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Anti-gravity

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Anti-gravity(also known asnon-gravitational field) is a hypothetical phenomenon of creating a place or object that is free from the force ofgravity.It does not refer to either the lack of weight under gravity experienced infree fallororbit,or to balancing the force of gravity with some other force, such aselectromagnetismoraerodynamic lift.Anti-gravity is a recurring concept in science fiction. Examples are the gravity blocking substance "Cavorite" inH. G. Wells'sThe First Men in the Moonand theSpindizzymachines inJames Blish'sCities in Flight.

Artistic depiction of a fictional anti-gravity vehicle

"Anti-gravity" is often used to refer to devices that look as if they reverse gravity even though they operate through other means, such aslifters,which fly in the air by moving air withelectromagnetic fields.[1][2]

Historical attempts at understanding gravity

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Main article:History of gravitational theory

The possibility of creating anti-gravity depends upon a complete understanding and description of gravity and its interactions with other physical theories, such asgeneral relativityandquantum mechanics;however, no quantum theory of gravity has yet been found.

During the summer of 1666,Isaac Newtonobserved an apple falling from the tree in his garden, thus realizing theprinciple of universal gravitation.[3]Albert Einsteinin 1915 considered the physical interaction between matter and space, where gravity occurs as a consequence of matter causing a geometric deformation of spacetime which is otherwise flat.[4][5][6]Einstein, both independently and withWalther Mayer,attempted to unify histheory of gravitywithelectromagnetismusing the work ofTheodor Kaluza[7]andJames Clerk Maxwellto link gravity andquantum field theory.[8]

Theoretical quantum physicists have postulated the existence of a quantum gravity particle, thegraviton.Various theoretical explanations ofquantum gravityhave been created, includingsuperstring theory,loop quantum gravity,E8 theoryandasymptotic safety theoryamongst many others.

Hypothetical solutions

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InNewton's law of universal gravitation,gravity was an external force transmitted by unknown means. In the 20th century, Newton's model was replaced bygeneral relativitywhere gravity is not a force but the result of the geometry of spacetime. Under general relativity, anti-gravity is impossible except under contrived circumstances.[9][10][11]

Gravity shields

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A monument atBabson Collegededicated toRoger Babsonfor research into anti-gravity and partial gravity insulators
Main article:Gravitational shielding

In 1948 businessmanRoger Babson(founder ofBabson College) formed theGravity Research Foundationto study ways to reduce the effects of gravity.[12]Their efforts were initially somewhat "crankish",but they held occasional conferences that drew such people asClarence Birdseye,known for his frozen-food products, and helicopter pioneerIgor Sikorsky.[citation needed]Over time the Foundation turned its attention away from trying to control gravity, to simply better understanding it. The Foundation nearly disappeared after Babson's death in 1967. However, it continues to run an essay award, offering prizes of up to $4,000. As of 2017, it is still administered out ofWellesley, Massachusetts,by George Rideout Jr., son of the foundation's original director.[13]Winners include California astrophysicistGeorge F. Smoot(1993), who later won the 2006Nobel Prize in physics,andGerard 't Hooft(2015) who previously won the 1999 Nobel Prize in physics.[14]

General relativity research in the 1950s

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Main article:United States gravity control propulsion research

General relativity was introduced in the 1910s, but development of the theory was greatly slowed by a lack of suitable mathematical tools.[clarification needed]It appeared that anti-gravity was outlawed under general relativity.

It is claimed theUS Air Forcealso ran a study effort throughout the 1950s and into the 1960s.[15]Former Lieutenant ColonelAnsel Talbertwrote two series of newspaper articles claiming that most of the major aviation firms had started gravity control propulsion research in the 1950s. However, there is little outside confirmation of these stories, and since they take place in the midst of thepolicy by press releaseera, it is not clear how much weight these stories should be given.

It is known that there were serious efforts underway at theGlenn L. Martin Company,who formed the Research Institute for Advanced Study.[16][17]Major newspapers announced the contract that had been made between theoretical physicistBurkhard Heimand the Glenn L. Martin Company. Another effort in the private sector to master understanding of gravitation was the creation of the Institute for Field Physics,University of North Carolina at Chapel Hillin 1956, by Gravity Research Foundation trusteeAgnew H. Bahnson.

Military support for anti-gravity projects was terminated by theMansfield Amendmentof 1973, which restrictedDepartment of Defensespending to only the areas of scientific research with explicit military applications. The Mansfield Amendment was passed specifically to end long-running projects that had little to show for their efforts.

