Uranus is known to be one of the most “strange” planets in the Solar System, but apparently its peculiarity may just be the result of an unfortunate coincidence. A recent study, published in Nature Astronomy led by Jamie Jasinski of the California Institute of Technology (Caltech), suggests that the anomalies in Uranus' magnetic field, observed in 1986 by the Voyager 2 probe, were caused by exceptionally intense solar activity, rather than by some strange characteristic of the planet itself.
Distance and mystery
The outermost objects in the Solar System, such as Uranus, are difficult to study: they are located at enormous distances and probes take years to reach them, facing enormous technological challenges and high costs. Uranus, for example, has only been visited up close once, in 1986, when Voyager 2 passed by at a distance of 81,000 kilometres, collecting fundamental data on its atmosphere, internal structure and magnetic field.
The “solar wind” and its effect on Uranus' data
During this historic passage, Voyager 2 recorded strong irregularities in Uranus' magnetic field, detecting asymmetries and the presence of highly energetic electrons. Until recently, these data were considered evidence of a unique and complex magnetic field, different from that of other gas giants such as Jupiter and Saturn.
But now, almost 40 years later, researchers have made a surprising discovery: on the days when the probe flew over Uranus, the planet was hit by an intense wave of particles from the Sun. This solar wind would have altered the planet's magnetic field, distorting it to the point of making it appear to have unusual characteristics.
If Voyager 2 had passed just one week earlier...
If Voyager 2 had flown over Uranus just one week earlier, it would most likely have recorded a magnetic field similar to that of the other giant planets, with no obvious anomalies. This study changes our perspective on Uranus, suggesting that its “oddities” may depend more on external conditions than on the planet's true peculiarities.
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