h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

So,..., if Centrifugal force =Inertia = Gravity, that means that if you stand on your head weighing 150 pounds (gravity), or I hit you on the head with 150 pounds of flooring (inertia), you'll be just as fine either way?

These are not the same forces, and there is no need for an additional 'mysterious force', the force you are discussing is acceleration. It is the movement of the object through space through the imparting of energy. It is basic propulsion for Bob's sake, Newtonian physics. It's what keeps planes, trains, and automobiles moving until a force acts upon them to slow them down.

And, Gravity is not a 'centre-seeking force' per se. Each bit of matter of the planet adds its little bit of gravity. We are all being attracted to each little bit, at each little moment. The overall effect may be a downward pull toward the center of the Earth, but it is not 'seeking' anything. We are still being pulled in all directions other than down as well.

You could probably convince me though, if your premise is sound. If the moon is constantly 'accelerating' toward the center of the earth, how much faster is it falling than it fell 200 years ago? Seems to me that the months are still about the same length, so what has changed that you use the word accelerate?

I like the subject matter, great mind-bending stuff; but the arguments are not compelling.

I'm sorry, but I can't help overlooking some dangerous fallacies in your arguments.

First off, you wrote (in jest) that hitting the author with 150 pounds of flooring would be analagous to him balancing his 150 pound body on his head. Smacking something around is not an instance of intertia. Inertia is a quality latent in an object of a given mass, and a quality which is constant regardless of motion (in fact, the Latin root of "inertia" means "idleness"). The force of a moving body is momentum, or impulse, which is equal to mass times acceleration (p=mv). Thus, if you were to unabligingly hit the author with the flooring, the author would not only feel force resultant of the mass of the flooring. The force would be a result of its mass and the velocity you imparted it with, compounding the author's detriment considerably (as if balancing one's self solely on one's head didn't hurt enough as is).

But that's just me being nitpicky. What I really want to address is simply an ugly misconception that's reared its head again. Acceleration is a change in velocity BUT velocity is a vector quantity, possessing both magnitude (speed) and direction. Thus, an object can accelerate (can change its velocity) by staying at a constant speed while changing direction. So, addressing your fourth point, the moon IS constantly accelerating, since it is moving in a circle which (as it is not a straight path) requires it to constantly change direction.

And, since I'm on it, I'll use vector geometry to go for the hat trick. You are right in saying that we are being pulled in by many many many forces other than those pulling us directly towards the center of the earth, but, if you plotted the infinite vectors that represent those infinte forces pulling on us, and if you combined those infinite vectors through "simple" vector addition, the result would be one very large arrow pointing to the center of the Earth. It's really only better living through denial, but it still works.

Hey there, Datsun, thanks for checking in!

Thank you for pointing out the fallacy, that 'Smacking something around is not an instance of intertia.' When one is swinging around a pail of water, vertically, and nothing drops out, this is the '... momentum, or impulse, which is equal to mass times acceleration (p=mv)' pressing it against the bottom. This is why the 'impulse is a different force than gravity. The water, (or being) inside the pail may feel a force equivalent to having gravity, but obviously this equivalent feeling does not have a 'gravitational' component, or things outside the pail would feel its force. Gravity is a non-directional, weak, long-distance force. The impulse provided through centrifugal force (not even a valid term, any longer, as it has been largely supplanted by 'centripetal force') is local, relative to speed, and no-distance.

[But, that is also nitpicky]

Thank you too for the etymology of the word inertia, as this more closely matches the meaning I would normally ascribe to the word. A rest state (or 'idleness') that needs to be overcome in getting an object to move.

On the subject of acceleration, perhaps this is a definition of the word to which I had not previously been exposed. But, as speed between two objects is relative, I have always thought of acceleration as relative. I would therefore assume that acceleration of the Moon, as regards the Earth, would require a relative speed increase. Perhaps the physics world views the term acceleration differently.

It sounds as if the 'vector' would need to change, for acceleration to be present. Topologically speaking, the vector remains unchanged.

'Vector Addition' does correlate with the author's concept of centralizing force (and this could be just nitpicky once more). But, it is just an end effect, or average of all the forces. My point was that gravity is related to each bit of mass, and not just the aggragate vector. And that, as we are being pulled by each bit of mass in the universe, it has some significantly different aspects than inertia.

