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Complete list of spotlightsComplete Spotlights
Black holes, cosmology, gravitational waves - our "Spotlights on Relativity" section invites you to take a look at some of the many facets of relativity. The following is a complete list of all our current spotlight texts. All but a few of these texts are completely independent of each other, so you can browse to your heart's content - it would help, however, if you already had some previous ideas about relativity, on the level of our introduction Elementary Einstein. Special relativityMore about the foundations and applications of special relativity. Basics
The dialectic of relativityHow relativity can reconcile statements that, at first glance, appear to be contradictory Special relativity and timeMore about simultaneity, time dilation and the famous case of the travelling twin The definition of "now"Why it is necessary to define simultaneity, and how best to go about defining it. Time dilation on the roadHow you can picture the relativity of simultaneity and time dilation, using a simple geometric analogy Twins on the roadHow one can picture the situation of the travelling twin, using a simple geometric analogy Energy and massSome background information about the most famous formula in all of physics Is the whole the sum of its parts?Why Einstein's famous formula tells us that the whole, as far as mass is concerned, is often less than the sum of its parts From E=mc² to the atomic bombThe subtle connections between Einstein's formula, nuclear fission and nuclear fusion General relativityConcepts and applications of general relativity The basics of general relativity
The elevator, the rocket, and gravity: the equivalence principleInformation about the principle that Einstein took as a starting point for developing his general theory of relativity Gravity: from weightlessness to curvatureSo what is gravity in Einstein's theory? The answer: in part, an illusion; in part, an aspect of geometry. ...that all coordinate systems are created equalWhy, in general relativity, all observers are on an equal footing - and why, nevertheless, you can say that the earth orbits the sun, but not the other way around Mass and other sources of gravity
Mass and moreAn account of which physical properties act as sources of gravity - includes consequences for collapsing stars and for cosmology The gravity of gravityAn important property of gravity in Einstein's theory is that it can create more gravity. The result is "non-linearity" - the gravitational influence of two bodies isn't just the sum of their separate influences! Light in general relativity
Gravitational deflection of lightOn one of the fundamental consequences of general relativity: the deflection of light by gravity The equivalence principle and the deflection of lightThe connection between one of the fundamental principles of general relativity and the gravitational deflection of light A brief history of gravitational lensingHistorical sketch of the derivation of general relativity's prediction of gravitational lenses and subsequent astronomical observations Gravitational redshift and White Dwarf starsOne of the fundamental effects predicted by general relativity, and some of its astronomical applications Singularities
Spacetime singularitiesInformation about the most disturbing feature of Einstein's theory - ragged edges of spacetime known as singularities. Of singularities and breadmakingAbout some characteristic properties of spacetime near singularities - and the violent deformations they cause for any object unlucky enough to approach a singularity Numerical relativity
The realm of relativistic hydrodynamicsModeling relativistic fluids and the phenomena associated with them - from supernovae and jets to merging neutron stars From Newton to Einstein - and beyond
Varying Newton’s constant: A personal history of scalar-tensor theoriesInformation about a modification of Einstein's theory of general relativity in which the gravitational constant is not a constant. The mathematics behind general relativity
The many ways of building an empty, unchanging universeMore information on one particular answer to the question of how much variety is permitted in general relativity - how many ways are there of constructing a universe that is completely empty of all matter? Gravitational wavesMore about gravitational waves, how they are produced and how they can be detected Basic properties
The wave nature of simple gravitational wavesA closer look at the way that simple gravitational waves propagate through space with time Gravitational wave sources
Chirping neutron starsFor some gravitational wave signals, one can go beyond graphs and animations - they can be made audible White Dwarf binaries as gravitational wave sourcesWhite Dwarf binaries, their properties, and the role they will play for the planned space-borne gravitational wave detector LISA. On the road to detectionMore about gravitational wave detectors on earth and in space Listening posts around the globeOverview of the gravitational wave detectors currently operational, or under construction Einstein@Home - gravitational waves for everybodyInformations about how you personally can help with the search for gravitational wave - by donating processing time on your private computer Catching the wave with lightSome information on how interferometric detectors such as LIGO or GEO600 work Small vibrationsSome information on how the vintage models among gravitational wave detectors work - resonant detectors LISA - Hunting waves in spaceInformation about the most ambitious gravitational wave project yet - a detector in space Cosmological applications
Of gravitational waves and spherical chickensInformation about a class of simple model universes, each an expanding cosmos filled with gravitational waves Black Holes & Co.Black holes, neutron stars and supernovae: Flight into a black hole, the black hole in the center of the Milky Way, how many different kinds of black hole are there, how black holes light up their neighbourhood Close encounters with black holes
