By Mark Gallaway in The Conversation.
It has happened to most of us: walking home late at night under clear skies you catch a glimpse of something bright moving, often from the corner of your eye. You turn to see what it is but it’s gone without a trace. And chances are you will have seen a meteor ending its multi-billion year journey in a burst of light 100km up.
We can see meteors in the night sky all year round, but at certain times of the year we get spectacular shows. Most meteors start their lives trapped in icy comets. Comets are the gritter lorries of the Solar System. When they come close to the sun at about the orbit of Mars, the sunlight begins to melt the comet. As it melts, it frees trapped bits of grit, which follow the comet around the sun in a lazy ellipse until the Earth passes through the trail left by the comet and these little 0.1 mm pieces of grit become – for a brief few seconds – a fiery meteor. It is these trails that form the bursts of meteoric activity known as showers that last a few days as the Earth moves through the celestial gritter lorry’s path.
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