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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/
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NEOWISE, NASA/Johns Hopkins APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher]
![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/[ NEOWISE, NASA/Johns Hopkins APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher]](https://pbs.twimg.com/media/Ec6Ga-sUYAAm4SC.jpg "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/[ NEOWISE, NASA/Johns Hopkins APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher]")
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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/
[: Comet Hale-Bopp, 1997. Brian Ventrudo]
![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/[: Comet Hale-Bopp, 1997. Brian Ventrudo]](https://pbs.twimg.com/media/Ec6G3-SUEAArnjw.jpg "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/[: Comet Hale-Bopp, 1997. Brian Ventrudo]")
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: 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/
[ yours truly on a particularly windy day in Edinburgh]
![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/[ yours truly on a particularly windy day in Edinburgh]](https://pbs.twimg.com/media/Ec6H2T4U8AE0o4v.png "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/[ yours truly on a particularly windy day in Edinburgh]")
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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's because the gas tail is ionised, and follows Solar magnetic field lines, while the dust tail lags in the comet's orbit. 5/
[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's because the gas tail is ionised, and follows Solar magnetic field lines, while the dust tail lags in the comet's orbit. 5/ [s Hong Kong university/ Tufts university]](https://pbs.twimg.com/media/Ec6ISoPU0AA8E9m.jpg "While both tails point away from the Sun, the dust tail curves and the gas tail points directly away. That's because the gas tail is ionised, and follows Solar magnetic field lines, while the dust tail lags in the comet's orbit. 5/ [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's because the gas tail is ionised, and follows Solar magnetic field lines, while the dust tail lags in the comet's orbit. 5/ [s Hong Kong university/ Tufts university]](https://pbs.twimg.com/media/Ec6IUUPUMAA3JvT.jpg "While both tails point away from the Sun, the dust tail curves and the gas tail points directly away. That's because the gas tail is ionised, and follows Solar magnetic field lines, while the dust tail lags in the comet's orbit. 5/ [s Hong Kong university/ Tufts university]")
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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.
[ WISE, NASA]
![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.[ WISE, NASA]](https://pbs.twimg.com/media/Ec6I7P1UMAEBe_0.jpg "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.[ WISE, NASA]")
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WISE, NASA]
