[Colin2B]

Notice that when the pulling begins, the motion is straight. If it was already curved, no force would be needed to curve it. A force that curves a trajectory needs to be applied to a straight trajectory, so since we don't observe such a motion at our scale, atoms are probably going straight line for a while when we apply a force on them.

The gravitational force is continuous, it doesn’t switch on and off so the object does not have the option of travelling in a straight line even for a fraction of time. In order to keep an object’s orbit (curved path) the gravitational force has to be continuous otherwise it would fly off at a tangent, it will not keep a curved path without that force.

That's probably the main reason for their quantified energy. Their quantified light is probably linked to their quantified motion. They probably move by steps to accommodate individually each photon that strikes them, and it is probably while they are executing a step that they emit a photon.

‘Quantified light’ has nothing to do with quantified motion. The energy of a photon is quantised because the electron, when bound to an atom, can only release or absorb energy in quanta. It’s worth noting that a free electron is not so constrained and can take on any energy value.

Let’s try and keep this thread on real physics rather than made up ideas.

[rmolnav]

MY ULTIMATE GO ? (3rd part)

To diminish the risk of misinterpretations, before delivering the conclusions I referred to on 2nd part, I´ll repeat here the "breakdown" of earth complex movement into its simpler (and more easily graspable) components ...
Earth´s movement (as a whole) is basically the addition of three simple, but quite different, movements:
1) Earth-moon common center of mass orbits the sun (once a year). Both celestial objects, as a "couple", are kind of linked to that CM (called barycenter), and move with it.
 That movement, and sun´s pull, originates what I call sun-related tidal effects (sea tides included).
For the sake of simplicity, I usually disregard that movement, when analyzing main component of tides: moon-related tides.
2) The "couple", as I said yesterday on 2nd part, revolves/rotates around the barycenter (once every some 28 days).
That is the movement I always refer to (unless clearly said the contrary), discussing and analyzing it as if only that movement were happening ... Moon´s pull, and dynamical effects originated by that movement´s features, causes two opposite bulges that continuously change position, logically with same periodicity of some 28 days (relative to the rest of the universe).
Details of the singularity that earth revolves (instead of rotating like the moon) are explained on #328, with a "handy" analogy ...
3) Earth also has its daily spinning, which, apart from causing the permanent equatorial bulge (by the way, thanks to huge centrifugal forces inherent to such fast circular movement), makes us to perceive the period of the movement of the pair of bulges as if it were once a day, instead of once every some 28 days.
Some time ago I posted the link of a youtube video relative to that:
"I suggest anybody interested to have a look at :

where it´s clearly seen that daily movement of the bulges is only apparent, that they are almost still and it is the solid part of our planet (though also the bulk of ocean waters due to friction) what is actually spinning …
The formation of the bulges is a rather slow process (some 28 days the complete cycle) … Nothing to do with all those daily local whirlpools, due to the much faster Earth spin, and with any other local singularity"
 
   

[Le Repteux]

by the way, thanks to huge centrifugal forces inherent to such fast circular movement

There is no more centrifugal force in the case of the equatorial bulge than in the case of the tidal ones. Both forces are due to massive bodies refusing to change their speed or their direction. They resist whether we pull them tangentially or perpendicularly to the motion they already have. They resist as if they were at rest. There is no centrifugal force when a car accelerates, it only resists to accelerate. If it stops accelerating, it only moves in the direction it is already moving, not in the other. The same thing is happening in the case of bodies on circular motion: no centrifugal force is exerted by them.

[Le Repteux]

The gravitational force is continuous, it doesn’t switch on and off so the object does not have the option of traveling in a straight line even for a fraction of time.

Gravitation looks continuous at our scale like any force, but considering that the atoms exhibit a randomness behavior when they are observed separately, it may very well be discontinuous at theirs. In other words, the constant forces or motions that we observe at our scale may very well be issued from a statistical phenomenon at theirs, and if it is the case, they could be free to move in whatever direction they chose for a while providing they chose the right one more often. In my simulations on motion, I have no other option than to move my particles by steps, and I also move them in the direction of the force, but in reality, I could move them statistically and I would get the same result after a while. If we could nudge an individual atom for so short a time that it wouldn't have time to exhibit a statistical answer, I think it might very well not take the direction or the speed we expect it to take.

