The Eastern Hemisphere is a geographical term for the half of Earth, east of the prime meridian and west of the antimeridian. It is used to refer to Afro-Eurasia and Australia, in contrast with the Western Hemisphere, which includes North and South America; the Eastern Hemisphere may be called the "Oriental Hemisphere". In addition, it may be used in a cultural or geopolitical sense as a synonym for the "Old World"; the perfect circle, drawn with a line, demarcating the Eastern and Western Hemispheres must be an arbitrarily decided and published convention, unlike the equator, which divides the Northern and Southern Hemispheres. The prime meridian at 0° longitude and the antimeridian, at 180° longitude, are the conventionally accepted boundaries, since they divide eastern longitudes from western longitudes; this convention was established in 1884 at the International Meridian Conference held in Washington, D. C. where the standard time concepts of Canadian railroad engineer Sir Sandford Fleming were adopted.
The Hemispheres agreed. Portions of Western Europe, West Africa and extreme northeastern Russia are in the Western Hemisphere, divorcing it from the continents which form the touchstone for most geopolitical constructs of "the East" and "the West"; the meridians of 20°W and the diametrically opposed 160°E are used outside of matters of physics and navigation, which includes all of the European and African mainlands, but includes a small portion of northeast Greenland and excludes more of eastern Russia and Oceania. Prior to the global adoption of standard time, numerous prime meridians were decreed by various countries where time was defined by local noon; the center of the Eastern Hemisphere is located in the Indian Ocean at the intersection of the equator and the 90th meridian east, 910 km west of Indonesia in the Ninety East Ridge. The nearest land is Simeulue Island at 2°35′N 96°05′E; the land mass of the Eastern Hemisphere is larger than that of the Western Hemisphere and has a wide variety of habitats.
82% of humans live in the Eastern Hemisphere, 18% in the Western Hemisphere. East Antarctica Media related to Eastern Hemisphere at Wikimedia Commons
The Magazine of Fantasy & Science Fiction
The Magazine of Fantasy & Science Fiction is a U. S. fantasy and science fiction magazine first published in 1949 by Fantasy House, a subsidiary of Lawrence Spivak's Mercury Press. Editors Anthony Boucher and J. Francis McComas had approached Spivak in the mid-1940s about creating a fantasy companion to Spivak's existing mystery title, Ellery Queen's Mystery Magazine; the first issue was titled The Magazine of Fantasy, but the decision was made to include science fiction as well as fantasy, the title was changed correspondingly with the second issue. F&SF was quite different in presentation from the existing science fiction magazines of the day, most of which were in pulp format: it had no interior illustrations, no letter column, text in a single column format, which in the opinion of science fiction historian Mike Ashley "set F&SF apart, giving it the air and authority of a superior magazine". F&SF became one of the leading magazines in the science fiction and fantasy field, with a reputation for publishing literary material and including more diverse stories than its competitors.
Well-known stories that appeared in its early years include Richard Matheson's Born of Man and Woman, Ward Moore's Bring the Jubilee, a novel of an alternative history in which the South has won the American Civil War. McComas left for health reasons in 1954, but Boucher continued as sole editor until 1958, winning the Hugo Award for Best Magazine that year, a feat his successor, Robert Mills, repeated in the next two years. Mills was responsible for publishing Flowers for Algernon by Daniel Keyes, Rogue Moon by Algis Budrys, Starship Troopers by Robert Heinlein, the first of Brian Aldiss's Hothouse stories; the first few issues featured cover art by George Salter, Mercury Press's art director, but other artists soon began to appear, including Chesley Bonestell, Kelly Freas, Ed Emshwiller. In 1962, Mills was succeeded as editor by Avram Davidson; when Davidson left at the end of 1964, Joseph Ferman, who had bought the magazine from Spivak in 1954, took over as editor, though his son Edward soon began doing the editorial work under his father's supervision.