Under general relativity, gravity is the result of following spatial geometry (change in the normal shape of space) caused by local mass-energy. This theory holds that it is the altered shape of space, deformed by massive objects, that causes gravity, which is actually a property of deformed space rather than being a true force. Although the equations cannot normally produce a "negative geometry", it is possible to do so by using "negative mass".The same equations do not, of themselves, rule out the existence of negative mass.

Both general relativity and Newtonian gravity appear to predict that negative mass would produce a repulsive gravitational field. In particular, SirHermann Bondiproposed in 1957 that negative gravitational mass, combined with negative inertial mass, would comply with thestrong equivalence principleof general relativity theory and the Newtonian laws of conservation of linear momentum and energy. Bondi's proof yielded singularity-free solutions for the relativity equations.[18]In July 1988,Robert L. Forwardpresented a paper at the AIAA/ASME/SAE/ASEE 24th Joint Propulsion Conference that proposed a Bondi negative gravitational mass propulsion system.[19]

Bondi pointed out that a negative mass will fall toward (and not away from) "normal" matter, since although the gravitational force is repulsive, the negative mass (according to Newton's law, F=ma) responds by accelerating in the opposite of the direction of the force. Normal mass, on the other hand, will fall away from the negative matter. He noted that two identical masses, one positive and one negative, placed near each other will therefore self-accelerate in the direction of the line between them, with the negative mass chasing after the positive mass.[18]Notice that because the negative mass acquires negativekinetic energy,the total energy of the accelerating masses remains at zero. Forward pointed out that the self-acceleration effect is due to the negative inertial mass, and could be seen induced without the gravitational forces between the particles.[19]

TheStandard Modelof particle physics, which describes all currently known forms of matter, does not include negative mass. Although cosmologicaldark mattermay consist of particles outside the Standard Model whose nature is unknown, their mass is ostensibly known – since they were postulated from their gravitational effects on surrounding objects, which implies their mass is positive. The proposed cosmologicaldark energy,on the other hand, is more complicated, since according to general relativity the effects of both its energy density and its negative pressure contribute to its gravitational effect.

Unique force

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Under general relativity any form of energy couples with spacetime to create the geometries that cause gravity. A longstanding question was whether or not these same equations applied toantimatter.The issue was considered solved in 1960 with the development ofCPT symmetry,which demonstrated that antimatter follows the same laws of physics as "normal" matter, and therefore has positive energy content and also causes (and reacts to) gravity like normal matter (seegravitational interaction of antimatter).

For much of the last quarter of the 20th century, the physics community was involved in attempts to produce aunified field theory,a single physical theory that explains the four fundamental forces: gravity, electromagnetism, and the strong and weak nuclear forces. Scientists have made progress inunifying the three quantum forces,but gravity has remained "the problem" in every attempt. This has not stopped any number of such attempts from being made, however.

Generally these attempts tried to "quantize gravity" by positing a particle, thegraviton,that carried gravity in the same way thatphotons(light) carry electromagnetism. Simple attempts along this direction all failed, however, leading to more complex examples that attempted to account for these problems. Two of these,supersymmetryand the relativity relatedsupergravity,both required the existence of an extremely weak "fifth force" carried by agraviphoton,which coupled together several "loose ends" in quantum field theory, in an organized manner. As a side effect, both theories also all but required that antimatter be affected by this fifth force in a way similar to anti-gravity, dictating repulsion away from mass. Several experiments were carried out in the 1990s to measure this effect, but none yielded positive results.[20]

In 2013CERNlooked for an antigravity effect in an experiment designed to study the energy levels within antihydrogen. The antigravity measurement was just an "interesting sideshow" and was inconclusive.[21]

Breakthrough Propulsion Physics Program

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During the close of the twentieth centuryNASAprovided funding for theBreakthrough Propulsion Physics Program(BPP) from 1996 through 2002. This program studied a number of "far out" designs for space propulsion that were not receiving funding through normal university or commercial channels. Anti-gravity-like concepts were investigated under the name "diametric drive". The work of the BPP program continues in the independent, non-NASA affiliatedTau Zero Foundation.[22]

Empirical claims and commercial efforts

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There have been a number of attempts to build anti-gravity devices, and a small number of reports of anti-gravity-like effects in the scientific literature. None of the examples that follow are accepted as reproducible examples of anti-gravity.

Gyroscopic devices

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A "kinemassic field" generator fromU.S. patent 3,626,605:Method and apparatus for generating a secondary gravitational force field

Gyroscopesproduce a force when twisted that operates "out of plane" and can appear to lift themselves against gravity. Although this force is well understood to be illusory, even under Newtonian models, it has nevertheless generated numerous claims of anti-gravity devices and any number of patented devices. None of these devices has ever been demonstrated to work under controlled conditions, and they have often become the subject ofconspiracy theoriesas a result.

