Why Do Stars Twinkle? If youve ever glanced skyward on a clear evening, youve 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 poin

发表于:2018-12-31 / 阅读(68) / 评论(0) 分类 英语听力文摘 English Digest

What happens is that, first the dark matter forms the structure, the ordinary matter then follows the dark matter. The ordinary matter is hydrogen and helium at this stage. And the hydrogen and helium fall/ to the center of the dark matter halos that

发表于:2019-01-22 / 阅读(63) / 评论(0) 分类 自然百科2011年

To understand how these calamities occur, astronomers need to catch a massive star in its death throes. Astronomers are like detectives. We have to figure out what's going on in the universe, sometimes based on a minimum number of clues. And in the c

发表于:2019-01-22 / 阅读(87) / 评论(0) 分类 自然百科2011年

Once theyve caught the light of a dying star with their state of our telescopes. The detective work can begin. We collect that light and we analyze it in great detail in order to determine whats going on, whats the chemical makeup of the star, whats

发表于:2019-01-22 / 阅读(72) / 评论(0) 分类 自然百科2011年

Weve recently been talking about the Fermi Paradox, attributed to Nobel-winning physicist Enrico Fermi. According to reasonable estimates of how many stars have planets, how many planets may be suitable for the evolution of organisms, and so on, our

发表于:2019-02-24 / 阅读(76) / 评论(0) 分类 英语听力文摘 English Digest