[ti:NASA to Launch Telescope to Explore Parts of Space Never Observed Before]
[by:www.21voa.com]
[00:00.00]更多听力请访问21VOA.COM
[00:00.04]The American space agency NASA
[00:03.64]is preparing to launch a new telescope
[00:07.64]designed to explore parts of space never observed before.
[00:15.08]The James Webb Space Telescope
[00:19.00]enters a new launch window on December 24.
[00:24.36]The mission has already been delayed many times in recent years.
[00:31.72]The telescope is named after NASA’s second administrator,
[00:38.12]who led the agency from 1961 to 1968.
[00:44.72]The orbiting observatory is set to launch on an Ariane 5 rocket
[00:52.44]from French Guiana in South America.
[00:57.24]The mission is a joint project between NASA,
[01:01.76]the European Space Agency (ESA) and the Canadian Space Agency.
[01:07.80]The James Webb is considered NASA’s new generation telescope
[01:14.68]after the Hubble and Spitzer space telescopes.
[01:20.28]Hubble was launched more than 30 years ago
[01:24.04]and Spitzer was deployed in 2003.
[01:28.80]Both of those telescopes led to numerous discoveries
[01:34.84]and provided more detailed, colorful space images than ever before.
[01:42.24]But NASA says the James Webb “is the largest
[01:47.72]and most powerful space science telescope ever built.”
[01:53.84]It is meant to build on the discoveries of the other telescopes,
[02:00.08]while gathering more in-depth data
[02:03.40]on the early development of the universe.
[02:07.44]The James Webb is a large infrared telescope,
[02:12.68]with a nearly seven-meter mirror for exploring space.
[02:18.20]Infrared waves are a kind of electromagnetic energy
[02:24.52]that cannot be seen with the human eye.
[02:28.36]But they exist at a wavelength that is good
[02:32.56]for observing distant objects through gas and dust in space.
[02:39.72]The whole telescope is designed to collapse inside
[02:45.20]the launch vehicle and open back up in space.
[02:50.52]The telescope’s mirror and scientific instruments
[02:55.24]are protected by a thick, sun shield.
[02:59.56]When fully open, the shield is about the size of a tennis court.
[03:06.04]The James Webb will travel to an orbit
[03:10.32]about 1.6 kilometers away from Earth.
[03:15.24]It will then complete a six-month “commissioning” period in space.
[03:22.16]It is during this time that the telescope will open its mirror,
[03:28.12]sun shield and other small systems.
[03:32.88]NASA engineers say this period
[03:36.72]will be the most difficult for the telescope.
[03:40.60]This is because of its massive size,
[03:44.76]the complex opening method
[03:47.48]and the extremely cold temperatures in space.
[03:52.44]Eric Smith is the telescope's program director and a program scientist.
[04:01.12]"I like to think of (the telescope) as NASA's vehicle
[04:06.56]for the deepest space exploration that humanity can do,"
[04:12.20]he told The Associated Press.
[04:15.76]"It will allow us to see farther back in time,
[04:20.44]to the time when the very first stars and galaxies were being born.”
[04:28.04]Smith added that the telescope’s infrared abilities
[04:33.36]will also permit it “to peer through clouds of gas and dust
[04:39.64]in our own galaxy, where stars and planets are being born today."
[04:46.64]NASA says the telescope aims to help scientists learn
[04:52.84]about all periods of the universe's history
[04:57.00]dating back to just after the Big Bang event,
[05:01.72]about 13.8 billion years ago.
[05:06.48]It is also designed to study exoplanets
[05:11.44]- planets that orbit stars other than the sun.
[05:16.20]John Mather is a project scientist for the mission
[05:21.80]at NASA’s Goddard Space Flight Center in Maryland.
[05:27.12]"We're going to look at everything there is in the universe
[05:31.68]that we can see,” he told Reuters news agency.
[05:37.16]“We want to know: how did we get here from the Big Bang,
[05:42.20]how did that work? So, we'll look."
[05:46.32]Klaus Pontoppidan is a project scientist
[05:51.08]at the Space Telescope Science Institute in Baltimore, Maryland.
[05:57.40]He says the James Webb
[06:00.36]is powerful enough to uncover the unexpected.
[06:05.64]“We can plan what we think we're going to see,” he said,
[06:11.28]adding, “But at the end of the day,
[06:14.88]we know that nature will surprise us more often than not."
[06:21.40]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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