首页
登录
职称英语
[img]2018m9s/ct_etoefz_etoeflistz_201808_0032[/img] [br] What features of Uranus
[img]2018m9s/ct_etoefz_etoeflistz_201808_0032[/img] [br] What features of Uranus
游客
2024-01-03
53
管理
问题
[br] What features of Uranus do some astronomers think were caused by its collision with another object? Click on 2 answers. .
Listen to part of a lecture in an astronomy class.
Professor: We’ve been focusing on the outer solar system and the planets Jupiter and Saturn. "Now let’s turn our attention to another gas giant planet Uranus, one of the most difficult planets for astronomers to study due to its distance from the Earth. To give you a hint how far away this planet is, one orbit around the sun takes Uranus 84 Earth years. Yes, Kevin?
Student: Didn’t the Voyager’s spacecraft get close enough to take pictures of it?
Professor: Yes, the spacecraft did get close enough to take pictures and measurements. Actually, we’ve learned a lot about its moons and rings from the Voyager flyby. Nonetheless, you can study a planet without making close-up observations. We have been able to deduce quite a lot about Uranus by observing it from Earth. For instance, when you look at Uranus through a telescope, it appears like a blue-green disk. What does this mean?
Student: What it’s made of?
Professor: Well, not exactly. lt tells us the composition of the planet’s atmosphere. It means that Uranus’ atmosphere has methane gas in it. Why? Well, the explanation for the blue-green color goes like this: methane gas absorbs red light, so as sunlight passes through Uranus’ atmosphere and is reflected back into space, the methane gas absorbs most of the red portion of the light and then allows the other light pass through. That’s the blue-green color we see. Using indirect observation, we can make inferences about the composition of the planet’s interior. For example, we know its mass volume, so we are able to calculate its density. Knowing Uranus’ density gives us ideas about its chemical makeup, because the density of a substance is consistent, so planets that have the same density usually are made of the same material, but not always. For example, Uranus and Jupiter have almost the same density; however, we know that Jupiter has a lot more material, a lot more mass than Uranus, and all that mass presses on itself, increasing its own density. So even though their densities are almost the same, Uranus probably is made up of heavier elements than Jupiter.
Student: So is Uranus made of rock? Of iron?
Professor: We’re discussing gas giant planets, aren’t we? Its density is much lower than that of rocky planets. Uranus might have a small core of rock or iron, but we think it’s primarily comprised of ordinary water mixed with methane and ammonia. Now another feature of Uranus is its rotation axis, which is nearly level with its path around the sun. No other planet in our solar system is tilted so far on its side.
Student: Do we know why Uranus’ tilt is so unusual?
Professor: Well, some researchers think it might be the result of a collision with another object in Uranus’ history, which changed its rotation. A result of this tilt is that the poles get most of the sunlight; half the time one pole and half the time the other within a year. And remember, that’s 84 years, so you get very long seasons.
Student: It probably doesn’t get warm anywhere there, so far away from the sun.
Professor: Right. And not only is Uranus far away from the sun, it doesn’t generate any heat, unlike the other giant planets which actually give off more heat than they get from the sun, so Uranus must have a very low core temperature and we don’t know the reason. Some astronomers think it is related to the unusual tilt, that the collision that knocked Uranus onto its side may have caused it to release much of its internal heat. Of course there are other theories. But getting back to your question earlier about the Voyager’s spacecraft. l don’t want you to think that these space missions are somehow superfluous in terms of what we can learn about a planet. For example, we know that Uranus has a magnetic field and this is something that we can’t learn from our standing point here on the Earth. You have to get up close for that.
选项
A、Its rapid rotation
B、Its low internal temperature
C、The composition of its core
D、The angle of its axis of rotation
答案
B,B
解析
细节题。教授陈述了天王星撞击促成的两个特点:Now another feature of Uranus is its rotation axis,which is nearly level with its path around the sun.No other planet in our solar system is tilted so far on its side…some researchers think it might be the result of a collision with another object in Uranus’history,which changed its rotation.即自转轴倾斜得厉害,因此D选项是正确答案。此外,教授还提到:Uranus must have a very low core temperature and we don’t know the reason.Some astronomers think it is related to the unusual tilt,that the collision that knocked Uranus onto its side may have caused it to release much of its internal heat.即撞击促成了温度的释放,导致内部温度低,因此B选项是正确答案。该部分未提到自转速度快及内核的组成,因此A选项和C选项不正确。
转载请注明原文地址:https://tihaiku.com/zcyy/3329096.html
相关试题推荐
EarthScience[img]2014m9s/ct_etoefm_etoeflistz_0305_20149[/img][br]Listento
EarthScience[img]2014m9s/ct_etoefm_etoeflistz_0305_20149[/img][br]Theprofes
EarthScience[img]2014m9s/ct_etoefm_etoeflistz_0305_20149[/img][br]Whatstart
EarthScience[img]2014m9s/ct_etoefm_etoeflistz_0305_20149[/img][br]Inthelec
EarthScience[img]2014m9s/ct_etoefm_etoeflistz_0305_20149[/img][br]Whatisth
CreativeWriting[img]2014m9s/ct_etoefm_etoeflistz_0298_20149[/img][br]Whatdo
CreativeWriting[img]2014m9s/ct_etoefm_etoeflistz_0298_20149[/img][br]Whatas
[img]2014m9s/ct_etoefm_etoeflistz_0292_20149[/img][br]ListentoTrack48.[img]
[img]2014m9s/ct_etoefm_etoeflistz_0292_20149[/img][br]Basedontheconversatio
Biology[img]2014m9s/ct_etoefm_etoeflistz_0285_20149[/img][br]Accordingtothe
随机试题
EarlyinthemorningMr.Smithiscuttingthegrassintheyard.Mr.Greenc
[originaltext]W:Thisfoodisterrible!Ican’tevenfinishmydinner.M:Ikno
中国古代选官制度关注官员的素质,内含治国理政的智慧。阅读材料,回答问题。 材料
维拉帕米A.具有二氢吡啶结构的钙通道阻滞药B.中效的镇静催眠药C.第一个开发的钙
电容器允许在()额定电压下长期运行105%;110%;115%;120%
某地上3层购物中心,耐火等级为三级,层高4m。每层建筑面积1000m2,中部设置
案例六: 一般资料:求助者,女性,22岁,大学生。 案例介绍:求助者最近总用
或有事项形成的或有资产只有企业基本确定能够收到的情况下,才能转换为真正的资产,从
某企业2016年综合资金成本为12%,全部投资收益率为8%,2017年拟投资新项
生命质量评价可应用于A.临床疗效的评价 B.卫生决策 C.治疗方法的选择
最新回复
(
0
)