英语听力文摘 English Digest 560、为何星星会闪烁?(在线收听) |
Why Do Stars Twinkle? If you’ve ever glanced skyward on a clear evening, you’ve probably noticed with some wonderment the sheer numbers of stars. Some are tiny, barely visible points. Others radiate strong white light. And from our earthly vantage point, these points of light seem fixed.
But, of course, stars and other celestial objects grow brighter and dimmer over time. Now, a massive new data set collected by astronomers at the California Institute of Technology and the University of Arizona documents the brightening and dimming of more then 200 million heavenly bodies.
The data come from images captured by a large telescope in Arizona looking for Near Earth Objects, or NEOs in other words, asteroids whose proximity to Earth could be cause for alarm.
Information about how celestial objects dim and brighten was a fortunate byproduct of the asteroid hunt. And it’s now proving valuable for helping astronomers and other scientists understand more about the evolution of stars, black holes, and the structure of the Milky Way.
For example, the data include information about more than 1,000 exploding stars, or supernovas. Being able to observe, as it were, how supernovas play out by measuring the increasing intensity of their brightness over time, allows scientists to better understand the life and death of stars.
And that’s only one example. As more scientists mine the data, new discoveries about how the heavens work are sure to follow.
为何星星会闪烁?
某个晴朗的夜晚,抬头瞥一眼夜空,你可能会惊奇地发现满天繁星。有些小到难以看见。其他一些恒星则发出强烈的白光。从地球这一有利视角看去,这些光点似乎总是这么亮。
但是,星星和其它天体当然会随着时间的推移逐渐变得明亮或是昏暗。如今,加州理工学院和亚利桑那大学的天文学家已搜集了大量数据,它们记录了2亿多天体变得明亮和黯淡的过程。
这些数据源自于科学家在亚利桑那州用大型望远镜探测近地天体,也就是NEOs时捕捉的卫星图片,近地天体是指那些接近地球时有可能会对地球构成威胁的小行星。
有关天体如何明暗变幻的信息是科学家探测小行星时意外的收获。如今,这一收获在帮助天文学家和其他科学家深入了解恒星,黑洞和银河系的演变过程方面有重要价值。
例如,这些数据涵盖了1千多个爆发星体,或称为超星体的信息。的确,人们可以通过观测并对比日益变亮的超星体的亮度来弄清它们爆发的过程 ,从而进一步了解星辰的诞生和灭亡。
这只是其中的一枚例子。随着越来越多的科学家探测相关数据,关于苍穹演变史的新发现指日可待。 |
原文地址:http://www.tingroom.com/lesson/englishdigest/190825.html |