At the start of 1966 Edward Ferman was listed as editor, four years he acquired the magazine from his father and moved the editorial offices to his house in Connecticut. Ferman remained editor for over 25 years, published many well-received stories, including Fritz Leiber's Ill Met in Lankhmar, Robert Silverberg's Born with the Dead, Stephen King's The Dark Tower series. In 1991 he turned the editorship over to Kristine Kathryn Rusch, who began including more horror and dark fantasy than had appeared under Ferman. In the mid-1990s circulation began to decline. Gordon Van Gelder replaced Rusch in 1997, bought the magazine from Ferman in 2001, but circulation continued to fall, by 2011 it was below 15,000. Charles Coleman Finlay took over from Van Gelder as editor in 2015; the first magazine dedicated to fantasy, Weird Tales, appeared in 1923. By the end of the 1930s, the genre was flourishing in the United States, nearly twenty new sf and fantasy titles appearing between 1938 and 1941; these were all pulp magazines, which meant that despite the occasional high-quality story, most of the magazines presented badly written fiction and were regarded as trash by many readers.
In 1941, Ellery Queen's Mystery Magazine appeared, edited by Fred Dannay and focusing on detective fiction. The magazine was published in digest format, rather than pulp, printed a mixture of classic stories and fresh material. Dannay attempted to avoid the sensationalist fiction appearing in the pulps, soon made the magazine a success. In the early 1940s Anthony Boucher, a successful writer of fantasy and sf and of mystery stories, got to know Dannay through his work on the Ellery Queen radio show. Boucher knew J. Francis McComas, an editor who shared his interest in fantasy and sf. By 1944 McComas and Boucher became interested in the idea of a fantasy companion to Ellery Queen's Mystery Magazine, spoke to Dannay about it. Dannay was interested in the idea, but paper was scarce because of World War II; the following year Boucher and McComas suggested that the new magazine could use the Ellery Queen name, but Dannay knew little about fantasy and suggested instead that they approach Lawrence Spivak, the owner of Mercury Press, which published Ellery Queen's Mystery Magazine.
In January 1946, Boucher and McComas went to New York and met with Spivak, who let them know in the year that he wanted to go ahead. At Spivak's request they began acquiring material for the new magazine, including a new story by Raymond Chandler, reprint rights to stories by H. P. Lovecraft, John Dickson Carr, Robert Bloch. Spivak planned the first issue for early 1947, but delayed the launch because of poor newsstand sales of digest magazines, he suggested that it should be priced at 35 cents an issue, higher than the original plan, to provide a financial buffer against poor sales. In May 1949 Spivak suggested a new title, The Magazine of Fantasy, in August a press release announced that the magazine would appear in October. On October 6, 1949, Boucher and McComas held a luncheon at the Waldorf-Astoria in New York City to commemorate the 100th anniversary of the death of Edgar Allan Poe and to launch "a new fantasy anthology periodical". Invitees included Carr, Basil Rathbone, Boris Karloff.
The first issue, published by Fantasy House, a subsidiary of American Mercury, sold 57,000 co
A solar flare is a sudden flash of increased brightness on the Sun observed near its surface and in close proximity to a sunspot group. Powerful flares are but not always, accompanied by a coronal mass ejection; the most powerful flares are detectable in the total solar irradiance. Solar flares occur in a power-law spectrum of magnitudes. Flares are associated with the ejection of plasmas and particles through the Sun's corona into outer space. If the ejection is in the direction of the Earth, particles associated with this disturbance can penetrate into the upper atmosphere and cause bright auroras, may disrupt long range radio communication, it takes days for the solar plasma ejecta to reach Earth. Flares occur on other stars, where the term stellar flare applies. High-energy particles, which may be relativistic, can arrive simultaneously with the electromagnetic radiations. On July 23, 2012, a massive damaging, solar storm missed Earth. According to NASA, there may be as much as a 12% chance of a similar event occurring between 2012 and 2022.
Solar flares affect all layers of the solar atmosphere. The plasma medium is heated to tens of millions of kelvins, while electrons and heavier ions are accelerated to near the speed of light. Flares produce electromagnetic radiation across the electromagnetic spectrum at all wavelengths, from radio waves to gamma rays. Most of the energy is spread over frequencies outside the visual range and so the majority of the flares are not visible to the naked eye and must be observed with special instruments. Flares occur in active regions around sunspots, where intense magnetic fields penetrate the photosphere to link the corona to the solar interior. Flares are powered by the sudden release of magnetic energy stored in the corona; the same energy releases may produce coronal mass ejections, although the relationship between CMEs and flares is still not well understood. X-rays and UV radiation emitted by solar flares can affect Earth's ionosphere and disrupt long-range radio communications. Direct radio emission at decimetric wavelengths may disturb the operation of radars and other devices that use those frequencies.
