Scientists report electric fields naturally occurring in the comet’s atmosphere in connection with its auroras. NASA calls them electromagnetic emissions.
Sept. 22, 2020: Imagine putting your thumb on a garden hose and sending a jet of water into the sky. At the apex of the stream, auroras form. It turns out, some comets can actually perform this trick.
In a paper published this week in Nature Astronomy, researchers described how comet 67P/Churyumov-Gerasimenko turns vaporous jets of water into auroras.
The European Space Agency’s Rosetta spacecraft observed the weird lights while it was orbiting Comet 67P in 2014-2016. At first researchers misunderstood what the glow was. It couldn’t be an aurora, could it? For one thing, the comet doesn’t even have a magnetic field–a key ingredient of geomagnetic storms. Also, the lights of Comet 67P are invisible to the human eye. They shine at far ultraviolet wavelengths, unlike the familiar red and green curtains that dance around Earth’s poles.
“Nevertheless, they are auroras,” says Marina Galand of Imperial College London…
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via Tallbloke’s Talkshop
September 23, 2020 at 02:36AM