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(Guardian)   Has the problem of Dark Energy been solved by Massive Gravity? Once we get the gravitational wave telescopes up and running, then we'll know for sure. Maybe we should get Space Farce involved   (theguardian.com) divider line
    More: Interesting, General relativity, Universe, Dark matter, Prof Claudia de Rham, Physical cosmology, De Rham, inward tug of gravity, latest acknowledgement of the breakthrough  
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1052 clicks; posted to Geek » on 26 Jan 2020 at 4:02 AM (23 weeks ago)   |   Favorite    |   share:  Share on Twitter share via Email Share on Facebook



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2020-01-26 2:47:13 AM  
Gravitons have mass?  Then how can they travel at the speed of light (as they seem to be doing)?
 
2020-01-26 3:58:00 AM  
In Einstein's version, gravitons are assumed to be massless.

This is complete shiate.  Gravitons are part of the standard model attempt to reconcile quantum mechanics with Einstein's general relativity, which had no particle interactions.

Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.
 
2020-01-26 4:33:48 AM  

syrynxx: In Einstein's version, gravitons are assumed to be massless.

This is complete shiate.  Gravitons are part of the standard model attempt to reconcile quantum mechanics with Einstein's general relativity, which had no particle interactions.

Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.


Um, that's exactly what "dark energy" means. Dark means we can't detect it, and it's accelerating mass so it's energy.
 
2020-01-26 5:45:29 AM  
There's a joke in here somewhere involving Massive Attack and Gravity Kills
 
2020-01-26 6:21:32 AM  

syrynxx: Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.


Speaking of morons, every scientist I've heard talk about dark energy says it's just a placeholder for something we don't understand yet.  Same with dark matter.

Moron.
 
2020-01-26 6:34:32 AM  

syrynxx: Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.


Yes, we should just call it "stuff we don't understand." Only there's lots of things we don't understand, so we should get a little more specific. So we can call it "the stuff we don't understand because we don't have much direct evidence for it but which we can infer causes the acceleration we can observe but don't understand."

Only that's a mouthful and would be very hard to write over and over again, and fortunately we have a term for "stuff that causes acceleration": energy. So we could maybe refine your idea by calling it "the energy we don't understand because we don't have much direct evidence for it."

Even that's a bit long though. Maybe we could take a page from historians, though, who sometimes refer to various historical periods we don't understand very well due to a lack of direct evidence as "dark" ages.

So we could maybe refine your idea a bit more by calling it "dark" "energy" then.

I don't know why those moron scientists don't follow your lead and do that.
 
2020-01-26 7:15:51 AM  
Dark energy is God playing hockey with the observable universe. Prove me wrong.
 
2020-01-26 7:22:30 AM  

Sgygus: Gravitons have mass?  Then how can they travel at the speed of light (as they seem to be doing)?


We can't tell the difference between the speed of light and the speed of neutrinos either and we know that neutrinos have a tiny mass.  So this reasoning does not rule out gravitons with mass but merely  puts an upper bound to the mass--a very tiny upper bound.

If her idea turns out to be true then two particles once thought to be massless will have mass. Would we need to consider photons? If they had mass then they too would not travel at the "speed of light" i.e. c. I would not bet on that ideas though it would be funny if the speed of light in a vacuum  was very slightly under the "speed of light in a  vacuum."
 
2020-01-26 8:03:00 AM  

pkjun: syrynxx: Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.

Yes, we should just call it "stuff we don't understand." Only there's lots of things we don't understand, so we should get a little more specific. So we can call it "the stuff we don't understand because we don't have much direct evidence for it but which we can infer causes the acceleration we can observe but don't understand."

Only that's a mouthful and would be very hard to write over and over again, and fortunately we have a term for "stuff that causes acceleration": energy. So we could maybe refine your idea by calling it "the energy we don't understand because we don't have much direct evidence for it."

Even that's a bit long though. Maybe we could take a page from historians, though, who sometimes refer to various historical periods we don't understand very well due to a lack of direct evidence as "dark" ages.

So we could maybe refine your idea a bit more by calling it "dark" "energy" then.

I don't know why those moron scientists don't follow your lead and do that.