Another "rotating device" example is shown in a series of patents granted to Henry Wallace between 1968 and 1974. His devices consist of rapidly spinning disks ofbrass,a material made up largely of elements with a total half-integer nuclear spin. He claimed that by rapidly rotating a disk of such material, thenuclear spinbecame aligned, and as a result created a "gravitomagnetic" field in a fashion similar to the magnetic field created by theBarnett effect.[23][24][25]No independent testing or public demonstration of these devices is known.

In 1989, it was reported that a weight decreases along the axis of a right spinning gyroscope.[26]A test of this claim a year later yielded null results.[27]A recommendation was made to conduct further tests at a 1999 AIP conference.[28]

Thomas Townsend Brown's gravitator

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Further information:Biefeld-Brown effect,Electrogravitics,andUnited States gravity control propulsion research § Brown's gravitator

In 1921, while still inhigh school,Thomas Townsend Brownfound that a high-voltageCoolidge tubeseemed to change mass depending on its orientation on a balance scale. Through the 1920s Brown developed this into devices that combined high voltages with materials with highdielectricconstants (essentially largecapacitors); he called such a device a "gravitator". Brown made the claim to observers and in the media that his experiments were showing anti-gravity effects. Brown would continue his work and produced a series of high-voltage devices in the following years in attempts to sell his ideas to aircraft companies and the military. He coined the namesBiefeld–Brown effectandelectrograviticsin conjunction with his devices. Brown tested his asymmetrical capacitor devices in a vacuum, supposedly showing it was not a more down-to-earthelectrohydrodynamiceffect generated by high voltage ion flow in air.

Electrogravitics is a popular topic inufology,anti-gravity,free energy,with government conspiracy theorists and related websites, in books and publications with claims that the technology became highly classified in the early 1960s and that it is used to power UFOs and theB-2 bomber.[29]There is also research and videos on the internet purported to show lifter-style capacitor devices working in a vacuum, therefore not receiving propulsion from ion drift orion windbeing generated in air.[29][30]

Follow-up studies on Brown's work and other claims have been conducted by R. L. Talley in a 1990 US Air Force study, NASA scientist Jonathan Campbell in a 2003 experiment,[29]andMartin Tajmarin a 2004 paper.[31]They have found that no thrust could be observed in a vacuum and that Brown's and otherion lifterdevices produce thrust along their axis regardless of the direction of gravity consistent with electrohydrodynamic effects.

Gravitoelectric coupling

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In 1992, the Russian researcherEugene Podkletnovclaimed to have discovered, whilst experimenting withsuperconductors,that a fast rotating superconductor reduces the gravitational effect.[32]Many studies have attempted to reproduce Podkletnov's experiment, always to negative results.[33][34][35][36]

Douglas Torr, of theUniversity of Alabama in Huntsvilleproposed how a time-dependent magnetic field could cause the spins of the lattice ions in a superconductor to generate detectablegravitomagneticand gravitoelectric fields in a series of papers published between 1991 and 1993.[37][38][39]In 1999, a Miss Li appeared inPopular Mechanics,claiming to have constructed a workingprototypeto generate what she described as "AC Gravity." No further evidence of this prototype has been offered.[40][41]

Douglas Torr andTimir Dattawere involved in the development of a "gravity generator" at theUniversity of South Carolina.[42]According to a leaked document from the Office of Technology Transfer at the University of South Carolina and confirmed toWiredreporter Charles Platt in 1998, the device would create a "force beam" in any desired direction and the university planned to patent and license this device. No further information about this university research project or the "Gravity Generator" device was ever made public.[43]

Göde Award

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The Institute for Gravity Research of the Göde Scientific Foundation has tried to reproduce many of the different experiments which claim any "anti-gravity" effects. All attempts by this group to observe an anti-gravity effect by reproducing past experiments have been unsuccessful thus far. The foundation has offered a reward of one million euros for a reproducible anti-gravity experiment.[44]

In fiction

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The existence of anti-gravity is a common theme infantasyandscience fiction.

