Astronomy Picture of the Day

Explanation:

在地球南半球，有2個星系特別吸睛，它們分別是大麥哲倫星系（LMC）和小麥哲倫星系（SMC）。 這兩個不規則星系，是距離我們的銀河系最近的星系之二。 最近針對LMC（左側）的觀測指出，它幾乎以圓形軌道繞著我們的銀河系運行，甚至對測定我們銀河系的暗物質組成提供幫助。 上面這幅照片之寬度為40度。 在LMC的左下方，可見到龐大的蜘蛛星雲（红色）。 在SMC的右前方的明亮光斑，則是球状星團杜鵑47。

Two galaxies stand out to casual observers in Earth's Southern Hemisphere: the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC). These irregular galaxies are two of the closest galaxies to our Milky Way Galaxy. Recent observations of the LMC (on the left) have determined that it is on a nearly circular orbit around our Galaxy, and have even helped in the determination of the composition of dark matter in our Galaxy. The above photograph spans 40 degrees. Visible on the lower left of the LMC is the Tarantula Nebula (in red). In the foreground to the right of the SMC is globular cluster 47 Tucanae, appearing here as a bright point of light.