I much enjoyed this post.
 
2020-01-26 8:03:35 AM  

PainInTheASP: Dark energy is God playing hockey with the observable universe. Prove me wrong.


As with all things... prove yourself correct first.
 
2020-01-26 8:17:10 AM  

syrynxx: In Einstein's version, gravitons are assumed to be massless.

This is complete shiate.  Gravitons are part of the standard model attempt to reconcile quantum mechanics with Einstein's general relativity, which had no particle interactions.

Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.


Oh man, imagine if Fark had a downvote option. Lucky you.
 
2020-01-26 8:17:25 AM  

TheMysteriousStranger: Sgygus: Gravitons have mass?  Then how can they travel at the speed of light (as they seem to be doing)?

We can't tell the difference between the speed of light and the speed of neutrinos either and we know that neutrinos have a tiny mass.  So this reasoning does not rule out gravitons with mass but merely  puts an upper bound to the mass--a very tiny upper bound.

If her idea turns out to be true then two particles once thought to be massless will have mass. Would we need to consider photons? If they had mass then they too would not travel at the "speed of light" i.e. c. I would not bet on that ideas though it would be funny if the speed of light in a vacuum  was very slightly under the "speed of light in a  vacuum."


What's important Is measuring the spectrum of graviton energies/mass calculated from times of arrival from an event. Thus the referral to the rainbow in the article. Yoji Kondo (also a scifi writer) et al. did similar with neutrinos from SN1987a to set an upper bound on neutrino masses. Not exactly sure what they have in mind here but probably just looking for unexplained factors in time of arrival after an event as higher mass gravitons will arrive later.
 
2020-01-26 9:35:48 AM  
Arguing about physics on Fark is stoopid, when there are "I lahk hur, she purdy" comments needing to be made.

i.guim.co.ukView Full Size
 
2020-01-26 10:03:01 AM  

dryknife: Arguing about physics on Fark is stoopid, when there are "I lahk hur, she purdy" comments needing to be made.

[i.guim.co.uk image 300x180]


You mean like
I'd teach her the meaning of Plank's Constant
/I am so shameful
 
2020-01-26 10:11:21 AM  

dryknife: Arguing about physics on Fark is stoopid, when there are "I lahk hur, she purdy" comments needing to be made.

[i.guim.co.uk image 300x180]


Boulder shoulder, would not inflate
 
2020-01-26 11:08:10 AM  

FarkaDark: dryknife: Arguing about physics on Fark is stoopid, when there are "I lahk hur, she purdy" comments needing to be made.

[i.guim.co.uk image 300x180]

You mean like
I'd teach her the meaning of Plank's Constant
/I am so shameful


So you are saying that your penis is a Planck length long?
 
2020-01-26 11:42:28 AM  

TheMysteriousStranger: We can't tell the difference between the speed of light and the speed of neutrinos either and we know that neutrinos have a tiny mass.


They key difference here is that to measure the speed of the neutrinos we must also produce the neutrinos (so that we know when and where the particle originates). This means the upper distance we're measuring is, astronomically, quite small, so the difference in speeds is hard to detect.

With gravity, especially gravitational waves, we can measure their speed much more accurately because we can measure from distant cosmological events. Even small differences in speed between gravitons and photons would be very obvious in the way gravitational waves propagate.

And wouldn't you know, but it sounds like gravitational wave observations have definitely created issues for the massive gravity theory. Specifically: while the gravitational wave observations don't confirm complete masslessness, they both set a very very low limit on mass and contain observations which massive gravity can't account for in terms of particle wavelengths.
 
2020-01-26 12:29:08 PM  

dsmith42: FarkaDark: dryknife: Arguing about physics on Fark is stoopid, when there are "I lahk hur, she purdy" comments needing to be made.

[i.guim.co.uk image 300x180]

You mean like
I'd teach her the meaning of Plank's Constant
/I am so shameful

So you are saying that your penis is a Planck length long?


Did I not mention shameful?
 
2020-01-26 12:47:12 PM  

dsmith42: So you are saying that your penis is a Planck length long?


Not really a factor if he's only going to last Planck time anyway.
 