Descent into a black holeThe story of an expedition's closer and closer approach to a black hole - too close? How to track compact objectsMore about the gravitational influence of black holes and neutron stars on their cosmic surroundings, from the orbits of nearby stars to accretion disks and the associated luminous phenomena. The dark heart of the Milky WayInformation about the closest supermassive black hole - the central object of our own galaxy Luminous disks: How black holes light up their surroundingsHow the fact that black holes are very efficient in attracting surrounding matter leads to some of the most spectacularly luminous phenomena in the whole of the cosmos Active black holes: Ultra-hot cosmic beaconsWhat astronomers can see once a black hole has heated up its cosmic neighbourhood, stimulating it to emit bright radiation The physics of black holes
How many different kinds of black holes are there?Once they have settled down, there are actually only very few different kinds of black hole - find out which, and how black holes shed other distinguishing marks. Particle accelerators as black hole factories?The intriguing possibility that the next generation of particle accelerators might produce - and allow the detection of - miniature black holes Changing places - space and time inside a black holeHow, in one sense, space and time switch their roles inside a black hole - and why this leads to a black hole's most characteristic property, namely that nothing can get out Physics in the background
What figure skaters, orbiting planets and neutron stars have in commonSome information about what is called the conservation of angular momentum, and its consequences for neutron stars, black holes and the matter disks around them Heat that meets the eyeThe connection between temperature and the emission of electromagnetic radiation, as well as the consequences for stars, matter disks around black holes, and cosmology CosmologyThe big bang and all the rest: The geometry of the universe, the formation of the first light chemical elements, cosmology and quantum gravity Basics
A tale of two big bangsIn cosmology, "big bang" has two different meanings - and if you want to understand what's going on, you should be aware of that difference. The shape of spaceThe different space geometries allowed by the big bang models - do we live on a hypersphere? The mathematical universeWhy cosmology is not only a matter for astronomers and physicists, but also for mathematicians The cosmic background radiation
Cosmic Sound: Curvature and the cosmic background radiationHow the spatial geometry of the universe can be derived by observing the cosmic background radiation The first chemical elements
Big Bang Nucleosynthesis: Cooking up the first light elementsHow the first nuclei of helium, lithium and other light elements were cooked up shortly after the big bang Equilibrium and Change: The physics behind Big Bang NucleosynthesisThe physics behind Big Bang Nucleosynthesis, the period shortly after the big bang that saw the first production of light elements such as helium and lithium Elements of the past: Big Bang Nucleosynthesis and observationHow to reconstruct the abundances of light elements shortly after the big bang, and thus test some important predictions of the big bang models against observation Cosmology and quantum gravityMore information about possible cosmological consequences of the attempts to formulate a theory of quantum gravity. Searching for the quantum beginning of the universeAbout attempts to understand the beginning of our universe using different approaches to quantum gravity Avoiding the big bangThe collapsing and then re-expanding quantum universe that loop quantum gravity offers as a replacement of the standard big bang models Taming infinity with loopsHow loop quantum gravity could replace the absurd state of infinite density, the big bang with which, according to Einstein's relativity, the universe began Physics in the background
Heat that meets the eyeThe connection between temperature and the emission of electromagnetic radiation, as well as the consequences for stars, matter disks around black holes, and cosmology Relativity and the QuantumRelativistic quantum theory, string theory, loop quantum gravity and other attempts to unify Einstein's gravitation with quantum theory; the uses of extra dimensions; quantum gravity and the big bang General aspects of quantum gravitySome aspects of quantum gravity that are independent of which of the possible approaches is chosen. Actors on a changing stage: quantum gravity and background independenceThe principle of background independence - space and time are no fixed structure, but take part in the dynamical evolution of the world - and its consequences for the problem of quantum gravity String theoryMore about string theory - at present, mostly about the extra dimensions that play such a central role in that theory Extra dimensions - and how to hide themWhy our universe could possess dimensions beyond length, width and depth - and why those dimensions need not be noticeable in everyday life Particle accelerators as black hole factories?The intriguing possibility that the next generation of particle accelerators might produce - and allow the detection of - miniature black holes Hunting for extra dimensionsWays of detecting extra dimensions - and why the fact that our earth orbits the sun is a relevant data point Simplicity in higher dimensionsWhy matters that seem rather complicated might be much more simple in higher dimensions Loop quantum gravityMore about loop quantum gravity, in particular its cosmological applications. Avoiding the big bangThe collapsing and then re-expanding quantum universe that loop quantum gravity offers as a replacement of the standard big bang models Taming infinity with loopsHow loop quantum gravity could replace the absurd state of infinite density, the big bang with which, according to Einstein's relativity, the universe began Other approaches to the problem of quantum gravityWhile string theory and loop quantum gravity are the most prominent approaches to the problem of quantum gravity, they are not the only ones. Some other approaches are described in the following spotlights. Searching for the quantum beginning of the universeAbout attempts to understand the beginning of our universe using different approaches to quantum gravity Geometry from order: causal setsAn overview of the causal set approach to a theory of quantum gravity Physics in the backgroundUseful physics background information that may help with a better understanding of the other spotlight texts on this page. The sum over all possibilities: The path integral formulation of quantum theoryAbout the path integral approach to quantum theory Document Actions |