‘Quantified light’ has nothing to do with quantified motion. The energy of a photon is quantised because the electron, when bound to an atom, can only release or absorb energy in quanta. It’s worth noting that a free electron is not so constrained and can take on any energy value.

I wasn't talking about unbounded bodies either: to me, gravitation is a kind of bonding. To follow a curved trajectory, a body has to suffer acceleration, and it is precisely during acceleration that I suspect the particles to behave statistically.

Let’s try and keep this thread on real physics rather than made up ideas.

What I'm suggesting doesn't seem to contradict the observations, but tell me if you see any and I'll stop arguing. I'm not suggesting to change the physics, but to use it to make another step further. In fact, I use what I had to figure out to build my simulations to convince Rmolnav that the equatorial bulge and the tidal ones are equivalent. I'm not really expecting him to change his mind though, just to take a closer look at what the particles might be doing during motion.

[Colin2B]

What I'm suggesting doesn't seem to contradict the observations, but tell me if you see any and I'll stop arguing. I'm not suggesting to change the physics, but to use it to make another step further.

It's OK to take the physics a (specualtive) step further, but not in this section.
It is worth setting up a new theory to discuss.
While we see quantum effects for energy, there is no evidence that that energy varies as the particle moves ie no stop start or quantised motion.
If you want to discuss it, let's do it elsewhere, here it just causes confusion amongst the readers.

[Le Repteux]

It's OK to take the physics a (speculative) step further, but not in this section.

What about the tides then? Aren't we speculating about the composition of the force? The way Rmolnav explains them, a centrifugal force is needed, whereas no centrifugal force is present when no orbital rotation is involved and the tidal bulges are still present.

[rmolnav]

MY ULTIMATE GO ? (4th part)

As said on 2nd part, I consider that rather than talking about “free fall” within a given gravitational field, it is more realistic to consider earth-moon interactions as if they were parts of an unique extended object, with no massive parts apart from where both celestial objects actually are, and rotating/revolving about their common center of mass, maintaining the distance between them due to their dynamic equilibrium.
An ice skating couple can spin like a single dancer, because they are linked usually through their hands … If one of them had a pony-tail, when spinning, instead of hanging vertically, the pony-tail would move upwards, against its own weight … Clearly due to centrifugal force.
The same would happen whatever the way they were linked to each other. If it were a kind of mutual “gravitational” pull sufficient not to need their hands (as earth-moon case), and they had suitable initial "tangential" speeds, the pony-tail would also “feel” that inertial force (why wouldn´t it?) … It would react to the TOTAL force acting DIRECTLY ON IT (WHATEVER the pull on other parts of the dancer, what the pony-tail “ignores" …), and raise where centrifugal force prevailed.
Earth particles react to those inertial forces in a similar way to what quite clearly explained for the diminishing of our weight on the equator, and causes the equatorial bulge (though the author prefers not to mention the adjective “centrifugal” … ):
“"The figure shows the force vectors W and mg, which are the only forces acting on the man. The vector F is their sum. W is directed along the radius of the Earth. Being the radial component of the net force (it is the net force in this case), its size is a = v2/R (the centripetal force). Now compare these two cases. On the non-rotating Earth the man's weight was of size mg. Remember, the weight of an object is the force required to support it, i.e., the force exerted upward by the weighing scale. With the Earth rotating, that force (man´s weight) is smaller than before. The contact force between the man's feet and the scale is reduced. But all other such stress forces are reduced as well, within the man, within the scale's springs, within the body of the Earth itself. This causes a slight decompression of these materials, a relaxation of the spring in the scales. In fact, the entire body of the earth expands slightly and the man and scale move outward from the axis of rotation slightly, until forces come into balance with the requirements of rotational stability at the new radius. This is the reason for the equatorial bulge of the Earth due to its own axial rotation"
https://www.lockhaven.edu/~dsimanek/scenario/centrip.htm
That´s why the NASA scientists I´ve referred to many times say:
"At the center of the Earth there is a balance between gravitational attraction (trying to pull the Earth and moon together) and centrifugal force (trying to push the Earth and moon apart as they revolve around that common point).
At a location on the Earth’s surface closest to the moon, the gravitational attraction of the moon is greater than the centrifugal force of the Earth (moving around the center of the revolving Earth-moon system).
On the opposite side of the Earth, facing away from the moon, the centrifugal force is greater than the moon’s gravitational attraction.
In a hypothetical ocean covering the whole Earth with no continents there will be two tidal bulges resulting from these imbalances of gravitational and centrifugal forces, one facing the moon (where the gravitational force is greater than the centrifugal force) and one facing away from the moon (where the centrifugal force is greater than the gravitational force)”
I DO KNOW many people (physicists included) will say: "But you are using a non-inertial frame of reference, where centrifugal forces are “added” by us, in order to keep Newton´s Motion Laws valid. But those forces are “fictitious”, they don´t actually exist" … (or something similar).
This post is already rather long. I´ll leave my refuting of what usually is deduced from that question of frames of reference for another post.

