Where do all the gases go that are photoevaporated ?

[dougettinger]

The photoevaporation process creates "fingers" or "elephant trunks" behind EGGS(evaporating gaseous globules), erodes protoplanetary disks, planetary atmospheres, and the surrounding regions of a star entering the main sequence. The word is a misnomer because evaporation or a phase change does not take place. Actually high energy photons interact and accelerate atmospheric or IMC molecules, most generally the lighter ones of H and He. These interactions with the lighter molecules and atoms can create a higher ratio of dust(higher metals) to gases. The better word is photoerosion which is sometimes used. The matter of IMC and star systems is being pushed away from its present position.

Now I pose the question. In galactic scales where are all these gases eroded to that do not form new stars ? Where do the vast "sinks" or "seas" of these eroded gases reside in a spiral galaxy ? Are IMCs or GMCs (interstellar or giant molecular clouds) thoroughly mixed within a galaxy's star field or do they eventually migrate to favored regions such as the perimeters of spiral galaxies ? or along the spiral arms of galaxies ? Or are these gases expelled from the spiral disks and reside above and below the disk in an elliptical or spherical fashion ?

[Nereid]

The photoevaporation process creates "fingers" or "elephant trunks" behind EGGS(evaporating gaseous globules), erodes protoplanetary disks, planetary atmospheres, and the surrounding regions of a star entering the main sequence. The word is a misnomer because evaporation or a phase change does not take place. Actually high energy photons interact and accelerate atmospheric or IMC molecules, most generally the lighter ones of H and He. These interactions with the lighter molecules and atoms can create a higher ratio of dust(higher metals) to gases. The better word is photoerosion which is sometimes used. The matter of IMC and star systems is being pushed away from its present position.

Now I pose the question. In galactic scales where are all these gases eroded to that do not form new stars ? Where do the vast "sinks" or "seas" of these eroded gases reside in a spiral galaxy ? Are IMCs or GMCs (interstellar or giant molecular clouds) thoroughly mixed within a galaxy's star field or do they eventually migrate to favored regions such as the perimeters of spiral galaxies ? or along the spiral arms of galaxies ? Or are these gases expelled from the spiral disks and reside above and below the disk in an elliptical or spherical fashion ?

I'm a bit surprised no one has attempted to reply to dougettinger's question, in over a month!

The interstellar medium (ISM), in a galaxy like our own, has several distinct phases. Broadly speaking, the phases are in (thermal) pressure equilibrium, with supernova remnants being an obvious exception. In all phases, the dominant element is hydrogen, followed by helium; all other elements - which astronomers confusingly call 'metals' - are mere minor constituents (again, supernova remnants may be exceptions). In GMCs (I'd not heard of 'IMC' until I read your post!), the hydrogen is in the form of molecules (mostly); this ISM phase is by far the most dense, and the coldest. In the phase called HII regions, which also may be quite dense, the hydrogen is (almost) entirely ionised (and in the centres of some such regions helium is singly ionised too). By volume, these two phases comprise ~1% of the galaxy's ISM. Hydrogen can be (mostly) neutral, and atomic, or it can be mostly but not completely ionised (and atomic); helium - which does not form molecules - is almost entirely neutral in these phases.

So, the short answer to your question is that a) the hydrogen molecules are split, forming either atomic hydrogen or ionised hydrogen (or both); and b) the newly heated gas (or, possibly, plasma) diffuses, or is blown, into the surrounding ISM.

In starburst galaxies, intense star formation in GMCs can create bubbles, or fountains, in which gas/plasma is sent far above the (spiral) galaxy plane (the pressure of the ISM keeps expansion in the plane to a minimum).

Wikipedia's Interstellar medium entry is a good place to start to explore this topic further (the usual caveats about Wikipedia apply, of course).

[Beyond]

I'm a bit surprised no one has attempted to reply to dougettingers question, in over a month!

Nereid wrote I thought you were a Legend from long ago that had faded off into the sunset never to return.
Well, Welcome back! YEE-HAA

[dougettinger]

In HII regions hydrogen can almost exist as ionized atoms or molecules, per a previous statement. Ionic matter supposely needs a certain elevated temperature to exist. The ISM is very cold; so how do these ions exist? This next associated questions may sound rather silly. Where do the electrons hang-out that will eventually combine with these positive ions ? And what is doing the accounting to be sure there will an equal number of electrons and positive ions ?

