Thin Rings Around Polarized Saturn 土星偏振光图像中的薄环

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[center]Astronomy Picture of the Day
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2005 December 19
http://antwrp.gsfc.nasa.gov/apod ... ng2_cassini_big.jpg


Thin Rings Around Polarized Saturn
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
Explanation: How thin are the rings of Saturn? Brightness measurements from different angles have shown Saturn's rings to be about one kilometer thick, making them many times thinner, in relative proportion, than a razor blade. This thinness sometimes appears in dramatic fashion during an image taken nearly along the ring plane. The robot Cassini spacecraft now orbiting Saturn has now captured another shot that dramatically highlights the ring's thinness. The above artistic looking image was taken early last month in infrared polarized light. If alone in space, the unlit part of Saturn would be much darker. Reflection of light off of moons like Enceladus (pictured) and the billions of small particles in Saturn's rings, however, gives the giant space orb an unusual glow, an effect highlighted in polarized light.


Tomorrow's picture: highway to heaven [/center]
[center]土星偏振光图像中的薄环

版权：Cassini Imaging Team, SSI, JPL, ESA, NASA



说明：土星环到底有多薄呢？不同角度的光度测量显示土星环大约只有1000米厚，即在相对的比例上，比剃须刀的刀刃还要薄很多倍。当在环平面附近拍摄照片时，薄环有时会以戏剧化的样子呈现出来。现正围绕土星运行的卡西尼号飞船又捕拍到一张环的照片，它生动地突出了薄环。上面这张具有艺术气息的 红外 偏振光图像拍摄于上月初。如果土星单独在太空中，那么它上面未被照亮的那部分将会非常暗，然而，土卫们（比如图上的土卫二）和土星环中成千上万的细小粒子反射的光，给这个巨大的天体蒙上一层异常的光辉，也带来一种效应——在偏振光上显现出来。（翻译：刘媛媛）[/center]

[ Last edited by Edelweiss on 2005-12-19 at 04:19 PM ]

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[center]http://www.phys.ncku.edu.tw/%7Ea ... ane_cassini_big.jpg

卡西尼号与土星的光环面呈十字

版权：Cassini Imaging Team, SSI, JPL, ESA, NASA


解释: 如果这是土星,那光环在哪里呢? 在 1612年，伽利略不了解为什么土星的“附加物”会消失。17世纪下半叶，这个迷已经被解开，土星最突出的特点就是它的光环，当地球与土星的光环呈十字时，土星光环的边缘看上去就消失了。这是因为土星光环的平面非常稀薄,如果按比例来说就像剃刀那么锋利。在现时代，正在做环绕土星轨道运行的卡西尼太空船也刚好与土星的光环面呈十字。西班牙天文爱好者Fernando Garcia Navarro从众多的在线照片中，挑选了2005年2月卡西尼飞船拍摄的一系列与土星光环面呈十字的图像。上面的图像经过数字处理，加入了有代表性的颜色，呈现出明显的效果。土星纤细的环面呈现出蓝色，在土星大气上的条纹和云带呈金色，光环弯曲的黑影横跨这个巨大气体星球的顶部。[/center]

[ Last edited by Edelweiss on 2005-12-19 at 04:24 PM ]

夜猫子

好图！已经加入索引贴了