GWs: General introduction

The topic I would like to ask or interrogate is how fourier analysis is used to sort out and measure the effects of a black hole merger by measuring the effects of GWs stretching and bending the arms of an interferometer.

A few pointers to get the audience interested in what GW’s are:

Gravitational waves are disturbances in the curvature (fabric) of spacetime, generated by accelerated masses, that propagate as waves outward from their source at the speed of light.

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Gravitational waves transport energy as gravitational radiation, a form of radiant energy similar to electromagnetic radiation.^[6] 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.

wikipedia

To begin with the in the essay, I want to have a general overview of what GWs are

• So there is this thing called spacetime,
• and its kind of like fabric?
• you can disturb it
• one way of disturbing the fabric is by accelerating masses
• this causes a radiation, which propagates as a wave
• this radiation is a gravitational wave
• it is an example of the limit of classical physics, as the group velocity of the propagated wave (gravity) travels at a finite speed, and not instantaneously 

After watching the following video: I made some notes below

Some interesting questions raised in the video early on, which I think would make a good starting point in the introduction, and that I would like to answer:

• What are gravitational waves?
  • what causes them?
    • celestial bodies merging
    • conservation of angular momentum
  • how are they propagated?
    • the elasticity of spacetime
  • what are their effects
• How are they detected?
  • detection equipment

GWs > what causes them?

From the video – Matt O’Dowd brings up some interesting points to talk about:

Any orbiting pair of massive objects generate GW’s

Only extremely massive objects orbiting extremely close together and produce GW strong enough for us to detect now

LIGO is sensitive to pairs of stellar mass black holes Neutron stars (Collapsed core of dead star -> stellar remnant)

Spacetime: LIGO’s first detection of gravitational waves