This thread is to continue the debate regarding measurements/calculations of the mass of the Sun which has been brought up in a number of threads, such as "Big Bang or Big Slam?"
Anyway, there are a number of flaws with this suggestion.

1) The bodies whose motion are well modelled by using the standard value for the Solar mass include those that are not confined to the same plane as the Earth.
2) The mass of the Sun can be derived on non-Newtonian grounds by looking at the "deflection" of starlight that passes close to it. The value derived is consistent with the standard value for the Solar mass. What non-gravitational force could reproduce the same orbital dynamics as well as the GR related effects?
3) If the "force" that is moving the Sun in the z direction is similar to gravity (i.e. the force on all of the bodies within the solar system is roughly proportional to their mass) then the resultant effect on orbital dynamics will be negligble, i.e. it wouldn't significantly change our value for the Solar mass.
4) If the force in the z-direction wasn't roughly proportional to the masses of the bodies being affected (and perhaps was primarily affecting the Sun) then we would observe that the Sun was not in the plane of the Earth's orbit, as well as the orbital planes of the other bodies. Observationally this is not the case, which suggests that any implied correction to the standard value for the Solar mass is negligble.
5) If the force involved some coupling of the magnetic fields of the planets and any plasma currents / Solar magnetic fields, then we would expect any non-negligible effect to vary considerably for each of the bodies within the Solar system (planetary magnetic fields vary considerably, and not as a simple function of the distance from the Sun.) As planetary orbits obey a 1/r^2 law to a good approximation we can thus assume that no significant correction is needed in our calculation of the Solar mass to account for this sort of an effect (if it exists).

Any more?

But always in the same movement plane of the solar system itself. You have essentially adopted a heliocentric notion of movement and have attempted to apply it to density. Show me the link and the math for the z movement, and any methods you've used to assure there is no movement of the z axis as the solar system moves around the galactic core.

Now we open up another can of worms where things that are presumably without mass are somehow bent by gravitational fields. It is a well documented phenomenon mind you, but how you correlate that to density will involve some interesting dances around the concept of "resting mass". Watch and see.

No one is disputing the notion that without including the z axis movement of the sun or the solar system itself, or any other external movements of any sort, these "relavitive" concepts of gravity and density are sound and apply. Once you start asserting "absolute density" however, you will have to include every single kind of movement that affects our solar systems movement in the universe, including it's movement around the galactic core and the universal acelleration of the universe itself. Some things we do understand work well within the relative movements of the solar system. When we try to apply this relative concept to "absolute" density of the sun however, I start to question it's value or it's ability to be accurate in any way.

That sure sounds like a great leap of faith to me. How do you know it will have a neglible effect? Start with the expansion of the universe itself. How do you know that this number alone won't have some affect on absolute density?

[quote]4) If the force in the z-direction wasn't roughly proportional to the masses of the bodies being affected (and perhaps was primarily affecting the Sun) then we would observe that the Sun was not in the plane of the Earth's orbit, as well as the orbital planes of the other bodies. Observationally this is not the case, which suggests that any implied correction to the standard value for the Solar mass is negligble.

Now wait a moment. Not all the planet are on 'exactly' the same plane. That is not so. Again, I haven't even seen a single density calculation that included that acceration of the universe itself. It seems to me if you apply that to z axis, and then do the math, you'll get a radically different answer.

Well, I have to agree that movement that is relative to the movement plane of the solar system does allow us to use these calculations effectively enough to reach other planets and land on them and things like that. There is no denying that 2D concepts of Newtonian gravity work well relative to the movement plane of the solar system. What remains an unknown are all the external electromagnetic energy fields that accelerate our universe. The currents that would be required to do something like that, even with relatively hollow metal balls would be enormous. If Birkeland was right, there is no way to know if these concepts of absolute density can be used as a scientific valid criticism of this model. Unless we know all the electromagnetic influences and the cause of acceleration, it would be very premature to ingore these factors in understanding absolute density.

Some other GR / mass related effects -

- frame-dragging and the precession of Mercury's perihelion is consistent with other measurements of the Sun's mass.

- Slowing clocks

- and there is a delay that is closely related to light deflection. Here is a good discussion of the issue:

http://www.astro.ucla.edu/~wright/deflection-delay.html

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What is 'the same movement plane'?

By definition, a 'plane' is two-dimensional.