[rmolnav]

There is no centrifugal force when a car accelerates, it only resists to accelerate. If it stops accelerating, it only moves in the direction it is already moving, not in the other. The same thing is happening in the case of bodies on circular motion: no centrifugal force is exerted by them.

Without sufficient imagination to think there can be manifestations of inertia different than what we are kind of used to, it´s impossible to properly grasp the concept of centrifugal force, and therefore tides ...
If a car accelerates in a straight line, LOGICALLY there cannot be any "centri***al" force, because there is no "center" at all !! Inertia manifests itself "trying" not to let the velocity of the passengers increase, and they somehow "feel" pushed backwards (relatively to the car). But if they had inflatable cushions between their backs and seat´s backs, and the acceleration were sufficiently big compared to the strength of the cushions, these could explode. And for them to blow up two opposite forces are required ... They backward one exerted by the passengers on the seat backs is clearly an inertial force (though not "centrifugal" whatsoever !!).
But if, e.g., one of the passenger shoulder were leaning on a side window glass not sufficiently strong, and the car were turning to the other side when going very fast, the window could get broken ...
Inertia certainly just tries to keep constant the passenger´s speed vector (similarly to the above mentioned straight-line case), but now the window is "forcing" the passenger to turn (centripetal force), and as an "inertial" reaction (3rd Newton´s Motion Law) the passenger pushes outwards on the window and brakes it (centrifugal force).   
I´ve said it many times: inertia manifests itself in different ways, depending on the type of individual forces exerted on the considered object, and especially on the type and degree of "freedom" to move the object actually has !!

[Le Repteux]

now the window is "forcing" the passenger to turn (centripetal force), and as an "inertial" reaction (3rd Newton´s Motion Law) the passenger pushes outwards on the window and brakes it (centrifugal force).

It is not a centrifugal force, but a relative or apparent centrifugal motion that results from the car changing direction and the passenger being forced to follow it. If the passenger was free to move, he would follow a straight line while the car would be moving away from him: in this case, motion is still relative but the driver knows it is the car that moves away because he suffers a force, and the passenger knows it too because he doesn't suffer a force while the car is still moving away.

[Colin2B]

It is not a centrifugal force, but a relative or apparent centrifugal motion that results from the car changing direction and the passenger being forced to follow it. If the passenger was free to move, he would follow a straight line while the car would be moving away from him: in this case, motion is still relative but the driver knows it is the car that moves away because he suffers a force, and the passenger knows it too because he doesn't suffer a force while the car is still moving away.

You have to be careful not to mix frames, which is something many people get confused over.
From the inertial frame the car is being forced in a circle by friction with the road and the driver/passengers are trying to travel in a straight line, but again centripetal forces pull them into a curve.
From the rotating frame the driver and passengers feel centrifugal force throwing them radially outwards and they are restrained by a reactive centripetal  force - either friction from the seats or force from the side of the car.
Both views are valid, just don’t mix frames or everyone gets confused.

The radial motion experienced by the observer in the rotating frame can easily be seen by plotting the locus of the tangential motion relative to the observer on the rotating curve. If you’re not sure what I mean I could try and draw it for you.

[Le Repteux]

Both views are valid, just don’t mix frames or everyone gets confused.

