BBC News Online: Sci/Tech

It came from the skies ...

The upper air burst into life!
And a hundred fire-flags sheen,
To and fro they were hurried about!
And to and fro, and in and out,
The wan stars danced between

And the coming wind did roar more loud,
And the sails did sigh like sedge;
And the rain poured down from one black cloud;
The Moon was at its edge

Literary scholars have long been intrigued by the description of a storm of light above the sea from the Rime of the Ancient Mariner. Some thought it was a work of imagination, possibly fuelled by narcotics.

However an astronomer in Australia says Coleridge was actually describing a meteor shower that he witnessed 200 years ago while walking along the Somerset coast with William and Dorothy Wordsworth.

Dr Duncan Steele says that the threesome observed the Leonid meteor shower - caused by the Tempel-Tuttle comet - back in 1797 and were so impressed by the celestial display that they set off on a rather long walk to the coast to get a better view.

Dr Steele says Coleridge's words mirror the real event, albeit in a rather poetic way: "'The upper air burst into life' really sounds like a meteor shower stretching across the sky, with lots of shooting stars all at the same time."

However, he says the Leonid showers have also had an adverse effect on people. Records show that when the meteors appeared in 1833 people hid under their beds in fear of the Second Coming and Judgement Day.

The Tempel-Tuttle comet comes around every 33 years. As it returns to the inner solar system it brings with it a dense swarm of minute dust particles, which enter the Earth's atmosphere at up to 72km/s, lighting up the sky.

The display has been seen only half a dozen times since Coleridge's day. It is due to recur later this year, allowing Coleridge fans to get a better insight into what the Mariner - and the poet himself - might have seen.

Dr Steele points out that although understanding is much greater than in Coleridge's day, the event brings with it new hazards.

He explains that there are no Space Shuttle launches due in November this year because of the danger of caused a dense flux of meteoroids in space - the speed is such that even something the size of a pea could cause catastrophic damage to a spacecraft.

Meteor facts

• Around 40 tonnes of space debris land on the Earth every year, but much more is burnt up in the atmosphere.
• There are an estimated 100,000 objects wider than a kilometre floating around the solar system close enough to pose a threat to the Earth.
• At least 100 space rocks large enough to cause global devastation are known to intersect the Earth's orbit.
• Some 500 'big impact events' have occurred in the last 540 million years.
• In November 1996, a five kilometre long asteroid passed around 5 million kilometres from Earth. If it had hit, it could have wiped out the human race.
• A search for a huge meteorite in Greenland was sparked off by dazzling flashes equivalent to a nuclear explosion and seismic signals in December, but was hampered by thick snow and winter darkness. Scientists believe the object may have weighed 50 tonnes and have been travelling at about 10,000 km/h.
• The largest crater formed by a meteorite is Coon Butte in Arizona, which has a diameter of more than 1,000m and a depth of just under 200m. It is thought to have been caused by an iron-nickel mass of around two million tonnes.
• The largest intact meteorite found on Earth was nearly 3 metres long and weighed around 60 tonnes. It was found in Namibia in 1920.
• A meteorite is thought to have caused the extinction of the dinosaurs 65 million years ago when it exploded with a force five billion times that of the Hiroshima bomb in the Yucatan peninsula in Mexico, leaving a crater at least 100 kilometres across.
• A fictional meteor shower caused widespread blindness in John Wyndham's The Day of the Triffids.

Internet Links

International Meteor Organisation
American Meteor Society
North American Meteor Network
Rime of the Ancient Mariner (University of Virginia Library)
A Coleridge Companion by John Spencer Hill

The BBC is not responsible for the content of external internet sites.

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