By observation (and definition), only the Earth moves (the 'movement' part) in the zero degree plane of the solar system (the ecliptic; the 'plane' part); all other solar system bodies have a non-zero inclination to this plane, and so, by definition, a component of motion in the 'z' direction. Here is a table of the planets and their moons; a similar table of minor planets (asteroids, Kuiper Belt objects, Scattered Disk Objects, Trojans, ...) and comets would show a much larger range of inclinations. Actually, the 'notion of motion' works just as well for geocentric motion (e.g. the orbit of the Moon, of artificial satellites), selenocentric motion (e.g. the various space probes put into orbit about the Moon, such as Smart-1, Clementine, Lunar Prospector), areocentric (sp?) motion (e.g. Phobos, Deimos; various spaceprobes), jovicentric (sp??) (e.g. its retinue of 60+ moons/satellites, Galileo), ... {it's a very long list}The JPL's Solar System Dynamics Group has a wealth of material, online, including an extensive list of publications of the Group members.

I expect that almost all good introductory courses in astronomy ("Astronomy 101") include a section on celestial mechanics; many of these are available online (e.g. Swinburne University of Technology).

You may need to do some work yourself; your notion of 'z movement' may be rather idiosyncratic. Help me out here Michael - what is the 'z axis'? How does it relate to 'solar system move[ment] around the galactic core'? Why did you choose the (presumably Milky Way) 'core' (presumably SagA*) as special (I presume it's special to you; you didn't just pick it at random, did you?)?

I'm not even entirely sure what's being argued here. I mean, since the mass of the sun can be determined using GR in ways that don't involve watching objects in orbit, why should the motion of the sun relative to the rest of the galaxy matter?
For that matter, why would the motion of our entire solar system with respect to the galactic centre impact the ability to measure the mass of the sun using Newtonian methods. I mean, we can watch various objects orbiting the sun from all angles, while the planets lie on one plane, comets certainly don't.
And if it isn't possible to measure the mass of the sun using these methods, then does that mean that we can't measure other objects in the solar system either?

It seems like someone is grasping at straws in order to save their theory from a conclusive debunking.

Yes.. the Mass of the sun should not be in question.

Just its composition, and the density of its layers.. and whether it has a solid nucleon core mass the size of earth inside of it.!
So it can keep the same mass.. As with those variables we can imagine the sun in many ways.. With still the same mass in Kilograms..

-MT

I think there is deeper problem; I think there is a disconnect between the way many folk who post here in BAUT view the science of (in?) astronomy and Michael's (and perhaps some others' too) view.

For example, many contributors to these discussions likely think that '(average) density' is simply the thing you get when you divide '(observed) mass' by '(calculated, or observed) volume'. Further, as Fortis succinctly put it in the OP (my bold) "This thread is to continue the debate regarding measurements/calculations of the mass of the Sun which has been brought up in a number of threads".

Here are some extracts from Michaels' response (my bolds): As I read this, Michael has such a different conception of mass, density, Newtonian gravity, General Relativity (and perhaps much more) than I do that I struggle to see how we can communicate.

If I were to generalise, I'd say my view of what physics (or even science) is only weakly coincides with Michael's. If so, then my discussing 'the average density of the Sun' with Michael may well lead to frustration (on my part, at least), unless and until Michael and I could reach some common ground, wrt physics (and science?), that we could build on.

In one respect, the newly posted Rules for Posting To This Board help - they provide a relatively clear framework within which to hold such discussions.

Allow me to explain.

#13, Alternative Concepts, says (in part):So, for example, if Michael proposes that the average density of the Sun is something other than its mass divided by its volume, then he is welcome to present his view, and will defend it (and he will answer* direct questions in a timely manner).

Or, if he proposes that the mass of the Sun cannot be determined (with the required degree of accuracy) from observations of solar system bodies, or the deflection of light or radio waves as they pass close to the solar limb, or ... , then he is also welcome to present his case, and will defend it.

However, while I think this new framework will allow much meatier threads, I also have a concern that we may lose Michael. You see, if we (Michael and I, and maybe others) do indeed have such a fundamental disconnect (e.g. we may not even be able to discuss something as straight-forward as Newtonian gravity, as it applies to the determination of the mass of the Sun, from observations of the positions of the planets and some spaceprobes), and Michael presents a case (e.g. the Sun has a solid iron/ferrite surface) that is built on dozens of layers of such disconnects, will this new process help us even identify those many-layered disconnects, let alone foster a robust examination of the case?

