charles 2009-3-23 10:46
碎裂的彗星
Crumbling Comet
[img]http://i14.tinypic.com/315zwqr.jpg[/img]
影像提供: William Reach (SSC/Caltech), et al., JPL, Caltech, NASA
[color=navy]Explanation:[/color]
This false-color mosaic of crumbling comet Schwassmann-Wachmann 3 spans about 6 degrees (12 full moons) along the comet's orbit. Recorded on May 4-6 by an infrared camera on board the Spitzer Space Telescope, the picture captures about 45 of the 60 or more alphabetically cataloged large comet fragments. The brightest fragment at the upper right of the track is Fragment C. Bright Fragment B is below and left of center. Looking for clues to how the comet broke up, Spitzer's infrared view also captures the trail of dust left over as the comet deteriorated during previous passes. Emission from the dust particles warmed by sunlight appears to fill the space along the cometary orbit. The fragments are near their closest approach in the coming days, about 10 million kilometers away, and none pose any danger to our fair planet.
[color=navy]說明:[/color]
這幅裂史瓦三號彗星的假色組成影像,沿著彗星軌道涵蓋大約六度的天區,相當於12個滿月的寬度。5月4日到6日,使用史匹哲太空望遠鏡紅外光相機所記錄的這些影像,捕捉到用英文字母編錄的60多塊彗星大碎片之中的40片。影像右上方最明亮的碎片是碎片C,中左下方的則是明亮的碎片B。拍攝史匹哲影像的目的在於找出彗星碎裂的線索,不過這些影像也捕捉前幾次彗星回歸時,因為彗星衰敗而散佈在軌道上的塵埃。這些塵埃微粒在陽光的加熱下發出紅外輻射,讓塵埃像是塞滿彗星軌道上的所有空間。在接在來的數天之中,這些碎片一同往最靠近地球的位置前進,屆時離地球有一千萬公里遠,所以沒有任何碎片會對我們美麗的地球構成危害。
[size=2]資料來源: Scientific American
Department of Physics, NCKU[/size]