From the photo, this is a very strange white "bright spot". Because it is abrupt in the dark gray background around it, it is speculated that this is likely to imply the existence of intelligent life forms underground on Mars.
However, some analysts believe that it is more likely that there is a small problem in the process of photo imaging. In the past, many similar "Martian life theories" have been proved to be wrong. According to Effie's 20 14 12.8 report, the latest data collected by American Curiosity Mars probe reveals the mystery of the formation of Shapu Mountain, the center of Mars Gael Crater: mount sharp was most likely formed by the accumulation and weathering of sediments in a large riverbed millions of years ago, which strongly supports the hypothesis that there were lakes on Mars.
The information collected by Curiosity in mount sharp shows that the climate on Mars was relatively warm for a long time, and the average temperature was higher than zero degrees Celsius, which provided an environment for the emergence of water circulation systems such as lakes. During this period, Gael Crater may turn into a lake many times and evaporate and dry up many times. The sediments in the lake have undergone continuous weathering, alternately accumulating layer by layer, forming the mount sharp.
Professor Pasadi of California Institute of Technology pointed out, "Curiosity continues to collect and study the low rock stratum at mount sharp 150m, and the data obtained all support the hypothesis that mount sharp is formed by precipitation and weathering of lake sediments. I hope that Curiosity will get more data at 20 15 and finally confirm this hypothesis. " The latest discovery of NASA's Curiosity: There was a lake on Mars (screen shot). Curiosity Mars probe collects data at Gail crater on Mars (screen shot). Mount sharp is located in the center of Gael Crater, with a height of about 5,000m (screen shot). Beijing time 65438+February 18 news, combining the British "Daily Mail" and the American Space Network, but there is a bigger question: Did life ever exist there, or does it still exist today?
Scientists may soon be able to give the same definitive answer to this question, because NASA's Curiosity Rover has recently made some key discoveries.
A device on Curiosity detected an abnormal increase in methane content in the air. Scientists believe that the formation of methane may be related to the activities of bacterial life-if confirmed, this will be the first time we have detected signs of life on another planet.
Sushil Atreya of the University of Michigan, a member of the science team of Curiosity Rover, said: "This phenomenon, that is, the concentration of methane rises temporarily and then drops quickly, tells us that there is a local source here. There are many possibilities, which may be biogenic or abiogenic, such as the interaction between water and rocks. "
Major discovery
Previously, detectors operating in orbit had also detected methane signals in the atmosphere of Mars. However, none of the previous findings can be compared with the sudden increase in methane content detected this time, and the place where this phenomenon occurred-Gail crater happened to be the area where liquid water activities existed billions of years ago. On August 20 12, the rover curiosity landed in this crater with a diameter of about 96 miles (about 154 km), and has been conducting geological surveys in the surrounding areas since then.
Recently, the National Aeronautics and Space Administration (NASA) said that scientific evidence shows that Gael Crater used to be a huge lake, and perhaps there are environmental conditions suitable for microorganisms to survive here.
This latest discovery has been published in Science magazine, which is the analysis result of the Tunable Laser Spectrometer (TLS) carried on Curiosity-the principle of this equipment is to analyze the chemical composition of samples by using intense laser. The analysis results show that the background value of methane content is very low, and its content has soared by 10 times in just 60 Mars days.
During the four consecutive measurements, Curiosity found that the methane content soared from 0.69 ppbv (one billionth unit volume) to 7.2ppbv, and the height difference of the area where the measured value soared was between 655 feet and 985 feet (200-300 meters), only 0.62 miles (about 1 km) away from the location where the low background value was measured.
When Curiosity continued to drive about 1 km, the phenomenon of high methane reading disappeared. In this latest article, the research team led by Dr. Chris Webster of NASA's Jet Propulsion Laboratory wrote: "The persistence of high-level methane content in 60 Mars days and the sudden drop in 47 Mars days are not consistent with the result of mixed effects, but more like the existence of local methane sources. Once it disappears, methane gas in the air will dissipate rapidly." The wind direction at that time showed that this local methane source should be located in the north of Curiosity.
On the earth, life is the main source of methane, but there are also many abiotic reasons for the formation of methane gas. Curiosity has previously detected a low background value of methane in the atmosphere of Mars, which can be explained as the product of organic matter degradation caused by solar radiation, which may be brought to Mars by meteorites.
However, such a sudden increase in methane content needs to be explained by local sources, which is unlikely to be related to comets or meteorites that hit Mars.
Because if a comet or meteorite really falls nearby and causes such an increase in methane content, then the falling rock must be several meters in diameter and will leave obvious craters on the ground, but Curiosity has not found such signs nearby.
At the same time, the content of methane gas has soared in such a short time, which cannot be explained by the release of volcanic gas captured in the ice layer, and it seems difficult to reasonably explain this phenomenon by the release of methane gas in the soil.
Explain carefully
Scientists at NASA are very cautious about drawing conclusions, but say that methane gas produced by life activities is indeed one of many possibilities. They wrote in the paper: "Our measurements on Mars for more than one Mars year show that there are traces of methane gas on Mars, and its formation mechanism may be more than one, or it may be the result of many possible mechanisms."
