Gravitational waves Definition and 334 Threads

Gravitational waves are disturbances in the curvature of spacetime, generated by accelerated masses, that propagate as waves outward from their source at the speed of light. They were proposed by Henri Poincaré in 1905 and subsequently predicted in 1916 by Albert Einstein on the basis of his general theory of relativity. Gravitational waves transport energy as gravitational radiation, a form of radiant energy similar to electromagnetic radiation. Newton's law of universal gravitation, part of classical mechanics, does not provide for their existence, since that law is predicated on the assumption that physical interactions propagate instantaneously (at infinite speed) – showing one of the ways the methods of classical physics are unable to explain phenomena associated with relativity.
The first indirect evidence for the existence of gravitational waves came from the observed orbital decay of the Hulse–Taylor binary pulsar, which matched the decay predicted by general relativity as energy is lost to gravitational radiation. In 1993, Russell A. Hulse and Joseph Hooton Taylor Jr. received the Nobel Prize in Physics for this discovery. The first direct observation of gravitational waves was not made until 2015, when a signal generated by the merger of two black holes was received by the LIGO gravitational wave detectors in Livingston and in Hanford. The 2017 Nobel Prize in Physics was subsequently awarded to Rainer Weiss, Kip Thorne and Barry Barish for their role in the direct detection of gravitational waves.
In gravitational-wave astronomy, observations of gravitational waves are used to infer data about the sources of gravitational waves. Sources that can be studied this way include binary star systems composed of white dwarfs, neutron stars, and black holes; and events such as supernovae, and the formation of the early universe shortly after the Big Bang.

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  1. M

    Black Holes and Gravitational Waves

    As far as I know, a black hole is a singularity in the space-time. The space-time becomes so curved that the geodesics can't get out, i.e., the gravitational field becomes so strong that information can not get out. OK! But what about gravitational waves? As far as I know, gravitational waves...
  2. T

    Gravitational waves - second question

    Gravitational "waves" - second question Assuming our concept of the universe expanding (perhaps) and that the fabric of space time is expanding at the same rate as our galaxy and solar system (velocity equal, so relatively motionless), would we still be able to detect gravitational waves when a...
  3. M

    Are gravitational waves bent by gravity?

    Gravitational waves travel at the speed of light. So do they also bend around massive objects? If we had an extremely sensitive differential accelerometer, would we "feel" a distant star to be where we saw it? This would seem logical if you consider the curved path of light to really be a...
  4. T

    Gravitational Waves: Constant Motion Through Spacetime

    Gravitational "waves" First, I confess that I am not a physicist by training; I work for an RF engineering firm. However, I study theoretical and astrophysics from those who have the extensive math background, and attempt to conceptualize their theories. I am not a conspiratist, and I certainly...
  5. I

    Quantum Gravity in Relation to Gravitational Waves

    As I am fairly new here (been a lurker for a long while), I was not quite sure where to post this topic as it has Relativistic and Quantum Mechanical basis. Apologies if this is the incorrect place. It's not a homework question in any sense, but I'm doing a project for my Advanced Science...
  6. D

    Understanding Gravitational Waves and Their Impact on Entropy

    Ok so there are gravitational waves traveling through as constantly, and these waves carry energy. Since they travel through space unabsorbed, does this mean they are undetectable (by direct observation) and that the energy they contain cannot be restored? Lastly then does this mean...
  7. N

    Gravitational Waves and Potential

    What's the relationship between gravitational waves and (traditional/stationary) gravitational potential? Does the (traditional/stationary) potential become a "wave" under acceleration? Or do both exist under acceleration? Do both use energy from the source? I think I saw somewhere that GR...
  8. Q

    How mathy are gravitational waves?

    I'm about to head off to graduate school and (like many other physics students) I love theory, and especially GR, which is what my undergraduate research has been in. But, I'm also aware of the limitations on eventually finding a job. I'd eventually like to work. So, I've been tossing around...
  9. S

    Gravitational waves adn Black holes frequency

    I'm reading this paper "Exact Gravitational Quasinormal Frequencies of Topological Black Holes" ...By D. Birmingham and S. Mokhtari : http://arxiv.org/abs/hep-th/0609028v2" and now i confusing what are meaning of gravitational quasinormal modes of Topological Black holes?. Can...
  10. wolram

    Einstein@Home search for periodic gravitational waves in LIGO S4 data

    arXiv:0804.1747 [pdf, other] Title: The Einstein@Home search for periodic gravitational waves in LIGO S4 data Authors: LIGO Scientific Collaboration: B. Abbott, et al Comments: 29 pages, 19 figures Subjects: General Relativity and Quantum Cosmology (gr-qc) A search for periodic...
  11. Dale

    Exploring Gravitational Waves and the EFE

    How do you get gravitational waves or gravitons out of the EFE? It certainly doesn't look like a wave equation. Are there some second derivatives hidden in the Einstein tensor?
  12. S

    LIGO detects no gravitational waves from gamma ray burst

    On February 1, 2007, the Konus-Wind, Integral, Messenger, and Swift gamma-ray satellites measured a short but intense outburst of energetic gamma rays originating in the direction of M31, the Andromeda galaxy, located 2.5 million light-years away. The majority of such short (less than two...
  13. H

    General Relativity: gravitational waves

    Could you help explain this? I know this is what gravity is, correct? what does it mean when they say; when a object emits gravitational waves mass should decrees. and how exactly does the binary pulsar system PSR 1913+16 help explain this?
  14. A

    How Are Gravitational Waves Produced?

