Astronomy Picture of the Day

Explanation: What's in a name? Since 1919, the International Astronomical Union has been charged with the task of establishing "conventional" nomenclature for planets, satellites, and surface features. For the remote Uranian system of moons, namesakes from Shakespearean works have been chosen. Thus Oberon, king of the mid-summer night fairies, is also Uranus' most distant and second largest moon. Hamlet is the tragically dark, large and princely crater on its surface (right of center). The above image represents known surface features of Oberon and was constructed by the U.S. Geological Survey (USGS) based on data from NASA's robot explorer Voyager 2. In 1986, Voyager 2 flew through the Uranian system - so far it has been the only spacecraft to do so.

名字有什麼含義呢？ 自1919年以來，國際天文聯盟負責訂定行星、衛星和表面特徵的“常規”命名。 對於遙遠天王星的衛星，其命名取自莎士比亞的作品。 因此，奧伯倫（天衛四）是仲夏夜仙女的國王，也是天王星最遠及第二大的衛星。 哈姆雷特是其表面上，悲劇性、黑暗和具有王子般尊貴特質的撞擊坑（中右側）。 上面這幅呈現天衛四已知表面特徵的影像，是由美國地質調查局（USGS），根據NASA的“旅行家2號”太空船所收集之數據構建而成。 旅行家2號在1986年飛越天王星系統，而至如今它仍是進行此飛越的唯一太空船。