Look at the news knows comprehensive
2020-09-15 10:25
According to a study published on September 14 in the journal Nature Astronomy, two telescopes in Hawaii and Chile found possible signs of life - the chemical characteristics of phosphine, a toxic gas on Earth that is only related to life. New discoveries in Venus' atmosphere suggest that microorganisms may be living in this greenhouse planet's clouds loaded with sulfuric acid.
The authors of the study and some outside experts said this is far from being the first ironclad evidence of the existence of life on other planets. Relatively, they called it "a hint of the possibility of (life being)" - although they all agreed that this discovery did not meet the strict requirements of the late Carl Sagan's "special conclusions need significant evidence to support", they could not find a better explanation, either chemistry or geology.
"This is not a smoke gun, not even a shooting residue on the hands of the main suspect, but there is a clear smell of gunpowder in the air (at the crime scene) which may suggest something." pictorially David Clements of Imperial College London, one of the authors of the paper.
Astronomers plan to find life on exoplanets in the future. One main method is to find biomarkers, namely chemical characteristics that can only be formed by biological processes. After meeting at a bar in Hawaii, three astronomers decided to target the technology at the planet closest to Earth: Venus.
What they are looking for is an unknown substance: phosphine, consisting of three hydrogen atoms and one phosphorus atom. On Earth, there are only two ways of forming phosphine, researchers say. One is artificial production in the industrial process, including as a chemical weapon in World War I. Another method is produced by functions that we have not yet understood in animals and microorganisms—the bottom of the pond, the guts of badgers and the feces of penguins.
The study’s co-author, Sarah Siegel, a planetary scientist at MIT and said the team looked at all the possibilities (phosphine-generating): volcanoes, lightning strikes, meteorites falling into the atmosphere, and finally eliminated them one by one. They found that no activity on Venus produced enough amounts of phosphine that they detected.
"So we have only two faint possibilities left. One is some unknown chemical reactions, some chemical reactions we don't know. The second more interesting possibility is that there may be some life form in the atmosphere of Venus that produces the phosphine we detect," Siegel added.
According to this study, phosphine may come from some kind of microorganism, and most likely a single-celled organism. However, the temperature on the surface of Venus is about 800 degrees (425 degrees Celsius), which means no form of water exists on the surface. To explain how life survives on this inhabitable planet, Siegel, Clements and his colleagues have proposed a possible idea.
Research team believes that all life activities can occur in thick carbon dioxide clouds 30 miles (50 kilometers) from the ground. The temperature there is about room temperature, or slightly higher, and the atmospheric pressure is the same as that of the Earth. These microorganisms may live in droplets of sulfuric acid in clouds. When the sulfuric acid drops fall during Venus acid rain, these microorganisms may dehydrate and then be absorbed into another droplet in the cloud and resurrected.
Now, NASA is already studying two possible Venus missions, but has not made a final decision yet. One of the tasks is called "Leonardo da Vinci+" and will enter the Venus atmosphere as early as 2026.
(Look at the news Knews reporter: Ren Meixing Editor: Pan Yi)