2020-01-26 1:37:01 PM  

t3knomanser: TheMysteriousStranger: We can't tell the difference between the speed of light and the speed of neutrinos either and we know that neutrinos have a tiny mass.

They key difference here is that to measure the speed of the neutrinos we must also produce the neutrinos (so that we know when and where the particle originates). This means the upper distance we're measuring is, astronomically, quite small, so the difference in speeds is hard to detect.

With gravity, especially gravitational waves, we can measure their speed much more accurately because we can measure from distant cosmological events. Even small differences in speed between gravitons and photons would be very obvious in the way gravitational waves propagate.

And wouldn't you know, but it sounds like gravitational wave observations have definitely created issues for the massive gravity theory. Specifically: while the gravitational wave observations don't confirm complete masslessness, they both set a very very low limit on mass and contain observations which massive gravity can't account for in terms of particle wavelengths.


Neutrinos also have been observed from an event outside of the Galaxy: Supernova 1987A. From that we can conclude that neutrinos travel VERY close to the speed of light and indeed this was cited at the time as evidence that they did travel at the speed of light. If neutrino oscillation had not observed, massless neutrinos would still be the orthodox view in physics.

And while if forced to bet I'd say that gravity is massless, the debates on the neutrino which I've observed for a few decades tells me that I'd rather not bet on this issue.
 
2020-01-26 1:46:48 PM  

Wave Of Anal Fury: Speaking of morons, every scientist I've heard talk about dark energy says it's just a placeholder for something we don't understand yet. Same with dark matter.



dark matter seems to have independent existence - that is if one accepts the observations of clumps of dark matter that are not predictable from their surroundings.

I don't know of any claims of observation or measurement of dark energy that could answer the questions:

1. Is dark energy a uniform property of space?
2. Does dark energy depend on local properties such as mass or photon energy production? Or can you find clumps in otherwise empty space?

I
 
2020-01-26 1:49:01 PM  
"If it does, gravitational rainbows would exist..."

Approves:
Fark user imageView Full Size


(That's Thomas Pynchon, author of Gravity's Rainbow.)
 
2020-01-26 1:57:46 PM  

syrynxx: In Einstein's version, gravitons are assumed to be massless.

This is complete shiate.  Gravitons are part of the standard model attempt to reconcile quantum mechanics with Einstein's general relativity, which had no particle interactions.

Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.


Ummm ... that is, literally, what "dark" means, in this context.
 
2020-01-26 2:10:38 PM  

t3knomanser: TheMysteriousStranger: We can't tell the difference between the speed of light and the speed of neutrinos either and we know that neutrinos have a tiny mass.

They key difference here is that to measure the speed of the neutrinos we must also produce the neutrinos (so that we know when and where the particle originates). This means the upper distance we're measuring is, astronomically, quite small, so the difference in speeds is hard to detect.

With gravity, especially gravitational waves, we can measure their speed much more accurately because we can measure from distant cosmological events. Even small differences in speed between gravitons and photons would be very obvious in the way gravitational waves propagate.

And wouldn't you know, but it sounds like gravitational wave observations have definitely created issues for the massive gravity theory. Specifically: while the gravitational wave observations don't confirm complete masslessness, they both set a very very low limit on mass and contain observations which massive gravity can't account for in terms of particle wavelengths.


It's entirely possible it's another piece of the puzzle, but not the final piece. That's why science is awesome.

It's like reading a story - sometimes you turn a page and get a little bit of foreshadowing, other times your turn the page and everything changes.
 
2020-01-26 2:28:59 PM  

Boudyro: It's entirely possible it's another piece of the puzzle, but not the final piece.


It's possible, but also unlikely. Remember: gravitons only exist as a mathematical construct, and create all sorts of problems when we try and glue the standard model to relativity. So we're already a few layers of "well, maybe..." deep.

Which, admittedly, is a LOT of particle physics. But gravitons are in a weird place, because they are by no means a requirement of the standard model, and we can certainly construct models which predict gravitons, we're trapped in the knot of: "I can build a model which predicts everything we observe, but is it right?"

