万物简史 第37期:埃文斯牧师的宇宙(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?

很自然产生了这样的问题：要是一颗恒星在近处爆炸，情况会怎么样?我们已经知道，离我们最近的恒星是α星，在4.3光年以外。我曾经想像，要是那里发生一次爆炸，我们在4.3年时间里都看得到大爆炸的光洒向整个天空，仿佛是从一个大罐子里泼出来的那样。要是我们有4年零4个月的时间来观看一次无法逃脱的末日渐渐向我们逼近，知道它最后到达之时会把我们的皮肉从骨头上刮得一干二净，情况会怎么样?人们还会上班吗?农民还会种庄稼吗?还有人把农产品运到商店去吗?

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."

几个星期以后，我回到了我居住的那个新罕布什尔州小镇，向达特茅斯学院的天文学家约翰•索尔斯坦森提出了这几个问题。"哦，不会了，"他笑着说，"这么一件大事的消息会以光的速度传开，还有那个破坏性，你一听顿时会被吓死。不过，别担心，这种事情不会发生。"

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.

至于超新星爆炸的冲击波会要你的命的问题，他解释说，你非得"离得近到荒唐可笑的程度"--很可能是10光年左右之内。"危险来自各种辐射--宇宙射线等等"。辐射会产生惊人的极光，像闪闪发亮的怪异光幕，充斥整个天空。这不会是一件好事情。任何有本事上演这么一幕的事儿会把磁层--地球高空通常使我们不受紫外线和其他宇宙袭击的磁场--一扫而光。没有了磁层，任何倒霉蛋只要踏进阳光，很快就会看上去--比如说--像个烤焦的比萨饼。