Thoughts?

*for avoidance of doubt, 'I don't know', and 'I haven't worked that out yet', and so on are perfectly good answers.

BTW, The Bad Astronomer has started a sticky thread for discussion of the new rules - please take a look (and join in if you think there's some way we could do a better job).

The problem with an idea like that is it would require a more massive sun. This is what has sparked the debate over the mass of the sun.

It is possible that Mike and the rest of us are talking at cross-purposes on the various threads, so, Mike, do you want to explain what your concept of density/mass is?

but that assumes that the mathmatics and estimates we use to describe matter at these temp and pressures is accurate...

i see no reason to have blind faith.. and to many times. to many times..
the greatest minds have toted formulas... and then within 10 years data changes..
and the scientist make all new formulas....
i.e.. alot of things change... and can change quickly..

And to assume we have it absolutly right about the density of the layers, is in my mind... not a good thing to do.. you can believe so.
but i will have my reservations, and just stand in the corner brooding.
-MT

It doesn't assume anything. We know that neutron stars are more massive than our sun. Considering that we have to add material to the neutron star in order to get an object the size of our sun that appears to be mostly hydrogen, we end up with an even more massive object.

Furthermore, the study of helioseismology suggests that the current view of the interior structure of the sun is accurate.

a nuetron stars are the left over core of much bigger stars right???

so our sun... since its smaller wont leave a nuetron star will it?
no its smaller so it will have a dwarf....?
right...?

-MT

You're the one who said it had a neutron star core. Or at least, that's the most sensical way to interpret what you said...

edit: You also ignored the rest of my post.

I'm suggesting it more complicated than this. For one thing, there is evidence IMO that supernova explosions resemble more like "exploding hollow balls" than "exploding fission cores" IMO. That "disturbs" me in the sense it doesn't really look like what I first expected to see. That is true of the newer Spitzer images in particular. From my perspective, that distribution pattern may lend some support to Dr. Manuel's model over my own in the sense that I would have to admit it doesn not "explode" the way even I would expect it to explode. Then again, I have no idea what a fission core that size might really do once the whole thing reached a critical mass and temperature. I can't really say.

Dr. Manual has also pointed out that density will be related to heat, and that also become difficult to predict just by looking at "surface" features alone. While the surface might be made of iron, the core may be xenon plasma or other kinds of elements that expand quite dramatically with heat. There are just too many variables to know for sure what the overall density will be.

Having said all that, I do personally believe that the sun is more dense than we think based on solar centric model alone. In other words, just as we could not assume our sun was the center of the universe, we cannot assume it sits still and is not "hugely" affected by the acceleration of the sun, waves from the galaxy itself, etc. What I do not see in density calculations is any sort of consideration of movement in the Z direction. All density measurements I've seen are "solar relative" concepts of density. I do not think it is that cut and dry.

The other issue here about this model that must at least be considered is the fact that such a model would mean the sun acts as a giant cathode in space. It would not only have gravitation affects on surrounding bodies, but electricomagnetic affects as well. If we only look at one component (gravity) we may not get a full picture of what is going on.

Now of course we are assuming that the gravitational affects "bend light", but light is presumed to be massless. How do you intend to determine mass of one body based on it's influence on a presumably massless particle?

How so? Doesn't it demonstrate a significant change of density and/or heat change at 4800km below the surface of the photosphere? What is that? How do you know it isn't a solid surface? How can a sun have a resonance cavity without a wall to resonate against?

I don't think our view of physics is much different frankly. I think you percieve it that way at the moment, but I think as I have time to talk about it, you'll see we aren't that far apart. I readily admit Newtonian concept of gravity work well within the confines of the the "relative" movement plane of our solar system. I am less convinced that Newtonian concepts of gravity alone can give us absolute density measurements that give no considering to everthing that the theory of relativity taught us. Somehow we must move beyond a solar centric "relative" concept of density and begin to include the movements of solar mass through the universe itself as part of our discussion.

The primary question I have with absolute measurements of density have to do with the lack of any consideration of the movement of the sun through the universe in any way. In other words, most density calculations don't even consider the sun's trip around the galactic core, let alone make any allowances whatsoever for "minor" little problems like the acceleration of the universe itself. There are no considerations for any solar movement along the Z plane.