So we're dealing with a particle we have no reason to believe exists beyond: "Well, something has bend spacetime! Something has to cause acceleration!" "Why do masses attract, Todd!?" "I don't know Margo!", and now ascribing properties to it which explain a phenomenon which does definitely exist (the universe is definitely expanding!). That's very convenient, but very unlikely to be true.
 
2020-01-26 3:00:26 PM  

syrynxx: In Einstein's version, gravitons are assumed to be massless.

This is complete shiate.  Gravitons are part of the standard model attempt to reconcile quantum mechanics with Einstein's general relativity, which had no particle interactions.

Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.


That's embarrassing
 
2020-01-26 3:32:11 PM  

t3knomanser: Boudyro: It's entirely possible it's another piece of the puzzle, but not the final piece.

It's possible, but also unlikely. Remember: gravitons only exist as a mathematical construct, and create all sorts of problems when we try and glue the standard model to relativity. So we're already a few layers of "well, maybe..." deep.

Which, admittedly, is a LOT of particle physics. But gravitons are in a weird place, because they are by no means a requirement of the standard model, and we can certainly construct models which predict gravitons, we're trapped in the knot of: "I can build a model which predicts everything we observe, but is it right?"

So we're dealing with a particle we have no reason to believe exists beyond: "Well, something has bend spacetime! Something has to cause acceleration!" "Why do masses attract, Todd!?" "I don't know Margo!", and now ascribing properties to it which explain a phenomenon which does definitely exist (the universe is definitely expanding!). That's very convenient, but very unlikely to be true.


Can theory work without a glitch and still be wrong?
 
2020-01-26 3:39:43 PM  

LewDux: Can theory work without a glitch and still be wrong?


I have a theory that I'm not sleeping with Alison Brie because she's too shy to call me.
 
2020-01-26 4:19:20 PM  

LewDux: Can theory work without a glitch and still be wrong?


... yes? It's not enough to "retrodict" current observations, you must also make new, testable predictions. So, for example, Superstring Theory is promising because it's a master of the retrodiction, and while it makes new predictions, there's no way to test them.

Or, to put it another way: if you're watching a magician do a trick, "it's actually magic" works without a glitch for explaining the trick, but it's also wrong.
 
2020-01-26 4:28:17 PM  

Wave Of Anal Fury: syrynxx: Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.

Speaking of morons, every scientist I've heard talk about dark energy says it's just a placeholder for something we don't understand yet.  Same with dark matter.

Moron.


sounds better than known unknown matter.
 
2020-01-26 4:30:21 PM  

Wave Of Anal Fury: syrynxx: Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.

Speaking of morons, every scientist I've heard talk about dark energy says it's just a placeholder for something we don't understand yet.  Same with dark matter.

Moron.


I don't think it (Dark Energy and Matter) is a placeholder.

I think it is evidence that the models are wrong.

Much like Mercury's orbit was evidence that Newton was wrong, these two kludges being inserted to balance equations is proof the Einstein and the current Standard Model is wrong. I suspect that we aren't going to suddenly discover what is behind Dark Matter and Energy, we are going to build a better model and there won't be dark anything anymore.

It would be nice if they could wrap this up in my lifetime. Out of the box thinking which focuses on the nature of gravity is probably a good place to start.
 
2020-01-26 5:10:16 PM  

madgonad: I don't think it (Dark Energy and Matter) is a placeholder.

I think it is evidence that the models are wrong.


The observed phenomenon is what it is. We don't have a model that accounts for it, so by definition, our models are wrong.
 
2020-01-26 5:11:46 PM  

TheMysteriousStranger: Sgygus: Gravitons have mass?  Then how can they travel at the speed of light (as they seem to be doing)?

We can't tell the difference between the speed of light and the speed of neutrinos either and we know that neutrinos have a tiny mass.  So this reasoning does not rule out gravitons with mass but merely  puts an upper bound to the mass--a very tiny upper bound.

If her idea turns out to be true then two particles once thought to be massless will have mass. Would we need to consider photons? If they had mass then they too would not travel at the "speed of light" i.e. c. I would not bet on that ideas though it would be funny if the speed of light in a vacuum  was very slightly under the "speed of light in a  vacuum."


