Astronomy & Astrophysics 101: Gravitational Waves

Gravity Waves Black Hole Merger

This illustration shows the merger of two black holes and the gravitational waves that ripple outward as the black holes spiral toward each other. Credit: LIGO/T. Pyle

Gravitational waves are distortions in spacetime that result from the movements of objects with mass.

Gravitational waves are not simple conceptually, as they require one to think of the fabric of the Universe in terms of spacetime. Spacetime is a four-dimensional quantity, described by Einstein’s general theory of relativity, which fuses three-dimensional space with time. Mass warps spacetime, and gravity is actually the result of spacetime’s being curved by an object’s mass. Ripples through spacetime are created by the movement of any object with mass, and these are known as gravitational waves. Gravitational waves are constantly passing unnoticed through the Earth. Only the waves created by extremely intense events — events that result in very rapid changes in the velocity of very massive objects — can be detected by present-day instruments. The gravitational waves that are currently detectable on Earth are generated by incredibly dramatic collision events, such as when two black holes or neutron stars merge.


Gravitational waves are distortions in spacetime which result from the movements of objects with mass. Credit: ESO/L. Calçada

In 2017 Hubble observed for the first time the source of a gravitational wave, created by the merger of two neutron stars. This discovery was the first glimpse of multi messenger astronomy (in which coordinated observations and interpretations are undertaken of different astronomical signals), bringing together both gravitational waves and electromagnetic radiation.

Word Bank Gravitational Wave

Credit: NASA & ESA

Also in 2017, an international team of astronomers using Hubble uncovered a supermassive black hole that had been propelled out of the center of the distant galaxy 3C186. They concluded that it was likely ejected by the powerful gravitational waves unleashed by the merger of two massive black holes at the center of its host galaxy. This was the first time that astronomers found a supermassive black hole at such a large distance from the center of its host galaxy.

6 Comments on "Astronomy & Astrophysics 101: Gravitational Waves"

  1. Tangential Waves first discovered in 1997. The LIGO Crew can’t record this phenomenon by their super sensitive interferometer so far. I think all gravitational waves are big fake. In YouTube #TWBell2005.

  2. BibhutibhusanPatel | March 27, 2022 at 10:26 pm | Reply

    The aim of all gravitational waves detection are oriented to a specific direction so as to enable for study in a fixed pattern of GR.This is sole important factor,yet.The reason is that maximum possible velocity of matter can not excced the velocity of light,which is constant.Sò no anomaly ìn studies present.

  3. BibhutibhusanPatel | March 27, 2022 at 10:52 pm | Reply

    The aim of all gravitational waves detection are oriented to a specific direction so as to enable for study in a fixed pattern of GR.This is sole important factor,yet.The reason is that maximum possible velocity of matter can not excced the velocity of light,which is constant.Sò no anomaly ìn studies present.

    Galaxies’ internal framework of stars show General Relativity to hold good.Resolution can produce other component due to rotation,defined by star dynamics.

  4. BibhutibhusanPatel | March 27, 2022 at 11:19 pm | Reply

    The aim of all gravitational waves detection are oriented to a specific direction so as to enable for study in a fixed pattern of GR.This is sole important factor,yet.The reason is that maximum possible velocity of matter can not excced the velocity of light,which is constant.Sò no anomaly ìn studies present.

    Galaxies’ internal framework of stars show General Relativity to hold good.Resolution can produce other component due to rotation,defined by star dynamics.
    One restriction is there,that Einstein’s theory of General Relativity simply able to predict effect of mass,without going to any detail of its origin.Or a physical descriptìon of Theory’s root is not found.So this can be deduced that GR is simply extension of Newton’s Law of Gravitation with conrelation of fourth Time Dimension.

  5. Bob Matheson | March 28, 2022 at 8:35 am | Reply

    Let’s call the entire visible universe (including Webb’s range) 1 VU (One VU); why is it not possible that what we think of the expansion of the universe, as simply, a ride on a tiny portion of a massive gravitational wave, whose wavelength is thousands of VU’s long? Such a small portion of a large wave would simply appear to be an endlessly expanding universe (or the opposite).
    (By the way the real reason for the expansion of the universe is; social distancing!)

  6. Very Interesting. Some Thoughts.

    1. Why do we think Space Deserves three dimensions and Time only one? Either Space should be treated as a single dimension (Not linear Length, Breath and Height– it could be non-linear) or Time should be treated as three dimensional (Past, Present and Future)! I prefer a two dimensional Space-Time.

    2. Einstein Energy – Matter equivalence I need not elaborate on. Only two phases visible matter and non-matter=Energy.

    3. Schrddingers Cat which is alive and dead simultaneously I dont need to go into this.

    4. So either we live in a 2-D world or a 6-D world.

    5. Assume that Speed of Light is not the Speed limit. Refer “2 Physics Girls Relative Speed”. This will make Enstien equivalence of Energy- Matter limitation by Speed of light in the gross world, a sub-set of the theory of Everyhing. Don’t know enogh about the quantum space.

    6. Assume Cosmic Consciousness at indivisible sub-atomic level, with unlimited connectedness to all Matter and Energy. Bose-Einstein Condensate. Explains Spooky!

    7. Now rework theory of everything mathematics, which fits ALL known universe related phenomenon. Not attempting to explain unknown universe.

    8. Coming to Gravity. Matter attract of repel each other depending on charge. We can use this property of matter to surf the Universe using the force of Gravity as a slingshot to travel through space. Have always wondered about the viscosity of Space. If it has none we shold be in free fall upwards in space, instead of floatng in it? The effect of Gravity waves is reduced considerably and not Zero in space!

    Views expressed are personal and not binding on anyone.

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