exact solution
In general relativity, a solution of Einstein's equations is a model universe that follows the law of gravity given by general relativity. If the properties of that model universe can be written down explicitly, for example by expressing the geometry at each ...
event
In the context of special or general relativity: Anything that is defined by a single point in time and a single point in space, i.e. something that happens at a definite time at a definite location. Synonym: spacetime ...
event horizon
In general relativity: A closed surface that is the boundary of a black hole. Whatever enters through this boundary from the outside can never again leave the inside. Near-synonym: ...
European Space Agency
The European Space Agency coordinates the space-faring activities of the European countries. It is a partner in projects such as the Hubble space telescope and the gravitational wave detector LISA. ESA ...
European Southern Observatory
A cooperative effort of 10 member states of the European union, ESO operates a number of large-scale telescopes such as the "Very Large Telescope" (VLT) and the "New Technology Telescope" (NTT). The telescopes themselves are located in Chile; the ...
Euclidean
In a stricter sense: Euclidean geometry is the standard geometry taught in school (synonym: plane geometry). In a more general sense: Euclidean geometry is the generalization of this geometry to include three-dimensional space and even higher-dimensional ...
ether
In 19th century physics: Hypothetical medium in which light and other types of electromagnetic radiation propagate as waves. Once the ether is postulated, certain questions arise: Does the earth move through this medium? If yes, how fast? And can this motion ...
error (measurement)
No measurement of a physical quantity is perfectly exact - all measurements have a certain resolution or error. In particular, in measuring a physical quantity there will be a myriad of tiny disturbances (such as fluctuations in the ...