I didn't mix frames, I simply didn't use the wording. A reference frame is a viewpoint experimented by an observer, so comparing the viewpoints of the two observers like I did is like comparing the two reference frames. If there is no mistake, there is no need to use the reference frame wording for people to understand what is going on. Knowing that one of the two observers is accelerating is enough for them to know that it is the one that is moving away. When acceleration is involved, adding the reference frame principle to the explanations confuses them. There are tons of pages written about the twins paradox on the forums that try to use the reference frame wording without being able to stop the questioning, whereas the questioning immediately stops if we simply say that the accelerating twin is the one that moves away. There is no reason to change reference frames either if we know an observer is accelerating, and if no observer is accelerating, then there is simply no need to use the reference frame principle since there is no use to the observations made by either of the observers anyway, except if they need to meet, and then they can use doppler effect and aberration to know their relative speed and direction. Changing reference frames only helps us to illustrate up to what point inertial motion can be relative, not to know which one of the observers is getting younger or older.

[rmolnav]

From the rotating frame the driver and passengers feel centrifugal force throwing them radially outwards and they are restrained by a reactive centripetal  force - either friction from the seats or force from the side of the car.

Though I´m much "closer" to what you say than to what said by L.R., please kindly note that, if the window glass breaks, an outward quite real force (centrifugal force, in the broad sense of the term) has to exist, whatever the reference system !!
To me the whole issue of reference systems is generally misunderstood and wrongly used.
Locations, speeds, and accelerations can be easily handled using different reference systems: it is just a question of deducting vectors.
But real forces (apart from exclusively "inertial" forces), as far as I can understand, either exist or not, no matter which reference system we use, or from where we observe reality !!

[Le Repteux]

if the window glass breaks, an outward quite real force (centrifugal force, in the broad sense of the term) has to exist, whatever the reference system !!

If the window breaks, it is still the car that will be moving away from the passenger, not the inverse. The passenger will simply be moving in the same direction the car was moving when the window broke.

[rmolnav]

if the window glass breaks, an outward quite real force (centrifugal force, in the broad sense of the term) has to exist, whatever the reference system !!

If the window breaks, it is still the car that will be moving away from the passenger, not the inverse. The passenger will simply be moving in the same direction the car was moving when the window broke.

You insist in speaking in a kind of layman language, without taking into consideration what I already told you: in physics science, "motion" is not a variable ... What "motion" units would you use when calculating real variables of physics science such as momentum, energy, etc ?
And "motion" can´t be what directly causes the breaking of the window glass ... Inertial forces originated by movements, only if not completely "free", can break (or just deform) things !!
The passenger was TRYING to move "in the same direction the car was moving". But the solidity of the window "forced" him to turn with the car for some short time (centripetal force). As a reaction the passenger´s shoulder pushed outwards on the glass, with a real force equal but opposite to centripetal one, until it broke (the window frame was also pushing the glass inwards ...).
And that outwards force has a name: centrifugal force, as I said, in the broad sense of the term.
If you only have layman ideas about physical phenomena, you had better learning something of the science called "physics", especially "dynamics" ... I´m sure there are many sites on the internet where that won´t be difficult.
But let me suggest you something: keep an open mind if you do that ... 
 

[Le Repteux]

As a reaction the passenger´s shoulder pushed outwards on the glass, with a real force equal but opposite to centripetal one, until it broke

It's the glass that pushes inwards on the shoulder, so the shoulder resists to the force, and the glass breaks. Whether the force is direct or centripetal, bodies behave the same when the are accelerated: they resist, and they nevertheless accelerate in the direction of the force, not in the opposed direction. The word centrifugal contains the suffix fugal, that derives from the french word fugue, which means run away, and there is simply no run away when a body resists to a force. We're actually orbiting around one another so close and so fast that tidal bulges are beginning to grow on us. We should shut off the force before we get dislocated! :0)

[rmolnav]

The word centrifugal contains the suffix fugal, that derives from the french word fugue, which means run away, and there is simply no run away when a body resists to a force.

