[PmbPhy]

The planets actually are falling into the Sun, but they keep missing it:

And the moon is falling towards the Earth....no, wait, it's moving away! I guess that's due to tidal forces. 

Does that mean that there are tidal forces involved in planetary orbits, but they are, relatively, so small that we can ignore them?

No.

[PmbPhy]

Does that mean that there are tidal forces involved in planetary orbits, but they are, relatively, so small that we can ignore them?

No. BTW - Don't buy into a theory merely because someone wrote an article about it. That's just bad juju.

[yor_on]

It's tricky Bill

Did you mean that finding a quote in which Einstein said that gravity is not a force, would be tricky?

Perhaps my interpretation is skewed, but your excellent posts seem to say quite clearly that Einstein saw gravity as a force, albeit one that was more complex, and perhaps less mysterious, than "simple" Newtonian gravity.

No, you have to reread it.
It's not about 'forces', then again it is. And it's not about 'fields', then again, it is :)

Seems to me he didn't agree wholeheartedly with any of the modern interpretations.
Do as I, reread and reread :) until it hurts
=

what he did believe though, is that it was relative
and that in itself demands some/one/thing to interact, doesn't it?
=

" Already in the first papers in which Einstein starts making use of the metric tensor to give an account of gravitation, he is at pains to establish the status of the geodesic equation as describing the motion of particles as “straight and uniform” (geradlinig und gleichförmig) even when subject to gravity.  ...   Einstein thought of (static) gravitational fields not as invariant force fields diverting particles from inertial motion. Already, in 1912, he thought of equation (1) as describing inertial motion on one hand, and as describing motion in the presence of (static) gravitational fields on the other. "

=

That's different from what the geometric idea describes today, a 'bent' SpaceTime. He's looking at it differently.
But we both have a hard time not reading into it what we ourselves think. I called a 'field' of sorts earlier, but I'm not sure Einstein would have agreed to that.

It's like he saw something we still are blind too. A 'SpaceTime' that isn't 'bent' at all. Which makes me wonder what he thought his 'fifth dimension' would do

[Colin2B]

No. BTW - Don't buy into a theory merely because someone wrote an article about it. That's just bad juju.

These are wise words.
There are post in this thread which are making this mistake. We haven’t had time to take this up, but can everyone be careful to avoid making statements of fact when there is only conjecture.

[Professor Mega-Mind]

Gravitational waves permeate the universe .  For large objects they cancel out each other , like many small waves striking a very large ship .  For sub-atomic particles the effect is much stronger , like a cork being moved all over the place by those very same waves .  A similar effect is experienced by free electrons in intergalactic space .  Long-wavelength EMR interacts with said electrons , transferring some of it's energy to them in the process .  This results in redder light , and hotter , faster electron .  This effect has been proven-out in lab experiments , but is not enough to vindicate tired-light theorists .  A similar effect can be postulated for gravitational waves , possibly for entire atoms .  Since more energetic particles have slightly greater mass , this is a possible explanation for Dark Matter , with all it's perplexing and undetectable characteristics .
Dark Matter mystery solved ! 
The doctor is in !
P.M.
》Search up Entropic Gravity .

[guest46746]

Gravity is defined as an attraction force. If it does more then attract via mass, it does not meet the definition! lol

[Professor Mega-Mind]

Psst , light attracts via virtual mass .  Ya gotta give gravity the benefit of the doubt !
P.M.

[guest46746]

Psst , light attracts via virtual mass .  Ya gotta give gravity the benefit of the doubt !
P.M.

virtual mass is used for displacement, are you saying virtual displaces light? lol

[Professor Mega-Mind]

Photons have mass - virtual mass .
It can be , and has been, measured.  They interact with the universe in this context .
P.M.

[guest46746]

Psst , light attracts via virtual mass .  Ya gotta give gravity the benefit of the doubt !P.M.

Photons have mass - virtual mass .It can be , and has been, measured.  They interact with the universe in this context .P.M.

I am attempting to place these two statements with in a framework that will allow me to connect dots.
I don't believe the connected dots willnot provide another type of GR gravity, but it may provide an insight into a quantum alternate gravity.

The photon and the gluon both share a similar configuration. Both have 0 mass, 0 charge and a spin value of 1. These similarity may point to a similar function.
The gluon is claimed to bond quarks, this may correspond to gravity in a quantum sense.

However, there is a differences between gluons bonding quarks and photon's virtual mass bonding light. There seems to be disparity that I cannot point to off the top of my head. But I do acknowledge that an agent must exist to give Light, EM frequency it's ubiquitous attribute. Is it the spin?   or is it that a photon has a particle and anti-matter particle properties in its constituency that provides its singularity potential (self actualized gravity)?