Always curious, Doug

[Chris Peterson]

In HII regions hydrogen can almost exist as ionized atoms or molecules, per a previous statement. Ionic matter supposely needs a certain elevated temperature to exist. The ISM is very cold; so how do these ions exist?

Because it is not accurate to say the ISM is very cold. The temperature of the ISM is dependent on various factors, and it ranges from very cold to very hot. You find HII regions where there is an energy source (one or more hot stars) to ionize the gas. In cold regions, you find neutral hydrogen.

This next associated questions may sound rather silly. Where do the electrons hang-out that will eventually combine with these positive ions ?

Not silly at all, but it reflects a common misunderstanding about just what it means to have a plasma. A hydrogen atom is ionized when it absorbs a photon of sufficient energy to eject an electron. That electron will quickly recombine with the resulting ion, or with a nearby one. Recombination times depend on many factors, but are very short in a diffuse HII region. Indeed, we would not easily detect such regions but for the continuous process of recombination that occurs, since that is what produces the distinctive emission lines we use for observation (H alpha, for example). In these regions, continuous and rapid ionization and recombination occur.

[Nereid]

I'm a bit surprised no one has attempted to reply to dougettingers question, in over a month!

Nereid wrote I thought you were a Legend from long ago that had faded off into the sunset never to return.
Well, Welcome back! YEE-HAA

Thanks Beyond.

Until fairly recently I too thought I'd be never returning. However, modern medicine seems to have voted otherwise (I'm told a certain frame of mind - optimistic, or ornery, take your pick - may have been involved too).

[dougettinger]

In HII regions hydrogen can almost exist as ionized atoms or molecules, per a previous statement. Ionic matter supposely needs a certain elevated temperature to exist. The ISM is very cold; so how do these ions exist?

Because it is not accurate to say the ISM is very cold. The temperature of the ISM is dependent on various factors, and it ranges from very cold to very hot. You find HII regions where there is an energy source (one or more hot stars) to ionize the gas. In cold regions, you find neutral hydrogen.

This next associated questions may sound rather silly. Where do the electrons hang-out that will eventually combine with these positive ions ?

Not silly at all, but it reflects a common misunderstanding about just what it means to have a plasma. A hydrogen atom is ionized when it absorbs a photon of sufficient energy to eject an electron. That electron will quickly recombine with the resulting ion, or with a nearby one. Recombination times depend on many factors, but are very short in a diffuse HII region. Indeed, we would not easily detect such regions but for the continuous process of recombination that occurs, since that is what produces the distinctive emission lines we use for observation (H alpha, for example). In these regions, continuous and rapid ionization and recombination occur.

Since you know about plasma, I will pose one more question, I promise. When a supernova very energetically creates and emitts plasma do the positive ions and electrons ever get randomly separately by large distances possibly creating pockets of ions and electrons that cannot easily recombine ?

[neufer]

When a supernova very energetically creates and emits plasma do the positive ions and electrons ever get randomly separately by large distances possibly creating pockets of ions and electrons that cannot easily recombine ?

Large pockets of ions and electrons create tremendous electrical forces that bring about rapid self destruction.

However, small Debye length pockets of ions & electrons do exist in plasmas:

<<In plasma physics, the Debye length (also called Debye radius), named after the Dutch physicist and physical chemist Peter Debye, is the scale over which mobile charge carriers (e.g. electrons) screen out electric fields in plasmas and other conductors. In other words, the Debye length is the distance over which significant charge separation can occur. A Debye sphere is a volume whose radius is the Debye length, in which there is a sphere of influence, and outside of which charges are screened. The notion of Debye length plays an important role in plasma physics, electrolytes and colloids (DLVO theory).

In space plasmas where the electron density is relatively low, the Debye length may reach macroscopic values, such as in the magnetosphere, solar wind, interstellar medium and intergalactic medium (see table):

• Debye length λ_D(meters)
  ------------------------------------------------
  10⁻¹¹ : Solar core
  10⁻⁴_ : Tokamak
  10⁻⁴_ : Gas discharge
  10⁻³_ : Ionosphere
  10²__ : Magnetosphere
  10___ : Solar wind
  10___ : Interstellar medium
  10⁵__ : Intergalactic medium

Source: Chapter 19: The Particle Kinetics of Plasma

Hannes Alfven pointed out that: "In a low density plasma, localized space charge regions may build up large potential drops over distances of the order of some tens of the Debye lengths. Such regions have been called electric double layers. An electric double layer is the simplest space charge distribution that gives a potential drop in the layer and a vanishing electric field on each side of the layer. In the laboratory, double layers have been studied for half a century, but their importance in cosmic plasmas has not been generally recognized."

