Scientists Search for Dark Matter in Old US Gold Mine
2022-07-15
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1Researchers have begun a new search in the United States for the mysterious material known as dark matter.
2Scientists believe dark matter makes up most of the mass of the universe.
3But they have not yet directly observed the material.
4Astronomers have theorized that dark matter exists because of gravity's observed effects on galaxies and groups of galaxies.
5The search is happening in a former gold mine in the midwestern state of South Dakota.
6The experiment aims to isolate dark matter inside a tank that is about one-and-one-half kilometers underground.
7Scientists have designed the experiment to block out nearly all cosmic rays and particles believed to move through our world every day.
8The hope is that by blocking these materials, dark matter particles will show up in the isolation tank.
9The experiment, called LUX-ZEPLIN, is being carried out in the Sanford Underground Research Facility.
10If it succeeds, the team said, dark matter will produce a reaction involving the element xenon.
11The researchers said dark matter would produce a flash of light and be seen by a device called a "time projection chamber."
12Scientists recently announced that the five-year, $60 million search effort finally got started after delays caused by the COVID-19 pandemic.
13Members of the search team said the device has not yet identified dark matter.
14But the equipment does appear to be keeping out most of the background radiation the researchers had hoped to block.
15"To search for this very rare type of interaction, job number one is to first get rid of all the ordinary sources of radiation, which would overwhelm the experiment," said project member Carter Hall.
16He is a physicist at the University of Maryland.
17The researchers said they expect only a few signs of dark matter to appear a year.
18The team of 250 scientists estimates the operation will produce 20 times more data in the future.
19During the experiment, the chance of finding dark matter with the device is "probably less than 50 percent, but more than 10 percent," said Hugh Lippincott.
20He is a physicist and spokesman for the project.
21Kevin Lesko is a physicist at the U.S. Department of Energy's Lawrence Berkeley National Laboratory in Berkeley, California.
22He told The Associated Press that finding dark matter is far from a sure thing.
23But Lesko said the scientists "need a little enthusiasm" to keep going.
24"You don't go into rare search physics without some hope of finding something."
25Another team member, physicist Aaron Manalaysay, explained the importance of xenon to the experiment.
26He said the element will permit researchers to see whether particle collisions that happen in the tank hit a xenon electron or its nucleus.
27If something hits the nucleus, it is more likely to be the dark matter that everyone is looking for, Manalaysay said.
28The scientists tried a similar, smaller experiment at the same place years ago.
29After that experiment produced no dark matter, the scientists decided to go much bigger.
30Another large experiment is currently being carried out in Italy.
31The scientists running that project have not yet announced any results.
32Manalaysay explained that even with a small chance of success, it is important for scientists to keep searching.
33He said this is because it will be nearly impossible to fully understand the history and development of the universe without identifying dark matter.
34I'm Bryan Lynn.
1Researchers have begun a new search in the United States for the mysterious material known as dark matter. 2Scientists believe dark matter makes up most of the mass of the universe. But they have not yet directly observed the material. Astronomers have theorized that dark matter exists because of gravity's observed effects on galaxies and groups of galaxies. 3The search is happening in a former gold mine in the midwestern state of South Dakota. The experiment aims to isolate dark matter inside a tank that is about one-and-one-half kilometers underground. 4Scientists have designed the experiment to block out nearly all cosmic rays and particles believed to move through our world every day. The hope is that by blocking these materials, dark matter particles will show up in the isolation tank. 5The experiment, called LUX-ZEPLIN, is being carried out in the Sanford Underground Research Facility. If it succeeds, the team said, dark matter will produce a reaction involving the element xenon. The researchers said dark matter would produce a flash of light and be seen by a device called a "time projection chamber." 6Scientists recently announced that the five-year, $60 million search effort finally got started after delays caused by the COVID-19 pandemic. 7Members of the search team said the device has not yet identified dark matter. But the equipment does appear to be keeping out most of the background radiation the researchers had hoped to block. 8"To search for this very rare type of interaction, job number one is to first get rid of all the ordinary sources of radiation, which would overwhelm the experiment," said project member Carter Hall. He is a physicist at the University of Maryland. 9The researchers said they expect only a few signs of dark matter to appear a year. The team of 250 scientists estimates the operation will produce 20 times more data in the future. 10During the experiment, the chance of finding dark matter with the device is "probably less than 50 percent, but more than 10 percent," said Hugh Lippincott. He is a physicist and spokesman for the project. 11Kevin Lesko is a physicist at the U.S. Department of Energy's Lawrence Berkeley National Laboratory in Berkeley, California. He told The Associated Press that finding dark matter is far from a sure thing. But Lesko said the scientists "need a little enthusiasm" to keep going. "You don't go into rare search physics without some hope of finding something." 12Another team member, physicist Aaron Manalaysay, explained the importance of xenon to the experiment. He said the element will permit researchers to see whether particle collisions that happen in the tank hit a xenon electron or its nucleus. If something hits the nucleus, it is more likely to be the dark matter that everyone is looking for, Manalaysay said. 13The scientists tried a similar, smaller experiment at the same place years ago. After that experiment produced no dark matter, the scientists decided to go much bigger. Another large experiment is currently being carried out in Italy. The scientists running that project have not yet announced any results. 14Manalaysay explained that even with a small chance of success, it is important for scientists to keep searching. He said this is because it will be nearly impossible to fully understand the history and development of the universe without identifying dark matter. 15I'm Bryan Lynn. 16The Associated Press reported this story. Bryan Lynn adapted the report for VOA Learning English. 17______________________________________________________________ 18Words in This Story 19isolate - v. to put or keep (someone or something) in a place or situation that is separate from others 20cosmic ray - n. high-energy particles that move through space at nearly the speed of light 21chamber - n. a contained room or closed space used for a particular purpose 22ordinary - adj. not special, different or unusual in any way 23overwhelm - v. to give too much of a thing to someone 24enthusiasm - n. the feeling of being very interested in something and wanting very much to be involved in it 25______________________________________________________________ 26What do you think of this story? We want to hear from you. We have a new comment system. Here is how it works: 27Each time you return to comment on the Learning English site, you can use your account and see your comments and replies to them. Our comment policy is here.