VOA标准英语2015--“黎明”号探测器成功将接近“谷神星”轨道
时间：2019-01-14 作者：英语课 分类：VOA标准英语2015年(一月)
Dawn Spacecraft Nears Rendezvous 1 With Dwarf 2 Planet Ceres “黎明”号探测器成功将接近“谷神星”轨道
LOS ANGELES—
NASA’s Dawn spacecraft is set to reach the dwarf planet Ceres in March and begin gathering 3 clues about whether the icy body may have once had conditions conducive 4 to supporting life.
Dawn left Earth more than seven years ago, on a course to explore two alien worlds in the solar system: Ceres and Vesta, both in the main asteroid 5 belt between Mars and Jupiter.
“This is the first time in more than 57 years of space exploration that we have a spacecraft targeted to orbit any two extraterrestrial destinations,” said Dawn chief engineer and mission director Marc Rayman.
Vesta and Ceres are considered protoplanets. They were "in the process of growing to become full-size planets when their growth was terminated,” Rayman said.
At the Dawn mission control center in Los Angeles, the flight team sends second-by-second instructions to the spacecraft, directing its every move, including the images it takes of what it sees.
Scientists believe Ceres is made of rock covered with a mantle 6 of ice. Dawn will take images and make a comprehensive map of this alien world. It will also examine Ceres’ composition to provide data on how its surface has evolved, said Carol Raymond, the mission's deputy principal investigator 7.
“One of the interests in bodies like Ceres and other icy bodies in the outer solar system is that when objects like that impacted the terrestrial planets, they brought a lot of water," she said. "So there’s a very vigorous debate at the current time as to whether wet asteroids 8 like Ceres — and we know there are other wet asteroids in the outer edge of the main belt — whether they were the dominant 9 source of water in the Earth’s ocean.”
Earlier in its mission, Dawn made an unexpected discovery while orbiting the protoplanet Vesta.
“Instead of being bone dry, which we expected, there were patches on the surface of Vesta that showed significant amounts of water bound in the rocks and possibly even free water that could have flowed on the surface in the past,” Raymond said.
Raymond said that if Earth’s water came from wet worlds like these, then life could have come with them as well.
If Dawn reveals that the environment on Ceres could be conducive to life, the finding may spur further explorations with other types of instruments to test that hypothesis.
As for Dawn, it will gather information on Ceres until the summer of 2016. Then it will continue to orbit the dwarf planet indefinitely.
- She made the rendezvous with only minutes to spare.她还差几分钟时才来赴约。
- I have a rendezvous with Peter at a restaurant on the harbour.我和彼得在海港的一个餐馆有个约会。
- The dwarf's long arms were not proportional to his height.那侏儒的长臂与他的身高不成比例。
- The dwarf shrugged his shoulders and shook his head. 矮子耸耸肩膀，摇摇头。
- He called on Mr. White to speak at the gathering.他请怀特先生在集会上讲话。
- He is on the wing gathering material for his novels.他正忙于为他的小说收集资料。
- This is a more conducive atmosphere for studying.这样的氛围更有利于学习。
- Exercise is conducive to good health.体育锻炼有助于增强体质。
- Astronomers have yet to witness an asteroid impact with another planet.天文学家还没有目击过小行星撞击其它行星。
- It's very unlikely that an asteroid will crash into Earth but the danger exists.小行星撞地球的可能性很小，但这样的危险还是存在的。
- The earth had donned her mantle of brightest green.大地披上了苍翠欲滴的绿色斗篷。
- The mountain was covered with a mantle of snow.山上覆盖着一层雪。
- He was a special investigator for the FBI.他是联邦调查局的特别调查员。
- The investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。
- Asteroids,also known as "minor planets",are numerous in the outer space. 小行星，亦称为“小型行星”，在外太空中不计其数。
- Most stars probably have their quota of planets, meteorids, comets, and asteroids. 多数恒星也许还拥有若干行星、流星、彗星和小行星。