- 3682 - MARS - was there water on Mars? Was there ever water on Mars? Some sand on Mars is green, showing that it was once wet. Green sand might sound like a strange thing to find on the Red Planet.
--------------------- 3682 - MARS - was there water on Mars?
- While observing Perseverance’s landing site from orbit, it became clear that the rover would be landing near some spectacular layered rocks in Jezero Crater. They were looking at volcanic rock rather than sedimentary rock.
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- This was a huge discovery for the geologists studying the crater. Scientists expected to find sedimentary rocks, which had been worn away by water when Jezero crater, and Mars more generally, was a much wetter place. And while they did find some sedimentary rocks, they were typically deposited near the floor of the crater, what would have been the lake bottom during that wetter period.
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- Rocks on the way up the sides of the crater, which are the ones that were the most visible from space, were igneous that is the type that forms from lava. The rocks were a lot older than they expected. After observing them in detail with Perseverance’s SuperCam, the rover’s geology team realized that these rocks were more than 4 billion years old. The Earth is 4.5 billion years old.
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- On Earth, rocks that old would be weathered down by our climate. But on Mars, they are almost pristine. They discovered a color they were not expecting – green. Mars is known as the Red Planet for good reason, oxidation has formed a red tint to almost everything on the planet’s surface.
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- Upon closer inspection these igneous rocks were actually made of a mineral called “olivine“. Olivine is a slightly less spectacular version of a commonly known gemstone here on Earth, “peridot“. Olivine is also what makes the beaches on Hawai’seem dark green, and it has the same effect on Mars.
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- It is also a fascinating window into what the earlier Earth might have been like, right around when life formed almost 4 billion years ago. Earth’s environment from that time is lost to us, changed irrevocably by the climate and tectonics over millions of years. But on Mars, the environment has remained largely untouched until Perseverance.
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- More detailed analysis is needed before anything conclusive can be said about the environment of Jezero crater earlier in the solar system and whether it could have been habitable. But that is one of the primary goals of Perseverance and its team of dedicated geologists. This newest discovery is a step in the right direction.
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- The accepted view of Mars is red rocks and craters as far as the eye can see. What the rover found once on the ground was startling: Rather than the expected sedimentary rocks, washed in by rivers and accumulated on the lake bottom, many of the rocks are volcanic in nature. They are composed of large grains of olivine, the muddier less-gemlike version of peridot that tints so many of Hawaii’s beaches dark green.
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- Perseverance’s “SuperCam“, which helps analyze the rock samples and determine their type and origin. The rocks and lava the “rover” is examining on Mars are nearly 4 billion years old. Rocks that old exist on Earth but are incredibly weathered and beaten, thanks to Earth’s active tectonic plates as well as the weathering effects of billions of years of wind, water and life. On Mars, these rocks are pristine and much easier to analyze and study.
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- Understanding the rocks on Mars, their evolution and history, and what they reveal about the history of planetary conditions on Mars helps researchers understand how life may have arisen on Mars and how that compares with early life and conditions on ancient Earth.
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- The rocks Perseverance is roving over in Jezero have more or less just been sitting at the surface for billions of years, waiting for us to come look at them. That’s one of the reasons that Mars is an important laboratory for understanding the early solar system.
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- The search for life is one of Perseverance’s main goals and one of the reasons it landed in Jezero Crater in the first place. Discovering the potential for habitable environments in something as uninhabitable as Jezero Crater’s aged lava flows raises hopes for what lies in the sedimentary rocks the mission is examining now.
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- It wasn’t until we were very close up and looked at the rocks, at the millimeter scale, that we understood that these are not sedimentary rocks. They’re actually ancient lava. It was a huge moment when we figured that out on the ground.
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September 16, 2022 MARS - was there water on Mars? 3682
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