‘Dayglow’ at Rosetta’s comet turns out to be unexpected ultraviolet aurora

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Comet Chury in all its glory


ESA/Rosetta/NAVCAM

Auroras, better known to we Earthlings as northern or southern lights, aren’t limited to planets and moons. For the first time, scientists have identified the same phenomenon at a comet.

The discovery comes courtesy of the European Space Agency’s Rosetta mission, which famously landed on the comet 67P/Churyumov-Gerasimenko, also known as Comet Chury, back in 2014. 

On Earth, we get auroras when energetic particles from the solar wind interact with our planet’s magnetosphere. When researchers looked at Chury in the far ultraviolet range of the electromagnetic spectrum, they were able to pick up a similar effect from solar wind electrons striking the cloud of gas, or coma, around the comet’s rocky nucleus.

“The resulting glow is one of a kind,” says Marina Galand of Imperial College

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