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The Library Of Congress and Dewey Decimal System have a major classification "Descriptive Astronomy" which they use instead of placing descriptive works into their huge "Geography" collections. ASTRONOMY Astronomical Methods See Also: Astronomy Astronomical methods are the equipment and techniques used to collect data about the objects in Space. Galileo's first astronomical method was to find and buy the best telescope of the time and then point that telescope to the heavens. Methods can be categorized according to the wavelength they are attempting to record. Radio Astronomy includes Radio Telescope s; devices that receive and record radio waves from outside the Earth. They record Cosmic Microwave Background Radiation resulting from the Big Bang , Pulsar s and other sources. Optical Astronomy is the oldest kind of astronomy. X-ray observatories include the Chandra X-ray Observatory and others. Gamma Ray includes the Compton Gamma Ray Observatory and others. Neutrino Astronomy observatories have also been built, primarily to study our Sun. Gravitational Wave observatories have been theorized. A Space Telescope is a telescope orbiting or travelling from the Earth, such as the Hubble Space Telescope . RXTE is Long Exposure Time Astronomy used to study Millisecond Pulsar s and Pulsar Deceleration . Spectroscopy Astronomy teaching tools include Planetarium s and others. Further information can be found at Library of Congress Classification QB1-139 General Astronomy (Dewey 520), QB140-237 Practical and spherical astronomy (Dewey 522), (Observatories Dewey 522), QB468-480 Non-optical methods of astronomy Descriptive Astronomy Galileo's second astronomical method was to describe what he saw in the telescope. Descriptive Astronomy is the highest sub-category of Astronomy used by the Library of Congress and Dewey Decimal systems to classify any knowledge related to describing celestial objects. Because we are seeing today portions of the Universe as they actually looked millions or billions of years ago we should have a historical section within Descriptive astronomy: History of The Universe includes the size, shape and structure of the historical universe), '''Cartography of The Historical Universe''', Early Universe and others. '''The Current Universe''' includes size shape and structure of the current Universe, cartography of the current Universe and others. Cartography of Space Bodies. Recording photograhic or similar images of the Earths surface from space is a well developed science, yet still expanding because of advances in the actual resolution of images taken from space or atmosphere and because of advances in digitizing and manipulating the images. Most of these advances are being applied to the cartography of space-located bodies, even though acquiring the original images of those bodies is extremely complicated and expensive, usually requiring long distance probes to carry the cameras. Further information is available at Library of Congress Classification: G3190-3191 Celestial maps. Visible matter in the universe is apparently organized geographically into structures with large amounts of space between them; either the space between planets, the space between stars or the space between galaxies. Even galaxies themselves are not spread uniformly but appear to be located in filaments. Therefore The Universe can be divided geographically into regions that follow this structure The Filaments of Galaxies are the furthest visible structures. Those filaments are made of , M51 , M58 , M59 , M60 , M61 , M63 , M64 , M65 , M66 . National Geographic magazine has produced a very good drawing of this region in its Map of the Universe Supplement, October 1999 issue. Local Group: Our Milky Way Galaxy is one of about 30 galaxies called the Local Group. The Local Group is about 4 million light-years across. In the Local Group our Milky Way Galaxy plays a large gravitational part because our galaxy is the second largest galaxy in our Local Group, second only to the Andromeda Galaxy. All of the other galaxies in our Local Group are gravitationally bound either to the Andromeda Galaxy or to our Milky Way Galaxy. Inside of our local group but outside of our Galaxy are objects 4,000,000 LY to 1,000,000 LY from the Sun: M31 , M32 , M33 . Milky Way Galaxy: Our Milky Way Galaxy is a massive mass-containing structure 100,000 light-years across and 30,000 light-years tall. Most of its billions of suns are organized into approximately 12 structures called "arms". Our Sun is located in what is called the "Orion Arm". The next arm outside of us is called the "Perseus Arm". The Crab Nebula M1 is located in the Perseus Arm. The arm outside of the Perseus Arm is called the Outer Arm. Palomar 1 is located in the Outer Arm. The next arm inside of us is called the Sagittarius Arm. The Ring Nebula M57 and the Carina Nebula (NGC 3372) are located in the Sagittarius Arm. The next arm inside of the Sagittarius Arm is called the Crux Arm. The inner arms are much shorter, obviously from being shifted by gravitational forces. Arms beside each other today may have at an earlier time been one. Orion Arm: The Orion Nebula Nearby-Stars Solar Systems: By measuring the extremely small movements of nearby stars astronomers have been able to prove that there are planets going around these Suns, therefore