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Galilean Moons
The Galilean moons (), or Galilean satellites, are the four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto. They were first seen by Galileo Galilei in December 1609 or January 1610, and recognized by him as satellites of Jupiter in March 1610. They were the first objects found to orbit a planet other than the Earth. They are among the largest objects in the Solar System with the exception of the Sun and the eight planets, with a radius larger than any of the dwarf planets. Ganymede is the largest moon in the Solar System, and is even bigger than the planet Mercury, though only around half as massive. The three inner moons— Io, Europa, and Ganymede—are in a 4:2:1 orbital resonance with each other. While the Galilean moons are spherical, all of Jupiter's much smaller remaining moons have irregular forms because of their weaker self-gravitation. The Galilean moons were observed in either 1609 or 1610 when Galileo made improvements to his telescope, which ena ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geocentric Model
In astronomy, the geocentric model (also known as geocentrism, often exemplified specifically by the Ptolemaic system) is a superseded description of the Universe with Earth at the center. Under most geocentric models, the Sun, Moon, stars, and planets all orbit Earth. The geocentric model was the predominant description of the cosmos in many European ancient civilizations, such as those of Aristotle in Classical Greece and Ptolemy in Roman Egypt. Two observations supported the idea that Earth was the center of the Universe: * First, from anywhere on Earth, the Sun appears to revolve around Earth once per day. While the Moon and the planets have their own motions, they also appear to revolve around Earth about once per day. The stars appeared to be fixed on a celestial sphere rotating once each day about an axis through the geographic poles of Earth. * Second, Earth seems to be unmoving from the perspective of an earthbound observer; it feels solid, stable, and stationary. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gan De
Gan De (; fl. 4th century BC), also known as the Lord Gan (Gan Gong), was an ancient Chinese astronomer and astrologer born in the State of Qi. Along with Shi Shen, he is believed to be the first in history known by name to compile a star catalogue, preceded by the anonymous authors of the early Babylonian star catalogues and followed by the Greek Hipparchus who is the first known in the Western tradition of Hellenistic astronomy to have compiled a star catalogue. He also made observations of the planets, particularly Jupiter. His writings are lost, but some of his works' titles and fragments quoted from them are known from later texts. Gan De may have been the first to describe one of the Galilean moons of Jupiter, usually invisible without the aid of telescopes. In the 20th century, a fragment of Gan's work, in a later compilation of astronomical texts, was identified by Xi Zezong as describing a naked-eye observation of either of the two largest and brightest moons, Ganymede ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xi Zezong
Xi Zezong (June 6, 1927, Yuanqu, Shanxi – December 27, 2008, Beijing) was a Chinese astronomer, historian, and translator. He was a member of the Chinese Academy of Sciences, and an awardee of the Astronomy Prize. He identified a possible reference to one of the Galilean moons of Jupiter in the fragmentary ancient works of the 4th-century BC Chinese astronomer Gan De, who may have made observation of either Ganymede or Callisto in summer 365. Honors Asteroid 85472 Xizezong, discovered by the Beijing Schmidt CCD Asteroid Program in 1997, was named in his honor. The official was published by the Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function ... on April 2, 2007 (). References External links 85472 Xizezong JPL Small-Body Database Browser {{DEFAU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copernican Heliocentrism
Copernican heliocentrism is the astronomical model developed by Nicolaus Copernicus and published in 1543. This model positioned the Sun at the center of the Universe, motionless, with Earth and the other planets orbiting around it in circular paths, modified by epicycles, and at uniform speeds. The Copernican model displaced the geocentric model of Ptolemy that had prevailed for centuries, which had placed Earth at the center of the Universe. Although he had circulated an outline of his own heliocentric theory to colleagues sometime before 1514, he did not decide to publish it until he was urged to do so later by his pupil Rheticus. Copernicus's challenge was to present a practical alternative to the Ptolemaic model by more elegantly and accurately determining the length of a solar year while preserving the metaphysical implications of a mathematically ordered cosmos. Thus, his heliocentric model retained several of the Ptolemaic elements, causing inaccuracies, such as the pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rice University