Apergy

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Apergyis a fictitious form of anti-gravitational energy first described byPercy Gregin his 1880sword and planetnovelAcross the Zodiac.[45]

John Jacob Astor IVused it in his 1894 science fiction novelA Journey in Other Worlds.[46]Jack Londondescribes it as "the hypothetical existence of a force, the converse of gravitation, which Astor has named 'apergy,'" in his short story entitled "A Thousand Deaths," first published inThe Black Catin 1899.[47]

Apergy can also be found in an 1896 article, "Some Truths About Keely,"[48]whereClara Jessup Bloomfield-Mooreused it to describe thelatentforceJohn Keelyharnessed, by employing frequency to release the latent force found within all atomicmatter.[49]

In an ostensibly non-fictitious article published in 1897 inThe San Francisco Calltitled "The Secret of Aerial Flight Revealed,"[50]science correspondentFrank M. Close,D.Sc., visits an unnamed Hindu man masquerading as aviticulturistsomewhere on thePacific coastwho claims to have invented a flying boat that uses an "apergent" —a rare metal called "radlum" —to produce controlled apergic force, allowing the vessel to ascend and descend. The inventor describes apergy as "a force obtained by blending positive and negative electricity with ultheic, the third element or state of electric energy" and calls apergy a "second phase of gravity," hinting at a third phase as well.

S. P. Meek's short story "Cold Light," which appeared in March 1930 inAstounding Stories of Super-Science,[51]mentions apergy as the opposite force of gravity.

InChris Roberson's short story "Annus Mirabilis" from the 2006 second volume ofTales of the Shadowmen,Doctor Omegaand Albert Einstein investigate apergy. Apergy is also mentioned in theWarren ElliscomicAetheric Mechanics,as being generated byCavoritetechnology fromThe First Men in the Moon.

Other terms

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H. G. Wells's 1901 novelThe First Men in the Moonhas space travel based on the gravity-blocking properties of "Cavorite."

Philip Francis Nowlan's 1928 storyArmageddon 2419 A.D.describes "inertron," a substance that falls up. The story was the basis for theBuck Rogerscomic stripand adaptations.