these suns have become "Solar Systems". Solar System includes Scientific Study of Solar System Planets, Venus , Mercury , Saturn , Jupiter , Uranus , Neptune , Mars , and Moon Further reading can be found in the Library of Congress Classification QB495-903 Descriptive astronomy (Dewey 523) PHYSICS OF THE UNIVERSE / ASTROPHYSICS See Also: Astrophysics After first looking at the planets, then second describing what he saw, Galileo's third astronomical method was to theorize about the reasons for what he saw in the telescope, specifically to theorize that the Earth goes around the Sun. The Physics of the Universe can be divided into several broad categories: Astrophysical Theory includes General Relativity and others. Astrophysical Processes includes Baryon ic and others. Physical Processes, General includes Mechanics , Electromagnetism , Electromagnetic Force s, Statistical Mechanics , Thermodynamics , Quantum Mechanics , Relativity , Gravity and others. Origins Of The Universe Universe Theories of the Origins of the Universe, Big Bang Theory , Early Universe, Evidence, Cosmic Microwave Background , Dark Ages, '''Interstellar Medium ''', Voids , Filaments of Galaxies , Galaxy Cluster s and others. Astrophysical Plasma includes Plasma and ''quasineutrality'' and others. Cosmic Plasmas Between Stars, (Diffuse Plasmas) includes Intergalactic Space , Intergalactic Medium , Interstellar Medium , Interplanetary Medium , Interstellar Space , Heliospheric Current Sheet , Interplanetary Medium , Solar Wind and others. Cosmic Plasmas Inside Stars, (Dense Plasma) includes Stars , Plasma Physicists , Active Galactic Nuclei , Fusion Power , Magnetohydrodynamic , X-ray s , Bremsstrahlung , Cosmology , Reionized , Ambipolar Diffusion , Particle Physics and others. Further information can be found at Library of Congress Classification QB460-466 Astrophysics, QB349-421 Theoretical astronomy and celestial mechanics, and QB980-991 Cosmogony. Cosmology (PHYSICAL COSMOLOGY ONLY), (Dewey "Theoretical Astronomy" 521) COSMOLOGY See Also: Galaxy Physics can explain the underlying physical science of any galaxy, yet many aspects of galaxies are not best described through their physics. Galactic physical science is the general term for all physical sciences that can be applied to any galaxy in the Universe or to a particular galaxy. Galaxy Formation and Evolution includes Galaxies , Elliptical Galaxies Giant Galaxies, '''Spiral Galaxies''', M31 The Andromeda Galaxy and others. Intra-Galaxy Processes, General includes Black Hole , Globular Cluster s, Satellite Galaxy, Retrograde Rotation , Halo Star s, High Velocity Cloud s, Monoceros Ring , '''accretion disc''', Gravitation , Angular Momentum , Centripetal Force , Tidal Effects , Viscosity , Orbit al momentum, Accretion Disk , Active Galactic Nuclei , Protoplanetary Disc s, Gamma Ray Burst s and others. Milky Way Galactic Physical Science is the overall science containing all the physical sciences related directly to the Milky Way Galaxy: Halo Star s, Milky Way High Velocity Cloud s, Milky Way Monoceros Ring , Milky Way '''accretion disc''', Milky Way Gravitation , Milky Way Angular Momentum , Milky Way Centripetal Force , Milky Way Tidal Effects , Milky Way Viscosity , Milky Way Orbit al momentum, Milky Way Event Horizon , Milky Way Black Hole and others. STELLAR SCIENCE Physics is the underlying physical science of any star, yet many aspects of stars are not best described through their physics. Stellar science is the general term for ALL physical sciences that can be applied to any star in the Universe or to a particular star. '''Solar science of the Sun''' Sun is the overall science containing all of the physical sciences related directly to our local Sun. Stellar-Processes, General Stellar Dynamics , Star s, Stellar Evolution , Event Horizon , Black Hole , X-ray s, Nuclear Fusion and others. In Astronomy , '''stellar evolution''' is the sequence of changes that a Star undergoes during its lifetime; the hundreds of thousands, millions or billions of years during which it emits light and heat. Over the course of that time, the star will change radically. Stellar evolution is not studied by Observing the life cycle of a single star—most stellar changes occur too slowly to be detected even over many centuries. Instead, Astrophysicists come to understand how stars evolve by observing numerous stars, each at a different point in its life cycle, and simulating Stellar Structure with Computer Model s. Birth of stars is discussed in ''Main article: Star Formation '' Stellar evolution begins with a s across. Very small protostars never reach temperatures high enough for Nuclear Fusion of hydrogen to begin; these are Brown Dwarf s of less than 0.1 solar mass. Brown dwarfs heavier than 13 Jupiter masses () do fuse Deuterium , and some astronomers prefer to call only these objects brown dwarfs, classifying anything larger than a planet but smaller than this a sub-stellar object. Both types, deuterium-burning or not, shine dimly and die away slowly, cooling gradually over hundreds of millions of years. The central temperature in more massive protostars, however, will eventually reach 10 Megakelvin s, at which point Hydrogen begins to fuse by way of the Proton-proton Chain Reaction to deuterium and then to Helium . The onset of nuclear fusion leads over a relatively short time to a Hydrostatic