Comet tail
A comet's tails are long streams of dust and gas pushed away from the Sun by sunlight and the solar wind.
Comets often grow two kinds of tail. The dust tail is made of tiny grains pushed away by the pressure of sunlight. It is usually yellowish-white and curved, because the grains spread along the comet's orbit as they are left behind. The ion tail, or gas tail, is made of charged gas swept straight back by the solar wind. It often looks blue and can be very long and straight.
Both tails point away from the Sun, not behind the comet's direction of travel. As a comet leaves the Sun, its tails can even lead the way. Tails can stretch for tens of millions of kilometres.
The dust in the tail is related to meteors. Larger grains do not get blown far and stay near the comet's orbit, forming the streams that make meteor showers. So when you see a shower, you are seeing pieces of a comet's dusty trail, perhaps shed centuries ago.
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Level: Beginner Ages 7 and up