We’re getting close to one of the most magical nights of the year, for lovers of astronomy at least. The Perseids, or Tears of St Lawrence as they are sometimes called, invite us to a natural party every summer with stars shooting across the night sky instead of fireworks.
During the second week of August the Earth passes through a cloud of dust from the Swift-Tuttle comet as it approaches the sun. The meteorites hit our atmosphere at 210,000 kilometres per hour, producing this light show which attracts thousands of people all over the planet. When they hit the atmosphere their temperature rises to about 5,000C in a fraction of a second, and they disintegrate at an altitude of between 80 and 100 kilometres. This effect is what makes them appear to flash. The biggest particles, the size of a pea or greater, can produce much brighter trails, known as fireballs.
Although the phenomenon begins at the end of July, the peak time to see them will be the nights of 11, 12 and 13 August although they may still continue for longer.
To enjoy the spectacle it is best to choose a place with no light contamination. The best time, according to Nasa, will be between 4am and 5am on 12 and 13 August and the early start will undoubtedly be worth the effort. About 100 meteorites are expected to be visible per hour.
However, there is one drawback: the National Geographical Institute’s Astronomy department warns that the moon will be full and this may make it more difficult to spot the shooting stars.
The Perseids can easily be seen by the naked eye so telescopes and binoculars are not needed. However, if you can, find a spot on a mountain or in the countryside away from towns with street lighting and tall buildings for the best sighting.