Telescope puts a new slant on saturn
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出版日期： 六月 17, 2007
The Hubble space Telescope has taken some of the best pictures of Saturn.The images show the planet''s rings at full tilt during a system that won''t be repeated for many years.
Saturn''s rotational axis is tilted, just like Earth and the other planets. On March seventh, the rings opened up to a greatest angle of 27 degrees. From its vantage point,Hubble was told to make uas of such a view. The new view showed Satutn''s south people the planet''s most attrative feature. Scientists wonder that Earth may once have been a ringed planedt, too. the result of a collision with a large space rock. Hubble studied Saturn in detail by gathering three images. taken with several camera filters and in several wavelengths of light.
"Tte set of 30 seleted filters may be the spectral coverage of Saturn observations ever obtained," said resercher Erlch Karkoschko of the University. For centuries, obsers have noticed the shadow Saturn always appeared colorless."The new images show that the farthest part of the shadow is orange,"Karkoschka said, similar to the moon during a deep total lunar eclipse .Saturn''s tilt produces seasons on the giant gas planet,for the same reason Earth has seasons. When saturn ''s north pole leans'' toward the sun ,spring turns top summre in the northern hemisphere,then fall follows.
Separate Hubble observations showed that Saturn''s top winds had lessoned by 40 percent over past teo decades, to 621 mph. Astronomers were surprised to learn that a planet so far from the sun could undergo such a great seasonal change.
Researchers will uae the new images to study Saturn''s atmosphere forther. Smll particles reflect different wavelengths of light depending on their structure .Only by combining images made in different wavelengths, can scientist get a true picture of the atmosphere''s chemical composition,and cloud shapes.
More will soon be learned. NASA''s spacecraft is on the way to Saturn and will arrive nect year.