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1833年11月13日清晨，北美洲的上空出現恍如天崩的駭人天象：在黎明前的4小時內，流星如暴雨般劃破天際，把原本漆黑的上空照耀得猶如白晝。據估計，流星數量高達每小時20多萬顆。這個現象在當時引起極大恐慌，目擊者以為天空已經崩塌，世界末日到臨。
流星是太空中的石塊或沙粒，以高速衝入地球大氣層時，燃燒所造成的現象。獅子座流星雨的流星體是來自「坦普爾．塔特爾彗星」在繞日運行至接近太陽時所遺留在軌道上的物質。
並非每年都可看到奪目的獅子座流星雨，但在今年11月18日凌晨開始，我們將可目睹星隕如雨的景象(觀測地點必須遠離光污染)。保守估計，最高峰期(約清晨5時半)可見每小時100顆或以上流星隕落，而於前後一、兩天亦有可能觀測到此現象。
The Night the Stars Fell
The Leonids(a meteor shower that originates in the direction of the constellation Leo)put on an extravagant show in the wee hours of an 1833 November morning. The sky was so brightly lit by meteors that for once people thought the Sun had risen. For 4 hours before the Sun rose, "stars" poured down as if the sky had broken apart and Judgment Day had finally come. It was estimated that some 200,000 meteors fell each hour.
Meteors are small grains of sand that plunge at high speed into the Earth's atmosphere and burn up. The Leonids are actually sand grains expelled from Comet Tempel-Tuttle while passing near the Sun.
The Leonids didn't always put on spectacular shows. However on the 18th of this November, we may be able to witness a brilliant meteor rainstorm. The shower peaks at around 05:30 with an estimated hourly rate of a hundred or higher meteors. Bracketing your observation by one or two days will be a wise strategy. ■甄枝強 資深天文愛好者
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