Gail Crater, near the equator of Mars, was formed when a meteorite hit Mars about 3.5 billion to 3.8 billion years ago. There is a high mountain in its center, named "mount sharp", which is more than 5,500 meters higher than the surrounding terrain. The foothills of this mountain and the rock wall on the edge of Gael crater seem to show traces of flowing water erosion. Another important achievement made by Curiosity was the discovery of water in the fine soil of Gael crater. The average moisture content of Saturn soil per cubic foot (about 0.028 cubic meter) is about two pints (about 1 liter). Of course, they are not free water, but exist in the form of combining with minerals.
At the same time, Curiosity also detected different Martian organic molecules in the drilling powder particles on a rock named Cumberland, which is the first time that humans have detected conclusive organic components in the surface materials of Mars. These organic substances may have been formed on Mars, but they may also have been brought by meteorites from other places. Roger Tombs, a scientist of Curiosity Project and MIT, said: "It is of great significance to detect organic carbon in a Martian surface rock for the first time. Organic substances are very important because they can tell us information about their formation and preservation conditions. "
He said: "In turn, this information will help us understand the differences between the Earth and Mars, and help us to judge that the sedimentary rocks represented by Gael crater are more or less favorable environmental conditions for the accumulation of organic matter. Now the challenge we face is to find other rocks that may contain more kinds of organic matter at the foot of Shapu Mountain. "
The researchers also reported the results that Curiosity detected water combined with minerals more than 3 billion years ago in Cumberland rocks in the ancient lake bed. This result shows that ancient Mars lost most of its water body and then continued to lose water.
65438+February 18, Curiosity has approached the foothills of mount sharp, and it will begin to climb gradually in the next few months. Scientists are eager to explore this mountain, because there are a lot of exposed sedimentary rocks here, which gives them the opportunity to explore the long history of Mars.
Whether there is life on Mars, or whether there was life once, the answer to this question may finally be given by ExoMars detector of European Space Agency (ESA). This 300kg rover will land on Mars in 20 19 as planned.
ExoMars rover will be equipped with a 6.5-foot (about 2 meters) long drilling rig and will be equipped with equipment for detecting biomarkers. However, the landing area of ExoMars rover will not be Gael crater. Because its landing accuracy is not as good as Curiosity, Gail Crater with a high mountain in the center is considered as a high-risk landing area.
Other progress
Prior to this, on February 3, 65438, scientists announced that NASA's Curiosity Rover had detected a complex organic chemical environment on the surface of Mars and detected a possible signal of organic matter that scientists had been looking for for for a long time. This organic matter may contribute to the birth of primitive life.
Curiosity's Mars Sample Analyzer (SAM) found signals of chlorine, sulfur, water and organic compounds in the Martian soil samples it examined. The so-called organic compounds refer to compounds containing carbon. However, the scientific team is not sure whether these compounds really come from Mars or the pollutants that Curiosity brought from the earth.
During the meeting of the American Geophysical Union in San Francisco, Paul Mahaffy, chief scientist of SAM equipment at NASA Goddard Space Flight Center, said: "SAM can't accurately detect organic matter."
John Grotzinger, a scientist of Curiosity, said: "Although Mahaffey's equipment has detected the signal of organic matter, we must first confirm whether these substances really come from Mars."
The reason for releasing this special information is that there were rumors last week that NASA's Curiosity Rover had made a "huge" discovery. To this end, NASA held a special press conference to try to quell this rumor.
Curiosity's observations also include perchlorate, a compound produced by the interaction between oxygen and chlorine, which was previously detected by NASA's Phoenix lander in the Arctic region of Mars.
Curiosity's SAM equipment uses a micro-furnace to heat Martian soil and dust samples and analyze the gases released by them to determine their chemical composition. The Martian soil samples used in the experiment were grabbed and sent by the spoon device on Curiosity manipulator.
When Curiosity heats a sample containing perchlorate in the SAM furnace, it releases methane chloride, a carbon-containing organic substance.
NASA officials said in a statement: "The chlorine here obviously originated from Mars, but the carbon in it may have come from the earth and was brought there by Curiosity. Because the detection sensitivity of SAM equipment is extremely high, it is detected. "
This discovery was made by Curiosity when it visited an area covered by wind and sand along the way. This area is called "rock nest". This area is flat, a few miles away from the foothills of mount sharp, the first destination of Curiosity, which is about 5000 meters high. Mount sharp is the landing area of Curiosity Rover, which is a high mountain in the center of the huge Gaelic crater. 2016,6543814 October, NASA released a 360-degree photo of the Namib Dune sent back by the Mars probe Curiosity. This is also the first time that human beings have witnessed the charm of Mars at close range since Curiosity landed on Mars in August 20 12.
These photos were taken on 20 15 12 18, and the high-resolution images of Mars were taken by Mastcam color camera. Namib Dune is a dune in Ba Gounord Dune, located in the northwest of Sharp Mountain. Namib Dune is located at the bottom of mount sharp, which was once called "dark zone" by scientists. However, through high-resolution images, scientists can understand what happened on Mars and successfully conducted the first close-up survey of sand dunes.
Curiosity is about 7 meters from the bottom of Namib sand dune, and it was shot at an altitude of 28 degrees. The height of the Namib dune is about 5 meters. You can clearly see the special texture formed by the sand falling from the top of the windward side. It can also be seen that the ripples of these dunes change with time under the influence of Martian winds and small landslides. Most of this happened on the leeward slope of the earth, so NASA scientists judged that these photos should be located on the leeward side of Namib Dune.