Solar flares were first observed on the Sun by Richard Christopher Carrington and independently by Richard Hodgson in 1859 as localized visible brightenings of small areas within a sunspot group. Stellar flares can be inferred by looking at the lightcurves produced from the telescope or satellite data of variety of other stars; the frequency of occurrence of solar flares varies, from several per day when the Sun is "active" to less than one every week when the Sun is "quiet", following the 11-year cycle. Large flares are less frequent than smaller ones. Flares occur when accelerated charged particles electrons, interact with the plasma medium. Evidence suggests that the phenomenon of magnetic reconnection leads to this copious acceleration of charged particles. On the Sun, magnetic reconnection may happen on solar arcades – a series of occurring loops following magnetic lines of force; these lines of force reconnect into a lower arcade of loops leaving a helix of magnetic field unconnected to the rest of the arcade.
The sudden release of energy in this reconnection is the origin of the particle acceleration. The unconnected magnetic helical field and the material that it contains may violently expand outwards forming a coronal mass ejection; this explains why solar flares erupt from active regions on the Sun where magnetic fields are much stronger. Although there is a general agreement on the source of a flare's energy, the mechanisms involved are still not well understood, it is not clear how the magnetic energy is transformed into the kinetic energy of the particles, nor is it known how some particles can be accelerated to the GeV range and beyond. There are some inconsistencies regarding the total number of accelerated particles, which sometimes seems to be greater than the total number in the coronal loop. Scientists are unable to forecast flares; the classification system for solar flares uses the letters A, B, C, M or X, according to the peak flux in watts per square metre of X-rays with wavelengths 100 to 800 picometre, as measured at the Earth by the GOES spacecraft.
The strength of an event within a class is noted by a numerical suffix ranging from 1 to 9, the factor for that event within the class. Hence, an X2 flare is twice the strength of an X1 flare, an X3 flare is three times as powerful as an X1, only 50% more powerful than an X2. An X2 is four times more powerful than an M5 flare. An earlier flare classification was based on Hα spectral observations; the scheme uses emitting surface. The classification in intensity is qualitative, referring to the flares as: faint, normal or brilliant; the emitting surface is described below. A flare is classified taking S or a number that represents its size and a letter that represents its peak intensity, v.g.: Sn is a normal sunflare. Solar flares influence the local space weather in the vicinity of the Earth, they can produce streams of energetic particles in the solar wind or stellar wind, known as a solar proton event. These particles
Galaxy Science Fiction
Galaxy Science Fiction was an American digest-size science fiction magazine, published from 1950 to 1980. It was founded by a French-Italian company, World Editions, looking to break into the American market. World Editions hired as editor H. L. Gold, who made Galaxy the leading science fiction magazine of its time, focusing on stories about social issues rather than technology. Gold published many notable stories during his tenure, including Ray Bradbury's "The Fireman" expanded as Fahrenheit 451. In 1952, the magazine was acquired by its printer. By the late 1950s, Frederik Pohl was helping Gold with most aspects of the magazine's production; when Gold's health worsened, Pohl took over as editor, starting at the end of 1961, though he had been doing the majority of the production work for some time. Under Pohl Galaxy had continued success publishing fiction by writers such as Cordwainer Smith, Jack Vance, Harlan Ellison, Robert Silverberg. Pohl never won the annual Hugo Award for his stewardship of Galaxy, winning three Hugos instead for its sister magazine, If.
In 1969 Guinn sold Galaxy to Universal Publishing and Distribution Corporation and Pohl resigned, to be replaced by Ejler Jakobsson. Under Jakobsson the magazine declined in quality, it recovered under James Baen, who took over in mid-1974, but when he left at the end of 1977 the deterioration resumed, there were financial problems—writers were not paid on time and the schedule became erratic. By the end of the 1970s the gaps between issues were lengthening, the title was sold to Galileo publisher Vincent McCaffrey, who brought out only a single issue in 1980. A brief revival as a semi-professional magazine followed in 1994, edited by H. L. Gold's son, E. J. Gold. At its peak, Galaxy influenced the science fiction genre, it was regarded as one of the leading sf magazines from the start, its influence did not wane until Pohl's departure in 1969. Gold brought a "sophisticated intellectual subtlety" to magazine science fiction according to Pohl, who added that "after Galaxy it was impossible to go on being naive."
