天文學入門.

Presentation on theme: "天文學入門."— Presentation transcript:

1 天文學入門

2 冬季的銀河

3 星空之美 謝恩 我們的銀河系, 直徑十萬光年

4 斗轉星移 example

5 天球----是天旋還是地轉﹖ Celestial sphere north celestial pole
south celestial pole latitude = angle east rise, west set 地平 horizon polar star path of the star circumpolar star

6 22.3o 22.3o Latitude=22.3o N 香港 地平線 北極 赤道
Latitude = angle of elevation of the polaris

7 In north hemisphere 3 views: North East South

8 肉眼可見恆星6000顆 星座88個 北天多神話主角及動物 南天多船上儀器

9 星星是太陽? 太陽是星星? 星座是由不同遠近及亮度的恆星組成 由幾光年至幾千光年遠 肉眼看到的叫目視星等, 織女星為0等. 太陽為-27等, 月亮為-13等 把恆星歸算到32.6光年遠所看到的叫絕對星等

10 黃道十三宮? 你信星座決定命運嗎﹖ Motion of the sun zodiac
constellation resp. to the season 你信星座決定命運嗎﹖

11 星相學星座和天文學星座的對照表 黃道星座 星相學 天文學 (2000) 實際天數 摩羯座 (Capricornus) 12.22 ~ 1.21 1.21 ~ 2.16 26 寶瓶座 (Aquarius) 1.22 ~ 2.21 2.16 ~ 3.11 24 雙魚座 (Pisces) 2.22 ~ 3.21 3.11 ~ 4.18 38 白羊座 (Aries) 3.22 ~ 4.21 4.18 ~ 5.13 25 金牛座 (Taurus) 4.22 ~ 5.21 5.13 ~ 6.22 40 雙子座 (Gemini) 5.22 ~ 6.21 6.22 ~ 7.21 29 巨蟹座 (Cancer) 7.21 ~ 8.10 20 獅子座 (Leo) 7.22 ~ 8.21 8.10 ~ 9.16 27 室女座 (Virgo) 8.22 ~ 9.21 9.16 ~ 10.31 45 天枰座 (Libra) 9.22 ~ 10.21 10.31 ~ 11.23 23 天蝎座 (Scorpius) 10.22 ~ 11.21 11.23 ~ 11.29 6 蛇夫座 (Ophiuchus) - 11.29 ~ 12.18 19 射手座 (Sagittarius) 11.22 ~ 12.21 12.18 ~ 1.21 36

12 從太陽系開始

13 水. 金.地.火. 木. 土 內行星 類地行星

14 天王. 海王. 冥王(陽光到此要5.5時) 外行星 類木行星

15 太陽---地球文明之源 日珥 單色光照片 109地球 6000度C 物質H=71%,He=27% 中心溫度1500萬度 4H->He
E=mc^2 日珥 單色光照片

16 米粒組織 光球層 黑子 4000度 11年周期 Each granule is about 1/10 the size of the Earth and will last about 20 minutes.

17 日珥. 色球層 日冕 日食的成因:三者成一直線, 月球的遠近 種類:日全食. 日環食. 日偏食

18 電漿(等離子體) 磁場匯聚令光球冷郤及下陷,4000度 本影及半影

19 春分 四季的成因地軸傾斜 冬至 夏至 Seasons 秋分

20 水星 Mercury has a thin layer of atmosphere, which is mainly made of sodium and a little helium. The atmospheric pressure is almost zero. The presence of gaseous sodium means that the temperature is high enough that sodium in rock is released. It is expected since Mercury is so near to the Sun. Because the atmosphere is thin, there is a great difference between day and night temperature. One of the most impressive surface features of Mercury is that the surface is full of craters. Most of them have been formed by the impacts of meteorites. Impact craters have some special features, for example, there are some ray systems and central mountains.

21 軌跡: 0.38 AU天文單位 半徑: 2,440 km (0.38地球) 公轉: 88天
公轉: 88天 質量: 3.30e23 kg (0.055地球), 質量太小,引力不能保存大氣 大氣: 無 溫度: 日430度C,夜-173度C 生物: 無 表面: 滿佈隕石坑 No moon

22 VLA甚大天線陣的射電圖 The bottom one is taken by VLA

23 金星的雷達回波照片 For the rotation of Venus, two points should be mentioned. First of all, the rotation of Venus is in anti-sense from most of the other planets (except Uranus). Secondly, the axis of rotation is almost perpendicular to the orbital plane. For Earth, the rotation axis tilts 23.5? As a result, there is no seasonal change in Venus. Venus has a thick atmosphere. The pressure is 90 times that of the Earth. The atmosphere consists of 90% of CO2 , 3% of N2 , and some SO2 . The whole planet is completely covered by clouds made of sulfuric acid (H2SO4). As a result, the rain in Venus is acidic. Due to the presence of so much carbon dioxide in atmosphere, there is a serious green house effect, which traps heat from the Sun. The surface temperature of Venus is very high, almost 500蚓. Moreover, the surface temperature is almost everywhere the same. Acid rain dissolves the carbonate and sulfate in rocks to produce more CO2 and SO2 , leading to further corrosion and green house effect. Unlike Mercury, there are not so many craters. It is due to the protection of the thick atmosphere.

