Special relativity in its Minkowski spacetime is accurate only when the absolute value of the gravitational potential is much less than c2 in the region of interest. In a strong gravitational field, o ...
Postulates “ Reflections of this type made it clear to me as long ago as shortly after 1900, i.e., shortly after Planck's trailblazing work, that neither mechanics nor electrodynamics could (except i ...
In a Euclidean space, the separation between two points is measured by the distance between the two points. The distance is purely spatial, and is always positive. In spacetime, the separation between ...
Throughout his life, Einstein published hundreds of books and articles. In addition to the work he did by himself he also collaborated with other scientists on additional projects including the Bose– ...
Albert Einstein was born in Ulm, in the Kingdom of Württemberg in the German Empire on 14 March 1879. His father was Hermann Einstein, a salesman and engineer. His mother was Pauline Einstein (née K ...
The theory of relativity transformed theoretical physics and astronomy during the 20th century. When first published, relativity superseded a 200-year-old theory of mechanics created primarily by Isaa ...
Measurements are most commonly made in the SI system, which contains seven fundamental units: kilogram, metre, candela, second, ampere, kelvin, and mole. Six of these units are artifact-free (defined ...
The standard International System of Units (SI) unit of mass is the kilogram (kg). The kilogram is 1000 grams (g), which were first defined in 1795 as one cubic decimeter of water at the melting point ...
A set of fundamental units is a set of units for physical quantities from which every other unit can be generated.In the language of measurement, quantities are quantifiable aspects of the world, such ...
Main article: Characterizations of the category of topological spacesThe utility of the notion of a topology is shown by the fact that there are several equivalent definitions of this structure. Thus ...
Function spaces appear in various areas of mathematics:In set theory, the set of functions from X to Y may be denoted X → Y or YX.As a special case, the power set of a set X may be identified with th ...
The concept of vector space will first be explained by describing two particular examples:First example: arrows in the plane The first example of a vector space consists of arrows in a fixed plane, st ...
After a line, the circle is the simplest example of a topological manifold. Topology ignores bending, so a small piece of a circle is treated exactly the same as a small piece of a line. Consider, for ...
Before the golden age of geometry In the ancient mathematics, "space" was a geometric abstraction of the three-dimensional space observed in the everyday life. Axiomatic method had been the main resea ...
A binary pulsar is a pulsar with a binary companion, often a white dwarf or neutron star. (In at least one case, the double pulsar PSR J0737-3039, the companion neutron star is another pulsar as well. ...
