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Leonid Meteor Shower Delights Many
http://www.sina.com.cn 2001/11/19 12:41  新快报

  Even veteran stargazers were amazed with the light show thousands of tiny meteors gave them early Sunday.

  This year's much-anticipated Leonids shower delighted people around the world who stayed up late or woke up early to see it, including a meteor-watching party of about 75 people atop Mount Wilson, northeast of Los Angeles.

  Every few seconds at least a bit of space dust burned harmlesslysintosthe atmosphere. The brightest flares left shimmering trails that hung for a few seconds.

  The shower was less intense than the 4,000 per minute some had predicted, but nonetheless it was a more impressive display than astronomers have seen in years.

  Between 800 and 1,000 meteors were falling an hour at the peak of the shower between 4 a.m. and 6 a.m. EST, said Mitzi Adams, astrophysicist for NASA.

  One observer in New York reported seeing three to five meteors a minute even after dawn broke, she added.

  The Leonids are minute dust particles shed by Comet Tempel-Tuttle. The meteors are called Leonids because they appear to come from the direction of the constellation Leo the Lion.

  The comet swings around the sun once every 33 years, leaving a trail of dust. Each November, the Earth's orbit takes it through that slowly dissipating trail.

  Comet Tempel-Tuttle most recently passed close to the sun in February 1998. However, the dust particles seen as shooting stars across North America on Sunday were shed during a 1766 pass.

  Those particles, each no larger than a grain of sand, enter the atmosphere traveling 45 miles a second. When they meet the friction of air molecules, they burn up harmlessly, leaving only a brilliant streak of light.

  But for the estimated 630 operational satellites in orbit around the Earth, the particles can be deadly. Many satellite operators, in preparation for the shower, turn the spacecraft to shield them from the meteoroids or shut down electronic operations.

昨夜流星雨让人眩目

  即使是最老练的星象观测者都被昨天凌晨出现的流星雨的壮观景象所折服。

  今年广受关注的狮子座流星雨没有让世界各地那些特意为之晚睡或者早起的人们失望。这些观星者中,就包括了在美国洛杉矶东北面的威尔逊山上举行流星雨晚会的75人。

  每隔几秒钟,至少都会有一丁点的太空尘埃燃烧着闯入大气层。强光过后,它们发着微光的尾巴都还会在空中保留几秒钟。

  今年的流星雨并不像有人预计的那样,每分钟会出现4000多颗流星。但即使这样,这次流星雨还是比近年来天文学家观测到的许多其它星光表演给人留下了更深刻的印象。

  据美国航空航天局的天体物理学家亚当斯说,在美国动部时间18日早上4点到6点之间的高峰时刻,每小时都有800到1000颗流星出现。

  她说,即使是在黎明时刻,纽约上空每分钟都还会出现3到5颗流星。

  狮子座流星是由坦普尔·塔特尔彗星释放的微小尘粒构成。这些流行之所以被冠之以“狮子座”的名称,那是因为它们好象与狮子星座来自同一方向。

  坦普尔·塔特尔彗星每隔33年接近太阳一次,留下一条长长的尘埃尾巴。每年的11月,地球都会穿过这条正在消逝的流星群。

  坦普尔·塔特尔彗星最近一次靠近太阳是在1998年2月。然而,本次流星雨的尘埃是该彗星在1766年留下的。




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