I will willing grant you that your concept of density work fine INSIDE the movement plane of the solar system. Whether or not you can extract "absolute" density, one that includes all forms of solar movement, is the issue here. I am not suggesting we abandon any scientific principles, I am simple insisting we include a few things like the theory of relativity, as we try to determine absolute density.

ok i re-read it.. and... if we imagine that a nuetron star decayed..

and emitted 3/4 of its mass as nucleons which became atoms...
then what we would have is an atom cloud that is free to condense onto the left over core which is now just a dwarf.... into a star with planets.

and when stars explode the dwarf is our evidense..
-MT

Sure, and more or less every planetary body moves along that same plane. That plane however is a relative plane.

Let me ask you a simple question before we go any further. If the plane of the sun and the planets is being accelerated up or down (or both) in some way by external influences, could that in any way affect the "absolute" density of the sun and how it 'looks' from our perpective in the plane?

Michael Mozina:
Do you suggest that the force of gravity is not constant and relative to only the masses in question?

and if so.. what more comes into play when contemplating the measurable and considerable values for the mass of the earth and sun?

and would not density be something which is only relative to the mass in question, i.e. individual star...
as i find it hard to imagine that the motion of the star would need effect the density of it..

-MT

Don't go crazy here. I'm not suggesting we abandon any laws of physics!

I am only suggesting that our solar plane only describes relative movement and relative density. It does not take into account any movement of that plane through the universe itself. If we do not include this movement of the plane through the universe, it is premature to claim we know the "absolute" density of the sun. We know the "relative" density of the sun.

I am suggesting we include Einstein's concepts of relativity, not abandon Newtonian forms of gravity. We must recognize the movement of the plane and acknowledge the acelleration of the universe itself and the acceration of our galaxy through the universe. Unless we take these and other forms of movement into consideration, we cannot suggest we know the "abolute" density of the sun. That is all I am suggesting. Newton applies in the plane. Einstein will have to tell us the density.

The operative word here is "average". I'm not even sure what the average cubic foot of helium weighs at it's temperatures, nor do I know what neon plasma might weight at it's temperatures, nor do I know what kind of plasma might exist under the surface. Dr. Manuel mentioned that density and heat and pressure are all interated here. I wish I did have a magic pair of glasses that let me look inside the sun to see the core, but at the moment I cannot do that. Even if the sun has a solid surface, it need not be all that "dense" throughout the sphere. I just don't know.

Now all that aside, I have been up front that I think there is a problem with how we percieve density here since it seems very "solar centric" from my perspective, a bit akin to having a solar centric view of the universe. I think before we can know absolute density, we will have to know not only what the inside looks like, but what outside factors affect us. That is really all I am suggesting. It's not that "out there". In fact in general terms, I'll bet you agree in some ways. Don't you?

There seems to be radical disconnect from what I'm trying to convey here, vs. what seems to be reflected back at me. Let's all step back and take a deep breath.

I don't claim to KNOW that there are external factors that "certainly" influence our understanding of "density". I likewise do not "know" that there are not external influences that should factor into this measurement. In short I just don't know. All I am suggesting here is the notion of ignoring the plane's movement through the universe seems like a recipe for disaster, especially if we aren't careful.

Having said that, I don't know how big a factor this might be. I was thinking relatively "small" terms. There seems to be a perception that I'm talking "huge". That could be the case as well, but I'm not assuming that. I'm simply suggesting that we live inside a moving, accelerating universe. We don't really know what all factors are in play, and trying to determine absolute densities of anything without considering these external factors may prove quite fruitless. That is ALL I am suggesting here. It's simply something we must consider if we are going to acknowledge our place in the universe itself.

Well, some of that article was interesting, till I got to this part:

What? Guth does not seem to grasp the concept of energy flow. The energy exists. It continues to exist. There never was a time it did not exist. The "virtual particles" he's talking about are simply subatomic waves of energy. Guth cannot suggest you get something for nothing but he was trying to peddle a something for nothing scheme last time I heard. This is totally bogus. You can't violate the first law of thermodynamics. Those are ENERGY particles, they are not "forming out of nothing and then annihilating back into nothing". It sounds like Guth hasn't moved out of the 19th century notion of energy.

I did however very much enjoy the "gravitational lensing" diagram. I sure wish I knew where to find it during our last discusion on the topic.

