NASA Says Asteroid's Path Successfully Changed in Recent Test
2022-10-13
LRC
TXT
大字
小字
滚动
全页
1The American space agency NASA says a recent experiment that crashed a spacecraft into an asteroid successfully changed the path of the orbiting object.
2NASA announced the results on Tuesday.
3It said it was the first time that human action had changed the motion of a space object.
4The operation was called the Double Asteroid Redirection Test, or DART.
5The DART spacecraft crashed into an asteroid called Dimorphos on September 26.
6Dimorphos is a small "moonlet" that orbits a larger asteroid named Didymos.
7The crash happened about 11 million kilometers from Earth.
8The crash, or impact, was observed by powerful telescopes.
9The observations showed the impact created a crater in the asteroid.
10It also led to dust and rock flows that stretched several thousand kilometers.
11The goal of the crash was to see how it might redirect the asteroid's path and speed.
12Before the impact, Dimorphos was completing one orbit around Didymos every 11 hours and 55 minutes.
13After the crash, the orbital period was reduced by 32 minutes, to 11 hours and 23 minutes.
14Scientists involved in the project had predicted a reduction of 10 minutes, so they were pleased with the actual test results.
15NASA described the crash as the world's first planetary defense test.
16But the asteroid targeted in the mission did not present any actual threat to Earth.
17However, NASA and its international partners continuously search the skies for what scientists call near-Earth objects (NEOs).
18Such objects include asteroids and comets that come within 50 million kilometers of Earth's orbit.
19Scientists estimate there are billions of asteroids and comets orbiting our sun.
20At a media event to announce the results, NASA Administrator Bill Nelson said, "This mission shows that NASA is trying to be ready for whatever the universe throws at us."
21Lori Glaze is NASA's director of planetary science.
22She said, "Let's all just kind of take a moment to soak this in ... for the first time ever, humanity has changed the orbit" of an object in space.
23NASA officials said four telescopes were involved in measuring the orbital period.
24All of them are in Chile and South Africa. Two American-based radar telescopes also helped confirm the results.
25Former American astronaut Rusty Schweickart said he was "clearly delighted" by the results and the attention the mission has brought to asteroid redirection.
26Schweickart helped launch the nonprofit B612 Foundation, which seeks to develop tools and technologies to protect Earth from asteroid strikes.
27NASA has said that no known asteroid larger than 140 meters in size has a reasonable chance of hitting Earth in the next 100 years.
28But scientists have predicted that in the very distant future, such a strike is possible.
29For example, historical records of Earth's geology show that a nine-kilometer wide asteroid struck Earth about 66 million years ago.
30This huge explosion put the planet into a long winter and killed off nearly all dinosaur life.
31NASA plans to launch a telescope in 2026 called the Near-Earth Object Surveyor.
32It will aim to better identify large asteroids and comets that could threaten Earth within 48 million kilometers.
33Planetary defense experts say changing the motion of threatening near-Earth objects is less dangerous than blowing them up and creating additional pieces that could fall down on Earth.
34This is especially the case when objects can be identified years ahead.
35Nancy Chabot is a planetary scientist with Johns Hopkins University's Applied Physics Laboratory in Maryland.
36She led the $325-million DART mission.
37Chabot said, "We really need to also have that warning time for a technique like this to be effective."
38NASA's Glaze added, "You've got to know they're coming."
39I'm Bryan Lynn.
1The American space agency NASA says a recent experiment that crashed a spacecraft into an asteroid successfully changed the path of the orbiting object. 2NASA announced the results on Tuesday. It said it was the first time that human action had changed the motion of a space object. 3The operation was called the Double Asteroid Redirection Test, or DART. The DART spacecraft crashed into an asteroid called Dimorphos on September 26. Dimorphos is a small "moonlet" that orbits a larger asteroid named Didymos. The crash happened about 11 million kilometers from Earth. 4The crash, or impact, was observed by powerful telescopes. The observations showed the impact created a crater in the asteroid. It also led to dust and rock flows that stretched several thousand kilometers. 5The goal of the crash was to see how it might redirect the asteroid's path and speed. Before the impact, Dimorphos was completing one orbit around Didymos every 11 hours and 55 minutes. After the crash, the orbital period was reduced by 32 minutes, to 11 hours and 23 minutes. 6Scientists involved in the project had predicted a reduction of 10 minutes, so they were pleased with the actual test results. 7NASA described the crash as the world's first planetary defense test. But the asteroid targeted in the mission did not present any actual threat to Earth. 8However, NASA and its international partners continuously search the skies for what scientists call near-Earth objects (NEOs). Such objects include asteroids and comets that come within 50 million kilometers of Earth's orbit. Scientists estimate there are billions of asteroids and comets orbiting our sun. 9At a media event to announce the results, NASA Administrator Bill Nelson said, "This mission shows that NASA is trying to be ready for whatever the universe throws at us." 10Lori Glaze is NASA's director of planetary science. She said, "Let's all just kind of take a moment to soak this in ... for the first time ever, humanity has changed the orbit" of an object in space. 11NASA officials said four telescopes were involved in measuring the orbital period. All of them are in Chile and South Africa. Two American-based radar telescopes also helped confirm the results. 12Former American astronaut Rusty Schweickart said he was "clearly delighted" by the results and the attention the mission has brought to asteroid redirection. Schweickart helped launch the nonprofit B612 Foundation, which seeks to develop tools and technologies to protect Earth from asteroid strikes. 13NASA has said that no known asteroid larger than 140 meters in size has a reasonable chance of hitting Earth in the next 100 years. But scientists have predicted that in the very distant future, such a strike is possible. 14For example, historical records of Earth's geology show that a nine-kilometer wide asteroid struck Earth about 66 million years ago. This huge explosion put the planet into a long winter and killed off nearly all dinosaur life. 15NASA plans to launch a telescope in 2026 called the Near-Earth Object Surveyor. It will aim to better identify large asteroids and comets that could threaten Earth within 48 million kilometers. 16Planetary defense experts say changing the motion of threatening near-Earth objects is less dangerous than blowing them up and creating additional pieces that could fall down on Earth. This is especially the case when objects can be identified years ahead. 17Nancy Chabot is a planetary scientist with Johns Hopkins University's Applied Physics Laboratory in Maryland. She led the $325-million DART mission. Chabot said, "We really need to also have that warning time for a technique like this to be effective." 18NASA's Glaze added, "You've got to know they're coming." 19I'm Bryan Lynn. 20Bryan Lynn wrote this story for VOA Learning English, based on reports from The Associated Press, Reuters, Agence France-Presse and NASA. 21___________________________________________________________________ 22Words in This Story 23asteroid - n. a rocky object that goes around the sun like a planet 24crater - n. a big hole left in the ground or an object by a force of impact 25mission - adj. a flight by an aircraft or spacecraft to perform a specific task 26soak - v. to take in an amount of something 27delighted - adj. happy and pleased 28technique - n. a method for doing something 29______________________________________________________________________ 30What do you think of this story? We want to hear from you. We have a new comment system. Here is how it works: 31Each 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.