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Universal Rotation Curve
The rotation curve of a disc galaxy (also called a velocity curve) is a plot of the orbital speeds of visible stars or gas in that galaxy versus their radial distance from that galaxy's centre. It is typically rendered graphically as a plot, and the data observed from each side of a spiral galaxy are generally asymmetric, so that data from each side are averaged to create the curve. A significant discrepancy exists between the experimental curves observed, and a curve derived by applying gravity theory to the matter observed in a galaxy. Theories involving dark matter are the main postulated solutions to account for the variance. The rotational/orbital speeds of galaxies/stars do not follow the rules found in other orbital systems such as stars/planets and planets/moons that have most of their mass at the centre. Stars revolve around their galaxy's centre at equal or increasing speed over a large range of distances. In contrast, the orbital velocities of planets in planetary sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotation Curve Of Spiral Galaxy Messier 33 (Triangulum)
Rotation or rotational/rotary motion is the circular movement of an object around a central line, known as an ''axis of rotation''. A plane figure can rotate in either a clockwise or counterclockwise sense around a perpendicular axis intersecting anywhere inside or outside the figure at a ''center of rotation''. A solid figure has an infinite number of possible axes and angles of rotation, including chaotic rotation (between arbitrary orientation (geometry), orientations), in contrast to rotation around a fixed axis, rotation around a axis. The special case of a rotation with an internal axis passing through the body's own center of mass is known as a spin (or ''autorotation''). In that case, the surface intersection of the internal ''spin axis'' can be called a ''pole''; for example, Earth's rotation defines the geographical poles. A rotation around an axis completely external to the moving body is called a revolution (or ''orbit''), e.g. Earth's orbit around the Sun. The en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vesto Slipher
Vesto Melvin Slipher (; November 11, 1875 – November 8, 1969) was an American astronomer who performed the first measurements of radial velocities for galaxies. He was the first to discover that distant galaxies are redshifted, thus providing the first empirical basis for the expansion of the universe. He was also the first to relate these redshifts to velocity. Early life and education Vesto Melvin Slipher was born in Mulberry, Indiana, to Daniel Clark and Hannah App Slipher. He spent his early years working on his family farm in Mulberry. Vesto had a younger brother, Earl C. Slipher, who was also an astronomer at Lowell Observatory. Slipher went to high school in Frankfort, Indiana. He then attended Indiana University Bloomington and earned his Bachelor's Degree in Mechanics and Astronomy in June 1901. Two years later, Slipher earned his Master's Degree in the same program. At the age of 33, Vesto graduated with his Ph.D. in Mechanics and Astronomy from Indiana Universi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnegie Telescope
The Carnegie telescope (i.e. Carnegie double astrograph) is a twin refractor telescope located at Lick Observatory in California, United States. The double telescope's construction began in the 1930s with a grant from the Carnegie institution, although it was not completed until the 1960s when a second lens was added. The telescope is not designed for visual observation, rather it has two lenses used for taking photographs for a specific wavelength recorded on a film emulsion. It was used for photographic sky surveys in the late 20th century, which were successfully completed. The overall goal of the telescope was to study the " problem of galactic rotation and proper motion.. " History The first survey was conducted between 1947 and 1954, using the blue-light corrected lens which was installed in 1946. Lenses: *Ross-Fecker lens added in 1946 **Corrected for blue light *Perkin-Elmer lens added in 1962 **Corrected for yellow light, four elements Description The double telesc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotation Curve (Milky Way)
The rotation curve of a disc galaxy (also called a velocity curve) is a plot of the orbital speeds of visible stars or gas in that galaxy versus their radial distance from that galaxy's centre. It is typically rendered graphically as a plot, and the data observed from each side of a spiral galaxy are generally asymmetric, so that data from each side are averaged to create the curve. A significant discrepancy exists between the experimental curves observed, and a curve derived by applying gravity theory to the matter observed in a galaxy. Theories involving dark matter are the main postulated solutions to account for the variance. The rotational/orbital speeds of galaxies/stars do not follow the rules found in other orbital systems such as stars/planets and planets/moons that have most of their mass at the centre. Stars revolve around their galaxy's centre at equal or increasing speed over a large range of distances. In contrast, the orbital velocities of planets in planetary sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 3115
NGC 3115 (also called the Spindle Galaxy or Caldwell 53) is a field lenticular (S0) galaxy in the constellation Sextans. The galaxy was discovered by William Herschel on February 22, 1787. At about 32 million light-years away from Earth, it is several times bigger than the Milky Way. It is a lenticular (S0) galaxy because it contains a disk and a central bulge of stars, but without a detectable spiral pattern. NGC 3115 is seen almost exactly edge-on, but was nevertheless mis-classified as elliptical. There is some speculation that NGC 3115, in its youth, was a quasar. One supernova has been observed in NGC 3115: SN 1935B (type and mag. unknown). Star formation NGC 3115 has consumed most of the gas of its youthful accretion disk. It has very little gas and dust left that would trigger new star formation. The vast majority of its component stars are very old. Black hole In 1992 John Kormendy of the University of Hawaii and Douglas Richstone of the University of Michigan an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kepler's Laws Of Planetary Motion
