Shooting stars visible at frequency of one a minute

THE annual meteor shower known as the Perseids, which reached its peak last night with one shooting star per minute, continues tonight. The shower of shooting stars, caused by debris from the comet Swift Tuttle, can be seen from all over Ireland, which is on the leading side of the Earth as it ploughs through the comet debris.

While an average rate of one shooting star per minute was calculated for last night, a rate of only half this is expected for tonight. The shower wilt fade out over the next two days.

Shooting stars are caused by particles as small as a grain of sand burning up as they fall through the earth's atmosphere at speeds of over 100,000 m.p.h. The particles burn out when they are still 100 miles from the Earth's surface. "It's the speed that makes them so bright," explained Mr David Moore, of Astronomy Ireland.

The normal average rate for shooting stars is one every 10 minutes.

Last night, there was a gathering organised by Astronomy Ireland at the Papal Cross car park in the Phoenix Park, the darkest site within Dublin. However the organisers said that the best place to watch was in dark rural areas.

The Perseids, sometimes called the "Tears of St Lawrence" after the saint whose feast day is August 10th, is one of the most reliable of the annual meteor showers. The meteors all appear to come from the direction of the constellation Perseus, hence their name.

Astronomy Ireland is holding a public lecture tonight in the Parnell Mooney pub, Parnell Square, Dublin, at 8 p.m. The lecture will include discussion of the possibility of life on Mars.

Tomorrow is the 400th anniversary of the first modern discovery of a variable star. Variable stars are ones which brighten and dim again and the first known recording of such a phenomenon was by the Dutch/German astronomer, David Fabricius, on August 13th, 1596. The discovery was made before the invention of the telescope and at a time when most people subscribed to the Aristotelian concept of an Earthcentred universe.