The basic forces; strong, weak, electromagnetic, and gravity (unless you want to combine weak and EM into electroweak), each have observable differences that allow us to separate and categorize them. And, if you accept their carriers as the gluon, an intermediate vector boson, photon, and graviton, you need to explain how you produce gravitons with inertia.

I'll go with the idea that there may be a unified field theory that makes sense, whether or not we have found it. But cannot accept that inertia, explainable through Newtonian as well as Einsteinian physics, is the same force as gravity. Or even that it is a 'force' in the physics sense of the word. There are precious few parts of gravity's formulae that work with centripetal force.

Perhaps, given that the gravitational constant is G = 6.67 x 10^-11, we could try an calculate the centripetal constant?

To sum the whole thing up, a Centrifugal force is an outward-directed "fictitious force" exerted on a body when it moves azimuthally in a noninertial rotating reference frame, which is simply not gravity.



PS: I do appreciate the creativity, research, and intellectual prowess that goes into these entries and responses; but, unproven, these notions should not be presented as so solid, or accepted a fact.

Hi FT,

It looks like even your positive comments are qualified with misconcdeptions.

"but, ubproven, these notions should not be presented as so solid or accepted a fact."

It should be clear to anyone who gives the Aticle a fair reading that it is only a theory. Theories are, by definition, unproven. Their value is in their explanatory power, and if they prevail, it is only because they account for things which conventionally accepted theories cannot. It is only natural that they will grate against some standard definitions.

These notions you bristle about--could it be their power which leads you to mistakenly construe that they have been presented as solid or accepted facts?

Datsun has taken away some of my thunder (nice job, Datsun), but I'll post what I had already written several days ago anyway.

Stand by.

perfectfluid

... a sudden avalanche!

Ok FT, let's take one snowball at a time.
Response to paragraph #1:
If I stand on my head, you can be assured there will not be any momentum involved. In order to keep your argument symmetrical, you may hit me with that 150 pounds of flooring gently, without momentum, and I'll be "just as fine either way".

Re Para #2
I cannot fathom the point you are trying to make here. I suspect it is because you are wrong about what makes planes, trains, and autos continue to move until acted upon by some force. To get a stationary object to move, it must be accelerated. Once it is moving, no more force is required to continue its uiform motion. Planes, trains and such must overcome frictional resistance from various earthly sources, so a bit of force continues to be applied to that end. Airplanes, of course, must also keep applying force to counter gravity. The point is, no energy needs to be "imparted," as you say, to keep an object moving through space once it's been given a start. That's Newton's first law of motion, and really basic stuff, for Bob's sake.

Re para #3
You said, "and gravity is not a 'centre-seeking force' per se."

You seem to have forgotten all about something called 'the centre of gravity'. Imagine a smallish planet consisting entirely of ordinary beach sand. Now allow some disturbance to seperate all those grains of sand so they are spread apart from each other by several centimeters. They would all feel some attraction toward one another, but the main attraction would be the centre of gravity within that 'cloud' of sand hanging in space. It would attract with the combined force of all those individual grains, overcoming any attraction from any other direction as they all attempt to crowd into the center of the 'cloud', eventually rebuilding the planet. Drop a grain of sand within this planet's gravitational field, and it does exactly what all those other grains did... does its darndest to reach the centre. What better than to call this the action of a centre-seeking force... per se? You can call it gravity; you can call it a depression in curved space-time, but whatever you call it, it's still a centre-seeking force, and every grain of sand has one because it has its own centre of gravity.

Re para #4
You said, "you could probably convince me... "

Let me use Isaac Newton's own famous example to convince you. He pointed out that if a cannon ball was fired horizontally across a flat field, and another cannon ball was dropped to the ground from gun-muzzle height, both balls would reach the ground at the same time. The fired ball falls toward the ground completely unaffected by its forward motion, just as if it had been dropped from the hand.

Newton reasoned that if the cannon was to be fired from the top of Earth's highest mountain, and with enough force, the ball would never reach the Earth's surface. The ball would, at every moment, be in free-fall toward the Earth, but the ground would also be constantly falling away from under it (curving away). Except for air resistance, the cannon ball would wind up in perpetual orbit.

