探索頻道 Cosmos 宇宙的邊疆03
These are the galaxies, drifting endlessly in the great cosmic dark. In our ship of the imagination, we're halfway to the edge of the known universe.
In this, the first of our cosmic voyages, we begin to explore the universe revealed by science. Our course will eventually carry us to a far-off and exotic world, but from the depths of space we can not detect even the cluster of galaxies in which our Milky Way is embedded, much less the Sun, or the Earth.
We're in the realm of the galaxies, eight billion light years from home. No matter where we travel, the patterns of nature are the same, as in the form of this spiral galaxy. The same laws of physics apply everywhere, throughout the cosmos. But we have just begun to understand these laws. The universe is rich in mystery.
Near the center of a cluster of galaxies, there's sometimes a rogue elliptical galaxy made of a trillion suns, which devours its neighbors. Perhaps this cyclone of stars is what astronomers on Earth call a quasar.
Our ordinary measures of distance fail us here in the realm of the galaxies. We need a much larger unit -- the light year. It measures how far light travels in a year, nearly ten trillion kilometers. It measures not time, but enormous distances.
In the Hercules Cluster, the individual galaxies are about 300, 000 light years apart. So light takes about 300, 000 years to go from one galaxy to another.
Like stars, and planets and people, galaxies are born, live and die. They may all experience a tumultuous adolescence. During their first hundred million years, their cores may explode, seen in radio light, great jets of energy pour out and echo across the cosmos. Worlds near the core or along the jets would be incinerated. I wonder how many planets ……
embed vt. 使插入, 使嵌入
elliptical adj.橢圓的, 省略的
cyclone n.旋風(fēng), 颶風(fēng), 暴風(fēng), 龍卷風(fēng), [氣]氣旋
tumultuous adj. 喧囂的, 動亂的,激動的
adolescence n.青春期(一般指成年以前由13至15的發(fā)育期)
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