卡西尼26日逼近土卫六探测其神秘表面[酷图]

按照预订计划卡西尼号土星探测器将在星期二逼近土卫六，到达土卫六大气上方。如果一切正常的话，探测器将用高光望远镜穿过土卫六浓密的橙色大气层，探测到土卫六的神秘表面。

　　美国宇航员喷气动力实验室卡西尼-惠更斯使命的科学家丹尼斯-马特森说：“这将是人类第一次清晰地看到土卫六的表面。”

　　卡西尼-惠更斯使命由美国宇航局和欧洲航天局联合完成。这次卡西尼近距离亲临土卫六可能使科学家解决对土卫六表面、大气、化学成分等长期以来的疑问。是否存在液态甲烷的湖泊？是否存在着冰川的山脉？是否有星体碰撞产生的陨石坑？科学家猜测，它的表面大气环境与地球几十亿年前生命形成之初的大气环境非常类似。

　　北京时间2004年07月02日17时30分，卡西尼曾从338958千米的上空掠过土卫六，几天之后，它进入了土星轨道。北京时间10月26日23时30分，它将再次从1200千米上空掠过土卫六。

　　即使在这样的高度，土卫六用肉眼看到的也仅是浓密的大气和云层。然而因为卡西尼装配有一些列高科技的仪器，将使科学家可以穿透大气，看到土卫六表面。

　　卡西尼将用一套遥感仪器穿透土卫六大气表面，拍摄它的表面情况。专业仪器将收集土卫六表面成分的数据，雷达装置将用来绘制土卫六表面地图。

　　同时，卡西尼所携带的子探测器——惠更斯号，将于2004年12月25日与卡西尼号分离，2005年1月15日进入土卫六大气层，并最终在土卫六表面南纬10°，东经160°附近区域着陆。这次卡西尼掠过土卫六将对惠更斯的着落点进行拍照。为科学家提供惠更斯着落地点的地形草图。(辰序)

　　稿源： 新浪科技 　

Eyes on Xanadu
10.25.04  


This image taken on Oct. 24, 2004, reveals Titan's bright "continent-sized" terrain known as Xanadu. It was acquired with the narrow angle camera on Cassini's imaging science subsystem through a spectral filter centered at 938 nanometers, a wavelength region at which Titan's surface can be most easily detected. The surface is seen at a higher contrast than in previously released imaging science subsystem images due to a lower phase angle (Sun-Titan-Cassini angle), which minimizes scattering by the haze.

The image shows details about 10 times smaller than those seen from Earth. Surface materials with different brightness properties (or albedos) rather than topographic shading are highlighted. The image has been calibrated and slightly enhanced for contrast. It will be further processed to reduce atmospheric blurring and to optimize mapping of surface features. The origin and geography of Xanadu remain mysteries at this range. Bright features near the south pole (bottom) are clouds. On Oct. 26, Cassini will acquire images of features in the central-left portion of this image from a position about 100 times closer.

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 Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

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

北京时间2004年10月26日22时33分26秒，卡西尼号距离土卫六20000千米，将于56.72分钟后，即北京时间2004年10月26日23时30分09秒到达距离土卫六的最近位置，距离土卫六3776千米。

北京时间2004年10月26日23时16分49秒，卡西尼号距离土卫六6000千米，探测器将于13分钟后，即北京时间2004年10月26日23时30分09秒到达距离土卫六的最近位置，距离土卫六3776千米。

北京时间2004年10月26日23时20分47秒，卡西尼号距离土卫六5000千米，探测器将于9分钟后，即北京时间2004年10月26日23时30分09秒到达距离土卫六的最近位置，距离土卫六3776千米。

北京时间2004年10月26日23时26分23秒，卡西尼号距离土卫六4000千米，探测器将于4分钟后，即北京时间2004年10月26日23时30分09秒到达距离土卫六的最近位置，距离土卫六3776千米

“亲爱的，我终于来了！”

：P

期待更清晰的照片。

High Haze in Color

10.26.04

A global detached haze layer and discrete cloud-like features high above Titan's northern terminator (day-night transition) are visible in this image acquired on October 24, 2004, as the Cassini spacecraft neared its first close encounter with Titan. This full disk view of Titan is a colorized version of the ultraviolet image released on October 25, 2004 (PIA 06120). The globe of Titan and the haze have been given colors that are close to what the natural colors are believed to be.