Equilibrium in which energy released by the core prevents further gravitational collapse. The star thus evolves rapidly to a stable state. New stars come in a variety of sizes and colors. They range in Spectral Type from hot and blue to cool and red, and in mass from less than 0.5 to more than 20 solar masses. The brightness and color of a star depend on its surface temperature, which in turn depends on its mass. A new star will fall at a specific point on the Main Sequence of the Hertzsprung-Russell Diagram . Small, cool Red Dwarf s burn hydrogen slowly and may remain on the main sequence for hundreds of billions of years, while massive hot Supergiant s will leave the main sequence after just a few million years. A mid-sized star like the Sun will remain on the main sequence for about 10 billion years. The Sun is thought to be in the middle of its lifespan; thus, it is on the main sequence. Once a star expends most of the Hydrogen in its core, it moves off the main sequence. MaturityAfter millions to billions of years, depending on its initial mass, the continuous fusion of hydrogen into helium will cause a build-up of helium in the core. The later years and death of stars: Low-mass star Some stars may fuse helium in core hot-spots, causing an unstable and uneven reaction as well as a heavy Solar Wind . In this case, the star will form no Planetary Nebula but simply evaporate, leaving little more than a Brown Dwarf . But a star of less than about 0.5 solar mass will never be able to fuse helium even after the core ceases hydrogen fusion. There simply is not a stellar envelope massive enough to bear down enough pressure on the core. These are the Red Dwarf s, such as Proxima Centauri , some of which will live thousands of times longer than the Sun. Recent astrophysical models suggest that red dwarfs of 0.1 solar masses may stay on the main sequence for almost six trillion years, and take several hundred billion more to slowly collapse into a White Dwarf . (S&T, 22) Mid-sized stars Once a medium-size star (between 0.4 and 3.4 solar masses) has reached the Red Giant phase, its outer layers continue to expand, the core contracts inward, and helium begins to fuse into carbon. In stars of less than 1.4 solar masses, the helium fusion process begins with an explosive burst of energy generation known as a Helium Flash .1 Helium burning reactions are extremely sensitive to temperature, which causes great instability. Huge pulsations build up, which eventually give the outer layers of the star enough Kinetic Energy to be ejected as a Planetary Nebula . At the center of the nebula remains the core of the star, which cools down to become a small but dense White Dwarf , typically weighing about 0.6 solar masses, but only the volume of the Earth. White dwarfs ''Main article: White Dwarf s'' White dwarfs are stable because the inward pull of gravity is balanced by the Degeneracy Pressure of the star's electrons. (This is a consequence of the Pauli Exclusion Principle .) With no fuel left to burn, the star radiates its remaining heat into space for thousands of millions of years. In the end, all that remains is a cold dark mass sometimes called a Black Dwarf . However, the universe is not old enough for any black dwarf stars to exist. Supermassive stars After the outer layers of a star greater than five solar masses have swollen into a gigantic red Supergiant , the core begins to yield to gravity and starts to shrink. As it shrinks, it grows hotter and denser, and a new series of nuclear reactions begin to occur. These reactions fuse progressively heavier elements, temporarily halting the collapse of the core. Neutron stars ''Main article: Neutron Star '' It is known that in some supernovae, the intense gravity inside the supergiant forces the Electron s into the atomic nuclei, where they combine with the Proton s to form Neutron s. The electromagnetic forces keeping separate nuclei apart are gone (proportionally, if nuclei were the size of dust motes, atoms would be as large as football stadiums), and the entire core of the star becomes nothing but a dense ball of contiguous neutrons or a single atomic nucleus. Black holes ''Main article: Black Hole s'' It is widely believed that not all supernovae form neutron stars. If the stellar mass is high enough, the neutrons themselves will be crushed and the star will collapse until its radius is smaller than the Schwarzschild Radius . The star has then become a black hole. NON-EARTH PLANETARY SCIENCE Planetary Processes, General includes Planetary Science , Planets , Comets , Asteroid s and others. Geophysics is the study of the ( Earthquake s and elastic Wave s), planetary gravity, Geodesy , Tectonophysics (geological processes in the planets), Mineral Physics and others. Geophysics can be both a part of physics and a part of Geology. Geodesy of The Solar System, also called '''geodetics''' of the solar system, is the scientific discipline that deals with the measurement and representation of the planets of the Solar System, their Gravitation al fields and geodynamic phenomena ( Polar Motion in three-dimensional, time-varying space. The science of geodesy has elements of both astrophysics and planetary sciences. The shape of the Earth is to a large extent the result of its rotation, which causes its equatorial bulge, and the competition of geologic processes such as the collision