Titan

Titan is the largest of Saturn's 62+ moons. The voyage of the Cassini spacecraft has yielded an abundance of information about Saturn and its moons.

土星的62颗卫星中，泰坦是最大的一颗。卡西尼探测器的旅程为土星及其卫星提供了大量信息。

This image of Titan is a composite of several images taken during two separate Titan flybys on Oct. 9, 2006 (T19) and Oct. 25 (T20).

这张泰坦星的图像由两次不同飞越期间拍摄的多张图像合成，分别于2006年10月9日（T19）和10月25日（T20）取得。

The large circular feature near the center of Titan's disk may be the remnant of a very old impact basin. The mountain ranges to the southeast of the circular feature, and the long dark, linear feature to the northwest of the old impact scar may have resulted from tectonic activity on Titan caused by the energy released when the impact occurred.

泰坦盘面中心附近的大圆形特征可能是非常古老的撞击盆地的残余。位于该圆形特征东南方的山脉，以及位于古老撞击痕迹西北方的长而暗的线性特征，可能是由于撞击发生时释放出的能量引起的泰坦上的构造活动所致。

The Oct. 9 images form the background globe for context, and the most recent images from the Oct. 25 flyby are overlaid. The Oct. 9 images were taken at an average distance of about 30,000 kilometers (18,000 miles). The Oct. 25 images were taken at a distance of 12,000 kilometers (7,200 miles). The images were taken at wavelengths of 1.3 microns shown in blue, 2 microns shown in green, and 5 microns shown in red.

10月9日的图像构成了背景地球以供参考，而10月25日飞越的最新图像则被叠加在上。10月9日的图像是在平均距离约30,000公里（18,000英里）处拍摄的。10月25日的图像是在12,000公里（7,200英里）处拍摄的。这些图像是在1.3微米（显示为蓝色）、2微米（显示为绿色）和5微米（显示为红色）波长下拍摄的。

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 mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The Visual and Infrared Mapping Spectrometer team is based at the University of Arizona where this image was produced.

卡西尼-惠更斯任务是美国国家航空航天局（NASA）、欧洲航天局和意大利航天局共同参与的项目。喷气推进实验室（JPL）是加州理工学院帕萨迪纳分校的一个部门，负责为NASA的科学任务局管理该任务。卡西尼轨道器是在JPL设计、开发和组装的。视觉和红外成像光谱仪团队位于亚利桑那大学，该图像就是在该团队制作的。

Titan along with Enceladus and Europa has drawn the attention of astrobiologists who are looking for evidence of life beyond the Earth. Titan is the only body in the solar system, other than the Earth, to have stable liquids on its surface. The bodies of liquids are composed of methane and ethane. The nitrogen-rich atmosphere plus the hydrocarbons raise the possibility of life, but the surface temperature is about -180° Celsius.

泰坦与恩克拉多斯和欧罗巴吸引了天体生物学家的注意，他们正在寻找地球以外生命存在的证据。泰坦是太阳系中除地球外唯一表面有稳定液体的天体。这些液体由甲烷和乙烷组成。富含氮的大气层加上碳氢化合物提高了存在生命的可能性，但表面温度大约为-180摄氏度。

如需了解卡西尼-惠更斯任务的更多信息，请访问 http://saturn.jpl.nasa.gov/home/index.cfm 。卡西尼成像团队的主页位于 http://ciclops.org 。

References:
"Alien-life hunters focus on moons in outer solar system", Nadia Drake, Science News 180, #8, Oct 8, 2011, p22.

参考文献：‘外太阳系卫星成为外星生命搜寻焦点’，Nadia Drake，科学新闻 180，第8期，2011年10月8日，第22页。