| 1. | Tpf terrestrial planet finder
类地行星发现者号 |
| 2. | Earth is believed to have formed into a terrestrial planet 4 . 56 billion years ago when swirling space debris and gas clumped together
当成漩涡状太空碎片聚集在一起的时候,地球被认为在45 . 6亿年前形成。 |
| 3. | Its density is roughly 2 . 3 times that of water . usually , the jovian planets have density less than 2 , while terrestrial planets have density more than 5
冥王星的密度约为水的2 . 3倍通常来说，类木行星的密度会小于2 ，而类地行星的密度则大于5 。 |
| 4. | They may have been a source of part of the atmosphere of the terrestrial planets , and they are believed to have been the planetesimal - like building blocks for some of the outer planets and their satellites
它们可能是陆地行星大气的部分来源，他们也被认为是一些外层行星及其卫星的像星子一样的构成石块。 |
| 5. | If such planets exist , these missions ? nasa ' s terrestrial planet finder and esa ' s darwin ? should be able to scan their atmospheres for the presence of gases that would indicate the existence of life
如果真的有这类行星存在， nasa的类地行星搜寻者，以及esa的达尔文计画等任务，将得以探测它们的大气，寻找象徵生命存在的气体。 |
| 6. | They may have been a source of part of the atmosphere of the terrestrial planets , and they are believed to have been the planetesimal - like building blocks for some of the outer planets and their satellites
他们本来可能是地球行星大气层的来源之一，而目前的说法一直是他们是类星子堆积块，由一些外部行星和他们的卫星所造成。 |
| 7. | America ' s terrestrial planet finderand europe ' s darwin are still on the drawing board , but astronomerswould like to use them to identify “ biomarkers ” such as oxygen in theatmospheres of exoplanets
虽然美国的“类地行星发现者”计划和欧洲的“达尔文”计划在筹备之中，但是天文学家希望用它们来确定系外行星的大气层中是否有“生命标记” ，例如：氧气。 |
| 8. | This article adopts the method of comparative planetology , suggests that meteorite strike event is the universal geological process in solar system , and the meteorite strike case occurred in the earth is as the same it did in other terrestrial planets
本文采用比较行星学的方法，认为陨击作为太阳系普遍的地质过程，地球跟太阳系其他类地行星受到陨击的情况是相类似的。 |
| 9. | The asteroids , occupying the transition region between the rocky terrestrial planets and the outer gas giants with special configuration , underwent the collision evolution process . thus , the physical parameters of the asteroids provide us with a blueprint about the conditions of the early solar system and the boundary conditions for the its evolution
按照太阳系的行星由星云塌缩而成的演化理论，对在太阳系中处于特殊位置和具有特殊存在形态的小行星的物理参数的研究，可以为太阳系早期演化条件提供证据；为小行星碰撞演化研究提供边界条件。 |
