[ti:NASA Releases New Black Hole ‘Sounds’]
[by:www.21voa.com]
[00:00.00]更多听力请访问21VOA.COM
[00:00.04]The American space agency NASA
[00:03.60]has released sounds it created with data
[00:08.00]collected from black holes.
[00:10.88]The sound production process is called sonification.
[00:17.12]NASA says it used astronomical data
[00:21.76]recorded by its Chandra X-ray Observatory.
[00:26.24]Special equipment then translates the data
[00:30.60]into audible sound.
[00:33.12]NASA says the Chandra orbiting observatory
[00:37.76]is the world's most powerful X-ray telescope.
[00:42.28]One of the black holes studied sits at the center
[00:47.08]of the Perseus galaxy cluster, or group.
[00:51.00]The Perseus cluster is home to hundreds of galaxies.
[00:56.52]They are 240 million light years from Earth.
[01:01.12]Black holes are areas in space where gravity is so strong
[01:07.80]that nothing – not even light – can escape them.
[01:11.92]They are believed to be formed by collapsed stars.
[01:17.20]The presence of black holes affects the surrounding environment
[01:22.60]in extreme ways.
[01:24.92]But black holes are not easy to capture with a camera.
[01:30.08]This is because they are surrounded
[01:32.60]by thick dust and extremely hot gases.
[01:36.96]NASA says it discovered in 2003 that the black hole
[01:43.04]deep inside the center of the Perseus galaxy cluster was linked to sound.
[01:50.24]Astronomers had earlier found
[01:53.40]that "pressure waves" sent out by the black hole
[01:57.36]caused ripples in the cluster's hot gas.
[02:01.72]Astronomers found that they could translate
[02:05.68]those ripples into a note of sound.
[02:09.36]But the note was at a very low range that humans cannot hear.
[02:15.20]Using new sonification methods, NASA says it was able
[02:20.96]to produce sounds from the ripples that we could hear.
[02:32.28]In a statement, the space agency said that in some ways,
[02:37.12]the latest sonification was "unlike any other done before."
[02:43.60]This is because the process "revisits the actual sound waves
[02:49.52]discovered in data" from the Chandra telescope.
[02:53.64]NASA explains that there is a popular misconception
[02:59.60]that there is no sound in space.
[03:02.68]It notes that it is true that most of space exists in a vacuum,
[03:09.24]meaning it is separated from outside events or influences.
[03:14.84]But a galaxy cluster contains large amounts of gas
[03:20.00]that surrounds the many galaxies within it.
[03:23.36]This, NASA says, "provides a medium for the sound waves to travel."
[03:30.64]For the new sonification of the Perseus black hole,
[03:35.56]the NASA team used the sound waves they had collected in the past.
[03:41.44]But the astronomers then had to put the signals into a range
[03:46.96]that the human ear could hear.
[03:49.76]To do this, they greatly raised the pitch of the waves
[03:54.72]to a level far above their own frequency.
[04:02.32]NASA published the sounds on its website.
[04:06.12]They are contained in videos that show visual representations
[04:12.12]of the X-ray data collected by Chandra.
[04:15.96]The video images can be used to follow the waves,
[04:21.28]which NASA says were sent out in different directions.
[04:26.24]The space agency also released a new sonification
[04:31.08]of a black hole that became famous in 2019.
[04:35.92]That black hole sits at the center of the Messier 87 galaxy,
[04:42.88]about 55 million light years from Earth.
[04:47.36]It gained fame when astronomers announced
[04:51.48]they had successfully produced the first image of a black hole.
[04:57.20]NASA says that sonification
[05:00.96]was based on X-ray data collected by Chandra,
[05:05.36]light captured by the Hubble Space Telescope,
[05:09.12]as well as radio waves from the Atacama Large Millimeter Array in Chile.
[05:26.40]The black hole sounds were released as part of NASA's Black Hole Week.
[05:32.72]As part of that event, the agency also released
[05:37.12]new "data visualizations" of black holes
[05:41.32]based on telescope observations.
[05:44.96]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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