時(shí)差N小時(shí):航天飛機(jī)為什么發(fā)光?

During the space shuttle's third flight, back innineteen eighty two, astronauts Jack Lousma and C.Gordon Fullerton saw something remarkable. Abovethe tail of the shuttle, where there should have beenempty space, they saw a faint orange glow instead,flickering with ghostly light. Was the space shuttlehaunted? What was going on?

時(shí)光倒轉(zhuǎn)回1982年，在宇航員杰克·洛思馬和查爾斯·戈?duì)柕?middot;福勒頓進(jìn)行第三次航天飛行時(shí)，他們看到了驚奇的一幕。在飛機(jī)尾部原應(yīng)是空白的地方，出現(xiàn)了微弱的橙色輝光，詭異地?fù)溟W著。難道航天飛機(jī)上也鬧鬼?這到底是怎么回事?

To understand this phenomenon, known as "shuttle glow," you should know something aboutthe region of space where the shuttle orbits. NASA shuttles stay in low Earth orbit, which isgenerally about a hundred and seventy miles above the Earth's surface. At that height, theatmosphere has tapered away to almost nothing--less than a billionth of the pressure it is atground level--but there are still gasses there. Indeed, low Earth orbit is well within theionosphere, a major part of our atmosphere.

為了弄清楚“航天飛機(jī)輝光”這一現(xiàn)象，有一點(diǎn)你應(yīng)該注意到，那就是航天飛機(jī)飛行軌道所在的區(qū)域。美航局的飛機(jī)飛行時(shí)，一般保持在近地軌道上，即距離地表一百七十英里的地方。在這樣的高度，大氣程錐形逐漸減少——大氣壓力比地表的十億分之一還小——但這里仍然有空氣存在。實(shí)際上，近地軌道基本被電離層覆蓋。而電離層是大氣的重要組成部分。

The thin gasses of the ionosphere rush past the space shuttle at about five miles per second,forming a very fast, very thin wind. This wind is so thin you'd never be able to feel it, even ifyou stuck your head out the space shuttle window the way a dog sticks it's head out a movingcar. The wind causes two things to happen.

飛機(jī)以每秒5英里的速度駛過(guò)之后，電離層稀薄的空氣就會(huì)形成一股快速流動(dòng)的細(xì)風(fēng)。人類無(wú)法感覺(jué)到這種細(xì)風(fēng)，即使你將頭伸到飛機(jī)窗外(像狗一樣將頭伸出飛速行駛的汽車(chē))也感覺(jué)不到。這種細(xì)風(fēng)會(huì)引起兩件事情。

First, it erodes the surfaces of some materials.The erosion is slight, but it can be significantfor camera lenses or other sensitive equipment. Second, the shuttle's surface can scoop upatoms from this wind, and these atoms can undergo chemical reactions. One reaction,involving nitrogen and oxygen, can produce a luminous orange glow. And that's what theastronauts saw. It wasn't a ghost--it was shuttle glow.

第一，它會(huì)侵蝕一些材料的表面。這種輕微的侵蝕用照相機(jī)或者其它敏感的設(shè)備看很明顯。第二，航天飛機(jī)的表面會(huì)從細(xì)風(fēng)中捕獲原子，并且這些原子能發(fā)生化學(xué)反應(yīng)。有一種氮和氧的反應(yīng)就能產(chǎn)生明亮的橙色輝光。這就是宇航員所看到的光。它不是鬼火，而是輝光。