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Albert Einstein's theory of relativity is a set of two theories in physics: special relativity and general relativity. The core idea of both theories is that two observers who move relative to each other will often measure different time and space intervals for the same events, but the content of physical law will be the same for both. Special relativity, developed in 1905, only considers observers in inertial reference frames which are in uniform motion with respect to each other. Einstein's paper that year was called "On the Electrodynamics of Moving Bodies". While developing this theory, Einstein wrote to his wife Mileva about "our work on relative motion". This paper introduced the special theory of relativity, a theory of time, distance, mass and energy. The theory postulates that the speed of light in vacuum will be the same for these observers (i.e. an observer invariant speed).

One of the strengths of special relativity is that it can be derived from only a few premises:

Special relativity thus makes a general principle with applications in physics, chemistry, and even life sciences. It not only depicts relationships between the perspectives taken from loose moving bodies. Often together with quantum mechanics, special relativity is also employed to describe microphysical motions inside lumps of condensed matter, like pebbles and biological organs such as kidneys or brain. It, e. g., was of help to electroneurobiology researchers trying to explain physiologicalPhysiology is the study of the mechanical, physical, and biochemical functions of living organisms. Physiology has traditionally been divided into plant physiology and animal physiology but the principles of physiology are universal, no matter what partic mechanisms that enact variations of attentionThis article discusses the psychological concept of Attention . Also see Pages needing attention. For the military concept, see Military courtesy. The word attention refers to the cognitive process of selectively concentrating on one thing while deliberat and disconnection states such as sleepSleep is the process in which humans and other animals periodically rest, with greater or lesser degrees of unconsciousness and decreased responsiveness to the surrounding world. Sleep occurs cyclically, roughly once every 24 hours even though the average and comaFor other meanings of the word "coma", especially in astronomy, see coma (disambiguation In medicine, a coma is a profound state of unconsciousness, which may result from a variety of conditions including intoxication ( drug, alcohol or toxins), metabolic, as well as for theorists developing tools for biomedical imaging.

General relativity was published by Einstein in 19161916 is a leap year starting on Saturday (link will take you to calendar) Events January 1 -The first successful blood transfusion using blood that had been stored and cooled. Impressionist Monet paints Water Lilies'. January 8 Allied forces withdraw from (submitted as a series of lectures before the Prussian Academy of Sciences November 25November 25 is the 329th (in leap years the 330th) day of the year in the Gregorian calendar. There are 36 days remaining. Events 1034 Malcolm II of Scotland died. Duncan, the son of his second daughter, instead of Macbeth, the son of his eldest daughter, 1915). However, it must be noted that German mathematician David Hilbert wrote and made public the covariant equations before Einstein. This resulted in not a few accusations of plagiarism against Einstein, but it is probably closer to reality that they both were co-creators of general relativity. The theory gave an introduction of an equation that replaced Newton's law of gravity. It uses the mathematics of differential geometry and tensors in order to describe gravity.

This theory considered all observers to be equivalent, not only those moving at a uniform speed. The laws of general relativity are the same for all observers, even if they are accelerated with respect to each other. In general relativity, gravity is no longer a force (as it was in Newton's law of gravity) but is a consequence of the curvature of space-time. General relativity is a geometrical theory which postulates that the presence of mass and energy "curves" spacetime, and this curvature affects the path of free particles (and even the path of light).


For more information see the respective articles on special relativity and general relativity.



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