[新闻] 卡西尼号最新图片(2004年06月12日)

距离近了，清晰度也提高不少！

Battered Moon

Early images returned from the first detailed reconnaissance of Saturn's small outer moon, Phoebe, show breathtaking details in the moon's pockmarked surface that already have imaging scientists puzzling over the body's history. The images are only a preview of what to expect from the high resolution images to be examined later today which will show details about 10 times smaller.

Phoebe has revealed itself to be a rugged, heavily cratered body, with overlapping craters of varying sizes. This morphology suggests a very ancient surface. There are apparently many craters smaller than 1 km, indicating that projectiles probably smaller than 100 meters once pommelled Phoebe. Whether these objects were cometary or asteroidal in origin, or were the debris that resulted from impacts on other bodies within the Saturn system, is hotly debated. There is also variation in surface brightness across the body. In parts of both images, the brightness is so great the image is overexposed

In the first image (at left) in which Phoebe looks somewhat like a sideways skull, the large crater near the bottom displays a complex and rugged interior. The lower right hand part of Phoebe appears to be covered by bright wispy material.

The second, higher resolution image further reveals the moon's battered surface, including a crater near the right hand edge with bright rays that extend outward from its center. This suggests that dark material coats the outside of what may be a predominantly icy body, and the underlying ice has been exposed and ejected by a recent impact. Features reminiscent of those seen on the Martian moon Phobos -- such as linear grooves are faintly visible in the upper part of this image. There are suggestions of linear ridges or grooves and of chains of craters, perhaps radial to a large crater just hidden on the unilluminated region in the upper left.


Left to right, the two views were obtained at phase, or Sun-Phoebe-spacecraft, angles of approximately 86 degrees, and from distances ranging from 143,068 kilometers (88,918 miles) to 77,441 kilometers (48, 130 miles); for reference, Cassini's closest approach to Phoebe was approximately 2,000 kilometers (1,240 miles). The image scale ranges from 0.86 to 0.46 kilometers (0.53 to 0.29 miles) per pixel. No enhancement of any kind has been performed on the images.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Credit: NASA/JPL/Space Science Institute
Released: Jun 12, 2004 (PIA 06066)

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http://www.oier.org.cn/cassini-huygens/cassini-huygens.gif

右面一张图片摄于北京时间2004年06月12日00时10分, 当时卡西尼号距离土卫九77441千米.

分辨率460米/像素, 图片未经任何增强处理.

好清晰哦，跟我一个朋友给我看他自己拍摄的木星的还要让人觉得不真实，像处理过的一样

因为是飞船在太空航行时拍摄的。。
所以不会有大气的干扰。。
所以会最接近被拍摄物体的本来面貌。。

多谢了

http://www.sina.com.cn 2004年06月14日 09:18 新浪科技

新浪科技讯 上周六，“卡西尼”号在2000千米的距离上为土卫九拍摄最完美的写真集。今天，美国宇航局公布了照片。美国宇航局的科学家兴奋地说，我们发现，这个卫星上有少量的冰和一些黑色的不明物质。除此之外，我们对这个小小的土星卫星了解甚少。不过，科学家表示，这些信息对于研究太阳系形成过程有非常重大的作用。

　　科学家们上一次拍摄土卫九是在1981年，那次使用的是安装在“旅行者”号探测器上的照相机。“卡西尼”号最近拍摄的土卫九照片比23年前“旅行者”号拍摄的照片质量提高了一倍多。这些新照片第一次让科学家们看清了土卫九的地貌状况，通过这些照片科学家们几乎可以分辨出土卫九表面的火山口和山峰。

　　土卫九最初被发现是在1898年，与土星的其它卫星相比从体积上来说它并算不上是老大，但是它却是土星最神秘的一颗卫星：在土星目前已探明的31颗卫星中，唯有它一个是逆向绕土星旋转的，它自转一周需要9小时16分钟。科学家们推测，土卫九这样独特的个性说明它最初可能不是太阳系的一分子，而是其它天外来客闯入太阳系后被土星重力场捕获并将其纳入了自己的卫星序列。

　　除此而外，土卫九还有另一个神秘之处：它的表面异常黑暗，但是却存在着水。这又不得不令科学家们相信它是构成土星的“建筑材料”的一部分。美国国家航空航天局的专家们期待着，本次对土卫九的近距离研究能够让他们获取更多有关太阳系形成的信息。