Leonid meteors to light up night

Last year's Leonids produced meteor "storms"

The Leonid meteors will be visible this week as Earth ploughs through the dust stream left by Comet Tempel-Tuttle.

Experts say up to 100 shooting stars could be seen streaking across the sky every hour during the peak period - if the dust conditions are favourable.

Astronomers say the best prospects for a good show are for the early hours on the morning of Tuesday, GMT.

However, they warn this year's event is unlikely to match the 3,000 meteors per hour seen over parts of Europe in 2002.

"It is unlikely to produce any real fireworks, but there is always a chance that there may be a sudden burst of activity, and the dedicated meteor watchers will be out there looking anyway," said Robin Scagell from the UK's Society for Popular Astronomy.

Most of the meteors are no bigger than a grain of sand and enter the Earth's atmosphere at speeds of about 65 or 70 kilometres per second.

As they bombard the air it heats up, engulfing the particles to produce the familiar streaks of light.

The rate at which they appear depends on whether the Earth moves through a particularly thick band of debris dumped by the four-kilometre-wide Tempel-Tuttle on one of its regular visits to the inner Solar System.

From a UK perspective, the focus of the shooting stars cannot be seen before 2300 GMT because the constellation Leo - the point in the sky where they appear to originate - does not rise above the horizon until then.

The best time to spot them will probably be about 0300 GMT or 0400 GMT - although it is very hard to predict meteor activity.

The position of the Moon in the sky will hamper viewing this year. The advice is to choose a field of view facing away from the Moon, but still watch as much of the sky as you comfortably can, and hope for the best.

There may be some Leonid activity, albeit slight, right through until 23 November.