I've long theorized that what we think of as "C" isn't truly a constant, because we've never measured it outside of our gravity well in our solar system. Our SS is gravitationally dense compared to intergalactic space, and I firmly believe that a lot of stuff makes more sense if you realize that the speed of light is faster out there where gravity isn't dense. It would also explain the apparent acceleration of distant galaxies, if the light traveling from them is going much faster than we think through the gravitationally sparse stretches.

IE, locally is the equivalent of thick glass that slows light down compared to thin air which doesn't.

Unfortunately, while I am a mathematician, I don't have enough background in theoretical physics to even start justifying the idea, but this conceptual piece fits in with the rest of what is needed to make it work.
 
2020-01-26 5:35:56 PM  
Of all the potential headlines the best we could do was two bland sentences and a dig a space force?

"Gravitons may be Catholic"

"Einstein gains weight"

"Marty McFly solves cosmological puzzle"

Fark user imageView Full Size
 
2020-01-26 5:47:48 PM  

Guildmaster: because we've never measured it outside of our gravity well in our solar system.


We haven't "measured" c. We've derived it, mathematically. It just so happens that photons propagate at c. The speed of light doesn't define c, c defines the speed of light.
 
2020-01-26 6:16:37 PM  

t3knomanser: Guildmaster: because we've never measured it outside of our gravity well in our solar system.

We haven't "measured" c. We've derived it, mathematically. It just so happens that photons propagate at c. The speed of light doesn't define c, c defines the speed of light.


Measure the speed of light at home! Minute Science
Youtube ky_HkElHgaM
 
2020-01-26 6:28:54 PM  

t3knomanser: Guildmaster: because we've never measured it outside of our gravity well in our solar system.

We haven't "measured" c. We've derived it, mathematically. It just so happens that photons propagate at c. The speed of light doesn't define c, c defines the speed of light.


Photons, and pirates.
 
2020-01-26 7:16:03 PM  

FarkaDark: dryknife: Arguing about physics on Fark is stoopid, when there are "I lahk hur, she purdy" comments needing to be made.

[i.guim.co.uk image 300x180]

You mean like
I'd teach her the meaning of Plank's Constant
/I am so shameful


You think a theoretical physicist needs to be taught the meaning of Planck's constant?
 
2020-01-26 7:37:43 PM  

Gordon Bennett: FarkaDark: dryknife: Arguing about physics on Fark is stoopid, when there are "I lahk hur, she purdy" comments needing to be made.

[i.guim.co.uk image 300x180]

You mean like
I'd teach her the meaning of Plank's Constant
/I am so shameful

You think a theoretical physicist needs to be taught the meaning of Planck's constant?


I case you missed it they are talking about a theoretical physicist, with decades of education, who is part of a team that might have been smart enough to modify freaking Einstein, like she is a piece of meat.

Assessing her as a person does not appear to be high on the agenda.
 
2020-01-26 7:50:18 PM  

Guildmaster: TheMysteriousStranger: Sgygus: Gravitons have mass?  Then how can they travel at the speed of light (as they seem to be doing)?

We can't tell the difference between the speed of light and the speed of neutrinos either and we know that neutrinos have a tiny mass.  So this reasoning does not rule out gravitons with mass but merely  puts an upper bound to the mass--a very tiny upper bound.

If her idea turns out to be true then two particles once thought to be massless will have mass. Would we need to consider photons? If they had mass then they too would not travel at the "speed of light" i.e. c. I would not bet on that ideas though it would be funny if the speed of light in a vacuum  was very slightly under the "speed of light in a  vacuum."

I've long theorized that what we think of as "C" isn't truly a constant, because we've never measured it outside of our gravity well in our solar system. Our SS is gravitationally dense compared to intergalactic space, and I firmly believe that a lot of stuff makes more sense if you realize that the speed of light is faster out there where gravity isn't dense. It would also explain the apparent acceleration of distant galaxies, if the light traveling from them is going much faster than we think through the gravitationally sparse stretches.

IE, locally is the equivalent of thick glass that slows light down compared to thin air which doesn't.

Unfortunately, while I am a mathematician, I don't have enough background in theoretical physics to even start justifying the idea, but this conceptual piece fits in with the rest of what is needed to make it work.


