Geomagnetism articles within Nature

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  • Article
    | Open Access

    Magnetic palaeointensity data from the Barberton Greenstone Belt (South Africa) as well as the Jack Hills (Western Australia) show nearly constant palaeofield values between 3.9 Ga and 3.4 Ga, providing evidence for stagnant-lid mantle convection.

    • John A. Tarduno
    • , Rory D. Cottrell
    •  & Gautam Mitra

  • Letter |

    Polarity reversals caused by dynamo waves are demonstrated in a magnetohydrodynamic model that is relevant to planetary cores, suggesting a possible mechanism of geomagnetic reversals.

    • Andrey Sheyko
    • , Christopher C. Finlay
    •  & Andrew Jackson

  • Letter |

    Experiments show that magnesium oxide can dissolve in core-forming metallic melts at very high temperatures; core formation models suggest that a giant impact during Earth’s accretion could have contributed large amounts of magnesium to the early core, the subsequent exsolution of which would have generated enough gravitational energy to power an early geodynamo and produce an ancient magnetic field.

    • James Badro
    • , Julien Siebert
    •  & Francis Nimmo

  • Letter |

    The pattern of geomagnetic secular variation observed on the Earth’s surface is shown to be reproduced by two mechanisms relying on the inner core; this bottom-up heterogeneous driving of outer-core convection dominates top-down driving from mantle thermal heterogeneities.

    • Julien Aubert
    • , Christopher C. Finlay
    •  & Alexandre Fournier

  • Letter |

    Variations in Earth's rotation show clear signals of a 5.9-year oscillation and jumps in Earth’s moment of inertia; correlation with the geomagnetic field suggests an origin in Earth’s core and constrains the conductivity and thus the composition and mineralogy of the deep mantle.

    • R. Holme
    •  & O. de Viron

  • Letter |

    Volcanic records of the reversals of the geomagnetic field can be well matched under the assumption of a common reversal duration, and imply that the reversal process comprises three phases—a precursor, a fast polarity switch and a rebound—the properties of which have remained unchanged for about 180 million years.

    • Jean-Pierre Valet
    • , Alexandre Fournier
    •  & Emilio Herrero-Bervera

  • News & Views |

    New calculations show that the electrical resistance of Earth's liquid-iron core is lower than had been thought. The results prompt a reassessment of how the planet's magnetic field has been generated and maintained over time. See Letter p.355

    • Bruce Buffett

  • Comment |

    We need to improve estimates of geomagnetic storm size, says Mike Hapgood, so we can be ready for huge disruptions to electrical systems.

    • Mike Hapgood

  • News |

    Researchers disagree over replication of study showing that cows line up with Earth's magnetic field.

    • Daniel Cressey

  • Letter |

    Here, an indirect estimate for the magnetic field strength within the Earth's core from measurements of tidal dissipation is presented. Previously reported evidence of anomalous dissipation in the Earth's nutations can be explained with a core-averaged field of 2.5 mT, eliminating the need for high fluid viscosity or a stronger magnetic field at the inner-core boundary.

    • Bruce A. Buffett

  • News |

    The movement of oxygen and sulphur at the heart of the planet may drive its magnetic field.

    • Geoff Brumfiel

  • Letter |

    Earth's diffuse aurora occurs over a broad latitude range, and is mainly caused by the precipitation of low-energy electrons originating in the central plasma sheet. Theory suggests that two classes of magnetospheric plasma waves — electrostatic electron cyclotron harmonic waves and whistler-mode chorus waves — could be responsible for the electron scattering that leads to diffuse auroral precipitation. Here it is found that scattering by chorus is the dominant cause of the most intense diffuse precipitation.

    • Richard M. Thorne
    • , Binbin Ni
    •  & Nigel P. Meredith

  • News & Views |

    Earth's spin rate varies with time. A six-year periodic signal in the planet's core is partly responsible, and increases the interior magnetic-field strength to much higher levels than previously thought.

    • Andy Jackson

  • News and Views Q&A |

    The ability to perceive Earth's magnetic field, which at one time was dismissed as a physical impossibility, is now known to exist in diverse animals. The receptors for the magnetic sense remain elusive. But it seems that at least two underlying mechanisms exist — sometimes in the same organism.

    • Kenneth J. Lohmann

  • Letter |

    Zonal jets are common in nature and are spontaneously generated in turbulent systems. Because the Earth's outer core is believed to be in a turbulent state, it is possible that there is zonal flow in the liquid iron of the outer core. By investigating numerical simulations of the geodynamo with lower viscosities than most previous simulations have been able to use, a convection regime of the outer core is now found that has a dual structure comprising inner, sheet-like radial plumes and an outer, westward cylindrical zonal flow.

    • Takehiro Miyagoshi
    • , Akira Kageyama
    •  & Tetsuya Sato

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