太阳光线照射到地球时，大量的热被反射回太空。
When the sun's rays hit the earth, a lot of the heat is reflected back into space.
只有当彗星接近地球时，我们才能看得见它们。
这样的话，当2023年样本到达地球时，会保证原封不动。
This way, it will be unchanged when it arrives on our planet in twenty-twenty-three.
试想象当月亮接近地球时，潮汐将会上涨直至覆盖海底的岩浆层！
Imagine the tides a moon that close would raise on an Earth awash with oceans of magma!
北极光的出现是，当太阳发射出带电的微粒子飞越地球时所产生的光线。
The ribbons stretch from one end of the Northern Lights appear when the sun sends charged particles flying toward Earth.
在这种距离下，即便是聚焦良好的光束到达地球时也会分散到上千公里宽的面积上。
Over those distances, even a sharp laser beam would spread to thousands of kilometres wide by the time it reached Earth.
当太空探测器信使号在三个月前到达离太阳最近的地方并回望地球时，它找到了答案。
The robotic spacecraft MESSENGER found out as it looked toward the Earth during its closest approach to the Sun about three months ago.
最遥远的爆炸光飞向地球时，被宇宙的膨胀拉长而呈红色——一种被称作红移的现象。
As light from the most distant explosions travels toward Earth, it is stretched by the universe's expansion so that it appears red, a phenomenon known as redshift.
的碰撞。例如月亮被认为形成于火星大小的星体急速撞向我们年轻的地球时产生的碎片。
The moon, for instance, is believed to have formed from debris stirred up by a Mars-size object careening into our young planet.
而且你们可以想象-，我把球儿扔起来，在球远离地球时，地球也同样，在远离着球。
But you may want to think about this — if I throw the ball up, going to be away from the earth I'll bet you anything that the earth will also go away from the ball.
——1969年7月23日，当阿波罗11号赶回地球时，发生了一件只有孩子才能解决的问题。
On July 23, 1969, as Apollo 11 hurtled back towards Earth, there was a problem — a problem only a kid could solve.
相当悠闲：汉姆在火箭准备起飞的时候非常轻松(左图)，而返回地球时也一样轻松(右图)。
Laid back: Ham appeared just as relaxed while preparing for take-off (left) as he did having come back down to earth.
宇航员在离开地球时拍摄下了著名的“蓝色玻璃球”（因为看上去就像孩子们爱玩的玻璃弹球）的地球照片。
The crew take The Blue Marble image as they leave the Earth.
这件事听起来像发生在电影里，但是这确是阿波罗11号于1969年在月球登陆后赶回地球时所发生的事情。
It sounds like something out of a movie, but that's what it came down to as Apollo 11 sped back towards Earth after landing on the moon in 1969.
然而，当2006年一个太空舱从一个叫做“星尘”的探测器回到地球时，他又一次面对了这个问题。
Yet this was the problem facing him when a capsule returned to earth in 2006 from a probe called Stardust.
这是抓拍到的日本隼鸟号探测器在2010年3月返回地球时途经澳大利亚南部上时空留下的身影。
The Hayabusa spacecraft was captured over Southern Australiaduring its re-entry on 13 June 2010.
当俄国最近又预测阿波菲斯99942可能于2036年4月13日撞击上地球时，该小行星再次引起媒体关注。
The asteroid hurtled back into the news when Russia recently predicted 99942 Apophis may hit Earth on April 13, 2036.
图15：从阿波罗17号着陆地点2号站仰望地球时所拍摄的照片，画面中最醒目位置是一块圆形巨石和月球地平线。
15：Looking up toward Earth, a boulder and the Moon's horizon in theforeground, at Station 2 of the Apollo 17 landing site.
当这些带电粒子接近地球时，便形成一个很强的磁场区--磁气圈--包围着地球并对地球起一定的保护作用。
When the charged electrical particles approach the Earth, they carve out a highly magnetized region —the magnetosphere —which surrounds and protects the Earth.
研究学者认为，我们的月球是在一个巨大如火星的物体撞击地球时形成的，碰撞产生圆形的碎屑沿着地球轨道飞行。
Researchers believe that our moon was created when a giant object the size of Mars hit the early Earth, sending out a disc of debris orbiting our planet.
联盟号飞船发生的一系列事故也让人感到担心。2008年四月着陆期间发生的问题导致它出现重返地球时的险情。
A string of incidents related to Soyuz has raised concerns. Problems during a landing in April 2008 resulted in a dangerously steep re-entry trajectory.
回到地球时正是圣诞节的开始，返程尽管谈不上平静，但也没有发生大事，航天员们自己对于这次飞行任务的打分是50比50。
The journey back to Earth, which began on Christmas Day, was uneventful, though hardly calm; the astronauts themselves had given their mission only a 50-50 chance of succeeding.
担当这一重任的是马来西亚天体物理学家马斯蓝•奥斯玛，她的职责是，假设有外星人接触地球时，协调人类的应对行动。
Mazlan Othman, a Malaysian astrophysicist, is set to be tasked with co-ordinating humanity’s response if and when extraterrestrials make contact。
不过，它仍然存在一个微小的机会可能在2036年或2068撞击地球，这取决于这颗小行星在未来经过地球时的确切路线。
However, there's still a tiny chance it will hit in 2036 or 2068-depending on the exact route the asteroid follows during its next pass near Earth.
马夸特考虑到了阿波菲斯行星在2029年4月13日靠近地球时与一颗或多颗围绕地球运转的卫星相撞的可能性。目前地球周围的卫星达四万颗。
The schoolboy took into consideration the risk of Apophis running into one or more of the 40, 000 satellites orbiting Earth during its path close to the planet on April 13 2029.
这在1978年发生过，当时ITF禁止了非传统的“意面式击球”，这是前一年罗马尼亚选手伊利.纳斯塔斯在击打落地球时双倍增加了上旋球的力量。
That happened in 1978, when the ITF banned the unconventional “spaghetti stringing” used the previous year by Romania's Ilie Nastase to double the amount of topspin on his groundstrokes.
该操作台会在重新进入地球大气层时烧掉。
The station would burn up on reentry into the Earth's atmosphere.
在重新进入大气层的过程中，大部分航天器会在穿过地球大气层时燃烧殆尽。
During re-entry, most of the spacecraft will burn up while passing through the Earth's atmosphere.
在重新进入大气层的过程中，大部分航天器会在穿过地球大气层时燃烧殆尽。
During re-entry, most of the spacecraft will burn up while passing through the Earth's atmosphere.
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