Gravitational radiation - The Nature of Gravitational Waves

Gravitational waves represent fluctatations in the metric of space-time. That is, they alter the relative distance between test particles. It follows that to directly detect a gravitational wave, you should in essence look for tiny relative motions between two objects. In the case of the LIGO detectors, this is essentially relative motion between two suspended mirrors, and as we saw above the motion to be detected is far smaller than the size of an atom, in fact smaller than the "size" of an atomic nucleus. Since thermal motion in each mirror is far larger than this, understa ...

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Gravitational radiation, Gravitational radiation - Overview, Gravitational radiation - The Nature of Gravitational Waves, Gravitational radiation - Sources of Gravitational Waves, Gravitational radiation - Detection, Gravitational radiation - Einstein@Home, Gravitational radiation - Prospects, Gravitational radiation - Derivation, Gravitational radiation - Perturbation of Flat Space-time, Gravitational radiation - Perturbation with Sources, Gravitational radiation - Far from Source Approximation, Gravitational radiation - Perturbative versus Exact, Gravitational radiation - Gravitational waves transmit energy

Read more here: » Gravitational radiation: Encyclopedia II - Gravitational radiation - The Nature of Gravitational Waves

Gravitational waves are caused by certain motions of mass or energy. The type of motion required is different from electromagnetism in one very important respect however: the strongest type of electromagnetic radiation is dipole radiation, while the strongest type of gravitational radiation is quadrupole radiation. [1] According to general relativity, the quadrupole moment (or some higher moment) of an isolated system must be time-varying in order for it to emit gravitational radiation. Here are some examples which illus ...

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Gravitational radiation, Gravitational radiation - Overview, Gravitational radiation - The Nature of Gravitational Waves, Gravitational radiation - Sources of Gravitational Waves, Gravitational radiation - Detection, Gravitational radiation - Einstein@Home, Gravitational radiation - Prospects, Gravitational radiation - Derivation, Gravitational radiation - Perturbation of Flat Space-time, Gravitational radiation - Perturbation with Sources, Gravitational radiation - Far from Source Approximation, Gravitational radiation - Perturbative versus Exact, Gravitational radiation - Gravitational waves transmit energy

Read more here: » Gravitational radiation: Encyclopedia II - Gravitational radiation - Sources of Gravitational Waves

Gravitational radiation - Perturbation of Flat Space-time. Consider that the full metric g is nearly the flat metric η plus some small perturbation h. gμν = ημν + hμν The Einstein equation in vacuum is Where R is the Ricci curvature. We will expand R in perturbatively in powers of See also:

Gravitational radiation, Gravitational radiation - Overview, Gravitational radiation - The Nature of Gravitational Waves, Gravitational radiation - Sources of Gravitational Waves, Gravitational radiation - Detection, Gravitational radiation - Einstein@Home, Gravitational radiation - Prospects, Gravitational radiation - Derivation, Gravitational radiation - Perturbation of Flat Space-time, Gravitational radiation - Perturbation with Sources, Gravitational radiation - Far from Source Approximation, Gravitational radiation - Perturbative versus Exact, Gravitational radiation - Gravitational waves transmit energy

Read more here: » Gravitational radiation: Encyclopedia II - Gravitational radiation - Derivation

Scientists are eager to directly measure gravitational waves from astronomical sources, as they can probe phenomena that are difficult or impossible to study with electromagnetic radiation. For instance, although a black hole emits no visible radiation in the way that a regular star does, gravitational waves can be emitted when an object falls into a black hole, or when two black holes collide. If the inspiraling mass is significantly smaller than the central black hole, the emitted gravitational waves may, at least in some circumstances, al ...

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Gravitational radiation, Gravitational radiation - Overview, Gravitational radiation - The Nature of Gravitational Waves, Gravitational radiation - Sources of Gravitational Waves, Gravitational radiation - Detection, Gravitational radiation - Einstein@Home, Gravitational radiation - Prospects, Gravitational radiation - Derivation, Gravitational radiation - Perturbation of Flat Space-time, Gravitational radiation - Perturbation with Sources, Gravitational radiation - Far from Source Approximation, Gravitational radiation - Perturbative versus Exact, Gravitational radiation - Gravitational waves transmit energy

Read more here: » Gravitational radiation: Encyclopedia II - Gravitational radiation - Prospects

Russell Alan Hulse and Joseph Hooton Taylor Jr. were awarded the Nobel Prize in Physics in 1993 for their observations of a remarkable binary pulsar, PSR B1913+16. According to general relativity, this system should emit gravitational radiation which carries off energy at a specific rate, which should in turn cause the orbit to decay at a rate of roughly 7 mm per day. This prediction agrees with the observations of Hulse and Taylor. But to directly detect gravitational waves you would have to look for any motion they cause. Typic ...

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Gravitational radiation, Gravitational radiation - Overview, Gravitational radiation - The Nature of Gravitational Waves, Gravitational radiation - Sources of Gravitational Waves, Gravitational radiation - Detection, Gravitational radiation - Einstein@Home, Gravitational radiation - Prospects, Gravitational radiation - Derivation, Gravitational radiation - Perturbation of Flat Space-time, Gravitational radiation - Perturbation with Sources, Gravitational radiation - Far from Source Approximation, Gravitational radiation - Perturbative versus Exact, Gravitational radiation - Gravitational waves transmit energy

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In Einstein's theory of General Relativity, gravitation is, essentially, identified with spacetime curvature. In the famous slogan promulgated by John Archibald Wheeler, matter tells spacetime how to curve, and spacetime tells matter how to move. For example, humans feel the ground pressing against their feet (or behind, according to stance). From the viewpoint of general relativity, this means that contact with the ground is preventing them from falling freely, thereby accelerating them. Since acceleration is identified with bending ...

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Gravitational radiation, Gravitational radiation - Overview, Gravitational radiation - The Nature of Gravitational Waves, Gravitational radiation - Sources of Gravitational Waves, Gravitational radiation - Detection, Gravitational radiation - Einstein@Home, Gravitational radiation - Prospects, Gravitational radiation - Derivation, Gravitational radiation - Perturbation of Flat Space-time, Gravitational radiation - Perturbation with Sources, Gravitational radiation - Far from Source Approximation, Gravitational radiation - Perturbative versus Exact, Gravitational radiation - Gravitational waves transmit energy

Read more here: » Gravitational radiation: Encyclopedia II - Gravitational radiation - Overview