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What you need

Warm clothes, possibly

ON ANY clear night, you can expect to see between five and 10 meteors in an hour. But in a meteor shower, they are far more frequent. To understand why, we need to know what causes them.

Meteors are streaks of light in the sky created by bits of rock and metal entering Earth’s atmosphere at high speed. They are usually no bigger than a grain of rice, though some are much larger. As they smash into air particles, the friction of these collisions creates heat and makes the objects burn brightly.

Earth regularly encounters particles like this as it orbits the sun. A meteor shower happens when it passes through the trails of dust and rock left by asteroids and comets. In the case of the Leonid shower, Earth is ploughing through debris from comet 55P/Tempel-Tuttle, a 3.6-kilometre-wide comet with a 33-year orbit around the sun.

Bits of space debris are called meteoroids. Any that are large enough to survive entry into Earth’s atmosphere and reach the ground are called meteorites.

Earth moves through the trails of certain comets at specific times of year, so spotting meteors can be easy if you know when to look. The Leonids can be seen between 6 and 30 November this year, peaking on 17 November.

Meteor showers tend to be named after the constellation in which they appear to start in the sky, a spot called the radiant. For the Leonids, the radiant is the constellation of Leo, which can be seen all over the world because it is a zodiacal constellation, as we learned in week 7 of the first series of stargazing at home.

To see a meteor shower, it is best to get as far from light pollution as possible. To check whether an area is dark enough, look for the Little Bear constellation, also known as Ursa Minor. If you can see it, you will be able to see meteors.

To find Leo, first find the Plough, also known as the Big Dipper, in the constellation Ursa Major. In week 2 of the first series, I showed how to use the Plough’s pointer stars to find Polaris. In this case, use the same stars, but go in the other direction to find Leo. If you live somewhere that doesn’t have a view of the Plough, use a star chart or an app to find Leo.

Now it’s time to get comfortable. Maybe bring some friends, a hot water bottle or your drink of choice. If it is your first time watching a meteor shower, don’t try to take photographs. You will struggle to capture the brief flashes, and you won’t enjoy the show. Leave that for next time.

If you don’t have good weather on the night of 17 November, don’t worry: the Leonids are visible until the end of the month. Then in December, we get the Geminids. There will always be another chance to see a meteor shower.

To download a printable version of the page click here.

For next week

A place where you can see the western horizon

Next in the series:

1 Mercury transits the sun

2 How to watch the Leonid meteor shower

3 Venus and Jupiter in conjunction
Two planets in the same part of the sky

4 Mercury at its greatest elongation

5 How to see the Northern Lights

6 Find the Andromeda galaxy

7 How to see Santa (the ISS) on Christmas Eve

Projects will be posted online each week at
Email: maker@newscientist.com