暮光里的卫星
Moons at Twilight
Image Credit & Copyright: Robert Fedez
Explanation: Even though Jupiter was the only planet visible in the evening sky on February 2, it shared the twilight above the western horizon with the Solar System’s brightest moons. In a single exposure made just after sunset, the Solar System’s ruling gas giant is at the upper right in this telephoto field-of-view from Cancun, Mexico. The snapshot also captures our fair planet’s own natural satellite in its young crescent phase. The Moon’s disk looms large, its familiar face illuminated mostly by earthshine. But the four points of light lined-up with Jupiter are Jupiter’s own large Galilean moons. Top to bottom are Ganymede, [Jupiter], Io, Europa, and Callisto. Ganymede, Io, and Callisto are physically larger than Earth’s Moon while water world Europa is only slightly smaller.
Tomorrow’s picture: light-weekend
暮光里的卫星
影像提供与版权: Robert Fedez
说明: 在2月2日那天的夜空中，虽然木星是唯一可见的行星，不过却有数颗太阳系最明亮的卫星，与它分享暮光时分的西方天空。在这幅刚日落后摄于墨西哥坎昆市的单曝光长焦镜头影像里，太阳系最大的气态巨行星出现在右上角。同时入镜的，还有新月相的地球天然卫星─月亮，而它看来庞大无比的月盘，主要受到地球反照光的照耀。而与木星排列成行的4个小亮点，其实是木星的四颗伽利略卫星。由上而下，分别有木卫三、木星、木卫一、木卫二和木卫四。木卫三、木卫一和木卫四都比月亮大，而有水世界之称的木卫二，只稍比月亮小一点。
明日的图片: light-weekend