As you undoubtedly know, anything in free-fall is in a constant state of acceleration toward the Earth. Newton used this example to show how the Moon is kept in its orbit, and I would add, accelerating toward Earth without gaining velocity ( my thanks to Datsun for a more formal explanation).

Mind-bending stuff? Yes... even after 300 years.

I will be disappointed if all this does not make my argument more "compelling".


perfectfluid

Hi fellows (no gender meaning attached),

This stuff can keep the old brain cells from hardening, I dare say.

PF: As I had responded to Datsun, this is mostly in response to you. First let me say that I am sorry to disappoint, but I am encouraged to see some areas of agreement.

Datsun and you were both right to see my first paragraph as a wry, facetious comment, but I did want to make the point that one effect is gravity in its ‘normal’ passive state (once two gravitational bodies are in touch), and movement or momentum, which is the source of the artificial gravity felt by an object (say an astronaut in G-force training) in what was termed centrifugal force. It has been widely accepted in the physics world that the actual force involved is centripetal force, and that centrifugal – being the result of the actual centripetal force – is just a reverse definition (like anti-gravity would be) and has been re-labeled a fictitious force. (Check up on it on Google, if you like.)
http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=Fictitious+Force&btnG=Google+Search

Re: Paragraph #2
We agree about the planes, trains, etc. What you wrote was a restatement of what I wrote, which is fine. Since yours is clear to me, then we can agree on Newton’s first law of motion. (Thank Bob.)

Re: Paragraph #3
This may well be considered nit-picky. I did feel as if the verbiage could clarify this because it is a very important when discussing whether or not inertia ‘is gravity’, as opposed to ‘is an effect that can simulate gravity’.
If the piece is discussing this simulation, then I feel it could be clearer on the point. If the piece is equating, rather than discussing Einstein’s ‘Equivalence Theory’, then it is far off the point.
Strange thing is that the grain of sand you mention will seek the planet’s center, it is not about to care one bit about a stone being swung on a string. The stone may experience the effect of a gravitational pull, but nothing outside of the device will feel anything but wind, and perhaps a sharp whistling sound.

Re Paragraph #4
Yes, locally Isaac Newton’s genius is well represented here. This is a wonderful experiment with which to display this property of gravity. It doesn’t do a thing for the inertia = centrifugal force = gravity equation, but it does show the ability of gravity to ignore speed.
Yes things stay in orbit because the ground is always moving away from where the object was headed. Astronauts feel an effect that they call weightlessness, when their weight is almost exactly what it is on Earth, except that they happen to be in free-fall such as a parachutist might feel before opening his chute. (if he was in a wind-proof capsule)

It may be that we are just using a different dictionary, but I’m still not sure how you can call the resultant vector ‘acceleration’ if speed is not increasing. Is the Moon falling ‘faster’ than it did 200 years ago? (Inquiring minds want to know.)

ac·cel·er·a·tion n.

1.
1. The act of accelerating.
2. The process of being accelerated.
2. Abbr. a Physics. The rate of change of velocity with respect to time.

ac·cel·er·ate v. ac·cel·er·at·ed, ac·cel·er·at·ing, ac·cel·er·ates v. tr.

1. To increase the speed of.
2. To cause to occur sooner than expected.
3. To cause to develop or progress more quickly: a substance used to accelerate a fire.
4.
1. To reduce the time required for (an academic course, for example); compress into a shorter period.
2. To make it possible for (a student) to finish an academic course faster than usual.
5. Physics. To change the velocity of.

v. intr.

1. To move or act faster. See Synonyms at speed.
2. To engage in an academic program that progresses faster than usual.


Still, again, this doesn’t do much in equating gravity and inertia.

Perhaps you are not comfortable with gravity being an effect involving gravitons; for if you did, the entry could only make reasonable sense by describing how inertia (forget the centrifugal force concept, the word does still exist in everyday speak) creates these gravitons. If there is not theory on inertia creating gravitons, make clearer that they are not the same force, but two forces with one similar effect.

Or, as a last resort, perhaps you could just make it more clear that the entry discusses an unproven theory, rather than state so much as established fact.

I, too, hope to have clarified – if not the subject, than at least my take on the subject. I also very much hope not to offend. Words and language are important things to me, and I am one who appreciates clarity of both thinking and communication. Perhaps I am not as good at it as I would like to think I am.