of plates and of Vulcanism , resisted by the Earth's Gravity field. These principles can be applied to the solid surface of Earth ( Orogeny ; Few mountains are higher than 10 km, few deep sea trenches deeper than that because quite simply, a mountain as tall as, for example, 15 km, would develop so much Pressure at its base, due to gravity, that the rock there would become Plastic , and the mountain would slump back to a height of roughly 10 km in a geologically insignificant time. Some or all of these geologic principles can be applied to other planets besides Earth. For instance on Mars, whose surface gravity is much less, the largest volcano, Olympus Mons , is 27 km high at its peak, a height that could not be maintained on Earth. The Earth Geoid is essentially the figure of the Earth abstracted from its topographic features. Therefore the Mars geoid is essentially the figure of Mars abstracted from its topographic features. Surveying and Mapping are two important fields of application of geodesy. Physics is the underlying physical science of any planet, yet many aspects of planets are not best described through their physics. Planetary science is the general term for ALL physical sciences that can be applied to planets in the Universe or else to a particular planet. '''Planetary science of the Earth''' is the overall physical science containing all the physical sciences related directly to our Earth. Planetary Science can be broadly divided into several major sciences: Geology, Oceanography and Atmospheres. Geology of Other Planets , Geomorphology ., Economic Geology , Mining Geology , Geodetics , Geomorphology , Geophysics , Historical Geology , Hydrogeology or Geohydrology , Mineralogy , Paleoclimatology , Sedimentology , Seismology , Stratigraphy , Structural Geology , Volcanology ,'''Hydrology'''. Geothermometry (heating of the earth, heat flow, Volcano logy, and hot springs), Hydrology (ground and surface water, sometimes including Glaciology ). Regional planetary geology contains Geology Of Mercury , Geology Of Venus , Geology Of The Moon Geology Of Mars , Geology Of Jupiter , Geology Of Saturn , Geology Of Uranus Geology Of Neptune , Geology Of Pluto Atmosphere of Other Planets / Extrasolar Atmosphere refers to the application of meteorological principles to other bodies of the solar system including the application of: Great Red Spot Great Red Spot http://www2.jpl.nasa.gov/galileo/mess44/promysso.html, Atmosphere on Jupiters-Moons , '''Atmosphere on Saturn''' http://www.nasm.si.edu/ceps/rpif/saturn/saturn.html http://www.physics.purdue.edu/astr263l/SStour/saturn.html http://www.abc.net.au/science/news/stories/s872839.htm. '''Atmosphere on Urnaus''' http://www.physics.purdue.edu/astr263l/SStour/uranus.html EXOBIOLOGY / EXTRATERRESTRIAL LIFE Earth telescopes can resolve some surface features of the nearby planets and so far, no life can be seen through the telescopes. However Earth telescopes cannot resolve the surface features of any planet outside the solar system, so the search for life on other planets continues. While no incontestable evidence has been found for life outside of Earth, the scientific study of the theoretical basis for life on other bodies is progressing. Some scientists are trying to theorize which kinds of stars would have planets that hold life. Because life has overall fragile parameters for survival the general consensus is that only older stars would have planets circling them with life. From this they theorize which sections of our Milky Way Galaxy would most likely hold life. Other scientists theorize the quantity of civilizations that might exist in a galaxy and others are actually listening for the possible radio chatter of extraterrestrial technical civilizations. These sub-sciences of exobilogy can be categorized as follows: Habitable Zone Astrobiology is discussed in Galactic Habitable Zone and Solar System Habitable Zone . Astrobiochemistry Exogenesis Most scientists hold that if extraterrestrial life exists, its Evolution would have occurred independently in different places in the Universe . An alternative hypothesis, held by a minority, is Panspermia , which suggests that life in the universe could have stemmed from a smaller number of points of origin, and then spread across the universe, from Habitable Planet to habitable planet. These two hypotheses are not Mutually Exclusive . Alternative biochemistry includes '''Alternative Carbon Biochemistry''' where water is not the Solvent of Carbon Chains: Life forms based in Ammonia rather than water are also considered, though this solution appears less optimal than water. http://www.daviddarling.info/encyclopedia/A/ammonialife.html daviddarling.info ''Ammonia based life''] Also included is Alternative Non-Carbon Biochemistry: Non-carbon based chemistry Silicon is usually considered the most likely alternative to carbon, though this remains improbable. Silicon life forms are proposed to have a crystalline morphology, and are theorized to be able to exist in high temperatures, such as planets closer to the sun. Astrobiosphere is the entire area of a planet that supports life and includes Astronomers also search for Extrasolar planets that would be conducive to life, especially those like OGLE-2005-BLG-390Lb which have been found to have Earth-like qualities. |
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