Jupiter Moon Io Imaged by Galileo

This image of Jupiter's moon Io was taken by Galileo on June 27, 1996. This is the side which faces Jupiter, and its appearance is very similar to images taken by Voyager I and II during the 1979 flybys. 这张照片是伽利略于1996年6月27日拍摄的木卫一。这是面向木星的一面，其外观与1979年 Voyager I 和 II 在飞越期间拍摄的图片非常相似。

The image at left shows a new blue-colored volcanic plume extending about 100 kilometers (about 60 miles) into space from Jupiter's moon Io (see inset at lower left). The blue color of the plume is consistent with the presence of sulfur dioxide gas and "snow" condensing from the gas as the plume expands and cools. Galileo images have also shown that the Ra Patera plume glows in the dark, perhaps due to the fluorescence of sulfur and oxygen ions created by the breaking apart of sulfur dioxide molecules by energetic particles in the Jovian magnetosphere. The images at right show a comparison of changes seen near the volcano Ra Patera since the Voyager spacecraft flybys of 1979

The imaged plume is believed to be a geyser-like eruption driven by sulfur dioxide or sulfur gas erupting and freezing in Io's extremely tenuous atmosphere. Volcanic eruptions on Earth cannot throw materials to such high altitudes. Ra Patera is the site of dramatic surface changes. An area around the volcano of about 40,000 square kilometers, area about the size of New Jersey, has been covered by new volcanic deposits. The image was taken in late June 28, 1996 from a distance of 972,000 kilometers (604,000 miles).

This image of Io is part of a series shot by the Galileo spacecraft. The large red ring shows the remarkable area covered by the ejecta from the volcano. 这张伊奥的图像属于伽利略探测器拍摄的一系列照片。巨大的红色环状区域显示了火山喷发所覆盖的广阔区域。

NASA images from the Galileo spacecraft.

NASA 从伽利略探测器传来的图像

Discussion of Io 关于Io的讨论

NASA的伽利略探测器拍摄了上述高分辨率的木卫一图像，该图像是在木星云层大气的背景前拍摄的。1996年9月7日，当这张照片拍摄时，伽利略距离木卫一约487,000公里（约302,000英里），而木星则距离木卫一约908,000公里（约564,000英里）。这张图像的中心位于始终背对木星的木卫一一侧。图像中的颜色是由伽利略探测器的固体状态成像相机在近红外、绿色和紫色滤波器中获取的数据组成，并经过增强，以突出木卫一火山遍布表面的非凡颜色和亮度变化。黑色和明亮的红色物质对应于最近的火山沉积物，可能不超过几年旧。近红外滤波器使木星的大气层看起来呈蓝色。活跃的火山Prometheus位于盘面右中央区域。