The important definition here is
2. Abbr. a Physics. The rate of change of velocity with respect to time.
Because velocity is a speed AND a direction then the speed does not have to change for there to be acceleration. A direction change will be sufficient. As the mmon is constantly changing direction then it is constantly changing its velocity (speed and direction) but not its speed. This equates to acceleration.
The everyday use of the word velocity is interchangeable with speed, but when used in its scientific sense then velocity does not mean speed.
Wick

Wick,

Welcome to the discussion.

I beg to differ. I am no physicist, but have a modicum of familiarity with the English language and simple physics formulas.

Velocity is, indeed, a factor of both speed and direction; but, acceleration is the ‘Rate of Change’ in the speed OR direction (or speed and direction).

I do not contend that the direction (and, therefore, velocity)is unchanged as the Moon orbits the Earth; but there is no ‘Rate of Change’, the change is constant. As such, it does not rise to the level of 'Acceleration'. The Vector and Velocity change, but the rate does not.

2. Abbr. a Physics. The rate of change of velocity with respect to time.

Ok FT:

In your responses, I've noticed a real barrier to understanding, and you are not alone, which worries me. It's that acceleration thing.

Physics does not define it differently from the way you or Mario Andretti would. It's just that you are unaware of how it is applied in the dance between the Earth and the Moon.

Before I get into it, I must now say that this is not my fantasizing, but solid mainstream stuff, or what you would call, a fact.

Check a textbook that deals with the subject, and you will see written that the orbiting Moon is in a constant state of acceleration TOWARD the Earth. IT IS NOT, as I believe you imagine, accelerating along the track of its orbit. The acceleration is ALONG A RADIUS of the orbit toward the center of the orbit, just as a falling stone accelerates toward the center of the Earth (no orbit in this case). Excuse me for shouting, but without understanding this *inward* acceleration, my Article cannot make any sense--to anyone.

Quite apart from Datsun's velocity vectors, the Moon's orbital motion also can be divided into 2 vectors. One is the straight-line, tangental (to the Earth's surface) movement of unknown primordial origin, and the other is the falling motion toward the Earth. Just as with Newton's two cannonballs, together these vectors give the Moon its curved path, but it is the vector of the falling motion which is getting the acceleration.

Once this bit of factual knowledge is digested, It may be plugged into the Article starting at the point under the Header, 'Like Two Evenly Matched Opponents', and a careful reading should reveal a whole new landscape.

The Moon is accelerating straight down toward the center of the Earth without ever getting any closer to the Earth's surface. Acceleration always produces inertia in the opposite direction, and along the orbit's radius (outward).

Rather than use this discussion space to rewrite and explain the pertinent parts of my Article, I will ask that you give it another shot. Some of your objections might wither away. If not, I am eager to deal with them in installments of 1 or 2 at a time so as not to put off any other's who may be following any of this.

I admire you for participating. It takes a bit of courage, and we all learn something from these exchanges.

Oh BTW--the word 'centripetal' comes from Latin and means 'center-seeking'. You might check 'Centrifugal Force' in the Edited Guide, or your own sources, and find stated that it is the centripetal force which is pulling on the Moon, and we all know that force as gravity, hence, gravity is a center-seeking force. (Is this one of those unproven notions passed off as facts that worried you?) I could have saved myself all that verbiage about a sand planet.


perfectfluid

PF,

This is wonderful stuff, and thanks for staying with me.

This is important enough for me to desire one of two outcomes. I would like either to understand what you are saying well enough to accept it as written; or, explain myself well enough that you will want to change it. (Even if only to make it more understandable to people like me.)

Which of these two outcomes occurs is not critical; and if neither happens, we will not likely be badly scarred by the act of open discussion. (Thank Bob)

The problem (for me) wasn't the emphasized word, TOWARD, ('the orbiting Moon is in a constant state of acceleration TOWARD the Earth'), but the word ACCELERATION. If this means that the moon is in Free-Fall because its 'acceleration' is counter-equal to Earth's gravitational pull, we can agree it is in free-fall and move on. I don't want the more important issue to be bogged down because of my limited usage of the word acceleration.

