放大圖片
太陽系位於一個龐大而扁平的漩渦狀星系內。每當我們望向星系盤的上方或下方,我們可見疏落的星星點綴黑漆夜空;但當我們望向星盤的側面,就發現繁星匯聚成一道銀帶,橫跨星空,這是大家熟悉的銀河。銀河被西方稱為「牛奶路」;這個有趣的名稱源於一個希臘神話傳說。
赫拉克勒斯是神王宙斯與凡人阿美妮所生的兒子,赫拉克勒斯出生後,宙斯把他帶到熟睡中的神后赫拉跟前,並試圖讓兒子從赫拉的乳房吸食乳液,從而得到如天神般的不死之身。可惜赫拉剛好醒來,並把赫拉克勒斯一手推開,而乳液也因此從她的乳房噴向天空,形成我們熟悉的「牛奶路」。上圖是意大利文藝復興晚期的偉大畫家丁托列托根據神話故事而繪成的《銀河的起源》。
The Legend of the Milky Way
Our Sun resides within a large galaxy with its stars lined up to form the shape of a disk-shaped spiral. When we look towards the top or bottom of the disk, we see dark skies sparsely populated with stars. But when we look towards the side of the disk we are looking into regions of the galaxy where stars are densely packed. Thus we see a silvery band spanning across the night sky. Perhaps this is why this band of stars is called the Milky Way in the western world.
In ancient Greece the Milky Way had its interesting origin. Heracles was the son of Zeus and Alcmene. After Heracles was born, Zeus took him to Hera and tried to feed him from her breasts while she was asleep. Doing so would make Heracles immortal. But Hera woke up and pushed the baby away and her milk squirted across the sky to form the Milky Way. This scene was depicted in the Renaissance painting, The Origin of the Milky Way, by Jacopo Tintoretto. ■甄枝強 資深天文愛好者
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