美国英语听力80篇2 Lesson39
Pictures of Io
The American space agency has released to the public the first of many new pictures of Jupiter's Moon,Io.NASA's Galileo spacecraft took the pictures last July and October using both black and white film and color film. Researchers combined the images to provide more detail of the moon's surface. The new pictures have given astronomers a great deal of information about the small moon.
They show areas affected by active volcanoes. One area clearly shows red material near the base of a mountain. Scientists say the material may be sulfur gases escaping along a large cut in the surface near the bottom of the mountain. They also say this release of volcanic material may be what helped form the mountain. The pictures provide enough information for scientists to guess at the size of several objects on the surface of Io. For example, the lengths of the shadows formed by the mountains make it possible to guess their heights.
The pictures suggest that one mountain may be about eight kilometers tall. Another is about four kilometers tall. The pictures are very colorful. They show red, yellow, white and orange-black places. The surface of Io is mostly sulfur with some frozen sulfur dioxide. The pictures also show a mostly flat surface except for the mountains created by volcanoes.
NASA scientists said the Galileo spacecraft made the pictures while working in areas with great amounts of radiation near Io.The scientists said the radiation did affect the spacecraft's computers but it did not damage them. Galileo took even closer pictures of Io on Tuesday,February twenty-second. These pictures were taken as Galileo passed as close as 198 kilometers from the moon. The newer pictures are now being sent back to Earth. They also will be released to the public as soon as scientists have studied Io is a very unusual place. Scientists say there is no evidence of holes caused by space objects on its surface. They say this means the surface of Io is much younger than one million years old. They say also that the surface of Io is always changing. The change is caused by intense volcanic activity.