**** As an aside, and only if you feel it may be helpful, I will insert the following:
In an effort to understand this usage of acceleration, I checked out an online source that I felt was reliable for our purposes. Perhaps we could include this quote in the conversation, and perhaps the site's formula will help you to explain my error.

['The force felt by a body being held at rest in a rotating reference frame is a fictitious force called centrifugal force, while the force (of the same magnitude but in the opposite direction) which must be exerted at the center of rotation to prevent the body from flying away is a real force called centripetal force.']
http://scienceworld.wolfram.com/physics/CentripetalAcceleration.html ****

But, because my real dilemma is not so much the term 'acceleration' (which I consider a minor point, and admitted that the science world may define it in a way that makes it ideal for this use), but the equating of any of those forces with gravity (except, of course, for centripetal).

I then turned to Dr. Anthony Zee who wrote of Einstein's Equivalence Principle. He wrote it (probably paraphrased or translated) as: "In a small enough region of space, the physical effects of a gravitational field as perceived by an observer are indistinguishable from the physical effects reported by another observer accelerating at a constant rate in the absence of a gravitational field.

Note '... indistinguishable from ...' (i.e. Like, but not the same), and '...in the absence of a gravitational field ...' (no gravity being present).

He discusses the 'April Fool Joke' of having a friend wake up in a mock up of their living room, accelerating at 1G and states:
"When the reality is that we are accelerating our friend deep in intergalactic space, she has the illusion that she is in a gravitational field. The illusion is equivalent to, but not equal to, the reality."

He says the equivalency theory "makes physicists happy because it saves them a lot of work." And, "Thus, once we master a physical law in the absence of gravity, be it the phenomenological law govering the flow of water or the more basic law governing the behavior of some subnuclear particle, we can immediately find out what the law is in the presence of gravity by appealing to the equivalency principle."

Finally, if gravity is curved space and time, how does Inertia play into it? Can swinging a potato on a string curve space and time more than it does while it sits on a table?

Trying to understand the concepts,

FT,

I'll answer the points you raised in somewhat the same sequence that you offered them.

1. ACCELERATION-
The Moon is in free-fall, which means that it is accelerating. Its constantly changing direction keeps things from getting out of hand (endlessly gaining speed). I agree it's time to get beyond ths one.

2. THE WOLFRAM WEB PAGE-
You said,"... and perhaps the Site's formula will help you to explain my error."

Whatever error it is you think you are making is probably not addressed by this Page. The point it makes is the same one I so strongly emphasized in my last posting-- the *inward* acceleration toward the center.

I don't speak the language of mathematics, but the Author has obligingly provided a plain text translation for diletants like myself. Notice the Header, 'Centripetal Acceleration', which can be read as, 'center-seeking acceleration'. A bit later, the Author explains the use of a negative symbol. (negative because the acceleration is directed *inward*). The rest of it is just the standard description of the forces acting on a body in a rotating reference frame. None of it conflicts with anything I wrote.

3. INDISTINGUISHABLE-
So alike that one cannot be distinguished from the other i.e., no way to tell which is which; may, or may not be the same.

4. DR ANTHONY ZEE-
I understand the point Dr. Zee is making by use of that word, but he is only reporting on the current state of knowledge. It begs the Big Question, why are the two situations in his 'April Fool Joke' so maddeningly similar? Where and what is the connection that makes them indistinguishable? Every theoretical physicsist knows the answer is out there somewere, and that the story does not end with Dr. Zee's (correct) observation that acceleration is not the same as, and does not create a gravitational field.

5. Equivalence-
I like your example, from a previous posting, of a bucket being swung around in a circle with a critter inside it. If a blindfold is placed on the critter, it will not be able to tell if it is being twirled around on a string, or if it is accelerating in a straight line through space. I should not have to add that the acceleration is in the direction of the open end of the bucket.

Every related circumstance surrounding these two different modes of producing the acceleration will be the same and feel the same. They will be equivalent--the effects; not the mode of production. If we want to find out what the law is in the presence of straight-line acceleration, we can appeal to Equivalency, and perform experiments on the twirling critter in the bucket (CIB), and vice versa.

The two situations being equivalent, they will produce the same effects. The CIB in straight-line, constant rate, accdeleration will produce inertia pulling in the direction of the closed end of the bucket, and the twirling CIB will do the same.

