Enceladus

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

恩克拉多斯是土星的62多颗卫星之一。卡西尼探测器的旅程为土星及其卫星提供了大量信息。

这张灰度图像来自NASA/JPL/Space Science Institute。

Information from the original picture caption: "Saturn's moon Enceladus reflects sunlight brightly while the planet and its rings fill the background of this Cassini view. Enceladus is one of the most reflective bodies in the solar system because it is constantly coated by fresh, white ice particles. This view looks toward the anti-Saturn side of Enceladus (504 kilometers, or 313 miles across). This view looks toward the northern, sunlit side of the rings from just above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 21, 2010. The view was obtained at a distance of approximately 102,000 kilometers (63,000 miles) from Enceladus."

This image is from NASA's Cassini spacecraft.

这张图片来自NASA的卡西尼号航天器。

原始图片说明中的信息：“土星的卫星恩克拉多斯反射着明亮的阳光，而土星和其环系统则位于此卡西尼影像的背景中。恩克拉多斯是太阳系中最反射率高的天体之一，因为它不断被新鲜的白色冰粒覆盖。此影像面向恩克拉多斯的背向土星一侧（直径504公里，或313英里）。此影像从环平面上方稍高于处，面向环系统的北侧，阳光照射的区域。该影像于2010年12月21日由卡西尼探测器窄角相机以可见光拍摄。该影像距恩克拉多斯约102,000公里（63,000英里）。”

以下是对恩克拉多斯的描述，来自卡西尼网站：

"Enceladus is one of the brightest objects in our solar system. Covered in water ice that reflects sunlight like freshly fallen snow, Enceladus reflects almost 100 percent of the sunlight that strikes it. Because Enceladus reflects so much sunlight, the surface temperature is extremely cold, about -201° C (-330° F)."

恩克拉多斯是太阳系中最亮的天体之一。其表面覆盖着水冰，这些水冰反射阳光如同新落的雪般明亮，恩克拉多斯几乎将所有照射到它的阳光都反射回去。由于反射了如此多的阳光，其表面温度极低，约为-201°C（-330°F）。

"About as wide as Arizona, Enceladus is quite similar in size to Mimas but has a smoother, brighter surface. Unlike Mimas, Enceladus displays at least five different types of terrain. Parts of the moon show craters no larger than 35 kilometers (about 22 miles) in diameter. Other areas show regions with no craters indicating major resurfacing events in the geologically recent past. There are fissures, plains, corrugated terrain and other crustal deformations. All of this indicates that the interior of the moon may be liquid today, even though it should have been frozen eons ago. Enceladus' surface is believed to be geologically "young," possibly less than 100 million years old."

与亚利桑那州一样宽，恩克拉多斯的尺寸与米玛斯相当，但其表面更加平滑且明亮。与米玛斯不同，恩克拉多斯显示出至少五种不同的地形类型。月球上的一些区域有直径不超过35公里（约22英里）的陨坑。其他区域则显示出没有陨坑的区域，这表明在地质学上最近的过去发生了重大地表重塑事件。还有裂缝、平原、起伏地形和其他地壳变形。所有这些都表明，这颗卫星的内部可能今天仍然是液态的，尽管它应该在数亿年前就已经冻结了。恩克拉多斯的表面被认为在地质学上是“年轻的”，可能不到1亿年。

Enceladus along with Titan and Europa has drawn the attention of astrobiologists who are looking for evidence of life beyond the Earth.

NASA/JPL/Space Science Institute

NASA/JPL/空间科学研究所

Unusual features of Enceladus include large water geysers spewing icy water hundreds of kilometers into space. This material forms one of Saturn's fainter rings, the E ring, and also rains down on the planet, according to Drake. The discovery of the giant water fountains of Enceladus solved the mystery of why water was being detected in the rings of Saturn. The water plumes show that there is subsurface water, contributing to the interest in Enceladus as a possible location for life. There are at least 70 jets bursting from fractures at the south pole.

恩克拉多斯的奇特特征包括巨大的水喷泉将冰水喷射到数百公里外的空间。这种物质形成了土星最暗淡的环之一——E环，并且也降落在星球上，据德拉克说。恩克拉多斯的巨大水喷泉的发现解答了为何在土星环中检测到水的谜团。水喷泉表明存在地下水，这使得恩克拉多斯成为可能孕育生命的地点之一。至少有70个喷射流从南极的裂缝中喷出。

恩克拉多斯与泰坦和欧罗巴吸引了天体生物学家的注意，这些科学家正在寻找地球以外生命存在的证据。

Enceladus has water, organics, nitrogen, and an energy source. At present, it is the only other place in the solar system besides Earth that has all four of these necessary precursors for Earth-type life.

恩克拉多斯拥有水、有机物、氮气和一个能量源。目前，它是在太阳系中除地球外唯一具备这四种地球生命必需前体的天体。

参考文献：卡西尼-惠更斯任务。

卡西尼成像团队主页。

NASA 埃欧利斯概述

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