Space storm alert: 90 seconds from catastrophe

IT IS midnight on 22 September 2012 and the skies above Manhattan are filled with a flickering curtain of colourful light. Few New Yorkers have seen the aurora this far south but their fascination is short-lived. Within a few seconds, electric bulbs dim and flicker, then become unusually bright for a fleeting moment. Then all the lights in the state go out. Within 90 seconds, the entire eastern half of the US is without power.

A year later and millions of Americans are dead and the nation's infrastructure lies in tatters. The World Bank declares America a developing nation. Europe, Scandinavia, China and Japan are also struggling to recover from the same fateful event - a violent storm, 150 million kilometres away on the surface of the sun.

It sounds ridiculous. Surely the sun couldn't create so profound a disaster on Earth. Yet an extraordinary report funded by NASA and issued by the US National Academy of Sciences (NAS) in January this year claims it could do just that.

Over the last few decades, western civilisations have busily sown the seeds of their own destruction. Our modern way of life, with its reliance on technology, has unwittingly exposed us to an extraordinary danger: plasma balls spewed from the surface of the sun could wipe out our power grids, with catastrophic consequences.

The projections of just how catastrophic make chilling reading. "We're moving closer and closer to the edge of a possible disaster," says Daniel Baker, a space weather expert based at the University of Colorado in Boulder, and chair of the NAS committee responsible for the report.

It is hard to conceive of the sun wiping out a large amount of our hard-earned progress. Nevertheless, it is possible. The surface of the sun is a roiling mass of plasma - charged high-energy particles - some of which escape the surface and travel through space as the solar wind. From time to time, that wind carries a billion-tonne glob of plasma, a fireball known as a coronal mass ejection (see "When hell comes to Earth"). If one should hit the Earth's magnetic shield, the result could be truly devastating.

The incursion of the plasma into our atmosphere causes rapid changes in the configuration of Earth's magnetic field which, in turn, induce currents in the long wires of the power grids. The grids were not built to handle this sort of direct current electricity. The greatest danger is at the step-up and step-down transformers used to convert power from its transport voltage to domestically useful voltage. The increased DC current creates strong magnetic fields that saturate a transformer's magnetic core. The result is runaway current in the transformer's copper wiring, which rapidly heats up and melts. This is exactly what happened in the Canadian province of Quebec in March 1989, and six million people spent 9 hours without electricity. But things could get much, much worse than that.

adaptes from http://www.newscientist.com/article/mg20127001.300-space-storm-alert-90-seconds-from-catastrophe.html

据英国媒体20日报道，太阳风暴指的是太阳黑子活动高峰期的剧烈爆发活动，通常每隔11 年就会进入一个太阳风暴的活跃期。美国科学家警告称，地球有可能在2012年9月遭遇一次百年未遇的“超级太阳风暴”，它的破坏力将等同于一场小型核战争，世界各地的电网都可能在1小时内被摧毁，与供电息息相关的行业都将成为受害者：手机网络将瘫痪，互联网将崩溃，没有任何信号的电视机也将形同废物，由于大面积停电，文明社会将陷入一片混乱，欧洲大部分国家和美国都将遭遇人类历史上最严重的经济灾难。到2013年末，欧洲将有10万人活活饿死。

　　从理论上说，一般太阳风暴的强度还不至于冲破地球大气和磁场的保护，但专家担心2012年的太阳风暴可能会成为一个例外。据报道，“超级太阳风暴”抵达地球后，首先将导致数十亿瓦特的额外电流穿过地球上的电网，地球上成千上万个将高压电流转变为家用电流的变压器上的铜线都将快速加热并融化，从而导致地球上多数地区的电网陷入瘫痪状态，人类将重回“黑暗时代”。西 悦

adapted from http://world.people.com.cn/GB/9163569.html