[ti:NASA’s Latest Mission to Explore Asteroids Near Jupiter’s Orbit]
[by:www.21voa.com]
[00:00.00]更多听力请访问21VOA.COM
[00:00.04]The latest mission of the American space agency, NASA,
[00:05.52]will explore a group of ancient objects
[00:10.24]orbiting the sun at the distance of Jupiter.
[00:15.88]Set to launch October 16, the Lucy spacecraft
[00:21.32]is designed to study Jupiter’s “Trojan” asteroids.
[00:27.52]These asteroids are small bodies left over
[00:32.24]from the formation of our solar system’s large planets.
[00:38.40]They share an orbit with Jupiter
[00:41.52]as the planet goes around the sun.
[00:45.60]The mission’s aim is to gather new information
[00:49.80]about the solar system’s formation 4.5 billion years ago.
[00:57.88]Lucy will observe eight asteroids over 12 years.
[01:03.40]One orbits in what is known as the Asteroid Belt,
[01:08.88]an area between Mars and Jupiter.
[01:13.60]Most known asteroids orbit within this area.
[01:19.32]The spacecraft will also observe seven Trojan asteroids.
[01:26.16]The Trojans circle the sun in two groups.
[01:30.96]One group leads Jupiter in its orbital path,
[01:35.88]while the other follows behind it.
[01:38.68]Lucy will be the first spacecraft to visit these asteroids.
[01:45.92]There are believed to be more than 7,000 Trojan asteroids.
[01:52.60]Scientists consider the Trojan asteroids
[01:56.84]to be the ancient remains of the formation of the solar system.
[02:03.56]They have stayed captured in Jupiter’s orbit
[02:07.60]for billions of years.
[02:10.00]Scientists hope that the NASA mission
[02:13.96]can provide new details about what conditions
[02:18.24]were like when the planets formed.
[02:21.48]They also hope the mission will lead to
[02:25.08]a better understanding of our own planet’s history.
[02:30.24]The spacecraft was named Lucy after the ancient fossil
[02:35.64]discovered in Ethiopia in 1974.
[02:40.48]Lucy was one of the most famous scientific finds of the 20th century.
[02:48.88]The collection of skeletal bones gave scientists
[02:53.36]a better understanding of the evolution of humans.
[02:59.12]Cathy Olkin is a planetary scientist
[03:02.92]at the Southwest Research Institute in Colorado.
[03:07.76]She is the deputy lead investigator for the Lucy mission.
[03:13.20]In a video explaining the mission,
[03:16.48]Olkin compared the NASA spacecraft to the Lucy fossil.
[03:22.52]“Just like the Lucy fossil
[03:25.44]transformed our understanding of human evolution,
[03:30.16]the Lucy mission will transform our understanding
[03:34.44]of solar system evolution,” she said.
[03:39.56]The spacecraft, built by NASA contractor Lockheed Martin,
[03:44.80]is expected to fly within 400 kilometers of its targets.
[03:51.64]The spacecraft is equipped with several imaging instruments
[03:56.84]designed to capture information about the composition
[04:01.56]of materials on the surface of asteroids.
[04:05.52]Other equipment will be used to record asteroid surface temperatures
[04:11.88]and measure the size of the objects the spacecraft observes.
[04:19.04]Lucy will depend on solar power to operate.
[04:24.44]NASA says the mission expects to set a record
[04:28.72]because Lucy will be deployed farther from the sun
[04:33.04]than any past solar powered spacecraft.
[04:38.12]Hal Levison is the mission's chief scientist.
[04:43.40]He recently told reporters that although the Trojan asteroids
[04:49.04]are in a very small area of space,
[04:52.44]they are physically different from each another.
[04:55.60]"For example, they have very different colors,
[05:00.28]some are grey, some are red," Levison said.
[05:04.84]He added that these differences suggest
[05:09.00]how far away from the Sun they might have formed
[05:13.04]before getting to their current positions.
[05:16.56]Lori Glaze is the director of NASA's planetary science division.
[05:23.84]She said: "Whatever Lucy finds will give us vital clues
[05:29.68]about the formation of our solar system."
[05:33.20]I’m Bryan Lynn. 更多听力请访问21VOA.COM
END OF TRACK. "END OF TRACK." The two men bowed. "Whoever was that person you were talking to?" she enquired, as soon as they stood together. The took of triumph faded from her eyes, she had grown worn and weary. The roses were wilting on the walls, the lights were mostly down now. Hetty, looking in to see if anything was wanted, found herself driven away almost fiercely. I only saw Master Jervie once when he called at tea time, The year 1747 was opened by measures of restriction. The House of Lords, offended at the publication of the proceedings of the trial of Lord Lovat, summoned the parties to their bar, committed them to prison, and refused to liberate them till they had pledged themselves not to repeat the offence, and had paid very heavy fees. The consequence of this was that the transactions of the Peers were almost entirely suppressed for nearly thirty years from this time, and we draw our knowledge of them chiefly from notes taken by Horace Walpole and Lord Chancellor Hardwicke. What is still more remarkable, the reports of the House of Commons, being taken by stealth, and on the merest sufferance, are of the most meagre kind, sometimes altogether wanting, and the speeches are given uniformly under fictitious names; for to have attributed to Pitt or Pelham their[112] speeches by name would have brought down on the printers the summary vengeance of the House. Many of the members complained bitterly of this breach of the privileges of Parliament, and of "being put into print by low fellows"; but Pelham had the sense to tolerate them, saying, "Let them alone; they make better speeches for us than we can make for ourselves." Altogether, the House of Commons exhibited the most deplorable aspect that can be conceived. The Ministry had pursued Walpole's system of buying up opponents by place, or pension, or secret service money, till there was no life left in the House. Ministers passed their measures without troubling themselves to say much in their behalf; and the opposition dwindled to Sir John Hinde Cotton, now dismissed from office, and a feeble remnant of Jacobites raised but miserable resistance. In vain the Prince of Wales and the secret instigations of Bolingbroke and Doddington stimulated the spirit of discontent; both Houses had degenerated into most silent and insignificant arenas of very commonplace business. "It certainly will be. Miss Widgeon," answered Maria, with strictly "company manners." "One who has never had a brother exposed to the constant dangers of army life can hardly understand how glad we all feel to have Si snatched from the very jaws of death and brung back to us." "Just plug at 'em as you would at a crow, and then go on your way whistlin'?" persisted Harry. "Hurroo!" echoed Hennessey; "that's the ticket." "Come forward, keeper," continued the baron, "and state how these arrows came into your hands!" "Yes." HoMEJULIA京香2018下载
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