说明: 虽然这颗卫星的相位可能看来很眼熟,但这颗卫星我们却很眼生,因为呈现渐盈相位的是木星的卫星木卫二 。这幅用无人太空船伽利略号在1995年至2003年拍摄的照片所组合出来之影像里,可见到数片明亮水冰之平原、绵延至地平面的裂缝及可能可时含有冰和尘土的暗斑区。在靠近日夜交界线的地球,高突的地貌尤为明显,因为它们投射出了暗影。木卫二的大小和月亮相当,但表面较平滑,几乎没有高地或大型陨石坑。伽利略号太空船回传的影像和证据,指出冰封的表面之下,可能有液态的海洋。为了验证这些海洋可能孕育生命的假说,欧洲太空总署也开始木卫二轨道船的初期规画工作。如果表面的冰层够薄,未来的任务可能会投放水下探测船,挖穿冰层到海里去找寻生命。
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Although the phase of this moon might appear familiar, the moon itself might not. In fact, this gibbous phase shows part of Jupiter's moon Europa. The robot spacecraft Galileo captured this image mosaic during its mission orbiting Jupiter from 1995 - 2003. Visible are plains of bright ice, cracks that run to the horizon, and dark patches that likely contain both ice and dirt. Raised terrain is particularly apparent near the terminator, where it casts shadows. Europa is nearly the same size as Earth's Moon, but much smoother, showing few highlands or large impact craters. Evidence and images from the Galileo spacecraft, indicated that liquid oceans might exist below the icy surface. To test speculation that these seas hold life, ESA has started preliminary development of the Jovian Europa Orbiter, a spacecraft proposed to orbit Europa. If the surface ice is thin enough, a future mission might drop hydrobots to burrow into the oceans and search for life.
[ 本帖最后由 Eldghost 于 2007-12-2 21:15 编辑 ] |