Many of you who don’t live in a Canadian rainforest that is overcast 340 days/year have had the privilege of seeing comet NEOWISE recently. 1/

[https://abs.twimg.com/emoji/v2/... draggable="false" alt="📸" title="Kamera mit Blitz" aria-label="Emoji: Kamera mit Blitz"> NEOWISE, NASA/Johns Hopkins APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher]
When I was a kid I thought comet tails always point away from the direction of motion, like that of a bird in flight. But really, a comet’s tail(s) always point away from the Sun. 2/
I say tail(s) because there are two: a gas tail and a dust tail. As a comet approaches the Sun, solar radiation vaporises ice in the comet, releasing gas in one tail and dust in another. 3/

[https://abs.twimg.com/emoji/v2/... draggable="false" alt="📸" title="Kamera mit Blitz" aria-label="Emoji: Kamera mit Blitz">: Comet Hale-Bopp, 1997. Brian Ventrudo]
Solar radiation pressure and winds push the tails away from the Sun. It’s like having long hair on a windy day - it’ll blow in whatever direction the wind is pushing, no matter which way you’re walking. 4/

[https://abs.twimg.com/emoji/v2/... draggable="false" alt="📸" title="Kamera mit Blitz" aria-label="Emoji: Kamera mit Blitz"> yours truly on a particularly windy day in Edinburgh]
While both tails point away from the Sun, the dust tail curves and the gas tail points directly away. That& #39;s because the gas tail is ionised, and follows Solar magnetic field lines, while the dust tail lags in the comet& #39;s orbit. 5/

[https://abs.twimg.com/emoji/v2/... draggable="false" alt="📸" title="Kamera mit Blitz" aria-label="Emoji: Kamera mit Blitz">s Hong Kong university/ Tufts university]
While both tails point away from the Sun, the dust tail curves and the gas tail points directly away. That& #39;s because the gas tail is ionised, and follows Solar magnetic field lines, while the dust tail lags in the comet& #39;s orbit. 5/ [https://abs.twimg.com/emoji/v2/... draggable=s Hong Kong university/ Tufts university]" title="While both tails point away from the Sun, the dust tail curves and the gas tail points directly away. That& #39;s because the gas tail is ionised, and follows Solar magnetic field lines, while the dust tail lags in the comet& #39;s orbit. 5/ [https://abs.twimg.com/emoji/v2/... draggable="false" alt="📸" title="Kamera mit Blitz" aria-label="Emoji: Kamera mit Blitz">s Hong Kong university/ Tufts university]">
While both tails point away from the Sun, the dust tail curves and the gas tail points directly away. That& #39;s because the gas tail is ionised, and follows Solar magnetic field lines, while the dust tail lags in the comet& #39;s orbit. 5/ [https://abs.twimg.com/emoji/v2/... draggable=s Hong Kong university/ Tufts university]" title="While both tails point away from the Sun, the dust tail curves and the gas tail points directly away. That& #39;s because the gas tail is ionised, and follows Solar magnetic field lines, while the dust tail lags in the comet& #39;s orbit. 5/ [https://abs.twimg.com/emoji/v2/... draggable="false" alt="📸" title="Kamera mit Blitz" aria-label="Emoji: Kamera mit Blitz">s Hong Kong university/ Tufts university]">
The futuristic name of this particular comet comes from the extended mission of the Wide-field Infrared Survey Explorer (WISE) telescope. NEO stands for Near-Earth Object, as its goal was to look for comets and asteroids close to us. 6.
[https://abs.twimg.com/emoji/v2/... draggable="false" alt="📸" title="Kamera mit Blitz" aria-label="Emoji: Kamera mit Blitz"> WISE, NASA]
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