Scientists Wonder About Possible Sign of Life on Venus
2020-09-16
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1Space scientists have found what could be a possible sign of life in the atmosphere of Venus.
2The finding comes from a study published Monday in Nature Astronomy.
3The astronomers studied Venus with the James Clerk Maxwell Telescope in Hawaii.
4They confirmed their observations with the ALMA radio telescope in Chile.
5The telescopes found evidence of the chemical phosphine in the thick clouds covering the planet.
6Phosphine is a poisonous gas.
7On Earth, it is only associated with life.
8However, the organizers of the study and other experts agree that the presence of phosphine is not proof of life on another planet.
9David Clements helped to prepare a report on the study.
10He is with Imperial College London.
11Clements said of the evidence, "It's not a smoking gun."
12But he added that it may "be suggesting something."
13As astronomers look for signs of life outside our solar system, one method is to look for chemicals that result only from biological processes.
14These processes are known as biosignatures.
15After three astronomers met in a bar in Hawaii, they decided to look for biosignatures a little closer to Earth - the planet Venus.
16The three looked for phosphine, a molecule made up of three hydrogen atoms and a single phosphorous atom.
17Phosphine can form only two ways on Earth.
18 It can be created by an industrial process, or it can come from a biological process in animals and microbes that is not well understood.
19Some scientists consider it a waste product.
20Clements said phosphine can be found in the bottom of ponds, the insides of animals like badgers and in the waste of penguins.
21Sara Seager, also involved in the study, is a planetary scientist with the Massachusetts Institute of Technology.
22She said the astronomers carefully looked at all the possibilities for production of the phosphine: volcanoes, lightning strikes or meteorites falling into the atmosphere.
23"...Not a single process we looked at could produce phosphine in high enough quantities to explain our team's findings," she said.
24The astronomers debated how life could exist on a planet like Venus, where there is no water and the surface temperature is 425 degrees Celsius.
25"Venus is hell. Venus is Earth's evil twin," said Clements.
26But Seager noted that 50 kilometers above the planet's surface, in Venus' thick carbon dioxide clouds, it is about room temperature.
27The clouds are mostly made up of sulfuric acid. But they also contain droplets with very small amounts of water.
28The scientists asked themselves if the phosphine could be coming from microbes living inside the sulfuric acid droplets.
29Seager and Clements suggested that, when the droplets fall to the ground,
30they might dry out but could collect in other droplets and reanimate.
31While life is a possibility, several other scientists say more proof is needed.
32Cornell University astronomer Lisa Kaltenegger said the idea of the gas possibly being a sign of a biological process is exciting.
33But she is not sure life is the only explanation.
34Justin Filberto, with the Lunar and Planetary Institute in Houston, told The Associated Press that the levels of phosphine might be explained by volcanoes.
35He said recent studies that were not considered in the new research suggest that Venus may have far more active volcanoes than scientists had thought.
36But Clements said that explanation would make sense only if Venus were at least 200 times more active than Earth.
37David Grinspoon is an astrobiologist with the Planetary Science Institute.
38He wrote a book suggesting that life could exist on Venus.
39 Grinspoon was excited, but "cautious" about the new study's finding. It "almost seems too good to be true," he said.
40Clements noted that his head tells him there is "probably a 10 percent chance that it's life."
41But he added, his heart "...wants it to be much bigger because it would be so exciting."
42I'm Mario Ritter Jr.
1Space scientists have found what could be a possible sign of life in the atmosphere of Venus. 2The finding comes from a study published Monday in Nature Astronomy. 3The astronomers studied Venus with the James Clerk Maxwell Telescope in Hawaii. They confirmed their observations with the ALMA radio telescope in Chile. 4The telescopes found evidence of the chemical phosphine in the thick clouds covering the planet. Phosphine is a poisonous gas. On Earth, it is only associated with life. However, the organizers of the study and other experts agree that the presence of phosphine is not proof of life on another planet. 5David Clements helped to prepare a report on the study. He is with Imperial College London. Clements said of the evidence, "It's not a smoking gun." But he added that it may "be suggesting something." 6As astronomers look for signs of life outside our solar system, one method is to look for chemicals that result only from biological processes. These processes are known as biosignatures. 7After three astronomers met in a bar in Hawaii, they decided to look for biosignatures a little closer to Earth - the planet Venus. The three looked for phosphine, a molecule made up of three hydrogen atoms and a single phosphorous atom. 8Phosphine can form only two ways on Earth. It can be created by an industrial process, or it can come from a biological process in animals and microbes that is not well understood. Some scientists consider it a waste product. 9Clements said phosphine can be found in the bottom of ponds, the insides of animals like badgers and in the waste of penguins. 10Sara Seager, also involved in the study, is a planetary scientist with the Massachusetts Institute of Technology. She said the astronomers carefully looked at all the possibilities for production of the phosphine: volcanoes, lightning strikes or meteorites falling into the atmosphere. "...Not a single process we looked at could produce phosphine in high enough quantities to explain our team's findings," she said. 11Could life be responsible? 12The astronomers debated how life could exist on a planet like Venus, where there is no water and the surface temperature is 425 degrees Celsius. 13"Venus is hell. Venus is Earth's evil twin," said Clements. 14But Seager noted that 50 kilometers above the planet's surface, in Venus' thick carbon dioxide clouds, it is about room temperature. The clouds are mostly made up of sulfuric acid. But they also contain droplets with very small amounts of water. 15The scientists asked themselves if the phosphine could be coming from microbes living inside the sulfuric acid droplets. Seager and Clements suggested that, when the droplets fall to the ground, they might dry out but could collect in other droplets and reanimate. 16While life is a possibility, several other scientists say more proof is needed. 17Cornell University astronomer Lisa Kaltenegger said the idea of the gas possibly being a sign of a biological process is exciting. But she is not sure life is the only explanation. 18Justin Filberto, with the Lunar and Planetary Institute in Houston, told The Associated Press that the levels of phosphine might be explained by volcanoes. He said recent studies that were not considered in the new research suggest that Venus may have far more active volcanoes than scientists had thought. But Clements said that explanation would make sense only if Venus were at least 200 times more active than Earth. 19David Grinspoon is an astrobiologist with the Planetary Science Institute. He wrote a book suggesting that life could exist on Venus. Grinspoon was excited, but "cautious" about the new study's finding. It "almost seems too good to be true," he said. 20Clements noted that his head tells him there is "probably a 10 percent chance that it's life." But he added, his heart "...wants it to be much bigger because it would be so exciting." 21I'm Mario Ritter Jr. 22Seth Borenstein reported this story for The Associated Press. Mario Ritter Jr. adapted it for VOA Learning English. George Grow was the editor. 23________________________________________________________________ 24Words in This Story 25associated - adj. connected or linked with something else 26solar - adj. involving the Sun 27bar - n. a place where alcoholic drinks are served 28microbe - n. an extremely small living thing only observed through a microscope 29pond - n. a small body of water 30meteorite - n. a rock or larger object that reaches Earth without breaking up in the atmosphere 31hell - n. a place of destruction 32droplet -n. a very tiny amount of a liquid 33reanimate -n. to give new life or energy to something 34We want to hear from you. Write to us in the Comments section, and visit our Facebook page.