Scientists estimate the ocean is 95 kilometres thick, which is about 10 times deeper than the earth's oceans. But unlike our salty waters, Ganymede's ocean is buried under 150 kilometres of ice.
While scientists have speculated(推测) since 1970s about the presence of an ocean on Ganymede—the largest moon in our solar system—until now the only observational evidence came from a brief flyby by the Galileo spacecraft, which didn't observe the moon long enough to confirm a liquid .
This discovery marks an important milestone, highlighting what only Hubble can accomplish. In its 25 years in orbit, Hubble has made many scientific discoveries in our solar system. A deep ocean under the icy surface of Ganymede opens up further exciting possibilities for life beyond the earth.
Scientists have already confirmed the existence of an ocean on Europa, another moon orbiting Jupiter, and NASA has announced plans to send an unmanned mission there searching for the life that might come with liquid water.
Hubble is a telescope that orbits the earth, but because of its impressive gravitational analyses it can be used to study the inside of far distant planets. Using these same principles, scientists could theoretically detect oceans on distant planets as well.
21.What can we learn about Ganymede from the passage?
A.It is a planet with the largest moon in our whole solar system.
【2017届(全国卷地区)高考英语一轮复习学生手册:必修3 Unit 4《Astronomy:the science of the stars》作业手册】相关文章:
★ 【北京专用】2014届高考英语一轮复习方案课时作业:必修1 Unit 5 Nelson Mandela
★ 【人教版】2014届高考英语一轮复习指导考点针对练:选修8 unit4《Pygmalion》
★ 【北京专用】2014届高考英语一轮复习方案课时作业:必修5 Unit 5 First aid
★ 2014届高考英语一轮复习课时作业(四十七)选修8Module 5《The Conquest of the Universe》(外研版)
★ 【三维设计】2017版(江苏专用)二轮复习练习:必修3 Unit 1《The world of our senses》课时跟踪检测B卷(含解析)
★ 2014届高考英语一轮复习课时作业(五)必修1Module 5《A Lesson in a Lab》(外研版)
★ 【浙江专用】2014届高考英语一轮复习课时作业(十)必修2Unit 5《Music》
★ 2017届江苏省淮安市新马中学高考牛津译林版英语一轮复习活动单:模块7 unit 1《Living with technology》
★ 【人教版】2014届高考英语一轮复习指导考点针对练:必修1 unit3《Travel journal》
★ 2017届江苏省淮安市新马中学高考牛津译林版英语一轮复习活动单:模块7 unit 2《Fit for life》
最新
2017-04-24
2017-04-24
2017-04-24
2017-04-24
2017-04-21
2017-04-21