03.01.22

Juno Spacecraft Detects Time Variation of Jupiter’s Magnetic Field

The Great Blue Spot (a localized patch of intense magnetic field on the equator near 80º west longitude) appears torn east and west by the action of deep zonal winds.

Juno measures a change in the magnetic field in time (secular variation) that is consistent with the eastward drift of the GBS – the anomaly slowly moves in the direction of the winds measured at the surface.
Jupiter’s radial magnetic field . 

The GBS drifts eastward at a rate of ~1.5 inches/s with respect to the solid body rotation of the planet; sufficient to lap the planet in 360 years time.
The change in the magnetic field observed during Juno’s 5 years in orbit. Connerney, J.E.P. et al., (2022), Journal of Geophysical Research – Planets, 127, e2021JE007055. https://doi.org/10.1029/2021JE007055.

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