In astronomy, Kepler's laws of planetary motion, published by Johannes Kepler in 1609 (except the third law, which was fully published in 1619), describe the orbits of planets around the Sun. These laws replaced circular orbits and epicycles in the heliocentric theory of Nicolaus Copernicus with elliptical orbits and explained how planetary velocities vary. The three laws state that: # The orbit of a planet is an ellipse with the Sun at one of the two foci. # A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. # The square of a planet's orbital period is proportional to the cube of the length of the semi-major axis of its orbit. The elliptical orbits of planets were indicated by calculations of the orbit of Mars. From this, Kepler inferred that other bodies in the Solar System, including those farther away from the Sun, also have elliptical orbits. The second law establishes that when a planet is closer to the Sun, it travels fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangulum Galaxy
The Triangulum Galaxy is a spiral galaxy 2.73 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC 598. With the D25 isophotal diameter of , the Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Andromeda Galaxy and the Milky Way. The galaxy is the second-smallest spiral galaxy in the Local Group after the Large Magellanic Cloud, which is a Magellanic-type spiral galaxy. It is believed to be a satellite of the Andromeda Galaxy or on its rebound into the latter due to their interactions, velocities, and proximity to one another in the night sky. It also has an H II nucleus. Etymology The galaxy gets its name from the constellation Triangulum, where it can be spotted. It is sometimes informally referred to as the " Pinwheel Galaxy" by some astronomy references, in some computerized telescope software, and in some public outreach websites. However, the SIMBAD Astronomical Databa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulletin Of The Astronomical Institutes Of The Netherlands
''Astronomy & Astrophysics (A&A)'' is a monthly peer-reviewed scientific journal covering theoretical, observational, and instrumental astronomy and astrophysics. It is operated by an editorial team under the supervision of a board of directors representing 27 sponsoring countries plus a representative of the European Southern Observatory. The journal is published by EDP Sciences and the current editors-in-chief are Thierry Forveille and João Alves. History Origins ''Astronomy & Astrophysics'' was created as an answer to the publishing situation found in Europe in the 1960s. At that time, multiple journals were being published in several countries around the continent. These journals usually had a limited number of subscribers, and articles were written in languages other than English. They were less widely read than American and British journals and the research they reported had therefore less impact in the community. Starting in 1963, conversations between astronomers from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Telescope
A radio telescope is a specialized antenna (radio), antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency portion of the electromagnetic spectrum, just as optical telescopes are used to make observations in the visible light, visible portion of the spectrum in traditional optical astronomy. Unlike optical telescopes, radio telescopes can be used in the daytime as well as at night. Since astronomical radio sources such as planets, stars, nebulas and galaxy, galaxies are very far away, the radio waves coming from them are extremely weak, so radio telescopes require very large antennas to collect enough radio energy to study them, and extremely sensitive receiving equipment. Radio telescopes are typically large Parabolic antenna, parabolic ("dish") antennas similar to those employed in tracking and communicating with satellites an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwingeloo Radio Observatory
The Dwingeloo Radio Observatory is a single-dish radio telescope near the village of Dwingeloo () in the northeastern Netherlands. Construction started in 1954, and the telescope was completed in 1956. The radio telescope has a diameter of 25 meters.Monumentnummer: 530829 - radiotelescoop Rijksdienst voor het Cultureel Erfgoed. Retrieved 20 January 2016. At the time of completion it was the largest radio telescope in the world, but it was overtaken in 1957 by the Lovell Telescope. As of 2000, it was no longer in operation in an official capacity. Since August 2009, the radio telescope has been a national heritage site (''rijksmonument''). The telescope dish was removed for restoration in June 2012. The "Christiaan Alexander Muller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lick Observatory Bulletin
The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The observatory is managed by the University of California Observatories, with headquarters on the University of California, Santa Cruz campus, where its scientific staff moved in the mid-1960s. It is named after James Lick. The first new moon of Jupiter to be identified since the time of Galileo, Amalthea, the planet's fifth moon, was discovered at this observatory in 1892. Early history Lick Observatory is the world's first permanently occupied mountain-top observatory. The observatory, in a Classical Revival style structure, was constructed between 1876 and 1887, from a bequest from James Lick of $700,000, . Lick, originally a carpenter and piano maker, had arrived from Peru in San Francisco, California, in late 1847; after accruing significant wealth he bega ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horace Babcock
Horace Welcome Babcock (September 13, 1912 – August 29, 2003) was an American astronomer. He was the son of Harold D. Babcock. Career Babcock invented and built several astronomical instruments and was the first to propose adaptive optics in 1953. He specialized in spectroscopy and the study of magnetic fields of stars. He proposed the Babcock Model, a theory for the magnetism of sunspots. During World War II, he was engaged in radiation work at MIT and Caltech. After the war, he began a productive collaboration with his father. His undergraduate studies were at Caltech, and his doctorate was from the University of California, Berkeley. Babcock's 1938 doctoral thesis contained one of the earliest discoveries of dark matter. He reported measurements of the rotation curve for the Andromeda galaxy (M31) and wrote, "The velocities therefore indicate a greater mass than that derived from the luminosity. This discrepancy can hardly be explained unless we postulate either a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
