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Summer is the season for shooting stars, and this year could
be among the best as the annual Perseid meteor
shower
promises to be better than
usual.
Anyone gazing at the summer night sky for even a
short length of time now through the end of August is likely to spot a few
streaks of otherworldly
light. In general, the Earth encounters richer meteoric
activity during the second half of the year.
The best meteor display of the summer comes during the second week of
August, during the Perseid event. At its peak around the nights of Aug. 11
and 12, the shower can produce 50 to 100 fast, bright meteors per hour for
any observer with a wide-open view of a dark sky.
This year will be an excellent one to watch for the Perseids, partly
because bright moonlight will not interfere as in past years, and also
because Earth might encounter a heavier concentration of meteoric debris,
astronomers predict, leading to better than normal meteor activity.
Perseid meteors are bits of debris -- typically no
larger than sand grains but sometimes up to marble size -- left behind
during repeated passes of comet Swift-Tuttle. The comet crosses the inner
solar system once every 128 years as part of its elongated
orbit around the Sun.
Because most meteors in a shower are tiny, there is little threat to
spacecraft, and virtually none to people on the ground.
Forerunners of the Perseid shower began to appear
around July 17. Try watching for them after the waxing moon
has left the sky, leaving the
predawn hours dark. You'll see only a few per hour at best, but the
numbers will begin to ramp up during the second week of August.
At the height of the event, you might spot one to two per minute, and
sometimes even more meteors can grace the sky during brief bursts.
The last Perseid stragglers may still be spotted as late as Aug.
24.
The only equipment you'll need are your eyes and a modest amount of
patience. Find a location away from bright lights and with a wide view of
the sky. Bring a blanket or lounge chair so you can relax while looking
up.
Early morning hours generally provide the best viewing, typically
offering up twice as many meteors as in the evening.
(Agencies)
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夏天是流星的季节，而今年将是观测流星最好的时机，预计一年一度的英仙座流星雨会比往常更精彩。
从现在到8月底，你只要凝望夏季的夜空，哪怕只是很短的一段时间，都很可能观察到超凡脱俗的星光划过长空时留下的痕迹。通常来说，每年的下半年，地球会遭遇更多的流星活动。
夏季最精彩的流星表演将出现在8月的第2周、英仙座流星雨爆发期间。这次流星雨的高峰期大约在8月11日和12日夜间，届时在视野开阔的黑色夜空下，每个观测者每小时都能看到50到100
颗飞驰而过的、闪亮的流星。
天文学家们预测，今年是观测英仙座流星雨效果极好的一年，一方面是因为明亮的月光将不会像往年那样妨碍观测，另一方面因为地球可能会遇到大量流星残骸，这使得流星的活动明显强于往年。
英仙座流星雨就是维弗特-图特尔(Swift-Tuttle)彗星不断经过地球时留下的片片残骸，这些残骸通常还没有沙粒大，但有时也有弹子球那么大。维弗特-图特尔彗星每隔128
年穿过太阳系内部一次，这是它绕太阳转动轨道延长的一部分。
因为流星雨中的很多流星都非常小，所以对太空飞船几乎没有威胁，事实上也决不会伤到地面上的人。
英仙座流星雨中的“先行者”已于7月17日左右开始出现。当上弦月落山后，在黎明前几小时的黑暗中，试着去观测它们，每小时最多只能看到几个，但到8月的第二周，（流星的）数量将开始明显上升。
在这次流星雨的高峰时期，你可能每分钟就能看到一到两颗，有时甚至更多的流星在空中瞬时燃烧，装点着夜空。
直到8月24日，可能还能看到英仙座最后的“落伍者”。
你唯一需要的设备就是你的眼睛和适度的耐心。找一个远离亮光、视野宽广的地方，带上一条毯子或一把躺椅，你就能轻轻松松地仰望天空了。
清晨的几个小时通常是观测效果最好的时候，特别是那时看到的流星要比晚上多一倍。
（中国日报网站译）
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Updated: 2004-07-28 15:01
