萬物簡史 第37期:埃文斯牧師的宇宙(6)

The question that naturally occurs is "What would itbe like if a star exploded nearby?" Our neareststellar neighbor, as we have seen, is Alpha Centauri, 4.3 light-years away. I had imagined that if therewere an explosion there we would have 4.3 years towatch the light of this magnificent event spreadingacross the sky, as if tipped from a giant can. Whatwould it be like if we had four years and four monthsto watch an inescapable doom advancing toward us,knowing that when it finally arrived it would blow theskin right off our bones? Would people still go towork? Would farmers plant crops? Would anyone deliver them to the stores?

很自然產(chǎn)生了這樣的問題：要是一顆恒星在近處爆炸，情況會(huì)怎么樣?我們已經(jīng)知道，離我們最近的恒星是α星，在4.3光年以外。我曾經(jīng)想像，要是那里發(fā)生一次爆炸，我們在4.3年時(shí)間里都看得到大爆炸的光灑向整個(gè)天空，仿佛是從一個(gè)大罐子里潑出來的那樣。要是我們有4年零4個(gè)月的時(shí)間來觀看一次無法逃脫的末日漸漸向我們逼近，知道它最后到達(dá)之時(shí)會(huì)把我們的皮肉從骨頭上刮得一干二凈，情況會(huì)怎么樣?人們還會(huì)上班嗎?農(nóng)民還會(huì)種莊稼嗎?還有人把農(nóng)產(chǎn)品運(yùn)到商店去嗎?

Weeks later, back in the town in New Hampshire where I live, I put these questions to JohnThorstensen, an astronomer at Dartmouth College. "Oh no," he said, laughing. "The news ofsuch an event travels out at the speed of light, but so does the destructiveness, so you'd learnabout it and die from it in the same instant. But don't worry because it's not going to happen."

幾個(gè)星期以后，我回到了我居住的那個(gè)新罕布什爾州小鎮(zhèn)，向達(dá)特茅斯學(xué)院的天文學(xué)家約翰•索爾斯坦森提出了這幾個(gè)問題。"哦，不會(huì)了，"他笑著說，"這么一件大事的消息會(huì)以光的速度傳開，還有那個(gè)破壞性，你一聽頓時(shí)會(huì)被嚇?biāo)?。不過，別擔(dān)心，這種事情不會(huì)發(fā)生。"

For the blast of a supernova explosion to kill you, he explained, you would have to be"ridiculously close"—probably within ten light-years or so. "The danger would be various types ofradiation—cosmic rays and so on." These would produce fabulous auroras, shimmeringcurtains of spooky light that would fill the whole sky. This would not be a good thing. Anythingpotent enough to put on such a show could well blow away the magnetosphere, the magneticzone high above the Earth that normally protects us from ultraviolet rays and other cosmicassaults. Without the magnetosphere anyone unfortunate enough to step into sunlight wouldpretty quickly take on the appearance of, let us say, an overcooked pizza.

至于超新星爆炸的沖擊波會(huì)要你的命的問題，他解釋說，你非得"離得近到荒唐可笑的程度"--很可能是10光年左右之內(nèi)。"危險(xiǎn)來自各種輻射--宇宙射線等等"。輻射會(huì)產(chǎn)生驚人的極光，像閃閃發(fā)亮的怪異光幕，充斥整個(gè)天空。這不會(huì)是一件好事情。任何有本事上演這么一幕的事兒會(huì)把磁層--地球高空通常使我們不受紫外線和其他宇宙襲擊的磁場--一掃而光。沒有了磁層，任何倒霉蛋只要踏進(jìn)陽光，很快就會(huì)看上去--比如說--像個(gè)烤焦的比薩餅。