William Marsh Rice University (Rice University) is a Private university, private research university in Houston, Houston, Texas. It is on a 300-acre campus near the Houston Museum District and adjacent to the Texas Medical Center. Rice is ranked among the top universities in the United States. Opened in 1912 as the Rice Institute after the murder of its namesake William Marsh Rice, Rice is a research university with an undergraduate focus. Its emphasis on undergraduate education is demonstrated by its 6:1 student-faculty ratio. The university has a Research I university, very high level of research activity, with $156 million in sponsored research funding in 2019. Rice is noted for its applied science programs in the fields of artificial heart research, structural chemical analysis, signal processing, space science, and nanotechnology. Rice has been a member of the Association of American Universities since 1985 and is Carnegie Classification of Institutions of Higher Education ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celestial Spheres
The celestial spheres, or celestial orbs, were the fundamental entities of the cosmology, cosmological models developed by Plato, Eudoxus of Cnidus, Eudoxus, Aristotle, Ptolemy, Copernicus, and others. In these celestial models, the diurnal motion, apparent motions of the fixed stars and classical planet, planets are accounted for by treating them as embedded in rotating spheres made of an aetherial, transparent fifth element (aether (classical element), quintessence), like jewels set in orbs. Since it was believed that the fixed stars did not change their positions relative to one another, it was argued that they must be on the surface of a single starry sphere. In modern thought, the Orbit#Planetary orbits, orbits of the planets are viewed as the paths of those planets through mostly empty space. Ancient and medieval thinkers, however, considered the celestial orbs to be thick spheres of rarefied matter nested one within the other, each one in complete contact with the spher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sidereus Nuncius
''Sidereus Nuncius'' (usually ''Sidereal Messenger'', also ''Starry Messenger'' or ''Sidereal Message'') is a short astronomical treatise (or ''pamphlet'') published in New Latin by Galileo Galilei on March 13, 1610. It was the first published scientific work based on observations made through a telescope, and it contains the results of Galileo's early observations of the imperfect and mountainous Moon, the hundreds of stars that were unable to be seen in either the Milky Way or certain constellations with the naked eye, and the Medicean Stars (later Galilean moons) that appeared to be circling Jupiter.Raphael, Renée. ''Sidereus nuncius; or, A Sidereal Message, by Galileo Galilei''. Isis, Vol. 101, No. 3 (September 2010), pp. 644-645. Published by: The University of Chicago Press on behalf of The History of Science Society. The Latin word ''nuncius'' was typically used during this time period to denote ''messenger''; however, it was also (though less frequently) rendered as '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galileo
Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642) was an Italian astronomer, physicist and engineer, sometimes described as a polymath. Commonly referred to as Galileo, his name was pronounced (, ). He was born in the city of Pisa, then part of the Duchy of Florence. Galileo has been called the "father" of observational astronomy, modern physics, the scientific method, and modern science. Galileo studied speed and velocity, gravity and free fall, the principle of relativity, inertia, projectile motion and also worked in applied science and technology, describing the properties of pendulums and "hydrostatic balances". He invented the thermoscope and various military compasses, and used the telescope for scientific observations of celestial objects. His contributions to observational astronomy include telescopic confirmation of the phases of Venus, observation of the four largest satellites of Jupiter, observation of Saturn's rings, and an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amalthea (moon)
Amalthea is a moons of Jupiter, moon of Jupiter. It has the third closest orbit around Jupiter among known moons and was the fifth moon of Jupiter to be discovered, so it is also known as . It is also the fifth largest moon of Jupiter, after the four Galilean Moons. Edward Emerson Barnard discovered the moon on 9 September 1892 and named it after Amalthea (mythology), Amalthea of Greek mythology. It was the last natural satellite to be discovered by direct visual observation; all later moons were discovered by astronomical photography, photographic or digital imaging. Amalthea is in a close orbit around Jupiter and is within the outer edge of the Rings of Jupiter#Amalthea gossamer ring, Amalthea Gossamer Ring which is formed from dust ejected from its surface. Jupiter would appear 46.5 degrees in diameter from its surface. Amalthea is the largest of the inner satellites of Jupiter and is irregularly shaped and reddish in color. It is thought to consist of porous water ice with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johannes Kepler
Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws of planetary motion, and his books ''Astronomia nova'', ''Harmonice Mundi'', and ''Epitome Astronomiae Copernicanae''. These works also provided one of the foundations for Newton's theory of universal gravitation. Kepler was a mathematics teacher at a seminary school in Graz, where he became an associate of Prince Hans Ulrich von Eggenberg. Later he became an assistant to the astronomer Tycho Brahe in Prague, and eventually the imperial mathematician to Emperor Rudolf II and his two successors Matthias and Ferdinand II. He also taught mathematics in Linz, and was an adviser to General Wallenstein. Additionally, he did fundamental work in the field of optics, invented an improved version of the refracting (or Keplerian) telescope, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
