Gan De (Chinese: 甘德; Wade-Giles: Kan Te, fl. 4th century BC) was a Chinese astronomer born in the State of Qi ^[1] also known as the Lord Gan (Gan Gong). Wade-Giles, sometimes abbreviated Wade, is a Romanization (phonetic notation and transliteration) system for the Chinese language based on Mandarin. ... (2nd millennium BC - 1st millennium BC - 1st millennium) The 4th century BC started on January 1, 400 BC and ended on December 31, 301 BC. // Overview Events Bust of Alexander the Great in the British Museum. ... An astronomer or astrophysicist is a person whose area of interest is astronomy or astrophysics. ... State of Qi (small seal script, 220 BC) See Qi (disambiguation) for other meanings of Qi. Qi (齊; pinyin: qi2) was a relatively powerful state during the Spring and Autumn Period and Period of the Warring States. ...

We know of two books which he wrote, namely, the Treatise on Jupiter and the 8-volumes Treatise on Astronomical Astrology ^[2], both of which have been lost. It can be seen on the quotations under Shiji (volume 27) and Hanshu (volume 26), but was preserved mostly in the Treatise on Astrology of the Kaiyuan Era ^[3]. In 1973, a similar catalogue by him and Shi Shen was uncovered in Mawangdui and was arranged under the name of Divination of Five Planets, it records the motion of Jupiter, Saturn, Venus and other planets in their orbits between 246 BC and 177 BC. The Records of the Grand Historian or the Records of the Grand Historian of China was the magnum opus of Sima Qian, in which he recounted Chinese history from the time of the mythical Yellow Emperor until his own time. ... The Book of Han (Ch: 漢書, Hanshu) is a classic Chinese historical writing covering the history of the Western Han Dynasty (206 BCE-9 CE). ... The Treatise on Astrology of the Kaiyuan Era (Chinese: ; pinyin: ), also known as the Great Tang Treatise on Astrology of the Kaiyuan Era in the full title, is a Chinese astrology encyclopedia compiled by the lead editor Gautama Siddha and a numerous of scholars from 714 to 724 during the... The Mawangdui Silk Texts (Chinese: ; pinyin: Mawangdui Boshu) are texts of Chinese philosophical and medical works written on silk and found at Mawangdui in China in 1973. ... Centuries: 4th century BC - 3rd century BC - 2nd century BC Decades: 290s BC 280s BC 270s BC 260s BC 250s BC - 240s BC - 230s BC 220s BC 210s BC 200s BC 190s BC Years: 251 BC 250 BC 249 BC 248 BC 247 BC - 246 BC - 245 BC 244 BC... Centuries: 3rd century BC - 2nd century BC - 1st century BC Decades: 220s BC 210s BC 200s BC 190s BC 180s BC - 170s BC - 150s BC140s BC 130s BC 120s BC 110s BC Years: 182 BC 181 BC 180 BC 179 BC 178 BC - 177 BC - 176 BC 175 BC 174...

He is reported to have seen one of the moons of Jupiter (possibly Ganymede) with his naked eye in 364 BC, long before Galileo Galilei's celebrated discovery of the same in 1610 (all four of the brightest moons are technically visible to the unaided eye, but in practice are normally hidden by the glare of Jupiter). By hiding Jupiter itself behind a high tree limb perpendicular to the satellites' orbital plane, one or more of the Galileans can be spotted in favorable conditions. Some of Jupiters moons and their highly inclined orbits Jupiter has 63 known natural satellites. ... Atmospheric characteristics Atmospheric pressure trace Oxygen 100% Ganymede (gan-ə-meed, IPA: ; Greek Γανυμήδης) is Jupiters largest moon, and indeed the largest moon in the entire solar system; it is larger in diameter than Mercury but only about half its mass. ... Centuries: 5th century BC - 4th century BC - 3rd century BC Decades: 410s BC 400s BC 390s BC 380s BC 370s BC - 360s BC - 350s BC 340s BC 330s BC 320s BC 310s BC 369 BC 368 BC 367 BC 366 BC 365 BC - 364 BC - 363 BC 362 BC 361... Galileo Galilei (15 February 1564 – 8 January 1642) was an Italian physicist, astronomer, and philosopher who is closely associated with the scientific revolution. ... // Events January 7 - Galileo Galilei discovers the Galilean moons of Jupiter. ...

Footnotes

The Records of the Grand Historian or the Records of the Grand Historian of China was the magnum opus of Sima Qian, in which he recounted Chinese history from the time of the mythical Yellow Emperor until his own time. ... State of Qi (small seal script, 220 BC) See Qi (disambiguation) for other meanings of Qi. Qi (齊; pinyin: qi2) was a relatively powerful state during the Spring and Autumn Period and Period of the Warring States. ... As a means of recording the passage of time, the 4th century was that century which lasted from 301 to 400. ... Lu (Chinese: 魯國; pinyin: ) was an ancient state in China during the Spring and Autumn Period. ... Europe in 450 The 5th century is the period from 401 - 500 in accordance with the Julian calendar in the Christian Era. ... State of Chu (small seal script, 220 BC) Chu (楚), originally known as Jing (荆) and then Jingchu (荆楚), was an independent state that existed during Chinas Spring and Autumn period and, subsequently, the Warring States period. ... Shi Shen (Chinese: ; Wade-Giles: Shih Shen, fl. ... The Song Dynasty (Chinese: ) was a ruling dynasty in China from 960-1279. ...

References

• Du Shiran et al (1992). Biographies of Ancient Chinese Scientists Series One: Gan De. Beijing: Kexue Chubanshe, 25-27. ISBN 7-03-002926-7.
• Ma Linghong (2002). Discoveries and Studies on the Bamboo and Silk Texts. Shanghai: Shanghai Shudian Chubanshe, 56-58. ISBN 7-80622-944-2.
• Gu Jianqing et al (1991). Great Lexicon on Chinese Arts of Necromancy. Guangzhou: Zhongshan University Press, 648. ISBN 7-306-00313-5.
• X. Zezong, The Discovery of Jupiter's Satellite Made by Gan De 2000 years Before Galileo, Chinese Physics 2 (3) (1982): 664-667.
• Sky and Telescope, February , 1981.