Great Balls Of Fire

DON'T sleep on Tuesday night, November 17. A couple of hours after the witching hour—2.10 am, to be precise—an army of meteors will come crashing into the earth's orbit and blaze off a two-hour-long magnificent pyrotechnic display, the kind you've never witnessed before. A celestial Diwali, if you please. In 1966, people in north America were treated to a similar display, and now 33 years later—the return of the cosmic invaders—east and south Asia are the privileged vantage points. Next November, it's the turn of the east Europeans.

But don't be carried away by the event's apocalyptic symbolism. There's no threat to human life whatsoever. The shooting stars, as blazing meteors are popularly called, are puny particles, no larger than small pebbles. They'll be reduced to flaming nothings as they chafe through the earth's atmosphere. However, this is the first time these cyclical bombers will run into over 500 active satellites circling the earth. The question is: will our telecommunications gear be jammed? Will we suffer an information blackout?

Maybe. In a testimony to the US Congress, scientists stated: "This meteoroid storm will be the largest threat ever experienced by our critical orbiting communication satellites. Furthermore, due to the very high speed of the particles, moving at over 70 km/s, the storm poses an even greater and somewhat unknown threat." At these speeds, even a tiny particle can cause damage or electrical problems.

While physical damage to solar panels and structures are unlikely, the bombardments may induce electrical shorts and failures in sensitive electronic components. That's what happened to the European Olympus satellite, which was hit by a meteor during the Perseid shower in 1993, knocking it out of service. Indian satellites INSAT and IRS series will bear most of the brunt of this 'sandblast' this year and the next, and possibly in 2001. While experts in the west predict a 4 per cent probability of satellites being hit, the ISRO estimates the odds at one hundredth of 4 per cent. "However, ISRO is taking all necessary precautions to minimise the impact."

Just the buffeting from the meteors equals about three years' wear and tear from normal operations, claim experts. Satellite operators, including ISRO, will send messages to have spacecraft tilt their solar panels so they face edge-on to the path of the particles. That would protect the delicate panels from being ripped off by the force of impacts. Stock exchanges linked to ISRO'S INSAT 2b and 2c have alerted members to square off transactions before D-Day to avoid panic.

NASA's Hubble Space Telescope will be swung around, so its lens faces away from the stream, and its solar arrays tilted to prevent damage. On board the Russian space station Mir, cosmonauts will wait out the storm in the Soyuz capsule, in case they need to make an emergency escape.

While scientists are gearing up to protect the satellites, astronomers are looking forward to this spectacle. On a clear night, one can see many blazing through the sky. But during certain periods in a year, many more meteors are seen in one night alone. They all appear to radiate from the same point in the sky. The increase in frequency and the spray-like appearance has earned them the name—meteor showers, each known by the constellation it emanates from. For instance, the Leonid, which emanates from the Leo constellation.

The annual shower of meteors have a more specific origin. The debris left by the passage of a particular comet through the inner solar system remains more or less in the same orbit as the comet. It merely spreads out in space along and around the comet's orbit. Such meteoroid streams may be a few million kilometres in diameter. If such an orbit intersects the plane in which the earth is revolving around the sun, the earth will plunge through this rubble once a year and at the same time of the year. The well-known comet Halley, for example, is responsible for two annual showers.

The comet associated with the Leonids, the Tempel-tuttle comet, visits earth every 33 years. This time, the earth is predicted to be farther from the freshly replenished meteoroid stream than it was in 1833 and 1966. The storm will not be as intense, but strong enough for a display of 5,000 meteors per hour during the 'crescendo'.

So don't forget. Select a place away from city lights and with a clear view of the horizon. If possible, carry a star map and a torchlight dulled by red cellophane paper to locate the Leo constellation. Ensconce yourself in a snug position as the fireworks will linger for almost two hours. Happy viewing!