Come on !
I´m Spanish, and know the origins of "fugal", actually from latin ...
But I said :
"... that outwards force has a name: centrifugal force, as I said, in the broad sense of the term" (mainly not to mislead people, because many dictionaries define "centrifugal force", in quite a restrictive sense, as a ficticious force, linked to the concept of non-inertial force).
But for the adjective "centrifugal" you can find, e.g. on Oxford English Dictionary:
"Physics
Moving or tending to move away from a centre.
The opposite of centripetal”
It is precisely when the circular movements are more kind of avoided when we actually have bigger centrifugal forces !!
By the way, as an “example sentence” they include:
"Einstein warmed to the idea that the gravitational field of the rest of the Universe might explain centrifugal and other inertial forces resulting from acceleration.’ ...
though I dare say that is a too far fetched idea ...

[rmolnav]

MY ULTIMATE GO ? (5th part)

Before trying and convey my stand on non-inertial frames issue, let us go back to the drawing board, as if we didn´t have any education on dynamics …
Same image with Earth (E) on upper part, and vertically below the Moon (M).
Let us suppose we only know how they move, with kind of the mind of a “smart” child.
And then we learn that (as David Cooper said many times), if Earth and Moon tangential speeds somehow became null, they would begin to accelerate straightly towards each other, because of gravitational mutual attraction …
If just stopping their circular movements, they get “free” to accelerate towards each other … THOSE CIRCULAR MOVEMENTS ARE WHAT, WHEN EXISTING, WERE SOMEHOW COUNTERING THOSE STRAIGHT ACCELERATIONS NOW THEY HAVE GOT !!  No other logical possibility for a “clean” child mind …
How come? Let us see …
Curiously, with a rotating (so called "non-inertial”) frame of reference, same thing happens, but let us say “virtually” …
As the frame of reference rotates with E and M, E and M don´t "rotate" anymore
relatively to that frame of reference … Centripetal forces are not required whatsoever, and gravitational pull would make them fall onto each other … But that´s far from reality …
Then physicists go on: "How can we do “real” maths with that “artificial” (the adjective is mine ...) reference system ? … We have to apply a “fictitious” force, which we´ll call centrifugal force". That way WE GET BACK TO THE REAL SCENARIO … as far as dynamics is concerned.
Well, that force is certainly “fictitious”, because it has been introduced by us to work with that non-inertial frame of reference … But that means that the real circular movements, not actually needing the addition of any “artificial” force, somehow produce an inertial effect that keeps E and M without falling straightly onto each other !! To me (and not only me), that is a REAL centrifugal force !!
In case B (# 362), as E and M were moving horizontally at same speed, Moon´s pull was able not only to bend E´s trajectory, but also to accelerate E straightly towards M with its full strength, quite a “free” acceleration. That “freedom” was made possible by the movement of the moon towards the left, with same horizontal speed as E.
The real case is dynamically quite the opposite: the movement of M in opposition to E´s speed, and with speeds which make them to revolve/rotate around the barycenter, makes impossible the decrease of E-M distance, and even any proper orbiting of E around M. It gives us a “rotating” scenario, where all forces have basically same direction as the line between centers of mass, and where the angular position doesn´t matter much (as far as Earth-Moon dynamics is concerned), as long as we accept centrifugal forces keep the separation constant …
After all, if Earth and Moon were the only celestial objects in the universe, to talk about angular position of the system would have no sense at all …
But, still, they would have to keep rotating.  That way inherent inertial force, the centrifugal force, would keep them without following straightly onto each other !! 
Therefore, as I´ve said many times, I find quite correct what a NOAA scientist told me:
"... to provide a basic description of the forces which create the tides.  It's intended audience were the grade school children and adults of that time.  It used terminology of science and forces which were common in the 1950s.  Such as centrifugal force.  Centrifugal force was always an "imaginary force" (not a real / measurable force).  But that type of description made the concepts easier to understand and explain.  That  description and use of centrifugal force continued to be common practice until the 1970-80's.  At that point, the terminology shifted and the textbooks used in grade schools were changed to use a more modern terminology and description of this "effect" being a result of inertia rather than an "imaginary force”.
Initially I didn´t fully grasp his point ... But later I did.
The problem is that many books, dictionaries included, keep following models with ideas which are several decades out of date …

   

[Le Repteux]

