Category Archives: Outer space

Perseids – August showers

August 10th to 13th are the dates all budding astronomers should put in their diaries. Coming up are the Perseids, a brilliant meteor shower visible before dawn.

They’re named the Perseids because of their proximity to Perseus (the Greek hero best known for slaying the terrifying snake-haired Medusa). This is an easy constellation to spot once you have found Andromeda and Auriga as he’s in between those two, both of whom have very distinctive patterns. The picture below and any night sky map should show you what it looks like.

Though they’re often called shooting stars and look like stars, meteors aren’t stars. They’re caused by debris in the sky, such as the leftovers of a comet, reaching the earth’s atmosphere. When they enter at very high speeds, the matter burns up, causing the “starry” bright light.

Radiant of the Perseid meteors (BBC images)

Radiant of the Perseid meteors (BBC images)

As in this picture, meteors appear to spread out from a single point (the radiant), which is inside Perseus. But this is an optical illusion. Imagine standing in the middle of a dozen very long, parallel train tracks. When the trains appear in the far distance, they’ll all seem to be at the same point. But as they approach (just as the meteors approach Earth), they appear to spread out. Really they are still running parallel.

We can predict when a meteor shower comes because we know when the Earth will pass through the remnants of a comet. There are many to see throughout the year, and we’ve got them all down in our diaries!

The Perseids continue for much of early to mid August but their peak time is before dawn on August 10th to 13th. Let us know if you get any good photos!

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