Alien Neighbors 寻访外星人 6

.....green plants ultimately. When it first appeared therefore, it would have been seen as a poison, it would have been a pollutant¹. But gradually, through Darwinian natural selection, living organisms have become more and more used to oxygen. They've been selected to thrive in the presence of oxygen, so that now, most living organisms can't live without oxygen.

Green plants can trap the sun's energy to produce not just the oxygen we breathe, but the food that supports the entire animal kingdom. The other great lifegiver on earth is water. Our water rich world is an oasis² for life. Earth's sister planet Venus may also once have had water, but soaring temperatures caused by a runaway³ greenhouse effect had made it a hostile environment to living things.

Venus and earth had roughly similar potential for developing into life-supporting planets. But, only earth succeeded. At Lulworth Cove⁴ in England, Ellen Stophan is trying to figure out why.

This rock is Jurassic limestone⁵ that was formed over about a hundred million years ago in shallow seas. This rock is made mostly of carbonates, it has a lot of carbon dioxide in it. On Venus, most of the carbon dioxide is actually in the atmosphere. On earth, it's tied up in limestones⁶ like these that were formed in the Jurassic. Why did Venus end up with all its carbon dioxide in the atmosphere and earth with it tied up in big rocks like this is a question that we are puzzling with right now. We think it might have to do with something with the evolution of life on earth. Maybe the earth was just far enough away from the sun that it was cool enough that it allowed life to evolve, took that carbon dioxide out of the atmosphere. On Venus, all the carbon dioxide remained in the atmosphere, and we ended up with a planet that's baking on in its own heat.

When the sun sets, Venus is often the brightest object in the sky, outshining the night lights of Tucson, Arizona. It twinkles like a star because the planet's dense⁷ cloud cover is extremely reflective.

In 1967, Venera IV became the first space probe to penetrate⁸ the Venusian clouds and transmit data. The first probe to softland on the surface and send back information was Venera VII in December 1970. The Venera landers only transmitted data for about an hour before being destroyed by the planet's intense heat and pressure. In August 1990, the Magellan Mission began a radar⁹ survey of Venus, which allowed imaging experts of the Jet Propulsion Lab to create this simulation of the Venusian landscape.

No traces of life were found. But, scientists were delighted to become more closely acquainted with our neighbor planet.

Looking at Venus through a telescope is, it's magical, because, you know, it is the evening or morning star,and you know, seeing it as a planet itself is kind of exciting. But at the same time, since it's totally covered by a set of dense clouds one would like to see more, and, so , with....

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words in this passage:

lifegiver:给予活力之人[事, 物]

runaway: out of control. 失去控制的
[sometimes it may mean surprisingly big. eg:Her first novel's runaway (= surprisingly big) success came as a great surprise.]

cove:a curved part of a coast which partly encloses an area of water; a small bay山凹, 小湾

Jurassic:[地质]侏罗纪的, 侏罗系的

Tucson:图森[美国亚利桑那州南部城市]

Jet Propulsion Lab:简称JPL， 喷气推进实验所[美]

1 pollutant   

n.污染物质，散布污染物质者

参考例句：

• Coal itself is a heavy pollutant.煤本身就是一种严重的污染物。
• Carbon dioxide may not be a typical air pollutant.二氧化碳可能不是一种典型的污染物。

2 oasis   

n.（沙漠中的）绿洲，宜人的地方

参考例句：

• They stopped for the night at an oasis.他们在沙漠中的绿洲停下来过夜。
• The town was an oasis of prosperity in a desert of poverty.该镇是贫穷荒漠中的一块繁荣的“绿洲”。

3 runaway   

n.逃走的人，逃亡，亡命者；adj.逃亡的，逃走的

参考例句：

• The police have not found the runaway to date.警察迄今没抓到逃犯。
• He was praised for bringing up the runaway horse.他勒住了脱缰之马受到了表扬。

4 cove   

n.小海湾，小峡谷

参考例句：

• The shore line is wooded,olive-green,a pristine cove.岸边一带林木蓊郁，嫩绿一片，好一个山外的小海湾。
• I saw two children were playing in a cove.我看到两个小孩正在一个小海湾里玩耍。

5 limestone   

n.石灰石

参考例句：

• Limestone is often used in building construction.石灰岩常用于建筑。
• Cement is made from limestone.水泥是由石灰石制成的。

6 limestones   

n.石灰岩( limestone的名词复数 )

参考例句：

• The isotopic signatures of most ancient limestones indicated the same process. 大多数古代石灰岩的同位素特征说明了同样的过程。 来自辞典例句
• There are four principal types of limestones. 石灰岩有四种主要类型。 来自辞典例句

7 dense   

a.密集的，稠密的，浓密的；密度大的

参考例句：

• The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
• The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。

8 penetrate   

v.透(渗)入；刺入，刺穿；洞察，了解

参考例句：

• Western ideas penetrate slowly through the East.西方观念逐渐传入东方。
• The sunshine could not penetrate where the trees were thickest.阳光不能透入树木最浓密的地方。

9 radar   

n.雷达，无线电探测器

参考例句：

• They are following the flight of an aircraft by radar.他们正在用雷达追踪一架飞机的飞行。
• Enemy ships were detected on the radar.敌舰的影像已显现在雷达上。