There is a reason why perseverance landed where it came from, and the reason goes back at least 3.5 billion years.
Early Mars is thought to have been Earth-like before solar radiation and other cosmic forces killed its atmosphere. This explains why the rover that has now gone viral in the Twitter verses and just about everywhere else, got into the Jezero crater, which was presumably once a large lake that could also crawl through microbial life. Scientists have now found evidence that Mars went through the same phase as Earth before both planets got their atmosphere – something that has not been proven so far.
“Reduced greenhouse gases such as methane (CH4) and hydrogen (H2) may be the only viable solution to explain the warming of the ancient Martian climate, but direct geological evidence that there is a reduced atmosphere on Mars is lacking,” Jiancheng Liu said. . , who led a study recently conducted in Natural Astronomy.
The timing for this discovery was right. Perseverance began to search the Red Planet for possible signs of life, and that life – if it were as we know it – would require an atmosphere. But wait. Before you can find out when Mars started to get an atmosphere, and what it was like with an atmosphere (it’s hard to imagine looking at what is now a space desert), you need to back up further before it’s a oxidized atmosphere. There was a time when things did not rust on Earth or on Mars because there was not enough oxygen in the atmosphere to communicate with substances rich in iron.
Instead of an oxidized atmosphere, Earth and Mars once had a reduced atmosphere. This is not the same as the massive reduction of the atmosphere that the Red Planet experienced after most of its atmosphere was destroyed by solar winds and other cosmic forces. A reduced atmosphere consists of mostly reduced gases such as methane, ammonia and hydrogen sulfide, which are hydrogen rich rather than oxygen rich. People would not be able to handle inhaling this poison. However, there are microorganisms that are fueled on this planet by methane, so it will 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 species have been released into the atmosphere by human pollution, the right amount of these atmospheric gases are needed to heat a planet just enough for life forms to flourish.
Previous studies have assumed that this phenomenon occurred on Mars with reduced gases instead of CO2, meaning 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 of weathered Mars rocks showing signs that they were exposed to such an atmosphere.
“The separation of Fe from Al in Mars paleosoles, which is comparable to trends observed in paleos before the Great Oxidation Event on Earth, indicates that the ancient Martian surface was chemically weathered under a reduced greenhouse atmosphere,” Liu said. .
A spacecraft orbiting the Earth is examining rocks on the surface of Mars remotely. This spacecraft was equipped with an instrument that could perform infrared spectroscopy, which revealed the chemistry of these primeval rocks. When infrared light hits a target, it alternates with the molecules that make up the object. How the object in question absorbs, reflects or emits this light can give away what its chemical composition is. What the researchers wanted to know was the composition of the paleosoles on Mars, soils that formed centuries ago and that are not physically and chemically related to soils that formed more recently. This is how they identified a chemical sign of weathering caused by a reduced atmosphere.
Mars later underwent an oxidation event, largely during Earth’s Great Oxidation Event on Earth, albeit during a different time and possibly for different reasons. The Earth’s atmosphere oxidized because oxygen was a by-product of processes such as photosynthesis in early organisms. To prove that Mars had a diminished atmosphere before the oxidation happened could mean that life was involved in the shift in some way.
As Perseverence explores the Jezero crater, it may find more to support this discovery, and perhaps even a petrified microbe.