Wouldn't that affect insterstellar gravitational lensing?
 
2020-01-26 8:23:42 PM  

madgonad: Wave Of Anal Fury: syrynxx: Dark Energy is shiate too.  Just call it "Stuff we don't understand" and have a bit of self-respect.  Morons.

Speaking of morons, every scientist I've heard talk about dark energy says it's just a placeholder for something we don't understand yet.  Same with dark matter.

Moron.

I don't think it (Dark Energy and Matter) is a placeholder.

I think it is evidence that the models are wrong.

Much like Mercury's orbit was evidence that Newton was wrong, these two kludges being inserted to balance equations is proof the Einstein and the current Standard Model is wrong. I suspect that we aren't going to suddenly discover what is behind Dark Matter and Energy, we are going to build a better model and there won't be dark anything anymore.

It would be nice if they could wrap this up in my lifetime. Out of the box thinking which focuses on the nature of gravity is probably a good place to start.


The problem which took over half a century to resolve from the first serious observations of the anomalous perihelion precession of Mercury wasn't inventing a modification of Newtonian gravity that would do that, it was inventing one that would do that AND do everything else exactly the same.

Coming up with a new theory that does what we need quantized spacetime to do AND is compatible with all existing observations (which is a bunch of them!) is extremely difficult.

Coming up with one that actually generates useful and conceivably-testable predictions, rather unlike string theory, is even harder.
 
2020-01-26 8:27:02 PM  

dryknife: Arguing about physics on Fark is stoopid, when there are "I lahk hur, she purdy" comments needing to be made.

[i.guim.co.uk image 300x180]


Add some glasses and she's half way to Hot Librarian.
 
2020-01-26 8:53:59 PM  

t3knomanser: We've derived it, mathematically.


Based on models we know are incomplete and with fudge factors, and based solely on experiments carried out in our gravity well. There's no pure equation that "derives" c without relying on these things.

WelldeadLink: Wouldn't that affect insterstellar gravitational lensing?


Gravitational lensing is already where you get hints that things might not be right with the current model. But I don't think that changing the theory would affect it the way you're thinking.

TedCruz'sCrazyDad: t3knomanser


Great video, but misses the point. That experiment takes place in a very dense gravitational area, not in a very sparse gravitational area. My entire point is that we *have no experiments we can conduct* that aren't under these conditions.
 
2020-01-26 9:02:34 PM  
In one of the intros to one of Dr Feynman's books he goes on to say any complex theory in science has been wrong and replaced by something much more simple.  He goes on to talk about alchemy and epicycles for planetary motion and how the theories got worse as they added more stuff on. The book then goes on about quantum mechanics.  The intro was almost like "the rest of this is most certainly wrong but it is all we have for now"

Is the "speed of light" that constant that should be used?  We know the speed of light decreases in glass but is the speed of gravity the real constant?
 
2020-01-26 9:32:05 PM  

Guildmaster: and based solely on experiments carried out in our gravity well


If by, "phenomena we can observe from across the universe" and "particles so small that gravity has little effect on them, if any at all," you mean "our gravity well," then sure. Also, you might want to get that checked out. The vast majority of astronomical experiments and observations do not happen within our gravity well, and the vast majority of particle physics involves things that basically ignore gravity.

Guildmaster: There's no pure equation that "derives" c without relying on these things.


Also untrue. There are a finite (and actually, singular) number of values of c that permit little things, like fusion, and black holes, and stellar formation and electromagetic fields. These are all things that we observe in the universe, not on Earth. Atoms! Atoms depend on c being a specific set of values. Unless you want to argue that atoms are a phenomenon unique to Earth, you might want to stop arguing.
 
2020-01-27 2:37:52 AM  

t3knomanser: Guildmaster: and based solely on experiments carried out in our gravity well

If by, "phenomena we can observe from across the universe" and "particles so small that gravity has little effect on them, if any at all," you mean "our gravity well," then sure. Also, you might want to get that checked out. The vast majority of astronomical experiments and observations do not happen within our gravity well, and the vast majority of particle physics involves things that basically ignore gravity.