Neither the straight-line aceleration nor the twirling action creates gravity. That already exists. The CIB has its own gravitational field just as any massive particle does. What IS being produced is inertia, and that's the Big Question I mentioned earlier. No theory gives a satisfactory accounting of where it comes from. It just magically appears the instant any force is applied.

I've run out of time, and will have to continue this in a later posting. See ya.

perfectfluid

Continuation of Posting #11

The following is my attempt to tease out the answer to the Big Question from the facts, with the help of a relatively recent arrival in theoretical physics--the Higgs field.

Look at our CIB traveling through outer space. The rocket which has been attached to the bucket for propulsion has just shut down, so it is in uniform motion (feeling no forces), and moving past us at a good clip. Imagine that its gravitational field is visible to us as a green halo or bubble. We see it sitting at the center of its gravitational field, where it remains, regardless of how fast or slow it moves relative to us.

We know this is so because uniform motion cannot be *distinguished* from a stationary state. Wheather moving or standing still, the CIB is located at the center of the bubble, and nothing about the shape of the bubble betrays its state of motion.

The moment the CIB's rocket fires up, however, the reacting force, (inertia) begins pulling in the opposite direction, and strongly suggests that space is causing a drag on the CIB.
Enter the Higgs field.
Conventional physics theorizes that this Higgs field permeates all of space, and causes a drag on any accelerating particle in proportion to its mass. What they haven't figured out is the mechanism of how and why this drag occurs.

6. YOUR DILEMMA
Enter perfectfluid.
My novel idea is the proposal that the drag indicated by inertia is on the gravitational field of an object rather than the object itself. In our CIB example, the green bubble representing the CIB's gravity field streams out behind the CIB, and becomes elongated. This places the CIB somewhat off-center of its field in the direction of travel.

Because the gravity field is a center-seeking field, it strives to retain the CIB at its center. This pull inward, against the direction of acceleration, is what we have been calling inertia. The instant that acceleration ceases, drag ceases also, and the gravity field reconfigures itself to its original symmetric shape around the CID.

So how does inertia equal gravity? Answer: We have a gravity field encapsulating an object, keeping it prisoner at its center by virtue of its center-seeking force. When an object is experiencing a drag-causing acceleration, it is being forced off-center within its field. Now the *same* gravity field, by virtue of its center-seeking force, is pulling on the object to retain it at the field's center. Whether we are talking about gravity or inertia, we are talking about the same center-seeking force. This is not only equivalence, but equality.

Of course, all of this is only a fantasy, and I don't expect you to accept it. What I want is for people to understand the logic. Before you raise objections based on gravitons or space-time, remember that you can't argue against one theory by throwing a competeing theory at it. All you can do is weigh each theory's relative power to explain, and decide which does a better job.

What Reltivity cannot explain:

1. The source of inertia.
2. What makes gravity and inertia indistinguishable.
3. Why should gravitational and inertial mass be proportional
4. Is inertia a bona fide force.
5. How to connect gravity to the Standard Model
6. What the nature of the Higgs mechanism is
7. How to unify gravity and inertia

The center-seeking model of gravity/inertia, solves all of the above, and eliminates the need for any references to ficticious forces.

7. FINALLY
"Finally, if gravity is curved space and time, how does inertia play into it?"

It doesn't. That's the problem with curved space and time.

"Can swinging a potato on a string curve space and time more than it does when it sits on a table?"

Yes. If you insist on calling a gravity field curved space-time, twirling that potato or critter in a pail will elongate (distort) the gravity field, and in a sense, put more curvature into space-time. Just kidding. As I said earlier, you can't mix up two competing theories.

perfectfluid

PF:

Thanks for taking the extraordinary time to flesh out your points. If what you desire is for readers to understand your logic, then you may be starting to get through to me.

I am, indeed, starting to understand where your logic brings the forces into play in a way that does make them maddingly similar. I shall have to revisit all the I have previously read about Higgs Fields and their ramifications.

With the minor disagreement on acceleration out of the way [and trying very hard not to throw competing theories at each other], may I suggest one last thought?

If the forces you list were to be considered manifestations of one common force, would not the force be consistent in all respects? As alike as the effects on our 'critter' seem, the one remaining caveat that has not been addressed is the critical part of the theory. Small a point as it may seem, it is the dividing issue.

