The sky is expected to brighten up this week – but it has nothing to do with sunshine: the annual Perseid meteor shower is approaching its peak.
Considered one of the best meteor showers of the year, the Perseids are active from mid-July and are predicted to peak overnight from Monday 12 August to Tuesday 13 August.
However, Dr Ed Bloomer, a senior astronomer at the Royal Observatory Greenwich, said there won’t be a dramatic rise and fall in visibility.
“The Perseids should give good viewing a couple of days either side, with local weather and light conditions probably more significant factors than the precise mathematical peak,” he said.
The meteors appear to come from between the constellations of Camelopardalis and Persus, from which they get their name. Bloomer said it is advisable to look at them out of the corner of the eye.
“Perseus is rising in the north-east as the sun’s going down, and so you want to look maybe more over towards the east,” he said, noting peripheral vision is more sensitive under low-light conditions than central vision.
Best viewed in the northern hemisphere, the spectacle occurs when the Earth slams into material shed from the comet 109P/Swift-Tuttle as the planet moves around the Sun.
When the fragments – often no bigger than a grain of sand – hit the atmosphere, the air in front of them becomes compressed, generating heat and causing the fragments to burn up. The result is the appearance of bright streaks across the sky.
“[The comet] is on this big, long 133-year orbit around the Sun, and it’s essentially debris that’s trailing off from behind that – so Swift-Tuttle makes its orbit, but the Earth then essentially crashes into that path year after year,” said Bloomer, adding that it means the meteor shower arises at the same time, and from the same part of the sky, each year.
To optimise the chance of catching a glimpse of the celestial show, stargazers are advised to head out at night into a dark area, or at least turn away from street lights and avoid glancing at phones.
“You might get lucky and see a fireball, [that’s] a bit of debris about the size of your fist coming through the atmosphere – that can go [on] for five, 10 seconds. You might even see it break up, and that’s pretty special,” said Bloomer. “But the majority of these things are little flashes.”
While Bloomer said it can be fun to watch with others, he noted the fleeting appearance of the Perseids makes for a personal experience. He recommends laying on the grass and gazing up.
“It’s not fireworks,” he said. “But you’re sort of seeing the mechanics of the solar system at work, which is quite an interesting thing.”
