[ti:Researchers: NASA Asteroid Samples Contain ‘Building Blocks’ of Life]
[by:www.21voa.com]
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[00:00.04]Scientists examining material
[00:03.52]collected from an asteroid
[00:06.20]say it appears to contain
[00:09.48]some of the chemical building blocks of life.
[00:13.48]The American spacecraft OSIRIS-REx
[00:18.32]collected the samples in 2020
[00:21.52]from the asteroid Bennu.
[00:24.40]In 2023, the spacecraft
[00:27.80]sent the rock and dust material
[00:30.92]back to Earth in a special container
[00:34.48]that landed by parachute.
[00:37.48]Scientists from the American space agency NASA
[00:42.92]recovered the samples in the western state of Utah.
[00:48.68]OSIRIS-REx is already on its way
[00:52.20]to another asteroid called Apophis.
[00:56.12]It is expected to reach that asteroid in 2029.
[01:02.72]On Bennu, the spacecraft collected a total
[01:07.36]of 122 grams of material.
[01:11.60]This is believed to be the largest sample
[01:16.00]collected from beyond the moon.
[01:19.24]NASA has shared some of the material
[01:23.24]with international researchers.
[01:25.76]Two research groups released studies last week
[01:31.20]describing results of their examinations
[01:34.88]of the asteroid material.
[01:37.48]One study, published in Nature Astronomy,
[01:42.00]suggested the samples
[01:44.24]contained a mixture of organic compounds.
[01:48.68]Organic compounds have one or more carbon atoms
[01:53.80]that attach to other elements, usually hydrogen,
[01:58.36]oxygen, nitrogen and sulfur.
[02:02.48]All life on Earth is based on carbon
[02:06.60]and is built from organic compounds.
[02:10.56]The other study, published in Nature,
[02:14.28]provides evidence that a much larger object,
[02:18.24]which Bennu is believed to have broken off from,
[02:22.72]once held salty, liquid water.
[02:26.36]The researchers said this suggests
[02:30.40]that in the early solar system,
[02:33.28]asteroids such as Bennu
[02:35.96]might have transported water
[02:38.56]and life-supporting chemicals
[02:41.24]to other planets and moons.
[02:44.76]Researchers from both groups noted
[02:48.60]it was important
[02:50.28]that the samples they worked with
[02:52.68]came directly from the asteroid itself.
[02:56.76]Asteroid pieces that fall to Earth
[03:00.64]turn into meteorites,
[03:03.16]and chemicals inside the samples
[03:06.48]can be changed or lost.
[03:09.44]In a statement, NASA said the findings
[03:13.92]do not provide direct evidence of life itself.
[03:18.48]However, the space agency said,
[03:22.44]"They do suggest the conditions necessary
[03:26.20]for the emergence of life were widespread
[03:29.92]across the early solar system."
[03:33.32]This increases the chances that "life
[03:37.52]could have formed on other planets
[03:39.88]and moons," the statement added.
[03:43.32]The parent of Bennu is believed
[03:46.92]to be an icy body
[03:48.88]measuring about 100 kilometers across.
[03:53.36]Scientists believe the body
[03:56.52]formed in the outer solar system
[03:59.20]and was later destroyed,
[04:01.60]possibly 1 to 2 billion years ago.
[04:05.36]The pieces that broke off
[04:08.00]likely formed Bennu and other asteroids
[04:12.08]observed to be masses of loose material,
[04:15.80]rather than solid objects.
[04:19.40]Nicky Fox is the associate administrator
[04:23.32]for NASA's Science Mission Directorate
[04:26.88]in Washington D.C.
[04:29.08]She praised the OSIRIS-REx mission,
[04:33.08]saying it was "already rewriting the textbook
[04:37.04]on what we understand about the beginnings
[04:40.76]of our solar system."
[04:43.36]Fox added that she hopes the samples
[04:47.40]can help scientists understand
[04:50.76]"what ingredients in our solar system
[04:53.96]existed before life started on Earth."
[04:58.96]Tim McCoy is a researcher
[05:01.92]at the U.S. Smithsonian Institution
[05:05.36]and was a lead writer of the Nature study.
[05:09.32]He told the Associated Press (AP)
[05:13.56]that the samples may provide details
[05:17.24]about "the kind of environment
[05:19.48]that could have been essential
[05:21.96]to the steps that lead from elements to life."
[05:26.48]He noted that combining the ingredients of life
[05:31.40]with an environment of sodium-rich water
[05:35.20]is "really the pathway to life."
[05:39.16]He added the samples suggest
[05:42.28]the processes involving the chemical compounds
[05:46.44]"probably occurred much earlier
[05:49.40]and were much more widespread
[05:52.24]than we had thought before."
[05:54.56]Yasuhito Sekine
[05:57.28]is with the Institute of Science in Tokyo.
[06:01.12]He did not take part in the new research.
[06:05.32]Sekine confirmed the findings
[06:08.52]were only made possible
[06:10.60]by examining samples "collected directly
[06:13.84]from the asteroid,
[06:15.80]then carefully preserved back on Earth."
[06:20.40]Jason Dworkin is a project scientist
[06:24.68]for the OSIRIS-REx mission
[06:27.20]at NASA's Goddard Space Flight Center in Maryland.
[06:31.76]He told Reuters news agency
[06:35.16]that all biology is made up of organic compounds.
[06:40.84]And some of those may have survived 4.5 billion years.
[06:47.44]Dworkin said the materials from OSIRIS-REx
[06:51.76]provide new details about a solar system
[06:55.72]that might have had the right elements to support life.
[07:00.56]But he added that one of the most
[07:03.52]interesting questions, still remains:
[07:07.52]"Why we, so far, only see life on Earth
[07:12.52]and not elsewhere."
[07:15.12]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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