SF historian David Kyle agreed, commenting that "of all the editors in and out of the post-war scene, the most influential beyond any doubt was H. L. Gold". Kyle suggested that the new direction Gold set "inevitably" led to the experimental New Wave, the defining science fiction literary movement of the 1960s; the first science fiction magazine, Amazing Stories, appeared in 1926. By the end of the 1930s, the genre was flourishing in the United States, but World War II and its resulting paper shortages led to the demise of several magazines. In the late 1940s, the market began to recover. From a low of eight active US magazines in 1946, the field expanded to 20 just four years later. Galaxy's appearance in 1950 was part of this boom. According to sf historian and critic Mike Ashley, its success was the main reason for a subsequent flood of new releases: 22 more science fiction magazines appeared by 1954, when the market dipped again as a side effect of US Senate hearings into the putative connection between comic books and juvenile delinquency.
H. L. Gold, Galaxy's first editor, had worked at Standard Magazines in the early 1940s as an assistant editor, reading for Standard's three science fiction pulps: Startling Stories, Thrilling Wonder, Captain Future. With the advent of the war, Gold left publishing and went into the army, but in late 1949 he was approached by Vera Cerutti, who had once worked for him. Cerutti was now working for a French-Italian publisher, Éditions Mondiales Del Duca founded by Cino Del Duca, that had opened an office in New York as World Editions, she asked Gold for guidance on how to produce a magazine, which he provided. World Editions took a heavy loss on Fascination, its first attempt to launch a US magazine, Cerutti returned to Gold asking for recommendations for new titles. Gold knew about The Magazine of Fantasy & Science Fiction, a digest launched in the fall of 1949, but felt that there was still room in the market for another serious science fiction magazine, he sent a prospectus to World Editions that included a proposal for a series of paperback sf novels as well as a periodical, proposed paying three cents a word, an impressively high rate, given that most competing magazines were paying only one cent a word.
World Editions agreed, hired Gold as the editor, the first issue appeared in October 1950. The novel series subsequently appeared as Galaxy Science Fiction Novels. Gold suggested two titles for the magazine, If and Galaxy. Gold's art director, Washington Irving van der Poel, mocked up multiple layouts and Gold invited hundreds of writers, editors and fans to view them and vote for their favorite. For the first issue, Gold obtained stories by several well-known authors, including Isaac Asimov, Fritz Leiber, Theodore Sturgeon, as well as part one of Time Quarry by Clifford D. Simak. Along with an essay by Gold, Galaxy's premiere issue introduced a book review column by anthologist Groff Conklin, which ran until 1955, a Willy Ley science column. Gold sought to implement high-quality printing techniques, though the quality of the available paper was insufficient for the full benefits to be seen. Within months, the outbreak of the Korean War led to paper shortages that forced Gold to find a new printer, Robert M. Guinn.
The new paper was of lower quality, a disappointment to Gold. According to Gold, the magazine was profitable within five issues: an "incredible" achievement, in his words. In
A gravity well or gravitational well is a conceptual model of the gravitational field surrounding a body in space – the more massive the body, the deeper and more extensive the gravity well associated with it. The Sun is massive, relative to other bodies in the Solar System, so the corresponding gravity well that surrounds it appears "deep" and far-reaching; the gravity wells of asteroids and small moons, are depicted as shallow. Anything at the center of mass of a planet or moon is considered to be at the bottom of that celestial body's gravity well, so escaping the effects of gravity from such a planet or moon is sometimes called "climbing out of the gravity well"; the deeper a gravity well is, the more energy any space-bound "climber" must use to escape it. In astrophysics, a gravity well is the gravitational potential field around a massive body. Other types of potential wells include magnetic potential wells. Physical models of gravity wells are sometimes used to illustrate orbital mechanics.
