 The Perseids occur when the Earth passes through dusty cometary debris |
Skygazers are getting ready to watch the annual Perseid meteor shower, which peaks on Wednesday.
The Perseid shower occurs when the Earth passes through a stream of dusty debris from the comet Swift-Tuttle.
As this cometary "grit" strikes our atmosphere, it burns up, often creating streaks of light across the sky.
This impressive spectacle appears to originate from a point called a "radiant" in the constellation of Perseus - hence the name Perseid.
"Earth passes through the densest part of the debris stream sometime on 12 August. Then, you could see dozens of meteors per hour," said Bill Cooke of Nasa's meteoroid environment office.
No special equipment is required to watch the sky show. Astronomers say binoculars might help, but will also restrict the view to a small part of the sky.
The Perseids can appear in any part of the sky, but their tails all point back to the radiant in the constellation Perseus.
In the UK, the best times to see the Perseids are likely to be on the morning of 12 August before dawn and from late evening on the 12th through to the early hours of the 13 August.
This year, light from the last quarter Moon will interfere significantly with the view.
The rock and dust fragments which cause the shower were left behind by Comet Swift-Tuttle when it last came near the Sun.
The comet orbits the Sun once every 130 years and last swept through the inner Solar System in 1992.