Einstein's theory of General Relativity works rather well for solar system dynamics, for the delay on relfections off Venus and for the bending of starlight by the Sun. All these work with the current accepted value of the mass of the Sun.

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I am not suggesting that they do not agree, I am simply suggesting that these measurements are all "relative" to the movement of the plane of the solar system itself.

Well, as Nereid pointed out, the usual definition of average density is simply the mass divided by the volume, which doesn't actually involve motion in any direction. So what's your definition of density?

Michael, there are new rules regarding posting to BAUT, and some specific to the ATM section (#13).

Here are some questions regarding your ideas on the average density of the Sun, as calculated from its mass and volume (my numbering):

1) What is (or are?) "2D concepts of Newtonian gravity"?

2) What is "the movement plane of the solar system"?

3) What is '"absolute" density'? b. How is it related to the average density of an object, calculated by dividing its mass by its volume?

4) Which measurements of the mass and volume of solar system bodies (not only the Sun, but the Earth, Moon, Mars, Jupiter, the Galilean moons of Jupiter, Saturn, Titan, Uranus, Neptune, binary asteroids and KBOs, Eros, and asteroids with satellites) are anomalous wrt Newtonian gravity?

5) Ditto, wrt General Relativity?

6) a. What is "the Z direction"? (as in "What I do not see in density calculations is any sort of consideration of movement in the Z direction"). b. In what respect is Newtonian gravity defined only in a 2D plane? c. Ditto, GR? d. Is it in respect of mass or of volume that this 'movement' matters?

7) What is a '"solar relative" concept of density'? (as in "All density measurements I've seen are "solar relative" concepts of density.")

What has this got to do with calculating the average density of the Sun, from its measured mass and volume?What has this got to do with calculating the average density of the Sun, from its measured mass and volume?What has this got to do with calculating the average density of the Sun, from its measured mass and volume?What has this got to do with calculating the average density of the Sun, from its measured mass and volume?In what way - even in principle - could 'movement in the Z direction' affect the measured mass or volume of the Sun, in either Newtonian gravity or GR?What observations of the position and velocity of any body in the solar system can you present that are consistent with this idea?Please make the effort to familiarise yourself with the theory of General Relativity. If you would like, I (or another BAUT member or ten) would be pleased to recommend some good resources (books, courses, ...).

If you have difficulty understanding one aspect or other in GR, please ask a question in the BAUT's Questions and Answers section.

If you would like to review the experiments and observations which have been performed, testing GR, please ask (Clifford Will's living review of GR is a very good place to start).

Once you've done this, I'm sure you will have a very comprehensive answer to your question.

If you have an alternative idea, to GR, you are welcome to present it here; be sure to read the rules, and dgruss23's excellent advice.

If we substitute 'geo' for 'solar' (as in 'solar centric "relative" concept of density), do you have the same problems?

Specifically, the Earth's average density, as measured by techniques derived from Newtonian gravity, is 5.52 g/cm^3. From lots of good observations and experiments here on Earth, many of which (AFAIK) are independent of Newtonian gravity, geophysicists find that the average density of the Earth is 5.52 g/cm^3. AFAIK, no 'movements of Earth mass through the universe itself' were included in any of these techniques and calculations.

BTW, it's your role to convince us that your ideas about this have legs; please be sure to bear this in mind.If you consider this sort of thing to be important for calculating the average density of the Sun from its measured mass and volume, then the onus is on you to present such a case.

Let me ask you two questions, based on your (apparent) views:
1) How does Newtonian gravity need to be modified, in order for the masses (and volumes?) determined using this theory to be accurate? Specifically, what terms in the various equations need to be added/removed/changed?
2) How does GR need to be modified, in order for the masses (and volumes?) determined using this theory to be accurate? Specifically, what terms in the various equations need to be added/removed/changed?

Do I conclude from your statement here that you abandoned the '2D' part in '2D concepts of Newtonian gravity'? After all, there are quite a number of bodies whose orbital plane is quite a bit 'less' in the ecliptic.What does this mean? And what 'plane' is it?Since I have no idea what you mean by "absolute" density, I have no way to answer this question.

But let's return to the original question: the average density of the Sun is calculated from the measured mass and volume of the Sun.

In terms of this question, are you asking about what might affect the measurement of the Sun's mass, or volume, by any one of a number of techniques (derived from Newtonian gravity or GR)?