An Unusually Smooth Surface on Saturn's Telesto
影像提供: Cassini Imaging Team, SSI, JPL, ESA, NASA
Explanation:
Why is Saturn's small moon Telesto so smooth? Possibly Telesto is covered with a type of granular icy material similar to that suspected of covering Pandora, another of Saturn's small moons. If so, Telesto might be more like a pile of rubble than a solid body. This recently uncovered Solar System mystery is currently a topic of research, however. The unexpected finding originated last October when the robot Cassini spacecraft, currently orbiting Saturn, swooped past the 24-kilometer moon and captured the first ever image of Telesto's surface. Telesto orbits Saturn always just ahead of the much larger moon Tethys. Pictured above, Telesto's unusually smooth surface was found to show some large craters and boulders, but not the high density of craters found on nearby Tethys or most other Saturnian moons.
說明:
土星的小衛星土衛十三為何這麼光滑？可能是土衛十三 (Telesto)被一種顆粒冰質物質所覆蓋，類似的物質可能也覆蓋著另一顆土星小衛星土衛十七 (Pandora)。如果這是真的，土衛十三很可能是一團亂石堆，而不是一顆結實的天體。這個剛發現的太陽系謎團，現在是科學探索的題材，它是由正在繞行土星的卡西尼號太空船在去年十月所發現的，當時它正飛掠過這顆24公里大小的衛星上空，拍攝了土衛十三表面的首張影像。土衛十三永遠在較大的土星衛星土衛三 (Tethys)前方不遠處領頭繞行土星。在上面影像中，土衛十三不尋常的平滑表面上有一些較大型的隕石坑和圓形團塊，但沒有像鄰近的土衛三或其他的土星衛星一樣上面有密密麻麻的隕石坑。
資料來源: Scientific American
Department of Physics, NCKU
