Hypothetical life cycle: how floating microbes live in the acid clouds of Venus?

Sina science and technology news, Beijing time, August 19 news, according to foreign media reports, a group of planetary scientists proposed a hypothetical life cycle, which can allow microorganisms to migrate between different atmospheres to survive on Venus. When it comes to the potential home of life, people usually don’t think of Venus because of its dense clouds of sulfuric acid and purgatory surface temperatures. But some planetary scientists believe that some microbes living in the atmosphere can survive in the lower clouds on Venus, which may also explain the mysterious atmosphere on Venus. The so-called lower clouds, which float about 30 to 37 miles (48 to 60 kilometers) above the sultry surface of Venus, are reasonably habitable in temperature, nutrients, and even a small amount of water dissolved in sulfuric acid droplets. < / P > < p > recently, a team led by an astrophysicist at the Massachusetts Institute of technology has proposed a new life cycle that can help microbes survive in the atmosphere of Venus. They are the first to propose this particular mechanism. According to this mechanism, microbes can survive in the haze and clouds of Venus, rather than die as rain falls on the hot surface. The team also outlined how microbes on Venus circulate between the different atmospheres and survive the most extreme environments in a dormant state. < / P > < p > microbes living in clouds are not unprecedented in the solar system. “On earth, we also have the so-called aerial biosphere, where microbes on earth are lifted into the air, float around, and then wrapped in water droplets and blown across continents and oceans in the wind.” < p > < p > with the passage of time, the water droplets wrapped with microorganisms gradually condense in the earth’s atmosphere, becoming larger and heavier. Eventually, they fall back to the surface of the earth. But on Venus, where the hot surface temperature can reach 860 degrees Fahrenheit (460 degrees Celsius), from clouds to such a ground, any microbes will die. < / P > < p > the team hypothesized that life on Venus could survive in sulfuric acid droplets in lower clouds in a metabolically active state (i.e., growth and reproduction). Over the next few months, sulfuric acid droplets will become heavier and heavier, just like water droplets in the earth’s atmosphere. Eventually, they grow large enough to fall from lower clouds like rain. Where did it fall? The lower haze on Venus, of course. < p > < p > the haze is 20 to 30 miles (33 to 48 kilometers) above the surface, much hotter than the clouds that go up. The temperature of the haze ranges from 170 to 368 degrees Fahrenheit (77 to 187 degrees Celsius). The researchers hypothesized that sulfuric acid droplets evaporate as they fall into this extremely hot haze. < p > < p > without the protection of droplets, hypothetical microorganisms will undergo metabolic transformation and enter protective dormancy state to survive in extreme high temperature and dehydration. The researchers call these dormant microbes “spores.”. Spores can continue to exist, floating in the lower haze of Venus. < p > < p > in the end, Venus’ updraft will blow spores back into temperate clouds. There, the spores that have been hydrated will wake up and become active. < / P > < p > shows the microbial life cycle in the middle of Venus’ sulfuric acid cloud. (1) Dehydrated microorganisms live in the lower haze of Venus as plants; (2) spores are brought back to habitable clouds by updraft; (3) once included in liquid, spores possess metabolic activity; (4) microorganisms divide and multiply, and droplets gradually condense and grow; (5) droplets become large enough to fall, and droplets evaporate due to the rising temperature in the lower layer Microbes transform into spores and float in the middle of a lower haze. < / P > < p > just like the biosphere in the sky on earth, Venus microbes can enter a dormant state to survive in harsh conditions, and this assumption has precedent on earth. Tardigrada (commonly known as water bear) is a small arthropod. Water bears are particularly good at using this method to survive in extremely cold, radiation and even vacuum spaces. < / P > < p > and, although this scenario of “life living in the clouds of Venus” is still a hypothesis, there is good reason to think about life on other planets in our solar system Because we haven’t actually explored life as thoroughly as we expected, it’s a testable hypothesis that there might be life on Venus. Therefore, it is also worth considering whether we need to invest resources to test the hypothesis. < p > < p > a possible way to find life among the clouds of Venus is to perform a flyover mission, that is, to fly a spacecraft through lower clouds to collect samples. Researchers can then remotely evaluate the samples to see if they contain any interesting organic molecules. If organic matter is found, it would be reasonable for researchers to send back samples of the Venus cloud back to earth for analysis using more sophisticated instruments. It’s a costly task, but if scientists are more convinced that life might exist on Venus, it’s worth a try, even if it costs a lot. < / P > < p > exploring how extraterrestrial organisms survive in unnatural environments is crucial for finding possible life on planets. Although acidophilic extremophiles, such as some archaea, are commonly used as examples of possible life on Venus, Venus clouds are more acidic than any environment found on earth. In addition, sulfuric acid also destroys DNA, RNA, sugar and protein essential for life on earth. < / P > < p > so, if there are floating microbes on Venus – active or dormant – it’s almost certain that they are alien. (Heng Lin)