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Gravitational Shielding
The term gravitational shielding refers to a hypothetical process of shielding an object from the influence of a gravitational field. Such processes, if they existed, would have the effect of reducing the weight of an object. The shape of the shielded region would be similar to a shadow from the gravitational shield. For example, the shape of the shielded region above a disk would be conical. The height of the cone's apex above the disk would vary directly with the height of the shielding disk above the earth. Experimental evidence to date indicates that no such effect exists. Gravitational shielding is considered to be a violation of the equivalence principle and therefore inconsistent with both Newtonian theory and general relativity. The concept of gravity shielding is a common concept in science fiction literature, especially for space travel. One of the first and best known examples is the fictional gravity shielding substance "Cavorite" that appears in H. G. Wells' class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothesis
A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous observations that cannot satisfactorily be explained with the available scientific theories. Even though the words "hypothesis" and "theory" are often used interchangeably, a scientific hypothesis is not the same as a scientific theory. A working hypothesis is a provisionally accepted hypothesis proposed for further research in a process beginning with an educated guess or thought. A different meaning of the term ''hypothesis'' is used in formal logic, to denote the antecedent of a proposition; thus in the proposition "If ''P'', then ''Q''", ''P'' denotes the hypothesis (or antecedent); ''Q'' can be called a consequent. ''P'' is the assumption in a (possibly counterfactual) ''What If'' question. The adjective ''hypothetical'', meaning "hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugene Podkletnov
Eugene Podkletnov (russian: Евгений Подклетнов, Yevgeny Podkletnov) is a Rossiyane, Russian Ceramic engineering, ceramics engineer known for his claims made in the 1990s of designing and demonstrating gravity shielding devices consisting of rotating discs constructed from High-temperature superconductivity, ceramic superconducting materials. Background and education Podkletnov graduated from the Mendeleev Russian University of Chemistry and Technology, University of Chemical Technology, Mendeleyev Institute, in Moscow; he then spent 15 years at the Institute for High Temperatures in the Russian Academy of Sciences. He received a doctorate in materials science from Tampere University of Technology in Finland. After graduation he continued superconductor research at the university, in the Materials science, Materials Science department, until his expulsion in 1997. After which he moved back to Moscow where it is reported that he took an engineering job. Since leaving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Fiction Themes
The following is a list of articles about recurring themes in science fiction. Overarching themes * First contact with aliens *Artificial intelligence **Machine rule/Cybernetic revolt/AI takeover *Extraterrestrials in fiction *End of humanity: Apocalyptic and post-apocalyptic fiction *The future **Apocalyptic and post-apocalyptic fiction: Apocalypses or worldwide disasters and new societies that develop after the event *History ** Alternate history **Scientific prediction of the future (e.g. psychohistory) *Human fears: List of science fiction horror films *Language **Alien languages (e.g. Klingon, Huttese) **The Sapir–Whorf Hypothesis (e.g. '' Babel 17'', ''The Languages of Pao'') ** Universal translators (e.g. Babel fish) * Military/conflicts **Interstellar war **Weapons in science fiction * Parallel worlds or multiverse * * Philosophies and philosophical ideas * Political ideas * Religious ideas * Sex and sexuality ** LGBT themes **Gender ** Reproduction and pregnancy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Relativity
General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime. In particular, the ' is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of second order partial differential equations. Newton's law of universal gravitation, which describes classical gravity, can be seen as a prediction of general relativity for the almost flat spacetime geometry around stationary mass distributions. Some predictions of general relativity, however, are beyond Newton's law of universal gravitat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Shielding
In electrical engineering, electromagnetic shielding is the practice of reducing or blocking the electromagnetic field (EMF) in a space with barriers made of conductive or magnetic materials. It is typically applied to enclosures, for isolating electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs (). Electromagnetic shielding that blocks radio frequency (RF) electromagnetic radiation is also known as RF shielding. EMF shielding serves to minimize electromagnetic interference. The shielding can reduce the coupling of radio waves, electromagnetic fields, and electrostatic fields. A conductive enclosure used to block electrostatic fields is also known as a '' Faraday cage''. The amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of holes in a shield to an incident electromagn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ning Li (physicist)
Ning Li (January 14, 1943 – July 27, 2021) was an Han Chinese scientist holding dual citizenship in both the USA and her birth country of China. She is known for her physics and anti-gravity research. In the 1990s, Li worked as a research scientist at the Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville. In 1999, she left the university to form a company, AC Gravity, LLC, to continue anti-gravity research. Anti-gravity claims In a series of papers co-authored with fellow university physicist Douglas Torr and published between 1991 and 1993, she claimed a practical way to produce anti-gravity effects. She claimed that an anti-gravity effect could be produced by rotating ions creating a gravitomagnetic field perpendicular to their spin axis. In her theory, if a large number of ions could be aligned, (in a Bose–Einstein condensate In condensed matter physics, a Bose–Einstein condensate (BEC) is a state of matter that is typically formed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artificial Gravity
