The rotation of Earth's core may have paused, scientists in China have suggested.
The rotation of Earth's core may have paused, scientists in China have suggested.
我国科学家认为，地核的自转可能已经暂停了。
The rotation of Earth’s inner core may have paused and it could even go into reverse, new research suggests.
新的研究表明，地球内核的自转可能已经暂停，甚至可能会发生逆转。
The Earth is formed of the crust, the mantle and the inner and outer cores. The solid inner core is situated about 3,200 miles below the Earth’s crust and is separated from the semi-solid mantle by the liquid outer core, which allows the inner core to rotate at a different speed from the rotation of the Earth itself.
地球是由地壳、地幔和内外核组成的。固体内核位于地壳以下约5150公里处，由液体外核与半固体地幔隔开，这使得内核能够以与地球本身旋转不同的速度旋转。
With a radius of almost 2,200 miles, Earth’s core is about the size of Mars. It consists mostly of iron and nickel, and contains about about one-third of Earth’s mass.
地核的半径约3540公里，与火星大小相当。它主要由铁和镍组成，约占地球质量的三分之一。
在1月23日发表在《自然地球科学》（ Nature Geoscience）杂志上的一项研究中，北京大学科学家杨毅和宋晓东研究了自20世纪60年代以来沿着相似路径穿过地球内核的地震产生的地震波，以推断内核旋转的速度。
What they found was unexpected, they said. Since 2009, seismic records, which previously changed over time, showed little difference. This, they said, suggested that the inner core rotation had paused.
他们发现的结果出乎意料。自2009年以来，地震记录随着时间的推移，几乎没有差别。他们说，这表明内核的旋转已经暂停了。
“We show surprising observations that indicate the inner core has nearly ceased its rotation in the recent decade and may be experiencing a turning-back,” they wrote in the study.
他们在研究报告中写道:“我们发现了令人惊讶的观察结果，表明在最近十年里，内核几乎停止了旋转，可能正在经历一次倒转。”
“When you look at the decade between 1980 and 1990 you see clear change but when you see 2010 to 2020 you don’t see much change,” added Song.
“从1980年到1990年的十年，你会看到明显的变化，但从2010年到2020年，你看不到太多变化，”宋晓东说。
The spin of the inner core is driven by the magnetic field generated in the outer core and balanced by the gravitational effects of the mantle. Knowing how the inner core rotates could shed light on how these layers interact and other processes deep in the Earth.
内核的旋转是由外核产生的磁场驱动的，并由地幔的引力作用平衡。了解地核的旋转方式可以帮助我们了解这些层之间的相互作用以及地球深处的其他过程。
However, the speed of this rotation, and whether it varies, is debated, said Hrvoje Tkalcic, a geophysicist at the Australian National University, who was not involved in the study,“The inner core doesn’t come to a full stop,” he said. The study’s finding, he said, “means that the inner core is now more in sync with the rest of the planet than a decade ago when it was spinning a bit faster.”
然而，这种旋转的速度，以及它是否有所变化，是有争议的。澳大利亚国立大学的地球物理学家Hrvoje Tkalcic说，他没有参与这项研究。他说，“这项研究发现内核并没有完全停止自转，这意味着，与十年前相比，现在的内核与地球其他部分的同步程度更高，当时它的旋转速度略快。”
“Nothing cataclysmic is happening,” he added.
“没有发生什么灾难性的事情”，他说。
Song and Yang argue that, based on their calculations, a small imbalance in the electromagnetic and gravitational forces could slow and even reverse the inner core’s rotation. They believe this is part of a seven-decade cycle, and that the turning point prior to the one they detected in their data around 2009/2010 occurred in the early 1970s.
宋和杨认为，根据他们的计算，电磁力和引力的微小失衡可能会减缓甚至逆转内核的旋转。他们认为这是一个70年周期的一部分，而他们在2009/2010年左右的数据中检测到的转折点发生在20世纪70年代初。
Tkalcic, who is the author of “The Earth’s Inner Core: Revealed by Observational Seismology,” said the study’s “data analysis is sound.” However, the study’s findings “should be taken cautiously” as “more data and innovative methods are needed to shed light on this interesting problem.”
Tkalcic是《地球的内核:由观测地震学揭示》一书的作者，他说这项研究的“数据分析是合理的”。然而，这项研究的发现“应该谨慎对待”，因为“需要更多的数据和创新的方法来阐明这个有趣的问题。”
Song and Yang agreed that more research was needed.
宋和杨都一致认为还需要更多的研究。
Studying the Earth’s core
研究地核
Tkalcic, who dedicates an entire chapter of his book to the inner core rotation, suggested the inner core’s cycle is every 20 to 30 years, rather than the 70 proposed in the latest study. He explained why such variations occur and why it was so difficult to understand what happens in the innermost reaches of the planet.
Tkalcic在他的书中用了整整一章来讲述地球内核的自转，他认为内核自转的周期是每20到30年，而不是最新研究中提出的70年。他解释了为什么会发生这样的变化，以及为什么很难理解在地球最深处发生了什么。
“The objects of our studies are buried thousands of kilometers beneath our feet,” he said.
“我们研究的对象被埋在我们脚下几千公里的地方”，他说。
“We use geophysical inference methods to infer the Earth’s internal properties, and caution must be exercised until multi-disciplinary findings confirm our hypotheses and conceptual frameworks,” he explained
他解释说:“我们使用地球物理推断方法来推断地球的内部属性，在多学科的发现证实我们的假设和概念框架之前，必须谨慎行事。”
“You can think of seismologists like medical doctors who study the internal organs of patients’ bodies using imperfect or limited equipment. So, despite progress, our image of the inner Earth is still blurry, and we are still in the discovery stage.”
“你可以把地震学家想象成医生，他们使用不完善或有限的设备研究病人的内部器官。所以，尽管取得了进展，我们对地球内部的印象仍然模糊，我们仍然处于发现阶段。”