仙女座星系
Andromeda Galaxy

context: zh_tw: 最早的仙女座星系觀測紀錄可能出自波斯的天文學家阿爾蘇飛，他在他的《恆星》一書中描述它是「小云」，星圖上的標記在那個時代也是「小云」。第一個以望遠鏡進行觀測和記錄是德國天文學家西門・馬裡烏斯，時為 1612 年，說它狀如牛角管中所見的燭光。在 1764 年梅西爾將他編目為 M31，並誤以為西門・馬裡烏斯是發現者，卻未察覺阿爾蘇飛在更加早期的工作。在 1785 年，天文學家威廉・赫歇爾注意到在星系的核心區域有偏紅色的雜色，使他相信這是所有星雲中最靠近的「大星雲」，並依據星雲的顏色和亮度估計（並不正確）距離應在天狼星的 2,000 倍之內。幾個世紀以來，天文學家都認為它是銀河系內的一個天體，所以才誤稱之為仙女星雲，把它當成是我們所在的星系內的、類似於其他發光氣體物質的旋渦星雲。直至 20 世紀 20 年代，美國天文學家哈伯才最終確定仙女座星系事實上是銀河系之外的分立的星系。
en: Around the year 964, the Persian astronomer Abd al-Rahman al-Sufi was the first describe to the Andromeda Galaxy. He referred to it in his Book of Fixed Stars as a "nebulous smear".Star charts of that period labeled it as the Little Cloud. In 1612, the German astronomer Simon Marius gave an early description of the Andromeda Galaxy based on telescopic observations. Pierre Louis Maupertuis conjectured in 1745 that the blurry spot was an island universe. In 1764, Charles Messier cataloged Andromeda as object M31 and incorrectly credited Marius as the discoverer despite it being visible to the naked eye. In 1785, the astronomer William Herschel noted a faint reddish hue in the core region of Andromeda. He believed Andromeda to be the nearest of all the "great nebulae", and based on the color and magnitude of the nebula, he incorrectly guessed that it was no more than 2,000 times the distance of Sirius, or roughly 18,000 light years. In 1850, William Parsons, 3rd Earl of Rosse  made the first drawing of Andromeda's spiral structure.
qas: question: zh_tw: 阿爾蘇飛是如何描述仙女座星系的？
en: How did Abd al-Rahman al-Sufi describe the Andromeda Galaxy?
answers: zh_tw: text: 小云
en: text: nebulous smear

question: zh_tw: 家西門・馬裡烏斯在發現仙女座星系時給了它什麼名字？
en: Which name did Charles Messier give to the Andromeda galaxy when he discovered it?
answers: zh_tw: text: M31
en: text: M31

context: zh_tw: 在 1998 年，來自歐洲太空總署的紅外線太空天文臺的影像顯示出仙女座星系的整體形象可能是會被轉換成圓環星系。在仙女座星系內的氣體含塵埃形成了幾個重疊的圓環，其中最突出的一個圓環在距離核心 32,000 光年的半徑上。這個環由冰冷的塵土組成，因此在可見光的影像中這個環是看不見。
en: Since the Andromeda Galaxy is seen close to edge-on, it is difficult to study its spiral structure. Rectified images of the galaxy seem to show a fairly normal spiral galaxy, exhibiting two continuous trailing arms that are separated from each other by a minimum of about 13,000 light-years (820,000,000 astronomical units) and that can be followed outward from a distance of roughly 1,600 light-years (100,000,000 AU) from the core. Alternative spiral structures have been proposed such as a single spiral arm or a flocculent pattern of long, filamentary, and thick spiral arms.The most likely cause of the distortions of the spiral pattern is thought to be interaction with galaxy satellites M32 and M110. This can be seen by the displacement of the neutral hydrogen clouds from the stars.In 1998, images from the European Space Agency's Infrared Space Observatory demonstrated that the overall form of the Andromeda Galaxy may be transitioning into a ring galaxy. The gas and dust within the galaxy is generally formed into several overlapping rings, with a particularly prominent ring formed at a radius of 32,000 light-years (2.0×109 AU) (10 kiloparsecs) from the core, nicknamed by some astronomers the ring of fire. This ring is hidden from visible light images of the galaxy because it is composed primarily of cold dust, and most of the star formation that is taking place in the Andromeda Galaxy is concentrated there.Later studies with the help of the Spitzer Space Telescope showed how Andromeda Galaxy's spiral structure in the infrared appears to be composed of two spiral arms that emerge from a central bar and continue beyond the large ring mentioned above. Those arms, however, are not continuous and have a segmented structure.Close examination of the inner region of the Andromeda Galaxy with the same telescope also showed a smaller dust ring that is believed to have been caused by the interaction with M32 more than 200  million years ago. Simulations show that the smaller galaxy passed through the disk of the Andromeda Galaxy along the latter's polar axis. This collision stripped more than half the mass from the smaller M32 and created the ring structures in Andromeda.
qas: question: zh_tw: 什麼星系可以改變形狀？
en: What galaxy could be changing shapes?
answers: zh_tw: text: 仙女座星系
en: text: Andromeda Galaxy