbiting spacecraft examined the rocks on the surface of Mars from a distance. This spacecraft was equipped with an instrument capable of infrared spectroscopy, which revealed the chemistry of these primordial rocks. When infrared light hits a target, it interacts with the molecules that make up that object. The way in which the object in question absorbs, reflects or emits this light can provide what its chemical composition is like. What the researchers wanted to know was the composition of paleosols on Mars, soils that formed aeons ago and that have no physical and chemical connection to the soils that formed more recently. This is how they identified a chemical sign of the weather caused by the reduced atmosphere.
Later, Mars underwent an oxidation event, the largest oxidation event of the Earth on Earth, although at a different time and possible for different reasons. The Earth’s atmosphere oxidized because oxygen was a byproduct of processes such as photosynthesis in early organisms. Demonstrating that Mars had a reduced atmosphere before its oxidation event occurred could mean that life was somehow involved in change.
As Perseverance analyzes the Jezero crater, it may find more to support this discovery and perhaps even a fossilized microbe.