2021-10-13

Looking for signs of life on Mars: perseverance found clues to explore biological imprints

By yqqlm yqqlm

Beijing, October 13 (Xinhua) the latest issue of science magazine published the first paper on the exploration results of the “perseverance”, which introduced the discovery of the rover in the jezelo crater – an ancient delta lake system and flood sediments, according to the BBC Chinese network reported on the 12th

Looking for signs of life on Mars: perseverance found clues to explore biological imprints

on May 12, 2021, NASA announced on May 12 local time the photo of Martian hill “Santa Cruz” taken by perseverance with its mast camera mastcam-z on April 29

it is reported that traces of ancient aquatic organisms are usually preserved in the sediments at the bottom of lakes

one of the main tasks of “perseverance” is to collect samples from the sedimentary layer at the edge of jezro crater, which will be transported back to earth for the research team to explore and identify whether there was life on Mars and whether it left a “biological mark”

BBC science and technology reporter Jonathan Amos said that the analysis confirmed that the location of the rover was once the bottom of a great lake, there was a lake mouth on the west side of the great lake, and a winding river flows into the great lake here; That should have been 3.7 billion to 3.5 billion years ago, when the climate of the red planet was much milder

by analyzing the picture data sent back from Mars, scientists concluded that when the dry, barren and wind eroded basin was still a lake, the inlet of the river formed an impact Delta

the scene pictures also show that the rivers in the lake system of the meteorite crater have suffered serious floods, which may be at the end of the history of the lake. It is powerful enough to carry boulders and sediment into the lake from dozens of miles upstream. The boulder sank to the bottom of the lake and has been there until now

previously, according to the pictures taken from Mars orbit, scientists inferred that the landform on the west side of jezro crater is similar to the River Delta on earth, and perseverance took pictures of exposed rocks there for the first time, and determined the tracking clues

according to the analysis of flood sedimentary layer, scientists infer that the lake is in a calm state most of the time until the drastic climate change causes huge floods. The researchers hope to find more clues to the evolution of climate there

Looking for signs of life on Mars: perseverance found clues to explore biological imprints(1)

on February 28, 2021 local time, NASA released photos of Mars sent back by perseverance

on February 18, 2021, perseverance landed at the bottom of the jezro crater. NASA engineers operated remotely from the earth control center to check and debug many instruments on the Mars rover. During this period, the rover remained stationary, but the two cameras on board did not stop working and continued to shoot the surrounding environment and landform

these pictures and videos are transmitted to the earth. After processing and combination, they carefully observe different sedimentary layers along the Kodiak formation with high resolution, measure the thickness, slope and transverse range of each layer, and then compare them with the sedimentary layer pictures along other sections of the pit. Finally, a conclusion is drawn

they believe that the sediments at this site are formed by water deposition, which determines that it was once a delta at the intersection of rivers and lakes, rather than a sedimentary layer formed by wind or sheet flood and its geological process

another surprising discovery is the large stones and pebbles embedded in the top layer of delta sediments, the largest of which is one meter wide and estimated to weigh several tons. The research team believes that the stones were brought into the crater by some force, probably from the edge of the crater or 40 miles or more upstream from the entrance of the river

according to the analysis of the current position and size of the stones, the water velocity of washing these large stones into the lake is as high as 9 m / s. They are embedded on the top of the older and finer delta sedimentary layer, indicating that they precipitated later

in other words, the sediment and fine gravel in a river flowing into the lake continuously deposited to form the delta. Then one day, a mountain torrent burst in the upper reaches, washed the boulders into the lake mouth, deposited in the Delta, and formed today’s appearance after billions of years of wind erosion

scientists hope that these sediments can help humans uncover what happened to Mars a long time ago, how the climate changed, and how the sea withered and the rocks rotted

professor Sanjeev Gupta of Imperial College London is one of the main authors of papers in science. He told BBC news that the analysis showed that “there have been some changes in hydrology, but we don’t know whether it is related to climate.”

he explained that “moving these boulders requires something like flood (huge energy). Maybe there is a glacial lake upstream, and the flood flows into Jazero.” he also said that lake outbursts can be seen in places such as the Himalayas on earth, In the Ganges basin, you can see that these large stones are mixed with normal river sand, which is the place where the glacier lake suddenly floods

the “perseverance” scientific team will send the rover to the bottom of the main delta formation and drill where it is estimated to be fine-grained mudstone. They will also explore a circle of carbonate rocks around the edge of jezro crater, which may be the coast of the deepest volcanic lake

if there is any significance in studying the sediment strata of the estuary delta of the jezelo crater, we should first hope to reveal the changes of climate, river and environment in the period before the lake dried up

the clue we are looking for now points out where we should focus our exploration first and from which level of sediment. Perseverance cruised for eight months after landing on Mars and found clues to look for signs of life. The next exploration will no longer be aimless, but will focus on in-depth excavation at a certain place