Artificial gravity is the creation of an inertial force that mimics the effects of a gravitational force, usually by rotation. Artificial gravity, or rotational gravity, is thus the appearance of a centrifugal force in a rotating frame of reference (the transmission of centripetal acceleration via normal force in the non-rotating frame of reference), as opposed to the force experienced in linear acceleration, which by the equivalence principle is indistinguishable from gravity. In a more general sense, "artificial gravity" may also refer to the effect of linear acceleration, e.g. by means of a rocket engine. Rotational simulated gravity has been used in simulations to help astronauts train for extreme conditions. Rotational simulated gravity has been proposed as a solution in human spaceflight to the adverse health effects caused by prolonged weightlessness. However, there are no current practical outer space applications of artificial gravity for humans due to concerns ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-gravity
Anti-gravity (also known as non-gravitational field) is a hypothetical phenomenon of creating a place or object that is free from the force of gravity. It does not refer to the lack of weight under gravity experienced in free fall or orbit, or to balancing the force of gravity with some other force, such as electromagnetism or aerodynamic lift. Anti-gravity is a recurring concept in science fiction. Examples are the gravity blocking substance "Cavorite" in H. G. Wells's ''The First Men in the Moon'' and the Spindizzy machines in James Blish's ''Cities in Flight''. "Anti-gravity" is often used to refer to devices that look as if they reverse gravity even though they operate through other means, such as lifters, which fly in the air by moving air with electromagnetic fields. Historical attempts at understanding gravity The possibility of creating anti-gravity depends upon a complete understanding and description of gravity and its interactions with other physical theories, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breakthrough Propulsion Physics Program
The Breakthrough Propulsion Physics Project (BPP) was a research project funded by NASA from 1996-2002 to study various proposals for revolutionary methods of spacecraft propulsion that would require breakthroughs in physics before they could be realized. The project ended in 2002, when the Advanced Space Transportation Program was reorganized and all speculative research (less than Technology readiness level 3) was cancelled. During its six years of operational funding, this program received a total investment of $1.2 million. The Breakthrough Propulsion Physics project addressed a selection of “incremental and affordable” research questions towards the overall goal of propellantless propulsion, hyperfast travel, and breakthrough propulsion methods. It selected and funded five external projects, two in-house tasks and one minor grant. At the end of the project, conclusions into fourteen topics, including these funded projects, were summarized by program manager Marc G. Millis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Dipole Moment
The electric dipole moment is a measure of the separation of positive and negative electrical charges within a system, that is, a measure of the system's overall polarity. The SI unit for electric dipole moment is the coulomb-meter (C⋅m). The debye (D) is another unit of measurement used in atomic physics and chemistry. Theoretically, an electric dipole is defined by the first-order term of the multipole expansion; it consists of two equal and opposite charges that are infinitesimally close together, although real dipoles have separated charge.Many theorists predict elementary particles can have very tiny electric dipole moments, possibly without separated charge. Such large dipoles make no difference to everyday physics, and have not yet been observed. (See electron electric dipole moment). However, when making measurements at a distance much larger than the charge separation, the dipole gives a good approximation of the actual electric field. The dipole is represented by a v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electret
An electret (formed as a portmanteau of ''electr-'' from "electricity" and ''-et'' from "magnet") is a dielectric material that has a quasi-permanent electric charge or dipole polarisation. An electret generates internal and external electric fields, and is the electrostatic equivalent of a permanent magnet. Although Oliver Heaviside coined this term in 1885, materials with electret properties were already known to science and had been studied since the early 1700s. One particular example is the electrophorus, a device consisting of a slab with electret properties and a separate metal plate. The electrophorus was originally invented by Johan Carl Wilcke in Sweden and again by Alessandro Volta in Italy. The name derives from "electron" and "magnet"; drawing analogy to the formation of a magnet by alignment of magnetic domains in a piece of iron. Historically, electrets were made by first melting a suitable dielectric material such as a polymer or wax that contains polar molecules, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward Teller
Edward Teller ( hu, Teller Ede; January 15, 1908 – September 9, 2003) was a Hungarian-American theoretical physicist who is known colloquially as "the father of the hydrogen bomb" (see the Teller–Ulam design), although he did not care for the title, considering it to be in poor taste. Throughout his life, Teller was known both for his scientific ability and for his difficult interpersonal relations and volatile personality. Born in Hungary in 1908, Teller emigrated to the United States in the 1930s, one of the many so-called "Martians", a group of prominent Hungarian scientist émigrés. He made numerous contributions to nuclear and molecular physics, spectroscopy (in particular the Jahn–Teller and Renner–Teller effects), and surface physics. His extension of Enrico Fermi's theory of beta decay, in the form of Gamow–Teller transitions, provided an important stepping stone in its application, while the Jahn–Teller effect and the Brunauer–Emmett–Teller (BE ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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