The image was acquired at a distance of about 1 million kilometers (621,371 miles) in a near ultraviolet filter that is sensitive to scattering by small particles. The Sun preferentially illuminates the southern hemisphere at this time; the north polar region is in darkness. The well-known global detached haze layer, hundreds of kilometers above Titan's surface, is produced by photochemical reactions and visible as a thin ring of bright material around the entire planet. At the northern high-latitude edge of the image, additional striations are visible, caused by particulates that are high enough to be illuminated by the Sun even though the surface directly below is in darkness. These striations may simply be caused by a wave propagating through the detached haze, or they may be evidence of additional regional haze or cloud layers not present at other latitudes.

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 Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

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

注：次贴为本人的第6000贴！

卡西尼探测器近距离探测“土卫六”的模拟动画连接：
http://www.nasa.gov/images/content/67825main_PIA06119_movie.gif

“土卫六”南部地区的云层运动动画连接：
http://www.nasa.gov/images/content/67830main_PIA06124_movie.gif

逐渐清晰的“泰坦”表面。

Revealing Titan's Surface
10.26.04  

These three pictures were created from a sequence of images acquired by Cassini's imaging science subsystem on Oct. 25, 2004, 38 hours before its closest approach to Titan. They illustrate how the details of Titan's surface can be revealed through image processing techniques.

The picture on the left is a single image that has undergone only basic cleaning of corrupted pixels and imperfections in the camera's charge coupled device, a light-sensitive detector similar to those found in digital cameras. In the middle frame, multiple images were used to enhance the contrast detected from Titan's surface and to reduce the blurring effect of atmospheric haze. The picture on the right has been further processed to sharpen the edges of features.

The processed images reveal sharp boundaries between dark and light regions on the surface; there are no shadows produced by topography in these images. The bright area on the center right is Xanadu, a region that has been observed previously from Earth and by Cassini. To the west of Xanadu lies an area of dark material that completely surrounds brighter features in some places. Narrow linear features, both dark and bright, can also be seen. It is not clear what geologic processes created these features, although it seems clear that the surface is being shaped by more than impact craters alone. The very bright features near Titan's south pole are clouds similar to those observed during the distant Cassini flyby on July 2, 2004.

The region on the left side of these images will be targeted by higher-resolution observations as Cassini passes close to Titan on Oct. 26, 2004.

All of these images were acquired by Cassini on Oct. 25, 2004, at an altitude of 702,000 kilometers (436,000 miles) and a pixel scale of 4.2 kilometers (2.6 miles). The Sun was illuminating Titan from nearly behind the spacecraft.

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 Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

是不是有些象火星呢？

Titan's First Close-Up
10.26.04

This image is one of the closest ever taken of Saturn's hazy moon Titan. It was captured by Cassini's imaging science subsystem on Oct. 26, 2004, as the spacecraft flew by Titan. At its closest, Cassini was 1,200 kilometers (745 miles) above the moon, 300 times closer than during its first flyby on July 3, 2004.

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 Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

2

This image is one of the closest ever taken of Saturn's hazy moon Titan. It was captured by Cassini's imaging science subsystem on Oct. 26, 2004, as the spacecraft flew by Titan. At its closest, Cassini was 1,200 kilometers (745 miles) above the moon, 300 times closer than during its first flyby on July 3, 2004.

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 Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

北京时间2004年10月26日23时30分摄于土卫六表面上空1200千米处



Titan's First Close-Up
10.26.04

This image is one of the closest ever taken of Saturn's hazy moon Titan. It was captured by Cassini's imaging science subsystem on Oct. 26, 2004, as the spacecraft flew by Titan. At its closest, Cassini was 1,200 kilometers (745 miles) above the moon, 300 times closer than during its first flyby on July 3, 2004.

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 Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

顶一顶！！！