24 軌跡: AU天文單位 半徑: 6,051.8 km (0.95個地球) 自轉: 224天 質量: 4.869e24 kg (0.8個地球) 大氣: 99%二氧化碳 氣壓: 90倍於地球 溫度: 485度C 表面: 熔融的岩漿,大山包

25

26 地球---正處太陽的生命帶

27 軌跡: 1.00 AU 半徑: 6, km 質量: e24 kg 大氣: 78% N2, 21%O2 溫度: -50至50度,水可以液態存在 陽光: 到此要8.35分 核心: 有鐵核外有6000度C的熔岩 外有: 磁場捕捉高能量的大陽及宇宙 射線 大氣頂層有臭氧層吸收紫外光

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29 火星的極冠及顏色變化 直徑=0.5地球 大氣=地球40公里高, 全為CO2, 溫度20到-139度 水份在地底 極冠為干冰
Like Earth, the axis of rotation tilts 24? Hence, there are seasonal changes in Mars. There is a thin layer of atmosphere on Mars. The pressure is only 1% that of Earth. The chemical composition is mainly carbon dioxide (95%) and nitrogen (3%). Clouds can be observed on Mars. Some are white, which is made of water vapor and carbon dioxide. Some clouds are yellowish, which is made of dust. Although the atmosphere consists mainly of carbon dioxide, it is too thin to trap heat. So, the surface temperature varies a lot, from -100蚓 to -10蚓. Moreover, due to the long distance from the Sun, the temperature is quite low on average. The atmospheric chemical composition of Mars and Venus are very similar. Actually, in the early stage of our solar system, the Earth, Venus and Mars atmospheres consisted of the volcanic gases like carbon dioxide and water vapor. It means at that time, there were active volcanos. On Earth, the amount of carbon dioxide is greatly reduced by dissolving in water, by photosynthesis, etc. These processes cannot take place in Venus and Mars. The surface of Mars is red in color. It is because of the rich iron oxide present on the surface. Besides, Mars possesses polar ice caps like Earth. The caps are made of carbon dioxide and water.

30 火星隕石上的細菌﹖ 奧林匹斯火山 水手大峽谷

31 木星 直徑: 11個地球 質量: 319個地球, 密度為1.33, H,He,CH4,CN4 自轉: 9.9小時 公轉:12年(歲星)
Jupiter is the largest and most massive planet in our solar system. It is almost completely made up of gases. The rotation period of Jupiter is about 10 hours, this high velocity makes Jupiter into a flattened shape. The mass of Jupiter is about 300 times that of the Earth, however its density is low. In fact, these are general features of Jupiter-like planets. Jupiter is mainly made of hydrogen, helium, with some methane and ammonia. The pressure is extremely large, over 1000 times than that of the Earth. Because of the great pressure, the core of Jupiter is made of metallic hydrogen. The rapid rotation of such metallic core explains the strong magnetic field of Jupiter. 大紅斑

32 環及極光 紋帶的顏色因上昇及下降氣流有不同溫度, 呈不同顏色 大紅斑已300年

33 艾奧 歐羅巴 木衛 Jupiter has a large number of satellites, including the four Galilean satellites, Io, Europa, Ganymede and Callisto. Io is famous for its active volcanic activity, which emits sulphuric compounds, and has a geologically young surface. Ganymede is the largest satellite in our solar system, where we believe that there are water lakes under the icy surfaces of Europa and Callisto. 伽米德 卡里士多

34 1994年 舒麥加-利維彗星撞木星

35 土星 成份與木星一樣 A=15500km, B=25000km, 卡西尼縫=5000km 光環為4至30cm冰及石所組成
Saturn has a large size and mass, but it has the lowest density among all planets, even lower than the density of water. In fact, Saturn is very similar to Jupiter in many ways, like the high speed rotation, the internal heating mechanism, the atmosphere composition, the presence of metallic hydrogen core and the strong magnetic field, etc. D=9.5地,M=95地, d=0.7 克,每CC 浮於水面, 陽光到此要80分鐘

36 In addition to the 18 named satellites, at least a dozen more have been reported and given provisional designations. Saturn is most famous for its ring system. In close up view, it consists of many thin ringlets. The thickness is about 1km. Actually, the ring is made of tiny dust and ice, size ranging from millimeter to meter. The formation of ring is due to the great tidal force by Saturn, tearing the body into smaller parts. In close look up, there are many gaps between the ringlets, the most obvious one is the Cassini division. For some ringlets, there are two satellites lie inside and outside the ringlet, they are called shepherd satellites, which keep the stability of the ringlet

