作者：余申芳

美国航天局３日发布了“信使”号探测器最近一次飞掠水星获得的观测数据，至此水星大约98％的表面已测绘完毕，科学家们已经获得了一幅几近完整的水星表面“地图”。

    美国航天局在新闻公报中介绍说，“信使”号于9月29日成功飞掠水星，其间，“信使”号上的照相仪等观测设备成功地拍摄了水星表面一些以前从未被观测过的地方，使得水星表面被测绘面积扩大到98％。

    在这次飞掠中，“信使”号获得不少新发现。例如，发现一处中间凹陷、四周明亮的区域，科学家分析认为这可能是一处火山的遗迹。另外发现一处直径达290公里的巨大双环撞击盆地，与“信使”号2008年第一次飞掠时观测到的一个盆地类似。这次观测还发现，水星表面物质中铁和钛的含量要比此前科学家认为的高。

    除了水星表面，“信使”号还对其外大气层进行了更为细致的观测。通过与前两次飞掠的观测数据对比，科学家发现，水星上也存在“季节变换”，外大气层中钙、镁、钠等的含量随季节都有不同的变化。这些研究结果对分析水星整个大气层提供了重要信息。

    水星是太阳系中最靠近太阳的一颗行星，人类对它的了解并不是很多。“信使”号于2004年8月升空，是人类发射的第一个绕水星运行的探测器。这已经是“信使”号第三次飞掠水星，除了进行重要的水星表面测绘等任务外，它还借助水星引力进行了一次关键的飞行调整，以保证于2011年能顺利进入绕水星轨道飞行。届时，“信使”号就可以观测到水星的两极地区，这是目前水星上唯一两个未被观测到的区域。

3, NASA issued the "Messenger" spacecraft obtained the most recent flyby of Mercury observational data, bringing about 98% of the surface of Mercury has been surveying and mapping is completed, scientists have gained an almost complete Mercury surface "map" .

     NASA press release said, "Messenger" was on September 29 successful flyby of Mercury, during which, "Messenger" was observed on the apparatus such as camera equipment, the surface of Mercury has successfully filmed a number of previously never been observed before place, making the surface of Mercury is mapping an area expanded to 98%.

     During the flyby, the "Messenger" was received a lot of new discoveries. For example, the discovery of a sunken middle section, surrounded by bright areas, scientists analysts believe this may be the remains of a volcano. Another found that a diameter of up to 290 kilometers of the great double loop impact basin, with the "Messenger" was in 2008 when the first flyby of a basin similar to the observed. The observations also found that Mercury's surface material of iron and titanium content than the previous scientists believe that high.

     In addition to the surface of Mercury, "Messenger" was also carried out to its outer atmosphere, a more detailed observations. By working with the two previous flyby of observational data comparison, the scientists discovered that Mercury has also exist "seasonal", outside the atmosphere, calcium, magnesium, sodium, etc. have different levels with the seasons change. These findings on the analysis of Mercury's atmosphere as a whole provide important information.

     Mercury is the closest to the sun in the solar system a planet, human understanding of it is not a lot. "Messenger" was launch in August 2004, is launching the first human to run around the Mercury probe. This was the "Messenger" was the third flyby of Mercury, in addition to carry out important tasks such as surveying and mapping the surface of Mercury, it also carried out with a critical Mercury gravity flight adjustments to ensure the successful 2011 flight into orbit around Mercury. By then, the "Messenger" number can be observed in the polar regions of Mercury, which is now the only two Mercury has not been observed area.