Gravitons

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George Gamow - Thu, 21 Feb 2019 04:17:57 EST 5UfVWq6v No.57539

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While we were all out I was wondering about gravitons. If they're analogues of photons in a sense then gravitons should exist in a spectrum like photons, etc. Our ability to manipulate and understand the photon is pretty miraculous, but how would something like a prism for gravitons work? Prisms function with light because the speed of light in the medium is different than it is outside, what is there that could change the speed of a graviton or reflect it?

Roger Penrose - Fri, 22 Feb 2019 17:13:08 EST 457vC2+I No.57540 Reply

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>>Prisms function with light because the speed of light in the medium is different than it is outside, what is there that could change the speed of a graviton or reflect it?

Mass is the only thing that gravitons respond to, and since mass warps spacetime, it alters the speed of light around it. Gravity is the weakest of the fundamental forces and the hardest to interact with directly.

From my understanding, how the gravitational observatory LIGO functions is a kind of gravity prism. It has up to three different interferometers placed as specific distances from each other on the earth's surface, and since the earth's mass is relatively known, through triangulation they kind of use the whole planet as a graviton 'prism' by measuring the subtle oscillations of the pull of graviton waves breaking upon and rippling through the planet, slowing as they pass through it, measuring that slowness to build a map.

It's spawned a whole new field of gravitational wave astronomy which is honestly the most exciting prospect in the field, it's also incidentally the only reason we now really think gravitons are physically real and not just a construct.

Annie Cannon - Thu, 28 Feb 2019 00:33:41 EST aGo2dCNY No.57543 Reply

Lets say that somehow or other the Earth suddenly became twice as wide without gaining mass. In that wide-earth case the orbits in the two-body solution for the earth sun systems under newtonian mechanics wouldn't change at all, however if you were in a system in which gravitons were carrying the force of gravity then an Earth with a doubled radius would subtend 400% more area when viewed from the sun and the wide Earth would intercept 400% more gravitons and the orbital solution would change substantially.
Photon as an analog of gravitons seems like a reasonable concept on the surface, but when you explore the topic to further depth the concept starts to fall apart. How is it that gravitons and photons interact so readily if they're both such infinitesimal particles? If gravitational redshift, which seems an observed phenomenon (it has the rubber stamp of approval from astrophysical officialdom), is real then how are the gravitons affected in that situation? Are they blue shifted? What about with gravitational lensing? Would polarized light be affected by gravity variably based the polarization angle?

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Nicolaus Copernicus - Thu, 28 Feb 2019 14:21:12 EST 457vC2+I No.57544 Reply

>>57543

>> but when you explore the topic to further depth the concept starts to fall apart.

I think any analogy breaks down when you strain it beyond the point where it makes sense. You're drawing connections between photons and gravitons that no one is implying, I think.

>>How is it that gravitons and photons interact so readily if they're both such infinitesimal particles?

All particles are relatively infinitesimal and interact. Things even more infinitesimal than photons interact, and their interactions produce all higher order interactions. For all we know that very framing of the question is false, and they interact more readily because they are so infinitesimal (the smallness of the graviton could both account for its relative weakness as well as its ability to travel so far with such apparently low energy.)

>>If gravitational redshift, which seems an observed phenomenon (it has the rubber stamp of approval from astrophysical officialdom), is real then how are the gravitons affected in that situation?

Gravitational redshift is redshift of photons in a gravity well, not redshift of gravitons. Gravitons are deformations in spacetime still, just quantized. So they aren't red or blue shifted, they don't participate in the property of color at all because they aren't photons with a wavelength. The 'red/blue shifting' of photons that you see is already the interaction of gravitons with light.

>>Would polarized light be affected by gravity variably based the polarization angle?

It would seem not, and my understanding being that because the size of the Schwarzchild radius of a graviton, given its very very low mass, is so much smaller than that of the photon that even if the photon's wave is constrained to a plane (polarized) its angle of impact can't 'bend' the wave. At least that's what I get out of this abstract, apparently 'polarization isn't affected by gravitational lenses' is a frequently replicated finding:
https://iopscience.iop.org/article/10.3847/1538-4357/833/1/82

>>Considering the far-field approximation (i.e., the impact parameter is greater than the Schwarzschild radius and rotation parameter), the amount of rotation of the polarization vector as a function of impact parameter has been obtained for a rotating body (considering Kerr geometry). The present work shows that the rotation of the polarization vector cannot be observed in the case of Schwarzschild geometry. This work also calculates the rotational effect when considering prograde and retrograde orbits for the light ray. Although the present work demonstrates the effect of rotation of the polarization vector, it confirms that there would be no net polarization of an electromagnetic wave due to the curved spacetime geometry in a Kerr field.

