第97期——地球磁场出现了无人能解释的异动

Cresarea

Earth's Magnetic Field Is Up To Some Seriously Weird Stuff And No One Knows Why
地球磁场出现了无人能解释的异动

                               
登录/注册后可看大图

Computer simulation of the Earth's magnetic field in a period of normal polarity. Dr Gary A. Glatzmaier/Los Alamos National Laboratory?US Department of Energy.
地球磁场极性正常期的电脑模拟图
加里·A·格拉兹麦尔/美国能源部洛斯阿拉莫斯国家实验室

By Tom Hale
11 JAN 2019, 16:07
作者/汤姆·黑尔 2019年1月11日16:07

The planet’s magnetic field is up to mischief again and geologists are pretty dumbfounded.
地球磁场的再一次恶作剧，让地质学家感到十分惊慌失措。
Earth’s magnetic poles can wander several kilometers every year, however, the north pole's movement has become increasingly stranger in recent years. For reasons that are currently unclear, the magnetic north pole seems to be increasingly slipping away from Canada and towards Siberia at an erratic rate, according to a news report in Nature.
地球的磁极每年会移动几千米，然而近几年磁北极的移动变得相当奇怪。根据《自然》杂志上的一篇新闻报道，由于一些目前尚未知的原因，磁北极似乎在以一种不稳定的速率从加拿大向西伯利亚加速移动。
“The location of the north magnetic pole appears to be governed by two large-scale patches of magnetic field, one beneath Canada and one beneath Siberia,” Phil Livermore, a geomagnetist at the University of Leeds in the UK said at the latest American Geophysical Union meeting, according to Nature.
根据《自然》报道，在最近的美国地质联盟会议上，英国利兹大学的地磁学家菲尔·利弗莫尔指出：“磁北极的位置看起来像被两个强大的磁场控制了，一个位于加拿大下面，另一个位于西伯利亚下面。”
“The Siberian patch is winning the competition.”
“现在是西伯利亚的磁场赢得了这场比赛。”
Every five years, the National Oceanic and Atmospheric Administration (NOAA) maps out the Earth’s magnetic field in the World Magnetic Model (WMM). This was last published in 2015, with the next edition planned for 2020, but this freak behavior forced scientists to revise the map earlier than anticipated. Unfortunately, the revamped WMM was supposed to be released on January 15, but it's been postponed until at least January 30 due to the ongoing government shutdown.
每隔五年，美国海洋和大气管理局（NOAA）都会在世界地磁模型（WMM）上标出地球的磁场位置。现存版本于2015年出版，下一版本原计划于2020年出版。但是磁极的异动迫使科学家比预期更早地去修订这个地图。不幸的是，原本计划于1月15号发布的地图，由于持续的政府停工而不得不推迟到至早1月30号发布。
Earth’s magnetic field is created by molten iron in its core swirling around through convection currents. It’s a fairly chaotic situation in there, resulting in a complex pattern of magnetism which can prove extremely difficult to model and predict. Just to make things even more complicated, an unusually punchy geomagnetic pulse occurred under South America in 2016, which is believed to have contributed to the recent unexpected changes.
地球的磁场是通过地球内核中的熔铁对流旋转产生的。熔铁对流旋转的情形相当混乱，因此导致磁力模式复杂，很难去据此制造模型或者预测未来的磁极走向。科学家认为2016年发生在南美洲之下的一次不寻常的强力地磁脉冲促使了最近磁场异动的发生，这让情况变得更为复杂。
However, it largely remains unclear why the magnetic field beneath Canada is appearing to weaken in such a strange way. 
然而，加拿大下面的磁场莫名其妙变弱的原因尚未明晰。
You might be wondering whether any of this matters. Well, the magnetic field is central to many forms of navigation. Most obviously, a compass relies on magnetic fields, but more advanced systems of navigation use the field as a bearing too. These currently anomalies shouldn’t be strong enough to completely screw this up, however, it’s most certainly something geologists need to keep on top of.
你可能在想这些事难道很重要吗？但是，磁场对很多种形式的导航都很重要。最明显的是，指南针就依赖于磁场，但是很多更为先进的导航系统也用磁场作为方位导航。目前出现的异动不会严重到完全破坏这些导航，但是有些情况地质学家必须抢先一步掌握。
Indeed, it is possible for truly monstrous changes to the magnetic field to take place. Scientists know the Earth can undergo a phenomenon known as a “geomagnetic reversal", where these magnetic poles literally switch sides. The last time this happened was 781,000 years ago, but it's believed to have occurred every 20,000-30,000 years over the last 20 million years (although there have been exceptions).
确实，很有可能磁场发生了真正的巨变。科学家知道地球会经历“地磁反转”现象，届时磁场的两极会转换方向。上一次的地磁反转发生在781,000年前，科学家相信过去两亿年间每隔两三万年就会发生一次地磁反转（尽管偶尔会有一些例外。）

文章来源：https://www.iflscience.com/envir ... -no-one-knows-why-/

翻译by 许文文
校对 by Susie
终校 by 何以
树屋字幕组-文翻组出品
翻译仅供学习交流，严禁任何商业用途