    This might seem simple... I'm having a bit of trouble both finding and interpretting information on how a gravitational wave is produced. I know they are analogous to EM waves, and that they are produced by accelerating masses, but it's more complicated than that, isn't it? Can anyone...
  15. V

    Gravitational Waves: Origin & Mass Impact

    How do gravitational waves originate? Does the mass of the body, from where they are originating,decrease?
  16. R

    Gravitational Waves from Mergers

    Why would gravitational waves be generated from the merging of two black holes or other types of mergers? What is different about the physical characteristics of the merged entity compared to the sum total of the pre-merged entities?
  17. M

    Does gravitational waves participate in gravitation interaction?

    Does gravitational waves participate in gravitation interaction?? Does gravitational waves participate in gravitation interaction?? When gravitational waves pass through the sun ,it will deflect?? Thank you in advance!
  18. quasar987

    Gravitational Wave Energy Transported by Unit Area

    Homework Statement I am given the form of the perturbation in the metric: h_{\mu\nu}=\left(\begin{array} {cccc} 0&0&0&0 \\ 0&1&0&0\\ 0&0&-1&0 \\ 0&0&0&0\end{array}\right) \gamma e^{-(z-t)^2} Where gamma<<1. That is to say, g_{\mu\nu}(\mathbf{r},t)=\eta_{\mu\nu}+h_{\mu\nu}(\mathbf{r},t) (we...
  19. M

    If I swing my arm, it can emit gravitational waves?

    If I swing my arm, it can emit gravitational waves?? If I swing my arm, it can emit gravitational waves?? Thank you in advance!
  20. D

    Rotational Symmetry & Gravitational Waves: Exploring the Connection

    Ok , during my study , I read that the bodies which are rotating spherically symmetrically do not emit GW;s as in don't dent the spacetime memberane...same is with the bodies moving with uniform velocity ...why is that??...has it something to do with conservation of angular momentum??:blushing:
  21. K

    What is the relationship between orbital energy and gravitational waves?

    The emission of gravational waves changes orbital energy right? If orbital energy O is a function of radius, what would O_{final}-O_{initial} be, using variables such as G, M, and r?
  22. N

    Gravitational waves everywhere ?

    Gravitational waves are usually associated with powerfull events (stars, black holes, etc.) but I just wonder if they are not also generated at more modest accelerations and masses. For instance when we accelerate a cup of coffee, or at the wing-flapping of a fly, a falling raindrop, etc. I...
  23. A

    Gravitational waves and negative energy.

    I was wondering what's the link between gravitational waves and negative energy, i heard that 'in the presence of large gravitational fields, negative energy fields are rather common' from one of michio kaku's book. what's the link between gravitational fields and gravitational waves/ gravity...
  24. R

    Can We Measure the Elusive Gravitational Waves?

    I'm trying to get my mind around this one. (stretching thin in the extreme) Black Holes Collide, and Gravity Quivers New York Times 05/02/2006 In the most precise effort yet to detect gravitational waves -- the quiverings of space-time predicted by Einstein's theory of general...
  25. J

    Understanding Gravitational Waves & Self-Taught GR

    Could someone please explain how gravitational waves are modeled within the theory? Is it some sort of time dependant metric, or is it simply an indirect consequence of the theory, etc.? Also, I am self-taught GR, and I learned almost everything I know about the theory straight out of...
  26. S

    Uncovering the Truth: Examining the Existence of Gravitational Waves

    A great recent article details the problems of GW's? http://www.physicstoday.org/vol-58/iss-9/p43.html#ref So do Gravitational Waves exist? This was meant to be placed in General forum!
  27. Garth

    Are Gravitational Waves Really Non-Existent? Examining the Evidence

    What do members think of http://arxiv.org/PS_cache/physics/pdf/0506/0506024.pdf paper? It reads as 'crackpot' to me, claiming as it does that gravitational waves cannot exist, however, it cites as supporting evidence the fact that GWs have not been detected yet. Is this a valid point? As...
  28. S

    Gravitational Waves of Early Universe

    Was the moment of 'first-light' or 'Lights-on' which occurred in the early Universe when Matter started to Shine 'light from the first galaxies', equivilent to the first Gravitational Wave signature from the Big-Bang? If one was do insinuate that the first primordial outward 'inflation' wave...
  29. X

    Gravitational Waves: Exploring the Validity of the Theory with Advanced LIGO

    If the advanced LIGO will not detect gravitational waves then is the theory dead?
  30. W

    Detect Gravitational Waves with LISA

    The LISA experimental setup is going to measure, or try and detect Gravitational Waves:http://lisa.jpl.nasa.gov/TECHNOLOGY/challenges.html I have been thinking about an experiment that Farady done in the RI lecture of some years ago, I recall a picture of Farady dropping cannonballs from the...
  31. K

    LIGO and speed of gravitational waves

    LIGO may have failed to detect gravity waves because they move faster than light and so have a greater wavelength than expected and probably a lower amplitude too.
  32. K

    LIGO and speed of gravitational waves

    LIGO may have failed to detect gravity waves because they move faster than light and so have a greater wavelength than expected and probably a lower amplitude too.
  33. H

    Gravitational waves and CMB polarization

    Gravitational waves generated during inflation should produce a special component in linear polarization in the CMB. Why? Could anyone give an easy qualitative explanation? Thanx.
  34. wolram

    Uncovering the Mystery of Gravitational Waves

    http://archive.ncsa.uiuc.edu/Cyberia/NumRel/GravWaves.html Eddington was not the only skeptic. Many physicists thought the waves predicted by the theory were simply a mathematical artifact. Yet others continued to further develop and test the concept. By the 1960s, theorists had showed...
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