Space-probe photographs indicate the existence of giant volcanoes on the Martian surface. From the small number of impact craters that appear on Martian lava flows, one can estimate that the planet was volcanically active as recently as a half-billion years ago—and may be active today. The g...
by carbon-based life on Earth.But the elements are still products of stars and would still be present in planetesimals everywhere.No matter what kinds of life we are looking for, we are likely to find the necessary elements on almost every planet, moon, asteroid, and comet in the universe...
The virgin forest with its richness and variety of trees was a veritable real treasure-house which extended from Maine all the way down to Georgia. 出自-2015年考研翻译原文 The first shiploads of immigrants bound for the territory which is now the United States crossed the Atlantic more than a...
is harder. The Dolomites' rocks were formed at a time when the sea's level, relative to the land, was going up and down. Such movements mean that marine (海的) and land sediments (沉积物) are sandwiched in these mountains, and the marine sediments provided the information needed. Most ...
carbon-based life on Earth. But the elements are still products of stars and would still be present in planetesimals everywhere. No matter what kinds of life we are looking for, we are likely to find the necessary elements on almost every planet, moon, asteroid, and comet in the universe....
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早在1962年时，美国的卡逊出版了《静寂的春天》一书，书中的标题如“不必要的大破坏”“再也没有鸟儿叫了”“死亡的河流”“自天而降的灾难”等。可是在今天，书中的警告，已一一出现在我们身边，历史以充分的理由再次证明（）
C.the Earth is the only planet with intelligent life D.why intelligent life exists in the universe 2. Why was it hard to look for intelligent life in the universe in the past? A.The astronomers were not interested in it. B.The Milky Way didn’t exist at that time. ...
and difficult to see unless they are backlit by the Sun. In fact, they were first discovered only fairly recently, by the Voyager I spacecraft in 1979. The rings formed when meteors hit the surface of Jupiter's small inner moons, kicking up dust then began to orbit around the planet. ...
No matter what kinds of life we are looking for, we are likely to find the necessary elements on almost every planet, moon, asteroid, and comet in the universe. [#paragraph5]A somewhat stricter requirement is the presence of these elements in molecules that can be used as ready-made ...