PARIS - Many parts of the Earth will be treated to celestial fireworks on Sunday as the annual Leonid meteor showers peak in what eager sky-watchers believe may be the most spectacular display for decades.

"Another opportunity to view a storm of this magnitude may not present itself for a century or more," says Rich Talcott, senior editor at a US magazine, Astronomy.

The annual display occurs when Earth ploughs through a debris trail left by the Comet Tempel-Tuttle, which zips by our planet every 33 years.

Dust and grit deposited by the lonely wanderer collide with the Earth's atmosphere at speeds approaching 250,000 kilometers (160,000 miles) per hour, burning up in the sky in a breath-taking, silvery streak.

The shower, which occurs over several days every mid-November, is called the Leonids because it appears to come from the constellation of Leo.

According to calculations made by Robert McNaught of Australian National University and David Asher of Northern Ireland's Armagh Observatory, a "likely meteor storm" is forecast for people living in North and Central America, while the forecast for East Asia and Australia is a "guaranteed" storm.

Full-fledged Leonid storms can crank out thousands of meteors per hour, making the show an exhilarating, unforgettable experience.

One of the most famous displays occurred in 1966, when watchers in the southwestern US were treated to up to 19,000 meteors per hour in a veritable snowstorm that lasted some 30 minutes.

Armagh Observatory spokesman John McFarland told Nampa-AFP on Tuesday that there would be three peaks on Sunday.

-- The first, when the Earth crosses the trail of a Tempel-Tuttle flyby in 1767, will be at 0955 GMT, with an estimated 800 meteors per hour.

-- That will be followed at 1724 GMT, when the debris left by a flyby in 1699 is crossed, yielding a possible 2,000 meteors per hour.

-- The climax will be at 1813 GMT, when as many as 8,000 meteors per hour are expected when the planet traverses the trail left by the comet in 1866.

"It should be quite memorable. It's not quite as good as the 1966 storm, but it should be pretty impressive," McFarland said.

Tempel-Tuttle was recorded as far back as 1366 as it swung through the Solar System on its vast egg-shaped orbit around the Sun.

It was independently identified as a comet by French astronomer Wilhelm Leberecht Tempel in December 1865 and American astronomer Horace Parnell Tuttle in January 1866.

Typical Leonid particles are only millimetres across, which means they burn up brightly in the Earth's upper atmosphere at about a height of 100,000 metres (60 miles).

Bigger particles, called bolides, which are several centimetres (inches) across, can produce fireballs that flare for a few dazzling seconds.

No-one on the ground should be at risk from the storm, but that does not apply to satellites, whose solar panels, imaging mirrors and other sensitive components could be damaged by abrasion and short circuits.

"If they impact a satellite, the particles would vaporise and form an electrically-charged plasma that could interfere with the satellite's electronics," McFarland said.

Satellite operators may turn off their satellite to prevent any electrical shorts, he said.

The specialist website space.com said that the satellite hunt for Osama bin Laden in Afghanistan was unlikely to be hampered by the Leonids storm.

This is because they are armoured to cope with such events, as is the International Space Station (ISS), which currently has a three-member US-Russian crew on board, it said.

The 2001 Leonid shower peaks will not be visible from the Europe-Africa time belt.

That region is best placed by the 2002 Leonids, which also are expected to be spectacular. The problem, though, is that next year's storm will also coincide with a full moon, whose brightness will greatly diminish the viewing potential.
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