A Geminid meteor

Image credit: Jimmy Westlake

What is a meteor?

Meteors are tiny particles of dust and rock which fall through the atmosphere of the Earth. The visible trail left behind is a result of the heat produced by ram pressure as the particle speeds through the air. Often these particles are leftover from the pass of a comet around the Sun. As a comet nears the Sun, it begins to heat up and the dirty surface ice begins to sublimate, leaving a stream of debris in it's wake. When the Earth encounters one of these streams of leftover particles we see an enhancement in the number of meteors coming from a particular part of the sky. These are known as meteor showers.

Although specific showers occur at particlar times of the year, meteors can appear on any night of the year, coming from any part of the sky. These meteors are not associated with the pass of a particular comet and are called sporadic meteors.

The peak activity of an individual meteor shower can be quite short, lasting less than an hour in some cases, but there is often an increase in meteor numbers associated with the shower over a period of a few days to a few weeks.

Meteors are easy to spot with just your eyes, but some people photograph them in order to work out their trajectory, while others take spectra to determine their composition. Visual records of meteor showers are used to calculate the orbits of the debris streams and predict future meteor shower activity.

But what about meteors that enter our atmosphere during the day? Not all meteor showers peak at night when we can see them. For those that peak during the day, we require other techniques to monitor and record them. One such technique uses radio waves instead of light.

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