评论
打印
5.Do Wildfires Always Cause Global Warming?
5.野火总会引起温室效应吗?
Conventional wisdom tells us that fires transmute trees and related foliage into pollution, in the form of greenhouse gasses like carbon dioxide.
社会传统的经验告诉我们：烈火能够把树木和树叶转化为污染物，例如二氧化碳之类的温室气体。
But the disintegration of large swaths of organic material can be beneficial as well. Clearing the shrubbery increases local albedo, or reflective value. The amount of sunlight bounced back out into space increases. This cooling is observed in boreal biomes. However, the immediate surge in burning pollution that accompanies a major fire does contribute to warming. And as the black ash falls back to Earth, it blankets the region, increasing absorption of solar radiation. But after the ashes clear, it's smooth sailing.First, a snowy and highly reflective surface is revealed to the Sun, and solar rays are reflected back into the cosmos. Then, new deciduous species replace the pre-fire conifers. And their young, glossy leaves offer additional reflective surfaces to thwart the Sun. In winter, the newcomers shed their leaves, unlike their piney predecessors, and a mirror-like terrain once again reveals itself.So yes, the initial fire is kind of an environmental hazard. But scientists predict that in only eight decades, the effects reverse. At this point, the deleterious effects of the fire will have been undone, yet local cooling will persist.
但是大量有机物的分解却是有益的。灌木丛被清理之后，当地地表的反射率或是反射值提高。反射回太空的日照量也随之增加。这种冷却现象是在寒带生物群落中观察到的。然而，重大火灾产生的污染物激增，确实加重了温室效应。随着火灾产生的灰屑落在大地上，大地就好像披上了一层黑色毛毯，随即增强了吸收太阳辐射的能力。但是当这些灰烬消失后，一切顺利进行。首先,盖满大雪的地表反射率很高，袒露在太阳之下，太阳光线就被反射回了太空。然后，新的落叶林就代替了大火之前的针叶林。它们新生的丛丛叶子对阳光的反射率更高，进一步阻挡了阳光。冬天，这些新生的树木叶子脱落，不像之前那些松柏类植物，于是镜子一样的地表就再次暴露在阳光之下。最初的大火确实是一种自然灾害。但是科学家们预测，仅在八十年内这种影响就会逆转。在这一点上，火灾造成的毁灭性后果将被消除，而局部气温降低则会持续。
4.What's Causing The Global Warming Hiatus?
4.为何全球变暖中断？
Global temperatures increased at high rates in the 20th century, but since 1998, there's been an unexpected lull. This has inspired optimism in the wasteful and righteousness in climate change deniers. To scientists, the decreased global warming rates are suspicious.
20世纪全球气温一直呈快速增长趋势，但自1998年以来却意想不到地稳定。这一现象支持浪费，否认了气候变化，让持这类观点的人乐观起来。科学家称全球变暖速度减缓这一点十分可疑。
It turns out that we're in the eye of the environmental tornado. The Pacific Ocean is doing us a huge favor by dissipating large chunks of solar radiation into its watery bosom, part of a natural cycle played out over tiny geological timeframes. The global warming hiatus—now seen as more of a “false pause”—started in the late '90s. This date syncs with the back end of the El Nino warming event of 1997–1998. The Pacific Ocean cycles through its hot and cold phases for 16-20 years, suggesting a return to warmer waters any day now. Sadly, the intermittent periods of calm won't do much to buck long-term trends. But at least now we know what's happening.
环境就像龙卷风，而我们正处于风眼中。太平洋帮了我们一个大忙，吸收了大量太阳辐射，在极短的地质时期内进行着部分自然循环。开始于上世纪90年代的全球变暖中断了，现在多被视为“虚假暂停”。中断时间与1997-1998厄尔尼诺引发气候变暖事件的后段时期相吻合。太平洋水温冷热变化每16-20年循环一次，这意味着现阶段它会随时回暖。可惜的是，断续出现的稳定对逆转长期以来变暖的趋势影响不大。但至少现在我们知道到底发生了什么。
3.What Do The Tectonic Plates Slide On?
3.什么支撑着板块漂移？
The theory of plate tectonics has been generally accepted for a while now, but it's never been clear what the continental slabs are sliding upon. To find out, researchers in New Zealand used one of the oldest scientific methods known to man: explosions.
目前，板块构造理论得到公认已有一段时间了，但人们却从未明确漂移的大陆板块下面藏着什么。为了找到答案，新西兰研究人员使用了一种人类已知最古老的科学方法：爆炸。
Seismic measurements are usually revealed by earthquakes. But Kiwi researchers didn't have time to wait for natural tremors, so they made their own. The team ventured to the southern tip of New Zealand's North Island and poured explosive slurry into a series of 50-meter-deep (160 ft), steel-insulated bore holes. The holes were drilled across a major subduction zone, where the Pacific plate joints the Australian plate. The explosion produced a downward-traveling earthquake and teased some telltale jiggles out of the crust. They found that the lithosphere (the crust) slides along a 5-kilometer-thick (3 mi) conveyor formed of a lubricating, jelly-like rock mixture. Officially the lithosphere asthenosphere boundary (LAB), this glorified Earth-lube disconnects the crust from the mantle and provides a cushy platform for continental shifts. It's believed the LAB's squishiness is a result of increased water or magma content. Surprisingly, a tiny increase of 1–2 percent compared to the crust is enough to form the gelatinous boundary. However, researchers still don't know whether the plates are pushed or pulled along the syrupy effluence and if this material is present underneath all plates. Whether a race of malefic mole men is implicated remains a mystery as well.
