Topic: general relativity

topics > Group: science

Newtonian physics
philosophy of science
science as measurement
special relativity
the effect of scale


General relativity is Einstein's explanation of gravity as curved space-time; i.e., the geometrical properties of space are determined by the objects in that space. Gravity is exactly the same as an accelerating frame of reference. Einstein gained world-wide fame when an eclipse confirmed that light bends around the sun. (cbb 4/06)
Subtopic: general relativity up

Quote: relativity is a general principle that applies with great accuracy to mechanics; it should apply to all physical domains [»einsA_1916b]
Quote: general relativity -- equations of the laws of nature must be covariant w.r.t. continuous coordinate transformations
Quote: laws of nature should be valid in any 4-d system of coordinates that preserves neighboring events; like Gauss's theory of surfaces [»einsA_1956, OK]
Quote: the general principle of relativity states that all Gaussian co-ordinate systems are equivalent relative to the general laws of nature; this restricts these laws [»einsA_1916b]
Quote: continuous transformations of 4-d coordinates express the topological order of points; i.e., neighboring points have nearly the same coordinates
Quote: the mathematical abstractions of general relativity enlarge the scope of objective description and eliminate subjective elements [»bohrN_1958]
Quote: if two tracts are measured as equal once and anywhere, they are equal always and everywhere; a foundation for the general theory of relativity

Subtopic: relativity as curved space-time up

Quote: by the general theory of relativity, the geometrical properties of space are determined by matter [»einsA_1916b]
Quote: in the general theory of relativity the space-time metric only applies to small regions of a gravitational field
Quote: geometry and dynamics are linked together; motion is not curves (world-lines) in space-time
Quote: consider a bug that lives on a hot plate and uses rulers effected by temperature; if the length of a ruler varies by the square of the distance from the origin, the geometry is that of a sphere [»feynRP_1964]
Quote: construct a consistent, non-Euclidean world as a sphere whose temperature decreases to zero at its surface, and whose lengths are proportional to temperature [»poinH_1902, OK]
Quote: by Einstein's general relativity, the earth has 1.5 millimeters more radius than it should have for its surface area [»feynRP_1964]
Quote: from Einstein, space-time is curved near heavy masses; gravitation is the result of going along straight lines in a curved space-time [»feynRP_1964]
Quote: space is curved, matter is the source of the curvature, and it is that curvature that we see as gravitational force
Quote: in a gravitational field with given starting and finishing conditions, an object moves so as to maximize the time of a clock traveling with the object [»feynRP_1964]
Quote: straight-line motion in a curved space-time is that motion which maximizes the elapsed time of an object over some fixed local time [»feynRP_1964]
Quote: a distance must be measured so there is no abstract distance; a property of straight lines includes the measurement [»poinH_1902, OK]
Quote: no experiment can contradict Euclid's postulate, nor can experiment contradict Lobatschewsky's postulate

Subtopic: gravity up

Quote: a body's force is proportional to the product of its size and the square of its speed; the law of gravity [»leibGW4_1695]
Quote: equivalence of inert and gravitational mass by non-linear transformation of 4-d space [»einsA4_1950]
Quote: gravity does not use lines of force; it acts in straight lines independent of third bodies and time; can't be isolated [»faraM_1855, OK]
Quote: does gravity require time and hence a physical agency?; can't prove since gravity and matter are unchangeable [»faraM_1855, OK]
Quote: the gravitational attraction of the earth to the sun must have preexisted in the sun; otherwise how did it arise [»faraM_1855, OK]
Quote: gravitational power exists around every particle that has existence
Quote: an inertial space is a gravitational field with constant space-time functions

Subtopic: space requires material things up

Quote: if one removes a gravitational field, absolutely nothing remains; neither inertial space nor topological space [»einsA_1916b]
Quote: material points are not fundamental; reality is a continuous field with regions of high energy density [»einsA4_1950]
Quote: relativity: time and space disappear if all material things disappear [»briaD_1996]
Quote: physical space is a field of the continuous functions of space-time that depend on the physical contents of space [»einsA4_1950]
Quote: space is in reality amorphous and the things which are therein alone give it a form [»poinH_1908, OK]
Quote: the gravitational field determines the metrical laws of the space-time continuum; only infinitesimal regions are non-gravitational with Euclidean geometry [»einsA_1956, OK]
Quote: the gravitational field describes the topological and metrical properties of the manifold

Subtopic: gravity as accelerating frame of reference up

Quote: general theory of relativity from the equality of inertial and gravitational mass; applied to coordinate systems accelerated relative to each other [»einsA_1934]
Quote: a body in a gravitational field receives an acceleration which is independent of the body's material or physical state [»einsA_1916b]
Quote: coordinate systems for inertial systems and uniformly accelerated systems or gravitational systems are physically equivalent; makes general relativity much better than classical mechanics [»einsA_1956, OK]
Quote: a homogeneous gravitational field is exactly the same as a uniformly accelerating system of reference; absolute acceleration does not exist, and all bodies behave the same in a gravitational field [»einsA_1911]
Quote: a uniformly accelerating frame of reference is indistinguishable from a homogeneous gravitational field; source of the general theory of relativity [»einsA_1916b]
Quote: Poincare's view of geometry is correct; in a rotating system of reference, the laws of rigid bodies do not correspond to Euclidean geometry [»einsA_1923]

Subtopic: mass vs. energy up

Quote: a body which absorbs energy E_0 without changing velocity has the same energy as a body of mass m+E_0/c^2; hence the inertial mass of a system is equivalent to an energy of mc^2 [»einsA_1916b]
Quote: E= m c^2, i.e., mass and energy are essentially alike [»einsA_1956, OK]
Quote: the kinetic energy of an object in classical mechanics is the second term of the equation relating energy to mass and velocity

Subtopic: limitations of relativity up

Quote: relativity does not apply to size; every atom of iron has precisely the same magnitude [»briaD_1996]
Quote: in mechanics one can not reason from the small to the large; even though geometry is independent of scale [»galiG_1638]
Quote: perhaps quantum phenomena and relativity theory can not be unified: different mathematical domains, even false theories can be amazingly accurate [»wignEP2_1960]
Quote: Faraday failed to unify gravity and electricity
Quote: there is relatively little tobacco but it comes from a good field

Related Topics up

Topic: light (46 items)
Topic: Newtonian physics (79 items)
Group: philosophy of science   (10 topics, 406 quotes)
Topic: physics (51 items)
Topic: science as measurement (36 items)
Topic: special relativity (73 items)
Topic: the effect of scale (17 items)
Topic: time
(49 items)

Updated barberCB 5/05
Copyright © 2002-2008 by C. Bradford Barber. All rights reserved.
Thesa is a trademark of C. Bradford Barber.