How would gravitational field propulsion craft appear to an observer?

Shadowprophet

Truthiness
Produce? No. Repel, yes. Robert L. Forward provided a simple schematic for a device that can do that in his 1963 paper "Guidelines to Antigravity."


The demise of a black hole is a lot like that if Hawking was correct about Hawking radiation - in the final moments of black hole evaporation they would erupt in a blast of energy, emitting the last of their mass as high-energy radiation. In fact they looked for that signature in the LHC experiments, in case the higher-dimensional theories were correct, but they never saw it.


No, quantum field theory doesn't explain the existence of spacetime. Not in its current form anyway. General relativity is our model of spacetime, and - oddly, it doesn't speak the same language as quantum field theory (which is still a huge problem in theoretical physics; unifying the two).


No, gravity isn't a wave. In the weak field limit gravitational charge is analogous to electrical charge, with a reverse sign interaction, which is why Coulomb's law has the same structure as Newton's law of gravitation:

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Electromagnetic waves are radiated whenever an electric charge distribution has a changing charge dipole (or higher) moment, and gravitational waves are radiated whenever a mass distribution has a changing mass quadrupole (or higher) moment, but that doesn't mean that the electric and gravitational fields generating those waves, are waves themselves. Electric and gravitational charges have the same radial spherical symmetry.

Surprisingly though, electromagnetic waves can be converted into gravitational waves when they pass through a very intense magnetic field at the proper angle - this is called the Gertsenshtein effect:

"Wave resonance of light and gravitational waves," Mikhail Gertsenshtein, Soviet Physics Journal of Experimental and Theoretical Physics, 1961
http://www.jetp.ac.ru/cgi-bin/dn/e_014_01_0084.pdf

I've got to look up that guidelines to antigravity paper Thank you :D

That's why I love it when you're around, There's a lot to unpack here and when I do I will probably learn about seven months' worth of GR. How have you been Brother?
 

Shadowprophet

Truthiness
While you are around Brother Thomas, I wanted to get your thoughts on Naked Singularities, To my understanding, a completely hypothetical concept, in which a Singularity could exist without an event horizon.


Hmm, I'm off tracking the thread again, My bad, This would probably work better in another thread.
 
I've got to look up that guidelines to antigravity paper Thank you :D
That's one of my most prized possessions - you'll love it. He gives you the linearized gravitational equations for easily calculating inductive gravitational field effects in the weak field limit (gravity obeying the same mathematical structure as Maxwell's equations: gravitoelectric induction and gravitomagnetism etc., made easy ; )

And then he shows you how to create a gravitational dipole without any need for negative mass-energies - pretty epic stuff. It turns out that we've known how to generate an antigravitational field, theoretically anyway, since 1963.

That's why I love it when you're around, There's a lot to unpack here and when I do I will probably learn about seven months' worth of GR. How have you been Brother?
Yeah I've got all the dope physics papers, haha - hit me up when you're ready for your next fix =D

I'm good - been busy. Our Physics Frontiers podcast is now the third most popular physics podcast on the planet - behind only a BBC physics podcast (#1) and Sean Carroll's physics podcast (#2), so that's encouraging. It's kinda shocking because we only talk about the most advanced theoretical physics concepts in the academic literature - I had no idea that so many people could bear to listen to that level of discussion, but I'm delighted about it.

While you are around Brother Thomas, I wanted to get your thoughts on Naked Singularities, To my understanding, a completely hypothetical concept, in which a Singularity could exist without an event horizon.

Hmm, I'm off tracking the thread again, My bad, This would probably work better in another thread.
Yeah I kinda skirted around these issues earlier because they're only tangentially related to the topic.

I don't expect our current understanding of singularities to survive in the context of a unified field theory; at the very least their density will be non-infinite due to the Heisenberg uncertainty principle, imo. There are negative mass solutions to the Schwarzchild equation which do allow a negative mass naked singularity, like you were talking about before. Dr. Manu Paranjape and his grad students wrote some great papers that talked about that stuff a few years ago:

“On negative mass,” Jonathan Belletête and M. B. Paranjape, 2013
https://arxiv.org/pdf/1304.1566.pdf

“Negative mass bubbles in de Sitter space-time,” Saoussen Mbarek & M. B. Paranjape, 2014
https://arxiv.org/pdf/1407.1457.pdf
 

Shadowprophet

Truthiness
That's one of my most prized possessions - you'll love it. He gives you the linearized gravitational equations for easily calculating inductive gravitational field effects in the weak field limit (gravity obeying the same mathematical structure as Maxwell's equations: gravitoelectric induction and gravitomagnetism etc., made easy ; )

And then he shows you how to create a gravitational dipole without any need for negative mass-energies - pretty epic stuff. It turns out that we've known how to generate an antigravitational field, theoretically anyway, since 1963.


Yeah I've got all the dope physics papers, haha - hit me up when you're ready for your next fix =D

I'm good - been busy. Our Physics Frontiers podcast is now the third most popular physics podcast on the planet - behind only a BBC physics podcast (#1) and Sean Carroll's physics podcast (#2), so that's encouraging. It's kinda shocking because we only talk about the most advanced theoretical physics concepts in the academic literature - I had no idea that so many people could bear to listen to that level of discussion, but I'm delighted about it.


Yeah I kinda skirted around these issues earlier because they're only tangentially related to the topic.

I don't expect our current understanding of singularities to survive in the context of a unified field theory; at the very least their density will be non-infinite due to the Heisenberg uncertainty principle, imo. There are negative mass solutions to the Schwarzchild equation which do allow a negative mass naked singularity, like you were talking about before. Dr. Manu Paranjape and his grad students wrote some great papers that talked about that stuff a few years ago:

“On negative mass,” Jonathan Belletête and M. B. Paranjape, 2013
https://arxiv.org/pdf/1304.1566.pdf

“Negative mass bubbles in de Sitter space-time,” Saoussen Mbarek & M. B. Paranjape, 2014
https://arxiv.org/pdf/1407.1457.pdf

Thank you for the links brother :D I'm reading them now, I'm gonna download them and add them to my google drive :D

I guess to be extremely specific with my gravity to matter idea, Okay so, the theory is, When the big bang exploded, It was just unbelievable energy, and it was Via the Higgs field that matter came into being. I guess what I'm asking is, Could likewise an antigravity device interact with the Higgs field in any meaningful way? To be fair, Not that I fully understand the boson or the Higgs field, I'm just thinking of all that energy and force and if it would have any effect on the Higgs field.
 

nivek

As Above So Below
Bump...:Whistle:

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