The equivalency principal
[ In a small enough region of space, the physical effects of a gravitational field as perceived by an observer are indistinguishable from the physical effects reported by another observer accelerating at a constant rate in the absence of a gravitational field. ]
contains the all important caveat "In a small enough region of space,..." If the forces were 'the same force', this distinction would not be necessary.

In the April Fool's Joke analogy, if the accelerating room (with a perfectly flat floor, not curved like the surface of the Earth) were as wide as our planet, the differences would soon become apparent. Objects dropped far enough apart on the planet do, as you insist, seek the center of the mass and would fall slightly toward each other. Objects dropped the same massive distance apart in the room, would seem to fall [the floor would actually be rushing up to meet them] in a straight, perpindicular line toward the floor, regardless of where they were dropped.

The equivalency principle could then be restated: "In a large enough region of space, the similar physical effects of a gravitational field as perceived by an observer are distinguishable from the physical effects reported by another observer accelerating at a constant rate in the absence of a gravitational field."

Is there anything in the Higgs drag that could explain the difference in the change in perception?



PS: Hoping that we are on the home stretch, as my brain is beginning to hurt!

You are asking all the right questions, FT

The accelerating room in the 'April Fools Joke' is an example of what, in Relativity, is called an inertial field. You have correctly observed that it is not quite the same as a gravitational field.

The gravitational field around the Earth, for example, has a spherical structure described by the equations of General Relativity. There are no field equations describing the structure of an inertial field. The equivalence that Relativity describes requires an inertial field to also have a geometrical structure, but Relativity is unable to provide it. This makes the notion of an inertial field a weak hypothesis, and does nothing to explain the source of inertia.

You said, "Is there anything in the Higgs drag that could explain the difference in the change in perception?"

The 'Higgs drag' idea eliminates the awkward need to differentiate between very small and very large areas of space.

First of all, there is no need to imagine an inertial field being created just because a surface like a floor is accelerating toward two objects. Inertia, as a reacting force, is created at the instant that the floor contacts the objects, but nothing happens before then (no inertial field).

Let the floor in the 'Joke' example be the top of a massive cube, and for convenience, let's say it is traveling upward. As it strikes the two objects, they are also accelerated upward. Their individual gravity fields will experience a pull downward by drag. This sets up a tension between the gravity fields and their objects as the center-seeking force of each field tries to retain the object within its center.

The arrows representing the direction of the center-seking force for both gravity fields are parallel and pointing downward. They are not pointing toward the center of the massive cube, although there is also the component of the cube's gravitational pull which we shall ignore.

The point is, that even when you have distinguished the scenaro of an accelerating floor from that of an actual gravitational field, it is still the gravitational fields of the two objects that are causing the arrows (vectors) to be parallel to each other and perpendicular to the floor.

In other words, you have distinguished between the situations creating the forces, but the forces are the same. Regardless of the size of the region in space, they are always, in any situation, the action of a gravity field's center-seeking force.

Anyway, that's the theory.

One final thought: Keep in mind that the Higgs mechanism is a very unsettled idea. There are several variations floating around, so don't expect to find one fitting like a jig-saw puzzle piece. The important part is the possibility of a cosmic drag on particles.

Looks to me like the home stretch, but I'll let you call the finish line.

perfectfluid

I believe that the long, enjoyable, and circuitous route to understanding the thrust of the article has been reached.

It is a shame, of sorts, if all this time my problem was simply not noticing wherever in the article you made it clear that it was merely a hypothesis, as opposed to the more observable working theories on gravity a la Newton and swinging critters.

But, I can't say that I didn't enjoy having my brain stretched a bit, and I will get back to a deeper investigation of the Higgs Hypothesis. An entry on something as potentially ground-breaking as redefining inertia would have to be a valuable subject for an entry.

I do appreciate the expenditure of time that this has cost you, and hope that (as I do) you found that having to explain a position from various angles, and at various levels, helped to clarify the subject in your mind, too. Otherwise, only I will have gained from the exchange, and that would be a pity.

Good luck on future entries! If anything further develops on the theoretical physics front, I'd appreciate a bit of notice.

Like I said, FT. We all learn something.
Thanks, and good luck to you, also.


perfectfluid