We can observe phenomena across the universe, but they bend the observations to fit the model, which includes the assumption that c is constant in a vacuum. Everything you're talking about is built on that assumption. If that assumption isn't true, the models aren't true, and thus, none of the "proofs" are true.

Guildmaster: There's no pure equation that "derives" c without relying on these things.

Also untrue. There are a finite (and actually, singular) number of values of c that permit little things, like fusion, and black holes, and stellar formation and electromagetic fields. These are all things that we observe in the universe, not on Earth. Atoms! Atoms depend on c being a specific set of values. Unless you want to argue that atoms are a phenomenon unique to Earth, you might want to stop arguing.



Again, you're assuming this based on the model, which is based on the assumption that c is constant in a vacuum. All of our local observations of atoms, etc, are in our local gravity well. You can't observe an atom in interstellar space.

The model is consistent with c being a constant, so long as you include fudge factors like a hubble constant and dark matter/dark energy which are hithertoo unexplained. However, it is possible that there is a model which fits the observable data which does *not* require c to be a constant, but to be a function of local gravity density, which might remove these fudge factors.

We're facing the same issue of Newton->Einstein. Newton's model is actually a second-degree approximation of Einstein's, and is equal if v is much much less than c (IE, scales Newton could observe). He was unable to come up with Einstein's model because his data only existed in places where V << C, meaning that only the terms up to second order could be found.

It's entirely possible that Einstein's model is an approximation of a more complex model, for a local value of C(X) where X is the local gravitational density which exists in our solar system. In that case, since X is a constant for us (as far as we can measure), our local observations are limited to c being a constant as well, and everything we observe outside that frame is interpreted through the lens of c being constant.
 
2020-01-27 2:49:27 AM  
And to be clear, I'm not saying "there aren't atoms outside of our solar system", I'm saying "we can't observe things on that scale that far away, so we don't know how they behave in intergalactic space".
 
2020-01-27 3:01:16 AM  

t3knomanser: like fusion, and black holes, and stellar formation


And to further explain the point that you missed, ALL of these phenomena happen in very dense areas of gravity, relative to the sparse gravity of interstellar space. Black holes might have a much simpler model if we realize that their insanely high local density means c is smaller in and around them than it is in the less dense area of a solar system.
 
2020-01-27 6:09:40 AM  

DON.MAC: In one of the intros to one of Dr Feynman's books he goes on to say any complex theory in science has been wrong and replaced by something much more simple.  He goes on to talk about alchemy and epicycles for planetary motion and how the theories got worse as they added more stuff on. The book then goes on about quantum mechanics.  The intro was almost like "the rest of this is most certainly wrong but it is all we have for now"

Is the "speed of light" that constant that should be used?  We know the speed of light decreases in glass but is the speed of gravity the real constant?


So this is where things get a bit twisted: What we call the speed of light (Or rather, "The speed of light in a vacuum" as being the hard limit for how fast things can travel, what we're actually talking about is the speed of causality: How fast anything can happen. The universe (at current) seems to have an upper bound. It's just that (in a vacuum), light travels at that speed. 
So it's not that the speed of light affects causality, it's that causality (or rather the speed of causality) affects the speed of light.
/According to current models.
//Waaayyy outside my wheelhouse in physics, I do nanophysics/engineering/fabrication.
 
2020-01-27 8:20:48 AM  

Guildmaster: which includes the assumption that c is constant in a vacuum


The very fact that you use "in a vacuum" shows that you don't understand what c is. c is a constant outside of a vacuum too. Light often moves slower than c because it stops to interact with intervening matter, so the speed of light itself is not a constant, but c is.

And the idea that c is a constant isn't an "assumption": it's the core discovery of relativity. You bring up the whole "we only see it from areas of high gravitational fields" but seem to forget that c, in part, is fundamental to the behavior of those fields. If c weren't a constant, gravity wouldn't work as we observe it to work. And while MOND is still a candidate for dark matter, it's not a good candidate.

Also: the Earth is not in a particularly strongly curved region of space. The Earth's mass is negligible, and we're far enough out from the sun that our little region of spacetime is effectively flat, unless the effect you're describing is incredibly strong. Which, if it were, we'd see it more clearly.
 
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