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Geminid Meteors
Friday the 13th brings a bit of bad luck for skywatchers this year. The Geminid meteor shower is at its peak, and it’s generally one of the year’s best, with peak rates of more than a hundred meteors per hour. But the Moon is almost full, so it’ll overpower all but the brightest meteors. A meteor forms when a bit of debris from a comet or asteroid rams into the atmosphere at tens of thousands of miles per hour. That generates intense heat, so the particle burns up, leaving a streak of light. Most of the streaks vanish in a few seconds. But some of them leave “persistent meteor trains” – glowing trails that can last for a few minutes to more than an hour. A recent study says that most of these long-lived trains are formed by particles that pass deeper into the atmosphere. Scientists recorded thousands of meteors above New Mexico. They found that about five percent of meteors left a train that was visible for at least five minutes – a much higher fraction than in earlier studies. There wasn’t much correlation between the persistence of the train and either the speed or brightness of the meteor. But there was a correlation with the meteor’s altitude. Those that descended to about 55 miles were much more likely to create long-lasting trains. At that altitude, metals in the chunk of space debris may react with ozone in the atmosphere long after the meteor burns up – creating a glowing trail in the night sky. Script by Damond Benningfield
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