Effects of salinity.
Effects of salinity.
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DOI：
10.1126/science.193.4250.311-a
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发表时间：
1976-07
期刊：
影响因子：
56.9
通讯作者：
L. Bernstein
中科院分区：
文献类型：
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作者：
L. Bernstein
地核的半径是地球的一半以上，地核无疑是地球磁场的所在地。近3000公里的岩石绝缘层有效地阻止了地核的秘密向我们揭示。我们对磁芯的性质和产生磁场的过程了解甚少。更不为人所知的是地核，它的半径大约是地球的五分之一，是地核的五分之二。外核的大尺度特征（半径、平均密度、平均声速以及一般的流动性）已经知道了40多年。从这些性质可以推断，外核可能是熔化的铁与一些未识别的较轻的元素合金化。外核的半径和内核的平均压缩波速度也是众所周知的，但直到最近才有可能测量内核的压缩率。这本书的作者是那些在25年前提出内核是来自外核的固体铁镍凝结物的人之一。其余的都是猜测。关于地核的热状态、磁场的起源、地核的起源和后来的历史等问题的答案，由于缺乏对内外核其他物理性质的精确了解而产生的不确定性，使问题变得模糊不清。关于月球和类地行星内核的状态，甚至是否存在，也存在类似的不确定性。
The radius of the earth's core is more than half that of the earth, and the core is the undoubted seat of the earth's magnet-ic field. Almost 3000 kilometers of rock insulation effectively prevents the secrets of the core from being revealed to us. We understand the properties of the core and the processes of the production of the magnetic field only poorly. Even less well understood is the inner core, a region with a radius about one-fifth that of the earth, two-fifths that of the outer core.The large-scale features of the outer core (radius, mean density, and mean sound velocity, as well as general fluidity) have been known for more than 40 years. From these properties it has been inferred that the outer core is probably molten iron alloyed with some uniden-tified lighter element or elements. The ra-dius of the outer core and the mean com-pression-wave velocity of the inner core are also well known, but only recently has it been possible to measure the com-pressibility of the inner core. The author of the book under review was one of those who proposed more than 25 years ago that the inner core is a solid ironnickel condensate from the outer core. The rest is conjecture. Answers to questions regarding the thermal regime of the core, the origin of the magnetic field, and the origin and subsequent histo-ry of the core are clouded in uncer-tainties generated by lack of precision in knowledge of the other physical proper-ties of the inner and outer core. There are similar uncertainties concerning the status, or even the existence, of the cores of the moon and the terrestrial planets.