Shooting stars begin their summer show

A spectacular meteor shower, which at its peak will produce 70 shooting stars an hour, began yesterday.

A spectacular meteor shower, which at its peak will produce 70 shooting stars an hour, began yesterday.

The Perseids shower, which will become visible in mid-August, is the most reliable of all the meteor showers seen in Britain each year.

It has previously provided up to 200 shooting stars an hour in its peak time after midnight, when the night sky faces in the direction of the earth's motion.

Meteor showers are caused by the earth passing through clouds of space dust - in the Perseids case the remains of a comet. The remnants are made up of particles of ice, dust and rock which burn up in the upper atmosphere.

The particles travel at 45 miles per second and usually burn up at a height of between 100 and 60 miles. They are not dangerous to the surface but they were blamed for sending a European spacecraft out of control in 1993.

Astronomers advise anyone hoping to see this year's display to wait until mid-August, then watch the sky after midnight. The naked eye is the best method for locating the shooting stars, which streak across the sky. Binoculars or telescopes are not advised as their field of view is too narrow.

The shower comes amid warnings that the earth is overdue for an asteroid strike. The Near Earth Objects task force is about to release a report calling for international co-operation to track asteroids and comets that could cross the earth's orbit. In 1908 a 50-metre wide asteroid exploded in the air above Siberia, destroying huge areas of forest and causing a dust cloud that affected the climate for years.