It gives us a “rotating” scenario, where all forces have basically same direction as the line between centers of mass, and where the angular position doesn't matter much (as far as Earth-Moon dynamics is concerned), as long as we accept centrifugal forces keep the separation constant …
After all, if Earth and Moon were the only celestial objects in the universe, to talk about angular position of the system would have no sense at all …

Reference frames were invented to account for inertial motion, not rotation. In a merry go round, we know we are rotating because of the force, and we also know we are orbiting because of the tides. Rotation and orbiting motion are not relative motions since we know we are moving. We can use a Sagnac interferometer to measure our orbital speed, so even if the earth and the moon were alone in the universe, we could know we are moving. That's mainly why I decided to attribute mass and motion to light, and to make simulations based on the absolute direction and speed of light. If I had to make a simulation of orbital motion, I wouldn't use equations based on an instantaneous force like David did, I would use photons that take time to transfer the information, and doppler effect and aberration produced at the source and at the observer as the only available information, apart from the photon's force weakening with distance of course. This way, no need for an external reference to know that the system is moving, and it is the light exchanged between the particles that drives it.

[David Cooper]

For any new readers of this thread who may only have read the start and end of it, the correct answer does not involve centrifugal or centripetal force.

The sun's pull on the Earth dictates the direction the Earth moves in much more strongly than the moon's pull, out-gunning it to the point that when the Earth is in between the Sun and moon, the moon is on the outside of the curved path that the Earth is following through space and not on the inside of it, so any imagined role for centrifugal force throwing water up on the sun-side of the Earth is revealed to be a fantasy, and the sun isn't responsible for lifting most of the water on that side either. If water was being thrown upwards by centrifugal force, it would be towards the moon at such times, but there is no such effect (other than from the Earth's rotation which raises the sea all the way round, most strongly at the equator).

The real answer is simply straight-line differential gravity, mostly from the moon. The moon's and sun's gravity decreases over distance, but it falls in strength most strongly over distance with greater proximity to the source, which is why the moon has a greater effect on the tides than the sun even though the sun's pull on the Earth is much stronger - the moon's effect on our tides is greater because the moon is so close to us, leading to its pull reducing more quickly over distance from one side of the Earth to the other, whereas the sun's so far away that its pull is much closer to an even pull across the planet.

The Earth simply moves where the combined pull of moon, sun, Juptier, etc. forces it to go, and the water of the sea has a slightly different amount of force acting on it due to differential gravity. The water nearest the moon is always pulled a bit more strongly towards the moon, and the water furthest from the moon is always pulled less strongly by it, so whenever the Earth is being pulled towards the moon (e.g. when the moon is between the sun and Earth), the water nearest the moon will try to move more quickly towards the moon than the Earth as a whole and the water furthest from the moon will try to move less quickly in that direction, whereas if the Earth is being pulled away from the moon (e.g. when the Earth is between the sun and moon), the water furthest from the moon will be pulled away most strongly (because it's held back the least by the moon's gravity) while the water nearest the moon will be held back most strongly by the moon.

The effect of these forces is that the pressure on the sea nearest to and furthest from the moon reduces a bit and the water tries to rise a tiny amount - it doesn't rise much directly because there isn't enough time for water to rush in from elsewhere to pile up there, so the actual tidal bulges that we see are a secondary effect built up by resonance responding to the input of the tidal forces. The tidal forces from the sun are smaller because the sun's gravity reduces less over distance where we are (it is spreading out less by the time it reaches us). When the tidal forces from the sun are aligned with the moon's, we get the biggest combined force and higher tides. When the tidal forces from the sun are acting at 90 degrees to those from the moon, we get lower tides, but note that the water is still being lifted slightly by the sun's tidal forces on the sides nearest and furthest from it, so it doesn't actually subtract from the moon's tidal forces, but merely masks their strength. This is why it's important to realise that the tides that we see are a secondary effect (through resonance) and not direct lifting of water into bulges.

Until the topic is locked, I'll repost this every page or two just to make sure that no one is misled by authoritative nonsense.

[Le Repteux]

But, still, they would have to keep rotating.  That way inherent inertial force, the centrifugal force, would keep them without falling straightly onto each other !! 

It is their speed with regard to one another that keeps them from falling, and speed is not a force, only a motion.