Classroom Aid - Gravitational Wave Source Spectrum (4k)

text - howfarawayisit...
In this segment of the “How Fast Is It” video book, we cover Gravitational Waves. We examine just what a ‘ripple in space-time’ is. We’ll cover the wave properties and how they contract objects it encounters. We’ll examine binary star systems and the waves they create. This includes the properties of the binary encoded in the created gravitational wave including luminosity distance. We’ll use stars the size and mass of our Sun to calculate the expected amplitude and wavelength magnitudes. We’ll move from normal stars to neutron stars to stellar mass black holes. Along that progression, we’ll see their signature waveforms and build the gravitational wave sensitivity graph. We’ll cover the Hulse-Taylor pulsar (PSR B1913+16) and how it provided indirect evidence for the existence of gravitational waves. We’ll then cover direct detection with Michelson Interferometers. We’ll cover the LIGO technology and sensitivity and then examine the first detection event, and show how it fit the waveform and magnitudes for merging stellar black holes. We’ll include a look at the future of gravitational wave observatories. We’ll finish by covering the nature of gravitational waves created during the Big Bang and how they might be detected today.

[@mirzasafarov]

Thank you David!

[@RichardKCollins]

My Comments: Start by labeling collective long wavelengths "gravitational" and short wavelengths "electromagnetic"
David. I wanted to write this out, and your video prompted me to see if I can sketch is out clearly. Thanks for the source spectrum.
Gravitational waves are created at a sub atomic level. Whole stars worth of atoms might be involved but the underlying process is rates of changes of acceleration of mass, and change of mass to energy and back - for every tiny voxel at attometer scales. The vacuum is not empty. The energy density of the vacuum is intimately connected to the gluon plasma properties. And gluon states include turbulent and rigid (as in magnetic rigidity) vacuum states we label as mass.
The speed of light and the speed of gravity are identical (not close, identical for good reason) . Because they share the same underlying vacuum potential from which many kinds of waves at all frequencies emerge. Your diagram extends to the right to wavelengths less than 1 meter, to higher energies, higher frequencies, to the maximum we can observe.
"Electromagnetic photons" are simply the high frequency parts of one underlying potential field that fills the universe. At long wavelengths and long time scales (low frequencies) things "move" or "flow". We can only see part of longer cycles of things and most things are never repeated exactly. Symmetrical Fourier methods need to be modified and supplemented by time series spectral methods for non-repeating (aperiodic) sequences.
There are high energy density regions of varying sizes and shapes and textures that can be created by cavitation or heating or acceleration of the underlying vacuum. You can think of fields as many smaller regions of turbulence of that one vacuum field. The gravitational potential field (Joules/Kilogram, and Joules/meter^3, on the left side at 2:13) can have many small energy fluctuations over large regions MegaLightYears and GigaLightYear, or larger energy fluctuations in small regions attoMeters and smaller.
On the right side is electromagnetism and the coupling constants are all related through, primarily, magnetic properties of particles. The strong force can be cast as a vector field with 1/r^3 potential for rough approximations. Magnetic dipole and higher multipole states can be represented as solutions of the linear and nonlinear 3D electromagnetic wave equation. [ I use Schrodinger solitons and jets and knots a lot.]
At earth scale for ordinary things, the "gravitational" interactions are likely all emergent from large numbers of independent masses with energy stored in complex local interactions, but then combined at global scale using those larger regions and global scale (earth global) distances and correlation measured by femto and atto scale sensors.
"Gravitational" sources like seismic wave and motion of planets, atmospheres, ocean flows and tides and current and density variations can now be imaged in 3D with arrays of sensitive gravimeters and gradiometers using atomic interferometry, Bose Einstein condensate detectors, quantum state detectors (monitor the errors), and many other devices including MEMS gravimeters, atomic force accelerometers and rotation detectors. If the acceleration are small, they can be labeled "gravitational" if the source is large and the gravitational potential field is what mediates.
I say, a motion of mass remotely will "diffuse" at the speed of light and gravity to the detector. The signal from the sun arrives through diffusion of the potential from the sun to earth at the speed of gravity (and light). You calculate the local potential from Newtonian gravity using retarted locations, and then use a linear regression for each axis to have a unique instrument calibration. But if you are working less than 1 meter, we are only now getting fast detectors to determine the direction and strength of the signal for imaging. I guess if you have money you can work real time. But continuous lossless shared recording works for people around the earth and solar system to track seismic waves, coronal mass ejections, track planets and map the interiors of planets and the sun.
[ I am fairly certain neutrinos make up part of the the potential. What ever is in the vacuum, even if it is moving at the speed of light, that is part of the "potential field" at any place. ]
If you want to keep gravity and electromagnetism separate, then all the wavelengths less than 1 meter are going to also have gravitational waves. GHz gravitational, MHz electromagnetic, THz gravitational, milliHertz gravitational, nanoHertz electromagnetic. The difference in the rotational and vibration, flow and turbulence spectrum of the potential field. Probably the marketers will try to sell you a true gravitational drone when it is just a hacked up electromagnetic one using drone ESC and an STM 32.
Any aliens will likely be using gravitational communication systems, not electromagnetic, since the gravitational potential is finer grained and can pass more or less un-attenuated or refracted by matter and charges and electric fields. On earth a three axis gravimeter at superconducting gravimeter sensitivity or better makes a convenient "gravitational GPS for precise position" and "gravitational compass for precise three axis positioning". Because gravitational and magnetic fields both share the underlying potential field, they differ by spectrum and sources. The earth's magnetic field apparently emerges from deep convection flows in molten materials in the earth. Gravitational sensors are also sensitive to variations in "magnetic" fields. And by creating pulsed magnetic field which now can reach KiloTesla and more - one can move and modify things using magnetism to simulate gravitational acceleration fields.
"Gravitational engineering" is a real field of study now. Many groups have been working at it. First detectors, then communication, levitation with magnetic fields and inductive fields targeting properties of the materials. The "stuff" of the magnetic field is the potential field and it is fine grained enough to create gradients identical to those natural ones we call gravity or gravitational. Inside atoms and and for particles and in lasers, the intensities are sufficient to make KiloTesla, MegaTesla and perhaps larger magnetic fields. Then the gradient of the magnetic field or the magnetic pressure (magnetic pressure gradient force) is smooth enough to be an effective "gravitational" acceleration field source.
To lift the SpaceX second stage to mission speed and orbital height requires something like 36 two GigaWatt field generators. I do not know if it is more efficient to lift from the ground all the way, or to simply beam the energy to the craft or to create KeV bond strength "atomic fuels" and "atomic electric storage devices". But all the fields are routine engineering calculations, perhaps a bit new, but "let the human life critical certified AIs do it".
Richard Collins, The Internet Foundation

[@handwrittenjello]

I feel there's a new chapter cooking in the labs :)