What must be considered however is that during recombination of Universe. All particles and sub particles regardless of mass, charge, spin shared the same environment prior to the advent of the four fundamental forces. They all experienced the divergence of gravity, electromagnetics, strong and weak nuclear. This includes fermion and quantum particles. With that being said, science says gravity diverged first, which strongly implies that it affects electromagnetic light and not visa versa. What makes Light responsive to gravity.  At this point, the dots no longer connect. Gravity has no spin, no real mass and no real charge to make a responsive connection to Light. Yet gravity affects light.

The only explanation is that Gravity existed outside of Universe during recombination and interacted with MASS as a foreign agent. Gravity being created by the warped space around MASS, as a result of MASS's own angular momentum. As Light escaped MASS, it interacted with gravity's attraction to MASS.  This interaction limited LIght's velocity but at the same TIME it stretched gravity's attraction to MASS outward. This Ying Yang, push pull relationship of Gravity and Light energizing each other, became fundamental to the Universal system. Yet their origins differ vastly, one based on Electromagnetics and internal to MASS, The other Gravity, for the lack of a better term, bosonic based and external to MASS. 

So does Light and Gravity have a symbiotic energizing relationship? Would one disintegrate without the other? no answer, just a meandering stream of in the moment. lol

[Professor Mega-Mind]

Truth be told , I think you're revving that brain a bit too high .  It's not necessary to go to those lengths to  get this .  It is almost mechanical .  First ; virtual particles .  As they pop into & out of existence , they momentarily have "real particle" characteristics . This means mass.  Conceding mass , you automatically arrive at gravitational  interaction .  Hawking Radiation depends on this completely ! 
Secondly ; fields . Electric,magnetic , gravitational fields contain energy, and consequently , virtual mass .  This mass also interacts with the universe gravitationally .  It is a small , but extant mass . Important nonetheless . 
That's the positive feedback loop .
......P.M.
Note : That gluon issue could be primarily a matter of range .

[guest46746]

Truth be told , I think you're revving that brain a bit too high .  It's not necessary to go to those lengths to  get this .  It is almost mechanical .  First ; virtual particles .  As they pop into & out of existence , they momentarily have "real particle" characteristics . This means mass.  Conceding mass , you automatically arrive at gravitational  interaction .  Hawking Radiation depends on this completely !  Secondly ; fields . Electric,magnetic , gravitational fields contain energy, and consequently , virtual mass .  This mass also interacts with the universe gravitationally .  It is a small , but extant mass . Important nonetheless .  That's the positive feedback loop .......P.M.

Truth be told you may need to overclock yours! To the extent that gravity exerts it's influence, random events of particles popping in and out of time, fall infinitesimally short of meeting a gravity criteria.  Here and then gone, wouldn't even suffice for quantum gravity's purpose. According to Hawking these events only occur under unique circumstances.

What you describe would Universally thought of as the transition of passing time!  The only gravity involved in that is the seriousness of it. These thoughts just keep popping in and out of my head! lol.  Virtual mass causes consciousness, maybe for some people! lol

[Professor Mega-Mind]

.....................Gravity ?
Einstein didn't believe it was a force or a field , and neither do I .
Mass/Energy causing an indent by space/time into the "Extra-verse" ?.
 As to virtual mass ; the latest , greatest theories propose that space itself is a field of virtual particles particles popping into , and out of , existence .  The virtual mass thus engendered may be tiny , but multiply that by the vastness of space , and you've got something !
P.M.

[yor_on]

It's tricky, and depending on views. For example the higgs field/boson do not explain all types of gravity.
https://profmattstrassler.com/2012/10/15/why-the-higgs-and-gravity-are-unrelated/

[Professor Mega-Mind]

In relation to virtual particles ...
Why do photons traveling in parallel , not gravitationally attract each other ?
My interpretation is that relative to each other , they are at rest . This of course , means that they have zero mass , from each other's perspective , but still have virtual-mass , as seen from all other perspectives .
*Insights welcome .
Ref : NSF. thread - How does the expansion of space work ?
www.thenakedscientists.com/forum/index.php?topic=79683.new;topicseen#new 

[DonnaSurles]

I think gravity difference in some point when it's gravity point changes. For example you check your weight at two different location you will find certain difference  between weight.

[Professor Mega-Mind]

Yup , like when I finally stand atop Mount Everest !
(it's on my bucket-list) .
P.

[Kryptid]

Why do photons traveling in parallel , not gravitationally attract each other ?

To be fair, it would be awfully hard to detect any such attraction, given their incredibly tiny masses.

[Professor Mega-Mind]

Sorry , but I'm avoiding conflict right now.