Many scientists today are convinced that life exists elsewhere in the universe---life probably much like that on our own planet. They reason in the following way.
As far as astronomers can determine, the entire universe is built of the same matter. They have no reason to doubt that matter obeys the same laws in every part of the universe. Therefore, it is reasonable to guess that other stars, with their own planets, were born in the same way as our own solar system. What we know of life on earth suggests that life will arise wherever the proper conditions exist.
Life requires the right amount and kind of atmosphere. This eliminates all those planets in the universe that are not about the same size and weight as the earth. A smaller planet would lose its atmosphere; a larger one would hold too much of it.
Life also requires a steady supply of heat and light. This eliminates double stars, or stars that flare up suddenly. Only single stars that are steady sources of heat and light like our sun would qualify.
Finally, life could evolve only if the planet is just the right distance from its sun. With a weaker sun than our own, the planet would have to be closer to it. With a stronger sun, it would have to be farther away.
If we suppose that every star in the universe has a family of planets, then how many planets might support life? First, eliminate those stars that are not like our sun. Next eliminate most of their planets; they are either too far from or too close to their suns. Then eliminate all those planets which are not the same size and weight as the earth. Finally, remember that the proper conditions do not necessarily mean that life actually does exist on a planet. It may not have begun yet, or it may have already died out.
This process of elimination seems to leave very few planets on which earthlike life might be found. However, even if life could exist on only one planet in a million, there are so many billions of planets that this would still leave a vast number on which life could exist.
1. Astronomers believe that matter in different parts of the universe
A) has different laws.
B) has one common law.
C) shares the same laws
D) shares no common law.
2. The existence of life depends on all of the following factors EXCEPT
A) the right amount of atmosphere.B) our own solar system.
C) steady heat and light D) the right distance from the sun.
3. Which of the following statements is INCORRECT?
A) The planet must be as big and heavy as the earth.
B) Proper conditions are essential to the existence of life
C) Double stars can provide steady light and heat.
D) The distance between a planet and its sun should be right.
4. What kind of planet might NOT support life?
A) Most of the planets of the stars.
B) Stars similar to our sun.
C) Planets similar to the earth.
D) Planets with proper conditions.
5. At the end of the passage the author suggests that
A) it is impossible for life to exist on planets.
B) earthlike life could only exist on a few planets.
C) life could exist on only one planet in a million.
D) life could exist on a great number of planets.
KEY:CBCAD
快乐很简单:20个提升幸福指数的小瞬间
蚂蚁金服与其大猩猩朋友
上海迪士尼今天开始售票!看点攻略票价全知道
国际英语资讯:China-Philippines relations have moved forward steadily, delivered tangible outcomes: Chines
日本爱知县高薪招募忍者
学会这4个爱情秘诀 让你永远处在热恋期
《BJ有喜》预告片首发 BJ新男友曝光
英豪宅玻璃多于墙面 售价近1300万
研究显示:适量巧克力可促进大脑认知功能
幸福的人都在做这8件事
外媒:成功女性的34个标准 你做到几点
荷兰足坛巨匠克鲁伊夫去世
国内英语资讯:China makes great strides in agriculture, poverty reduction over 70 years: officials
告别堵车:飞行汽车明年上市
与捷克人打交道 这些商务准则要记牢
中捷合拍动画片《熊猫和小鼹鼠》开播
国际英语资讯:UN rights session adopts resolution to mark 25th anniversary of the Beijing Declaration
国内英语资讯:President Xi to grant national medals and honorary titles
70年来,国人都学过这些英语教材......有你的那版吗?
美国选秀节目给我们的5大启示
语死早如何和别人闲聊下去?试试中度交谈吧
填色书风靡 致铅笔脱销
为什么你减肥总是不成功?警惕这十大绊脚石
体坛英语资讯:Serbia, Spain meet no challenge, China grabs first home win at FIBA World Cup
体坛英语资讯:Juventus beat Napoli 4-3 in stoppage time
身兼多职有何不妥?只是这些好处你不知道
研究发现:太极对心脑血管疾病有积极作用
研究显示:听自己吃东西的声音有助减肥
验智商:罗马尼亚球衣惊现数学题
国内英语资讯:Chinese FM calls for exchanges, dialogue among civilizations
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |