[ti:NASA to Launch Telescope to Explore Parts of Space Never Observed Before] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.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51VOA.COM