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再見 「九大行星」. 張師良 可觀自然教育中心暨天文館. Credit: ESO. Pluto 冥王星. (1930 – 2006). Credit: A. Stern(SwRI), M. Buie(Lowell Obs.), NASA, ESA. Credit: KAGAYA. What is a “planet”? 甚麼是「行星」?. Credit: NASA. This?. This?. This?. This?. Dec 29, 2000. Sept 28, 2000. Credit: Jerry Lodriguss.
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再見 「九大行星」 張師良 可觀自然教育中心暨天文館 Credit: ESO
Pluto 冥王星 (1930 – 2006) Credit: A. Stern(SwRI), M. Buie(Lowell Obs.), NASA, ESA
What is a “planet”? 甚麼是「行星」? Credit: NASA
This? This? This? This?
Dec 29, 2000 Sept 28, 2000 Credit: Jerry Lodriguss Credit: Akira Fujii
金星軌跡 Path of Venus 2004 English “Planet” = wanderer 中文 「行星」 日本語 「惑星」 Credit: Tunc Tezel
Neptune 海王星 Urbain Le Verrier, John Couch Adams, Johann Galle Sept 23, 1846 Uranus 天王星 William Herschel March 13, 1781 Credit: NASA, JPL
Jan 1, 1801 - Ceres 谷神星 Mar 28, 1802 - Pallas 智神星 Sept 1, 1804 - Juno 婚神星 Mar 29, 1807 - Vesta 灶神星 Credit: Scott Hudson
18 Planets 1850 Annual of Scientific Discovery Courtesy : Joe Pollock, Appalachian State University
Asteroid Belt 小行星帶 Credit: NASA
Lowell Observatory 羅威爾天文台 Clyde W. Tombaugh 湯博 Credit: Thomas O'Neil Pluto Discovery Plate 冥王星發現底片 Credit: Smithsonian Institution Credit: Lowell Observatory Archives
Blink Comparator 閃視比較儀 Feb 18, 1930 Pluto Discovered!冥王星被發現!
Jupiter-like planets / Jovian planets 類木行星 Giants 巨星 恆星 Star 行星 Planet 太陽 Sun 土星 Saturn 木星Jupiter 冥王星Pluto 天王星Uranus 海王星Neptune 金星Venus 火星Mars 水星Mercury 地球Earth Earth-like planets / Terrestrial planets 類地行星 Rocky planets 固體行星 Credit: Calvin J. Hamilton
Meteoroid 流星體 衛星 Satellite Asteroid 小行星 彗星 Comet Credit: Jerry Lodriguss, JAXA, NASA, JPL, SSI
6.8 light hours 光時 1 AU 50 AU Credit: Addison Wesley
Jun 22, 1978 Charon 冥衛一(查龍) 1205 km Pluto 冥王星 2306 km Credit: Dr. R. Albrecht, ESA/ESO Space Telescope European Coordinating Facility; NASA
彗星之謎 Mysteries of Comets Credit: Shigemi Numazawa
Dusty Planetary Disks Credit: NASA, ESA, and P. Kalas (University of California, Berkeley)
Accretion Disk 吸積盤 Planetesimal 星子 Credit: NASA/JPL-Caltech/T. Pyle (SSC)
Oort Cloud 奧爾特雲 50,000 to 100,000 AU
Kuipler Belt 凱伯帶 Kuiper belt objects (KBOs) Trans-Neptunian Objects (TNOs) ~ 30-50 AU Credit: KAGAYA
1992 QB1 1st KBO Aug 30, 1992 43 AU ? km Credit: Peter Samek, Jane X. Luu, David C. Jewitt
Kuiper Belt Computer Simulation 凱伯帶電腦模擬 Kuiper Belt Objects (KBO) 凱伯帶天體 Credit: Peter Samek
Credit: ESO, ESA, Astrovirtel & G. Hahn (German Aerospace Center, DLR)
The Largest Moons and Smallest Planets Credit: Calvin J. Hamilton
Pluto, a planet? Is? Or Isn't? Credit: Terry E. Smith
Samuel Oschin Telescope Credit: SOT/Caltech
1.2m Telescope Michael E. Brown Credit: Misha Gravenor, Discover Credit: Samuel Oschin Telescope
Jun 4, 2002 Quaoar 夸奧亞 Nov 14, 2003 Sedna 塞德娜 Credit: Michael E. Brown
Jan 5, 2005 2003 UB313 Eris 不和女神星 Credit: Michael E. Brown
2003 UB313 Eris 不和女神星 Keck Observatory Image Hubble Space Telescope Image 2400 km diameter, -240 degree Credit: Keck Observatory, NASA, ESA, and M. Brown (Caltech)
2004 IAU Division III Planetary Systems Sciences 國際天文聯會第三分組 - 行星系統科學組 19 planetary scientists 19 名行星科學家 FAILED 失敗 Credit: NASA, JPL, SSI
Dr. Andre Brahic Dr. Iwan Williams Dr. Junichi Watanabe Dr. Richard Binzel Dr. Catherine Cesarsky Dava Sobel Dr. Owen Gingerich IAU EC Planet Definition Committee 國際天文聯會委員會行星定義小組 2006 Jun Credit: IAU
What is a planet? 甚麼是行星? 機密 Confidential Credit: NASA, JPL, SSI
IAU General Assembly 2006 Prague, Czech Public 國際天文聯會大會 2006 捷克 布拉格 Aug 14 – 25, 2006 Credit: IAU
Option 1: 10 Planets Option 2: 8 Planets Option 3: (a) Not a Star (b) Round Option 4: Subdivide into Rocky Planets, Gas Giants, Ice Dwarfs 估計的可能方案 Possible Resolutions Credit: NASA, ESA and G. Bacon (STScI)
First Draft 第一稿 • A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet. • (2) We distinguish between the eight classical planets discovered before 1900, which move in nearly circular orbits close to the ecliptic plane, and other planetary objects in orbit around the Sun. All of these other objects are smaller than Mercury. We recognize that Ceres is a planet by the above scientific definition. For historical reasons, one may choose to distinguish Ceres from the classical planets by referring to it as a “dwarf planet.” • (3) We recognize Pluto to be a planet by the above scientific definition, as are one or more recently discovered large Trans-Neptunian Objects. In contrast to the classical planets, these objects typically have highly inclined orbits with large eccentricities and orbital periods in excess of 200 years. We designate this category of planetary objects, of which Pluto is the prototype, as a new class that we call “plutons” • (4) All non-planet objects orbiting the Sun shall be referred to collectively as “Small Solar System Bodies”. Credit: IAU
Original New Map of Solar System 原訂新太陽系版圖 天王星 海王星 冥王星 穀神星 水星 金星 地球 火星 木星 土星 查龍 Credit: IAU/Martin Kornmesser