37 天王星 直徑=4地, 質量=14.6地, 密度=1.24克/CC, 溫度-216 公轉=84年, 自轉軸平衡於黃道面, 有環, 氣體為主
One of the most interesting things about Uranus is that its rotation axis is almost parallel to the orbital plane. It seems to be rolling on the orbital plane. It is blue in color, due to the scattering of blue light by methane. It is similar to Saturn and Jupiter in many respects, like atmosphere composition, the internal heating mechanism, presence of magnetic field, processing many satellites and a ring system, etc. However, unlike Saturn and Jupiter, it has a rocky core and the atmosphere seems to be less dynamic, not much surface features can be observed. 直徑=4地, 質量=14.6地, 密度=1.24克/CC, 溫度-216 公轉=84年, 自轉軸平衡於黃道面, 有環, 氣體為主

38 海王星 Neptune is similar to Uranus in many ways, it has a rocky core, a ring system, many satellites, magnetic field, etc. However, it seems to be more dynamic, its surface has a Great Dark Spot, which is a typhoon similar to the Great Red Spot in Jupiter. It is less persistent, lasted for only 2 years. 直徑=3.9地, 質量= , 公轉=165年, 大氣有閃電

39 冥王星 直徑5.5冥=1地, 是月亮的66%, 溫度=-230度 太陽光到這裡要5.5小時, 查隆(Charon) 為其衛星
Pluto is not classified into either the Earth-like or Jupiter-like due to its special features. Pluto is the smallest major planet in our solar system, its mass is less than 1% of the Earth, and its diameter is about 2300km. Its density is about 2.3 times that of water. Usually, the Jupiter-like planets have density less than 2, while Earth-like planets have density more than 5. The orbit of Pluto is special. It is inclined 17.2?to the ecliptic. Moreover, part of the orbit lies inside Neptune's orbit. As a result, the most distant planet in our solar system is Neptune from 1979 to 1999. Pluto has a weak atmosphere made of nitrogen, its surface is made of nitrogen too. From its density, we know that it is rocky. Pluto has a satellite called Charon. Although Pluto is very small, Charon is relatively very large, its diameter is about 1200km, over one half of Pluto's. Moreover, the time for Charon to go around Pluto is the same as the rotation period of Pluto. As a result, it is a synchronous satellite. That is to say, you always cannot see Charon on half of surface of Pluto, and you can always see it at a fixed position on the sky on the other half of Pluto. It is the only natural synchronous satellite in our solar system. 直徑5.5冥=1地, 是月亮的66%, 溫度=-230度 太陽光到這裡要5.5小時, 查隆(Charon) 為其衛星

40 新太陽系

41 2006年新太陽系行星新定義 1. 行星:a:繞太陽轉, b:質量夠大令本身成球形, c:清除軌道上其他天體, 有8個
2. 矮行星(Dwarf):a: 附合1a及1b的條件,b:不能清除軌道上其他天體,c:不是衛星 代表為穀神星, 冥王星, 查隆(Charon) 及Eris(前名Xena齊娜), 暫時4個,可以幾十個 3. 太陽系小天體(SSSO):不是2及3, 代表為小行星, 海外天體(TNO) 及彗星等

42 冥外行星 UB313

43 Xena齊娜2006年定名為Eris

44 小行星 在火木之間約50萬顆 直徑100公尺到1000公里

45 彗星

46 骯髒的乾冰球

47 流星

48 獅子座流星雨

49 殞石

50 放眼宇宙

51 恆星的產房----星雲 成份: H, He, N, O SiO2, 砂, 石 種類: 發光 吸收(暗黑) 反射

52 因萬有引力作用 星雲會演化成恆星 歷時數千萬至數億年

53 三裂星雲及礁湖星雲 三裂及礁湖

54 鷹狀星雲M16 Daniel Cheung

55 恆星演化

56 恆星的中小學---疏散星團 七姊妹星團 見反射星雲

57 恆星的老人----紅巨星

58 恆星的墓碑---行星狀星雲 介子星雲

59

60 恆星的壯烈死亡--超新星爆炸

61 超新星爆炸的條件----鐵核

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63 恆星狀星雲

64 人類----超新星的孩子

65 恆星的老人院----球狀星團

66 8萬5光年大---我們的銀河系 天鵝臂 英仙臂 棒狀核球 分子雲環 南十字盾牌臂 人馬船底臂

67 宇宙島----星系 仙女座大星系 距離220萬光年 直徑20萬光年

68 旋渦星系的旋臂 成員

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70 全宇宙有二千億個宇宙島---星系 This narrow, deep view of the universe reveals a plethora of galaxies (reaching fainter than 28th magnitude), as seen in visible and infrared light by NASA Hubble Space Telescope. The reddish galaxies are glowing in infrared light, and the bluish galaxies are glowing in visible light. Several distinctive types of galaxies can be seen in these views: blue dwarf galaxies, disk galaxies, and very red elliptical galaxies. A bright, nearby face-on spiral galaxy appears at upper right. Some of the brightest objects in the field are foreground stars in the halo of our own Milky Way galaxy. By combining views in infrared light and visible light astronomers have a better idea of the shapes of galaxies in the remote universe, and of the fraction which are old or dust-obscured at early epochs.

71 黑洞

72 You’re not alone系外行星

73

74 完 讓我們一起探求宇宙的奧秘 及 人類在宇宙中生存的意義