Changes

In the first [[mathematically]] accurate description of gravity, [http://en.wikipedia.org/wiki/Newton%27s_law_of_universal_gravitation Newton's law of universal gravitation], [[gravity]] was an external [[force]] [[transmitted]] by unknown means. However in the early part of the [http://en.wikipedia.org/wiki/20th_Century 20th century] Newton's [[model]] was replaced by the more general and complete description known as [[general relativity]]. In general relativity, gravity is not a force in the [[traditional]] sense of the [[word]], but the result of the [[geometry]] of [[space]] itself. These geometrical solutions always cause [[attractive]] "forces". Under general relativity, anti-gravity is highly unlikely, except under contrived circumstances that are regarded as unlikely or impossible. The term "anti-gravity" is also sometimes used to refer to hypothetical [http://en.wikipedia.org/wiki/Reactionless_propulsion reactionless propulsion drives] based on certain solutions to general [[relativity]], although these do not oppose gravity as such.

In the first [[mathematically]] accurate description of gravity, [http://en.wikipedia.org/wiki/Newton%27s_law_of_universal_gravitation Newton's law of universal gravitation], [[gravity]] was an external [[force]] [[transmitted]] by unknown means. However in the early part of the [http://en.wikipedia.org/wiki/20th_Century 20th century] Newton's [[model]] was replaced by the more general and complete description known as [[general relativity]]. In general relativity, gravity is not a force in the [[traditional]] sense of the [[word]], but the result of the [[geometry]] of [[space]] itself. These geometrical solutions always cause [[attractive]] "forces". Under general relativity, anti-gravity is highly unlikely, except under contrived circumstances that are regarded as unlikely or impossible. The term "anti-gravity" is also sometimes used to refer to hypothetical [http://en.wikipedia.org/wiki/Reactionless_propulsion reactionless propulsion drives] based on certain solutions to general [[relativity]], although these do not oppose gravity as such.

 

There are more recent [[theories]] that add to general [[relativity]] or replace it outright, and some of these appear to allow anti-gravity-like solutions. However, according to the current widely accepted [[physical]] theories, verified in [[experiments]], and according to the major directions of physical [[research]], it is considered highly unlikely that anti-gravity is possible.[1][2][3]

There are more recent [[theories]] that add to general [[relativity]] or replace it outright, and some of these appear to allow anti-gravity-like solutions. However, according to the current widely accepted [[physical]] theories, verified in [[experiments]], and according to the major directions of physical [[research]], it is considered highly unlikely that anti-gravity is possible.[1][2][3]

==Empirical claims and commercial efforts==

==Empirical claims and commercial efforts==