Gravity wells are confused with embedding diagrams used in general relativity theory, but the two concepts are distinctly separate and not directly related. If G is the universal gravitational constant, the external gravitational potential of a spherically symmetric body of mass M is given by the formula: Φ = − G M | x |. A plot of this function in two dimensions is shown in the figure; this plot has been completed with an interior potential proportional to |x|2, corresponding to an object of uniform density, but this interior potential is irrelevant since the orbit of a test particle cannot intersect the body. The potential function has a hyperbolic cross section. A black hole would not have this "closing" dip due to its size being only determined by its event horizon. In a uniform gravitational field, the gravitational potential at a point is proportional to the height, thus if the graph of a gravitational potential Φ is constructed as a physical surface and placed in a uniform gravitational field so that the actual field points in the −Φ direction each point on the surface will have an actual gravitational potential proportional to the value of Φ at that point.
As a result, an object constrained to move on the surface will have the same equation of motion as an object moving in the potential field Φ itself. Gravity wells constructed on this principle can be found in many science museums. There are several sources of inaccuracy in this model: The friction between the object and the surface has no analogue in vacuum; this effect can be reduced by using a rolling ball instead of a sliding block. The object's vertical motion contributes kinetic energy; this effect can be reduced by making the gravity well shallower. A rolling ball's rotational kinetic energy has no analogue; this effect can be reduced by concentrating the ball's mass near its center so that the moment of inertia is small compared to mr². A ball's center of mass is not located on the surface but at a fixed distance r, which changes its potential energy by an amount depending on the slope of the surface at that point. For balls of a fixed size, this effect can be eliminated by constructing the surface so that the center of the ball, rather than the surface itself, lies on the graph of Φ.
Consider an idealized rubber sheet suspended in a uniform gravitational field normal to the sheet. In equilibrium, the elastic tension in each part of the sheet must be equal and opposite to the gravitational pull on that part of the sheet; the mass density may be viewed as intrinsic to the sheet or as belonging to objects resting on top of the sheet. This equilibrium condition is identical in form to the gravitational Poisson equation ∇ 2 Φ = 4 π G ρ where Φ is the gravitational potential and ρ is the mass density. Thus, to a first approximation, a massive object placed on a rubber sheet will deform the sheet into a shaped gravity well, a second test object placed near the first will gravitate toward it in an approximation of the correct force law. Both the rigid gravity well and the rubber-sheet model are misidentified as models of general relativity due to an accidental resemblance to general relativistic embedding diagrams, Einstein's employment of gravitational "curvature" bending the path of light he described as a prediction of general relativity.
The embedding diagram most found in textbooks, an isometric embedding of a constant-time equatorial slice of the Schwarzschild metric in Euclidean 3-dimensional space, superficially resembles a gravity well. However, embedding diagrams fundamentally differ from gravity wells. Embedding takes a shape, but a potential plot has a distinguished "downward" direction. Turning a gravity well "upside down" by negating the potential of the attractive force, turns it into a repulsive force. However, turning a Schwarzschild embedding upside down, by rotating it, h
All the Myriad Ways
All the Myriad Ways is a collection of 14 short science fiction stories and essays by American writer Larry Niven published in 1971. "All the Myriad Ways" "Passerby" "For a Foggy Night" "Wait it Out" "The Jigsaw Man" "Not Long Before the End" "Unfinished Story #1" "Unfinished Story #2" "Man of Steel, Woman of Kleenex" "Exercise in Speculation: The Theory and Practice of Teleportation" "The Theory and Practice of Time Travel" "Inconstant Moon" "What Can You Say About Chocolate Covered Manhole Covers?" "Becalmed in Hell" The title story can be read as a response to stories featuring the many-worlds interpretation as a key plot point, by taking the social implications of infinite realities to a depressing conclusion. A police detective, pondering a rash of unexplained suicides and murder-suicides occurring since the discovery of travel to parallel universes, begins to realize that if all possible choices that might be made are made in parallel universes, people will see their freedom of choice as meaningless.
