Mercury, which is now scorched, may have microbes in ancient times
Mercury, the smallest and closest planet of the eight planets in the solar system to the Sun, is also the planet with the largest temperature difference between day and night on the surface, and the atmosphere is extremely thin and cannot effectively conserve heat. The picture shows a non-realistic mercury landscape. Source: NASA
Mercury, the closest planet to the Sun, is one of several places in the solar system that is least likely to have potential life. Research has shown that Mercury's interior once had the basic ingredients suitable for life, and this discovery is enough to change the way we think about this hot and afflicted planet.
New research published in Scientific Reports suggests that although Mercury's surface temperature is as high as 430 degrees Celsius (806 degrees Fahrenheit) during the day because of its absence of an atmosphere, Mercury may have had an organism-friendly underground layer that contained the basic components of life.
This extraordinary claim is based on a study of Mercury's "chaotic terrain," an area of deep valleys, grooves and steep peaks. Mercury's chaotic terrain was first discovered by NASA's Mariner 10 spacecraft in 1974, when scientists hypothesized that Mercury formed such chaotic terrain due to massive celestial impacts from the other side of the planet and subsequent continuous earthquakes. The new study, led by Alexis Rodriguez of the Planetary Science Institute (PSI), points to the many loopholes in the above theoretical hypothesis and proposes a completely new hypothesis: such a strange geographical feature (i.e., chaotic terrain) was formed by the volatilization of large amounts of volatile material, which escaped from mercury long ago.
Chaotic terrain refers to the surface of some planets, ridges, cracks, flat plains, etc. mixed with each other. The picture shows the local surface of Mercury. Image source: Baidu
The above volatile substances are compounds, such as water, nitrogen, methane, these substances are easy to produce biological changes, such as liquid into a solid state, or the solid is directly converted into gas or steam, this chemical process is also known as sublimation. For astrobiologists, the mere mention to them of the possibility of volatile substances on a celestial body will make them rush up like a dog that suddenly sees a squirrel nearby. Volatile matter is a prerequisite for life, and it also implies that Mercury was once in a potentially dynamic environmental condition and had a rich supply of volatile substances, which raises some interesting questions about Mercury's ancient history.
Admittedly, it's hard to believe that Mercury was once probably suitable for life, or even harder to believe that tiny microbes might be creeping slowly beneath Mercury's surface, but this new paper challenges our notion about which object in the solar system could ever nurture life. At the same time, it also provides astrobiologists with a new goal to explore.
The idea that Mercury's chaotic topography may have arisen after mercury was hit by a celestial body on the other side is not an odd idea. Pluto's Sputnik Planitia was formed in exactly the way described above. Long ago, Pluto collided with a huge object, during which the oscillating wave was transmitted to the other side of Pluto's toe point area, leaving a very iconic heart shape.
Sputnik Planitia (also known as the "Heart of Pluto") is the largest glacial plain on a celestial body in the solar system formed by the strong convection of "nitrogen ice", reaching 1,000 kilometers wide. Image source: CSSAR
As for the new study mentioned above, the data cited by Rodriguez and his colleagues was collected by NASA's MESSENGER Spacecraft, which meticulously scanned the surface of Mercury between 2011 and 2015.
An analysis of the cited data shows that the chaotic terrain formed about 1.8 billion years ago, 2 billion years after the aforementioned impact, and the evidence for this conclusion lies in the shape of Mercury's caloris impact basin and is still visible today. This discovery is critical, although on the surface it seems to have made the entire timeline very abnormal. Not only that, but scientists say the seismic activity generated by the impact can interfere in much less areas than the size of chaotic terrain. In addition, researchers have found many other chaotic landscapes throughout the planet— including near Mercury's equator and near-Earth's polar regions— suggesting that Mercury's chaotic topography is not just a geographic phenomenon in a local area.
The MESSENGER Mercury Probe (THE ACRONICS OF MErcury Surface, Space ENvironment, GEochemistry, and Ranging) was nasa's first mercury probe since 1975 and was launched on August 3, 2004. In March 2015, New Scientist magazine reported that the probe would run out of fuel. Source: NASA
According to this, Rodriguez and his colleagues argue that calorie impact theory does not effectively account for chaotic terrain — so they offer an entirely new theory to explain.
"What we are showing now is a detailed morphological field-of-view survey of the first chaotic terrain based on a dataset collected by the Courier Mercury probe," the authors write in the study, "and our findings underpin the cause of a chaotic terrain: a wide-ranging, but less harmful, event that occurred on the surface of the upper crust (collapse) several kilometers thick with layers of volatile material." ”
The area outlined by the white line is the chaotic terrain mentioned above, and the smaller part of the yellow box is supposed to be the opposite toe point that mercury will be affected when it is hit by a celestial body. Image source: PSI
Well, billions of years ago, this area began to collapse on its own, a process that lasted for a long time. And that justifies one explanation: "Volatile material in the extremely large volume of the crust converted into gas and escaped out of Mercury's upper crust, an event that occurred in a slightly larger surface area than California, about 500,000 square kilometers (193,000 square miles)," Gregory Leonard, who is from the University of Arizona, explained in a news release Arizona) is a scientist and co-author of the new study. As volatile matter rises to the surface, cracks and other deformations appear in the landscape.
Studies have shown that magma at a deep level is likely to provide the necessary heat for the above process, or that the "increasing sunlight" at that time provided heat for this process.
As mentioned earlier, this new discovery suggests that ancient Mercury had a rich and diverse supply of volatile material. The study points to an interesting point to the fact that these compounds ( including water ice and organic matter ) that should be exposed to changing environmental conditions and face large temperature differences between morning and evening , may have developed stable and habitable conditions. Living in comfortable niches, far from Mercury's harsh surfaces, simple microbes are likely to have been born deep underground.
Still, this possibility is premised on the presence of water in other volatile compounds, a thorny unknown.
"While not all volatile substances can constitute habitable conditions, water ice can do this when the temperature is right." Jeff Kargel, a researcher at the Institute of Planetary Sciences (PSI) and co-author of the study, explained in a news release, "Some of the other volatile materials on Mercury may have added characteristics from the previous period [of aquatic environment]." Even if habitable conditions exist for a short period of time, remnants of pre-life chemistry or primitive life may still exist in chaotic terrain. ”
Mark Sykes, co-author of the new study and also from the Institute of Planetary Sciences, said: "If these results can be confirmed, this collapse region and other similar regions will be an alternative to future landing sites when investigating the origin of Mercury's crust rich in volatile material, and even investigating the potential astrobiology of Mercury's existence." ”
It's breathtaking. Suddenly, Mercury — instead of Mercury — became a destination worthy of retrospective priority habitability and extraterrestrial life. This is a major, unexpected disclosure, and just as exciting.
BY: George Dvorsky
FY: Fareton
If there is any infringement of the relevant content, please contact the author to delete it after the work is published
Please also obtain authorization to reprint, and pay attention to maintaining completeness and indicating source