Perseverance spent 1,000 "Martian Days" inside the Jezero Crater. This crater was once an ancient impact site on Mars, with a river and lake that once meandered through. Now, there is a huge delta here, like a gallery of stone-carved rivers where rovers are exploring. It has gathered enough information that it can map out the course of this location over eons without the need for a time machine.
It all started 4 billion years ago. An asteroid smashed Mars, creating a large crater — we call it Jezero Crater. The crater's floor is made of igneous rock, which is evidence of possible volcanic activity or magma formation on the surface of Mars after this impact. Hundreds of millions of years later, water came to Jezero.
Perseverance found sandstone and mudstone that showed that water flowed into this crater so long ago. However, above these rocks, there are other types of rocks. More mudstones, but these mudstones are rich in salt. Due to the inflow of water, a shallow lake is formed. It is estimated to be 35 kilometers (22 miles) long, but its deepest depth is only 30 meters (100 feet). The evaporation of the lake water leaves behind the salt.
However, the water history of this place does not end there. The new period of the last chapter, which lasts for a long time, is the rapid flow of water on the delta that the rover is exploring. This mighty river carries huge stones and scatters them on the surface of the delta.
"We chose Jezero Crater as the landing site because the orbital imagery showed a delta – a clear indication that a large lake was once filled with this crater. The lake is a potentially habitable environment, and the delta rocks are a good environment for burying traces of ancient life, such as fossils, in the geological record," Ken Farley, a scientist at the Perseverance project and a scientist at Caltech, said in a statement. "After thorough exploration, we have pieced together the geological history of this crater, mapping its lake and river phases all the way to the end. "
While this area is an ideal candidate for possible ancient life, the rover has yet to find any signs. Perseverance carries a set of equipment that can detect ancient fossil structures as well as the chemical changes brought about by ancient life. A thorough investigation has been carried out on many of the collected samples, but no findings have been made yet.
The area currently being explored contains carbonate material, suggesting that ancient aquatic environments may have bred life. Iron phosphate is also found, and phosphorus is a key ingredient in life. It is also rich in silica and is considered an ideal substance for the preservation of ancient life.
"Where carbonates and phosphates have been discovered, we have the ideal conditions to find signs of ancient life, which point to a moist, livable environment where silicates are also very good at preservation," added Morgan Cable, associate chief scientist at Pereseverance's planetary petrochemistry X-ray.
The rover didn't stop after spending 1,000 sols, and now it's time to explore the rim of Jezero's massive crater.