The choice not to commit suicide, or not to commit a crime, seems meaningless if one knows that in some other universe, the choice went the other way. They therefore commit the crime, because they abandon the sense of choice; the oft-discussed essay "Man of Steel, Woman of Kleenex" is a humorous discussion of the difficulties Superman might encounter in trying to conceive a child with Lois Lane. In "Wait It Out", an astronaut marooned on Pluto exposes himself to the planet's extreme cold, intending to go into frozen sleep until rescue comes, but finds his brain still functioning due to superconductivity, and "What Can You Say About Chocolate-Covered Manhole Covers" explains all of the creation myths as a breeding experiment by aliens
Asteroid mining is the exploitation of raw materials from asteroids and other minor planets, including near-Earth objects. Hard rock minerals would be mined from a spent comet. Precious metals such as gold and platinum group metals could be transported back to Earth, whilst iron group metals and other common ones could be used for construction in space. Difficulties include the high cost of spaceflight, unreliable identification of asteroids suitable for mining, ore extraction challenges. Thus, terrestrial mining remains the only means of raw mineral acquisition today. If space program funding, either public or private increases, this situation is to change as resources on Earth become scarce and the full potentials of asteroid mining—and space exploration in general—are researched in greater detail. However, it is yet uncertain whether asteroid mining will develop to attain the volume and composition needed in due time to compensate for dwindling terrestrial reserves. Based on known terrestrial reserves, growing consumption in both developed and developing countries, key elements needed for modern industry and food production could be exhausted on Earth within 50 to 60 years.
These include phosphorus, zinc, lead, silver and copper. In response, it has been suggested that platinum and other valuable elements from asteroids may be mined and sent to Earth for profit, used to build solar-power satellites and space habitats, water processed from ice to refuel orbiting propellant depots. Although asteroids and Earth accreted from the same starting materials, Earth's stronger gravity pulled all heavy siderophilic elements into its core during its molten youth more than four billion years ago; this left the crust depleted of such valuable elements until a rain of asteroid impacts re-infused the depleted crust with metals like gold, iron, molybdenum, osmium, platinum, rhodium and tungsten. Today, these metals are mined from Earth's crust, they are essential for economic and technological progress. Hence, the geologic history of Earth may well set the stage for a future of asteroid mining. In 2006, the Keck Observatory announced that the binary Jupiter trojan 617 Patroclus, large numbers of other Jupiter trojans, are extinct comets and consist of water ice.
Jupiter-family comets, near-Earth asteroids that are extinct comets, might provide water. The process of in-situ resource utilization—using materials native to space for propellant, thermal management, radiation shielding, other high-mass components of space infrastructure—could lead to radical reductions in its cost. Although whether these cost reductions could be achieved, if achieved would offset the enormous infrastructure investment required, is unknown. Ice would satisfy one of two necessary conditions to enable "human expansion into the Solar System": physical sustainability and economic sustainability. From the astrobiological perspective, asteroid prospecting could provide scientific data for the search for extraterrestrial intelligence; some astrophysicists have suggested that if advanced extraterrestrial civilizations employed asteroid mining long ago, the hallmarks of these activities might be detectable. An important factor to consider in target selection is orbital economics, in particular the change in velocity and travel time to and from the target.
More of the extracted native material must be expended as propellant in higher Δv trajectories, thus less returned as payload. Direct Hohmann trajectories are faster than Hohmann trajectories assisted by planetary and/or lunar flybys, which in turn are faster than those of the Interplanetary Transport Network, but the reduction in transfer time comes at the cost of increased Δv requirements; the Easily Recoverable Object subclass of Near-Earth asteroids are considered candidates for early mining activity. Their low Δv makes them suitable for use in extracting construction materials for near-Earth space-based facilities reducing the economic cost of transporting supplies into Earth orbit; the table above shows a comparison of Δv requirements for various missions. In terms of propulsion energy requirements, a mission to a near-Earth asteroid compares favorably to alternative mining missions. An example of a potential target for an early asteroid mining expedition is 4660 Nereus, expected to be enstatite.
This body has a low Δv compared to lifting materials from the surface of the Moon. However it would require a much longer round-trip to return the material. Multiple types of asteroids have been identified but the three main types would include the C-type, S-type, M-type asteroids: C-type asteroids have a high abundance of water, not of use for mining but could be used in an exploration effort beyond the asteroid. Mission costs could be reduced by using the available water from the asteroid. C-type asteroids have a lot of organic carbon and other key ingredients for fertilizer which could be used to grow food. S-type asteroids carry little water but look more attractive because they contain numerous metals including: nickel and more valuable metals such as gold and rhodium. A small 10-meter S-type asteroid contains about 650,000 kg of metal with 50 kg in the form of rare metals like platinum and gold. M-type astero