Radio waves are (1) to our eyes. But if you could see them, the sky would dance with random tiny flashes. Thousands of what are called “fast radio bursts” are estimated to occur every day. And though each pinprick flash lasts only a (2) of a second, they represent a faraway source briefly shining a billion or more times brighter than our sun.
Fast radio bursts have been known for nearly a decade, but scientists have (3) to determine exactly where they come from. And they’d like to know. Because finding their origins would help astronomers use the bursts as (4) to map the history and structure of the universe in (5) detail.
Now researchers have found the source of one particular burst. They used radio telescopes in Australia and the giant Subaru optical telescope in Hawaii to trace a burst observed last April. And they determined it came from an old elliptical galaxy full of exhausted, dying suns some six billion light-years away. The findings are in the journal Nature. [Link to come] (6) the source galaxy provides crucial clues. For one thing, such a galaxy is short on some of the objects expected to cause bursts, such as supernovae or rapidly spinning and flaring pulsars, suggesting this burst came from something else. And, although the burst in question lasted only milliseconds, astronomers were able to (7) its faint, fading radio afterglow for about six days. That’s the sort of afterglow expected from a colliding pair of ancient neutron stars, which would be a relatively common occurrence among an elliptical galaxy’s geriatric suns.
Even though this particular burst has probably been explained, many mysteries remain—not all bursts seem to come from the same cosmic source. (8) , most possible burst sources could be (9) by the gravitational waves they emit, like those recently seen by the Laser Interferometer Gravitational-Wave Observatory, or LIGO. That means researchers may soon be searching the skies for both radio and (10) waves for these bursts, to help draw an ever more detailed map of the cosmos.
小伙伴们,开学啦,新的学期, 我们要打起精神好好学习,好好工作,坚持学英语,坚持每周一听,让我们一起进步, 语言的学习贵在积累,坚持,小伙伴们如果每周都坚持这个活动,一段时间后,你们会发觉自己听力及英语水平的提高,所以大家和我一起努力学习,共同进步,让英语成为我们的爱好,接下来的活动我会出一些新的鼓励政策,具体政策还在筹划,主要目的当然是鼓励小伙伴们坚持学英语。新的学期,让我们共有努力,一起加油,共同进步!!!
上期答案
1.responsible
2.unfairly
3.trapped
4.contributions
5.versus
6.incurring
7.extreme
8.addressing
9. mobilization
10. vulnerable