Irma

托福分類單字 "Astronomy" 天文學 (二)

以下的單字其實都是一般天文新聞滿常出現的單字，只是要注意Intergalactic 、Interplanetary 和 Interstellar 這三個單字間的差異性到底是什麼，拚字非常相像但是意義上卻是大大的不同，後面也都標註了這三個單字的使用差異，從這裡也可以發現在背單字的時候一定要注意拚字相近的單字到底只是因為詞性的變化，還是從根本就換了一個新的單字，避免運用上的錯誤。

1) Gravitational force 重力；引力 

2) Massive (Adj.) 巨大的 ；大量的

3) High resolution 高清晰度

4) ignite (V.)  點燃；（使）燃燒；（使）爆炸； 激起  

5) illusive object 幻影物體

6) illusive (Adj.) 虛假的；幻覺的；不實際的

7) Infinite (Adj./N.) 無限的 ；極大的；上帝

8) Infrared ray 紅外射線 (IR)

9) Interferometer (N.) 干擾儀

10)International date line 國際換日線

11) Greenwich mean time 格林威治標準時間

12) Leap year 閏年

13) Light year 光年 

14) Luminosity (N.) 光度

15) Intergalactic  (Adj.) 星系際的 ( between galaxies ) 

16) Interplanetary (Adj.) 行星間的( between planets ) 

17) Interstellar (Adj.) 星際的( between the stars )

18) Lunar (Adj.) 月亮的，月球的

19) Meteor (N.) 流星 

20) Meteor shower 流星雨

截取部分網路新聞資料(天文類)：

Another prominent feature of Mars’s surface is cratering. The Mariner spacecraft found that the surface of Mars, as well as that of its two moons, is pitted with impact craters formed by meteoroids falling in from space. As on our Moon, the smaller craters are often filled with surface matter-mostly dust-confirming that Mars is a dry desert world. However, Martian craters get filled in considerably faster than their lunar counterparts. On the Moon, ancient craters less than 100 meters across (corresponding to depths of about 20 meters) have been obliterated, primarily by meteoritic erosion. On Mars, there are relatively few craters less than 5 kilometers in diameter. The Martian atmosphere is an efficient erosive agent, with Martian winds transporting dust from place to place and erasing surface features much faster than meteoritic impacts alone can obliterate them.

As on the Moon, the extent of large impact cratering (i.e. craters too big to have been filled in by erosion since they were formed) serves as an age indicator for the Martian surface. Age estimates ranging from four billion years for Mars’s southern highlands to a few hundred million years in the youngest volcanic areas were obtained in this way.

The detailed appearance of Martian impact craters provides an important piece of information about conditions just below the planet’s surface. Martian craters are surrounded by ejecta (debris formed as a result of an impact) that looks quite different from its lunar counterparts. A comparison of the Copernicus crater on the Moon with the (fairly typical) crater Yuty on Mars demonstrates the differences. The ejecta surrounding the lunar crater is just what one would expect from an explosion ejecting a large volume of dust, soil, and boulders. However, the ejecta on Mars gives the distinct impression of a liquid that has splashed or flowed out of crater. Geologists think that this fluidized ejecta crater indicates that a layer of permafrost, or water ice, lies just a few meters under the surface. Explosive impacts heated and liquefied the ice, resulting in the fluid appearance of the ejecta.