通常地震会留给我们很多相关数据。但是新西兰研究人员没有时间等地壳自然震动，因此他们制造了地震。研究队冒险来到了新西兰北岛的南端，并将爆炸性浆液倒入许多50米（160英尺）深的钢制隔热钻孔中。这些孔分布在一个主要的俯冲带，即太平洋板块和澳大利亚板块的接合处。爆炸产生了向下传导的地震，引起地壳轻微晃动。他们发现，果冻状的岩石混合物形成了一条5公里（3英里）厚的传送带，岩石圈（地壳）便随着传送带滑动。正式的说法是，岩石圈软流圈边界（LAB）是重要的地球润滑油，它隔开了地幔与地壳，并为大陆漂移提供了一个方便的平台。他们相信软流圈边界如此柔软是水或岩浆增加的结果。令人惊讶地是，地壳增加1-2％的微量就足以形成凝胶状边界。然而，研究人员仍然不知道板块是否随着岩浆流动而分离或挤压，这种物质又是否存在于所有板块之下。至于是否涉及邪恶的鼹鼠人自然还是一团谜。
2.What's Happening With Earth's Core?
2.地心在发生着什么？
If finding a lubricating belt of tectonic sludge wasn't exciting enough, collaborators from the University of Illinois and Nanjing University have discovered Earth's second core. This breaking seismic research shows that Earth's innermost core is, in fact, Earth's second-innermost core. And the smaller sphere roiling within it sits mysteriously on its side, with its constituent iron crystals aligned east to west (as opposed to north to south).
如果地层里的污泥润滑带还不够震撼人心，那么这一定可以：伊利诺伊大学和南京大学组成的研究合作团队发现了地球的第二个核心。这项破天荒的地理发现表明，最里边的地核实际上是地球的第二个核心。较小的核心在外核内旋转，奇怪的是其位置始终偏向一方，而组成它的铁晶粒由东到西连成了一条线（与从北向南相反）。
Obviously, a discovery of this magnitude deserves the good champagne. The additional core reveals Earth as a complicated, planetary onion full of inner tumult. The newly observed core churns against an outer shell of molten iron alloys as it steadily grows larger, at less than 1 millimeter a year.The new core is also geologically akin to a time capsule. Researchers estimate that it solidified 500 million–1.5 billion years ago. That's not too long ago, on a global timescale 4.5 billion years long. Some major primeval event or catastrophe must have befallen the core soon after its birth, which would explain its sideways orientation.
显然，这项重大发现值得我们举杯同庆。第二地心揭示了地球是一个复杂的，像洋葱一样的行星，内部充满摩擦。新发现的第二地心在外壳内转动，而其熔融铁合金外壳正以小于每年1毫米的速度稳步变大。第二地心类似地质上的一个时间囊。研究人员估计，它于5亿至15亿年前凝固成形。相对于地球45亿年之久的历史来说，这并不能算是很久以前。地心形成后不久，很可能发生了什么大事或灾难，这就可以解释为什么地心偏向一边。
1.What Causes The Theta Aurora?
1.θ极光是怎样形成的？
The theta aurora, named for its resemblance to the eponymous Greek letter, is an oval-shaped region of electromagnetic activity at the edge of Earth and space. It cannot be seen from the ground, and its existence was undetermined until space-age observations let us view the Earth from an external vantage point.
θ极光的名字源于和它外形相似的同名希腊字母，它出现在地球和太空的边缘，是电磁活动的一片椭圆形区域。人们从地面上是看不到它的，它的出现也具有不确定性，直到太空时代的观察结果让我们可以借用外太空的有利位置一睹地球的风采。
Unlike the regular auroras popularized on postcards and such, the cosmic mechanisms that birth theta aurora outbursts were poorly understood. One possible explanation credits unusually hot globules of plasma crashing against our magnetosphere. Then combined satellite data fingered another culprit: funneled solar winds and magnetic mirrors (when ions bounce from high-density to low-density fields).It appears the theta aurora is caused by plasma confined within enclosed fields. The charged particles are heated and bounce against closed lines as if trapped inside a giant, magnetic bouncy house. This explanation differs from the original supposition that the theta was caused directly by sweeping solar winds against our planet's magnetic mane.
θ极光并不像那种印在明信片上的普通极光，对于突然诞生θ极光的宇宙机制，人们还不是很清楚。一种可能的解释是，它是由极其灼热的等离子球撞击地球磁层而产生的。组合卫星数据找到了另一罪魁祸首：地球磁场漏斗状的太阳风和磁镜（当离子从高密度地带弹到低密度地带的时候）。这样看来，θ极光是因为等离子体在封闭环境中活动受限而形成的。这些带电粒子温度很高，在闭合线中弹跳，就好像被困在一个巨大的，有磁力的的弹性房子里。这种解释有别于最初的假设，即θ极光是由太阳风扫过地球磁场直接产生的。
翻译:步懒懒6+5 来源:前十网