Joseph-Louis Lagrange - Fri, 01 Mar 2019 01:01:44 EST aGo2dCNY No.57546 Reply

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>>57544

>I think any analogy breaks down when you strain it beyond the point where it makes sense

I agree, but stressing theory to the breaking point is what gedankenexperiment is all about. Thats one of the things I learned in school. I lot of people were convinced black holes existed well before any observations suggesting such a thing were made. They were able to estimate that these things were around based on thought experiments (gedankenexperiment) with extreme mass densities.
The case of a larger, less dense object intercepting more flux of gravitons could easily be explained away by the weakly interacting nature of the graviton. Observations of the moon during eclipse suggest that graviton shadowing doesn't happen. Somewhere or other I read that gravitons interact with matter at about the same rate as a neutrino, so they don't behave like a photon as far the graviton's force carrying concept goes.
To take an even broader view of the situation, it also seems unlikely that a person who has all of the modern distractions facing them 24/7 is likely to think up something better than some professional nerd from the 1950s who only had books and slide rules to look at, but neglecting that for the moment, its still a fascinating topic.
Given that gravity bends space and time in the way that it does, I don't even completely buy the idea that gravity is the force in question. If distances apparently increase as one travels towards a massive object then maybe the mass is emitting space.
Anyway its something interesting to think about. Kip Thorne has a thousand and one alternative cosmologies that he invented to match observations which have potential explanation outside the mainstream, one of which is that the expansion of the universe is due to the random winking into existence of a single hydrogen nuclei once every million years per cubic parsec. He doesn't believe any of his own bullshit I don't think.

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George Gamow - Fri, 01 Mar 2019 15:11:37 EST 457vC2+I No.57547 Reply

>>57546
You're pointing out the intellectual poverty on a meta-theoretic level of standard cosmology, and I think for some people that's so obvious as to not need statement, but most rank-and-file academics and science-literate people are still wholly convinced that LCDM has everything figured out, which is why we're stuck where we are. I think the reason you're seeing such a marked uptick in hangwringing over LCDM in the literature is precisely because the 'average' physicist has been exposed to these realities long enough to realize just how little ground they cover, and for just how long science is willing to wander into blind alleys, and are now figuring out how to communicate that to the faithful masses. Actually making a fundamental revolution in theory on the order you're suggesting (something that could recontextualize relativity) would create a shockwave in world affairs just as severe as Einstein's discovery did. So I would suggest it's not just that science has become dogmatic, or that scientists and people in general are buried under waves of distraction (which were all, incidentally, made possible by the scientific breakthroughs of the previous generation) but that the broader socio-cultural conditions aren't favorable to another drastic change. There are plenty of people who have alternative concepts, but it isn't in the zeitgeist to take them seriously, especially during the process of the breakdown of the current zeitgeist whose intellectual foundations lie in the previous wave of discovery.

So what I'm really saying is, wait 20 years. Breakthrough does not come out of comfort and distraction, it comes out of strife on the edge of oblivion. Einstein came up with relativity in a filthy trench under artillery bombardment -- and don't think that European academia's willingness to jettison the luminiferous aether in the face of relativity had nothing to do with national spirits broken by adherence to the previous centuries' failed philosophies and perspectives.

Democritus came up with the atom and Alexander of Hero came up with the steam engine thousands of years before either would become accepted and used, and not because of any particular flaw in their inventions, but because the broader social conditions were not favorable to an intellectual/cultural revolution at that time. So it is now for any bright physicist trying to find the holes in the standard model; only just now is the bulk of the science responding to the reality that a few luminaries could probably have told you in 1950: we're heading into a dead end. In 20 years a new generation will have come up with the failure of LCDM as their base view, and the time might be right for a change.

One last thing--

>>maybe the mass is emitting space.

Would this be observationally different than a curved space? Not saying you're wrong, but maybe you're just expressing a different way of verbalizing the exact same concept. If there is 'more' space in the same volume of space (the distance between point A and an egg and point A and a neutron star the size of the egg are the same, so a sphere with their centers at its circumference would have the same volume regardless of either's mass) then how could 'space' fit more 'space' in itself other than by curling it up/curving it? In fact I think that's a pretty succinct way of describing what's going on with gravity.

Thomas Henderson - Sat, 02 Mar 2019 02:52:25 EST aGo2dCNY No.57549 Reply

>>57547
All of what your wrote about societal unwillingness to accept new discoveries rings true even if does seem so stupid. Greeks could've had steamships, but they were already satisfied with what they had? Oh well, too bad for them I guess.
The Wright brother's invention wasn't acknowledged by the general public until years after they'd been flying.

The idea of space or time being created beyond the event horizon must be a retarded alternative explanation for the apparent expansion of the universe given that it takes place beyond the event horizon, I just pulled that one of out my ass when I was wondering what happens at the bottom of a gravity well when it changes from being part of the curvature to the XYZ plane into being a hole with sides that are nearly or eventually perpendicular to the XYZ plane.

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>>	Tycho Brahe - Mon, 20 May 2019 15:32:11 EST 9YXtXzja No.57712 Reply >>57539 There is no such thing as a graviton.

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