See also

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References

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  1. ^Thompson, Clive (August 2003)."The Antigravity Underground".Wired.Archivedfrom the original on 18 August 2010.Retrieved23 July2010.
  2. ^"On the Verge of Antigravity".About.Archived fromthe originalon 23 February 2017.Retrieved23 July2010.
  3. ^Department of PhysicsA Brief History of Isaac Newton's Apple Tree,University of York,Retrieved 2019-07-20
  4. ^Papachristou, Costas J. (2016). "Electromagnetic waves, gravitational waves and the prophets who predicted them".arXiv:1603.00871[physics.pop-ph].
  5. ^Albert EinsteinGrundgedanken der allgemeinen Relativitätstheorie und Anwendung dieser Theorie in der Astronomie (Preussische Akademie der Wissenschaften, Sitzungsberichte, 1915 (teil 1), 31), Zur allgemeinen Relativitätstheorie (Preussische Akademie der Wissenschaften, Sitzungsberichte, 1915 (teil 2), 778–786, 799–80) Retrieved 2019-06-16
  6. ^Charles W. Misner,Kip S. Thorne,John Archibald WheelerGravitation,p. 1231,Princeton University Press, 24 October 2017ISBN0691177791,ISBN9780691177793,Retrieved 2019-06-16
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  8. ^Einstein, Albert (1879-1955). Autograph manuscript, comprising calculations and arguments from the Einheitliche theorie von Gravitation un ElektrizittChristie'sRetrieved 2019-06-16
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  19. ^abForward, R. L. (1990). "Negative matter propulsion".Journal of Propulsion and Power.6(1): 28–37.doi:10.2514/3.23219.;see also commentaryLandis, G.A. (1991). "Comments on Negative Mass Propulsion".Journal of Propulsion and Power.7(2): 304.doi:10.2514/3.23327.
  20. ^Supergravity and the Unification of the Laws of Physics,byDaniel Z. Freedmanand Peter van Nieuwenhuizen, Scientific American, February 1978
  21. ^Jason Palmer, Antigravity gets first test at Cern's Alpha experiment, bbc.co.uk, 30 April 2013
  22. ^Tau Zero Foundation
  23. ^U.S. patent 3,626,606
  24. ^U.S. patent 3,626,605
  25. ^U.S. patent 3,823,570
  26. ^Hayasaka, H. & Takeuchi, S. (1989). "Anomalous weight reduction on a gyroscope's right rotations around the vertical axis on the Earth".Physical Review Letters.63(25): 2701–2704.Bibcode:1989PhRvL..63.2701H.doi:10.1103/PhysRevLett.63.2701.PMID10040968.
  27. ^Nitschke, J. M. & Wilmath, P. A. (1990)."Null result for the weight change of a spinning gyroscope".Physical Review Letters.64(18): 2115–2116.Bibcode:1990PhRvL..64.2115N.doi:10.1103/PhysRevLett.64.2115.PMID10041587.
  28. ^Iwanaga, N. (1999). "Reviews of some field propulsion methods from the general relativistic standpoint".AIP Conference Proceedings.Vol. 458. pp. 1015–1059.doi:10.1063/1.57497.
  29. ^abcThompson, Clive (August 2003)."The Antigravity Underground".Wired Magazine.
  30. ^Thomas Valone, Electrogravitics II: Validating Reports on a New Propulsion Methodology, Integrity Research Institute, page 52-58
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  33. ^N. Li; D. Noever; T. Robertson; R. Koczor; et al. (August 1997). "Static Test for a Gravitational Force Coupled to Type II YBCO Superconductors".Physica C.281(2–3): 260–267.Bibcode:1997PhyC..281..260L.doi:10.1016/S0921-4534(97)01462-7.
  34. ^Woods, C.; Helme, J.; Cooke, S.; Caldwell, C. (2001). "Gravity modification by high-temperature superconductors".37th Joint Propulsion Conference and Exhibit.doi:10.2514/6.2001-3363.
  35. ^Hathaway, G.; Cleveland, B.; Bao, Y. (2003). "Gravity modification experiment using a rotating superconducting disk and radio frequency fields".Physica C: Superconductivity.385(4): 488–500.Bibcode:2003PhyC..385..488H.doi:10.1016/S0921-4534(02)02284-0.
  36. ^Tajmar, M.; De Matos, C.J. (2003). "Gravitomagnetic field of a rotating superconductor and of a rotating superfluid".Physica C: Superconductivity.385(4): 551–554.arXiv:gr-qc/0203033.Bibcode:2003PhyC..385..551T.doi:10.1016/S0921-4534(02)02305-5.
  37. ^Li, Ning; Torr, DG (1 September 1992). "Gravitational effects on the magnetic attenuation of superconductors".Physical Review.B46(9): 5489–5495.Bibcode:1992PhRvB..46.5489L.doi:10.1103/PhysRevB.46.5489.PMID10004334.
  38. ^Li, Ning; Torr, DG (15 January 1991). "Effects of a gravitomagnetic field on pure superconductors".Physical Review.D43(2): 457–459.Bibcode:1991PhRvD..43..457L.doi:10.1103/PhysRevD.43.457.PMID10013404.
  39. ^Li, Ning; Torr, DG (August 1993). "Gravitoelectric-electric coupling via superconductivity".Foundations of Physics Letters.6(4): 371–383.Bibcode:1993FoPhL...6..371T.doi:10.1007/BF00665654.S2CID122075917.
  40. ^Wilson, Jim (1 October 2000)."Taming Gravity".Popular Mechanics.Archived fromthe originalon 5 November 2012.Retrieved5 January2014.
  41. ^Cain, Jeanette."Gravity Conquered?".light-science. Archived fromthe originalon 6 July 2013.Retrieved5 January2014.
  42. ^"Patent and Copyright Committee List of Disclosures Reviewed Between July 1996 and June 1997 - USC ID".Archived fromthe originalon 2 May 2014.Retrieved2 May2014.
  43. ^Platt, Charles (1 March 1998)."Breaking the Law of Gravity".Wired.Retrieved26 August2021.
  44. ^"The Göde award - One Million Euro to overcome gravity".Institute of Gravity Research. Archived fromthe originalon 28 April 2015.Retrieved2 January2014.
  45. ^Peter Nicholls (1979).The Encyclopedia of Science Fiction: An Illustrated A to Z.Unknown Publisher.ISBN978-0-246-11020-6.
  46. ^Astor, John Jacob (1894).A journey in other worlds. A romance of the future.D. Appleton and Company.Retrieved11 March2020.
  47. ^Haining, Peter, ed. (1976).The Fantastic Pulps.New York: Vintage Books. p. 26.ISBN0-394-72109-8.
  48. ^J. M. Stoddart (1895).The New Science Review: A Miscellany of Modern Thought and Discovery.Transatlantic Publishing Company. pp. 321–.
  49. ^Theo Paijmans (2004).Free Energy Pioneer: John Worrell Keely.Adventures Unlimited Press. pp. 221–.ISBN978-1-931882-33-0.
  50. ^http://chroniclingamerica.loc.gov/lccn/sn85066387/1897-01-17/ed-1/seq-20/The San Francisco Call,January 17, 1897, p.18.
  51. ^"The Project Gutenberg eBook of Astounding Stories of Super-Science, March 1930".

Bibliography

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Criteria:

Further reading

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  • Cady, W. M. (15 September 1952). "Thomas Townsend Brown: Electro-Gravity Device" (File 24–185). Pasadena, CA: Office of Naval Research. Public access to the report was authorized on 1 October 1952.
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