[Chris Peterson]

Since you know about plasma, I will pose one more question, I promise. When a supernova very energetically creates and emitts plasma do the positive ions and electrons ever get randomly separately by large distances possibly creating pockets of ions and electrons that cannot easily recombine ?

I wouldn't use your terminology for what happens in a supernova. I'd simply say that the event ejects a lot of gas, and because it is a high energy environment, much of that gas is ionized (that is, in a plasma state). And aside from the rather esoteric separations that occur on a very small scale, as described by neufer, there is no mechanism that could produce the sort of separation you suggest. You can consider the matter purely in terms of basic thermodynamics- do you imagine that if you had a uniform mix of hydrogen and helium that you could create an explosion and end up with all the hydrogen in one place and the helium in another? That would suggest a decrease in entropy, which isn't normally what you see in that sort of environment. The only way you could get separation would be if you had some sort of energetic process actively creating it. I can't think what that would be in the case of neutral gases, let alone charged plasmas which produce huge recombination forces.

I remember doing a problem years ago where you assume two apples hanging on trees a kilometer apart, and you take all the electrons in one apple and move them to the other, and calculate the attractive force between the two apples. I recommend the exercise... it's a very impressive answer. If your calculator can't display really huge numbers, just assume a measly coulomb charge difference between the apples- you'll find charges like that in capacitors inside your computer.

[Nereid]

When a supernova very energetically creates and emitts plasma do the positive ions and electrons ever get randomly separately by large distances possibly creating pockets of ions and electrons that cannot easily recombine ?

There are physical processes which result in some ions being separated from some electrons by very large distances indeed, in a supernova.

These are the processes which create what we call cosmic rays, particles that move at highly relativistic speeds.

Of course, only a trivial fraction of the matter involved in a supernova ends up as cosmic rays, and any resulting charge separation occurs over such vast distances as to be essentially irrelevant (because the charge to mass ratio of electrons is far greater than that of any ion, very few can escape the galaxy the supernova occurs in, while the ions can, easily - for a given particle energy).

Gravitationally bound plasmas do (better, can) produce charge separation, resulting in what is called a Pannekoek-Rossland electric field; basically, the scale height of the electrons is considerably greater than that of the ions, in a plasma that is otherwise in thermodynamic equilibrium (or close to it), because the electron has a much smaller mass than that of any ion (this is also why the outer layers of a white dwarf star are stratified by atomic mass, and why finding a white dwarf with lots of metals - other than C, N, and O - is so exciting).

So, is it possible that, somewhere, somehow, positive ions and electrons can get separated by large distances, possibly creating pockets of ions and electrons that cannot easily recombine? Yes, at the base of the jets produced by AGNs (active galactic nuclei) and GRBs (gamma ray bursts).

[dougettinger]

Thank you all for your replies about the possible separations of atomic ions and electrons. You sort of connected most of the strings of knowledge for me about this subject.

I have always wondered whether a conglomeration of particles that we call a mass always has some minute, statistically, equivalent (with respect to its mass) imbalance of charge that creates gravitational attraction. Of course, with larger masses such as our Sun or planet, the imbalance of charge would be proportionately larger creating the gravity and tides on earth as we know it. This possibility could easily resolve the unified force theory. The amount of electrons to create the Sun's gravity force field would only need to be a few tons. The asymmetry of particles and anti-particles in the universe could possibly have parallels such as the asymmetry of electrons and protons, and also the asymmetry of protons and neutrons. Asymmetry may be the main reason for the universe's existence; and the reason the dark void was defeated.

[Chris Peterson]

I have always wondered whether a conglomeration of particles that we call a mass always has some minute, statistically, equivalent (with respect to its mass) imbalance of charge that creates gravitational attraction. Of course, with larger masses such as our Sun or planet, the imbalance of charge would be proportionately larger creating the gravity and tides on earth as we know it. This possibility could easily resolve the unified force theory.

It is as certain as anything can be that this is not the cause of gravity. The forces are completely different ones. If electrical charges were somehow involved, you'd expect the mass of a charged object to change, wouldn't you? Or if you have some other definition of mass, the weight would change with charge and the mass and weight would be unrelated. The force required to accelerate an object would depend on charge, wouldn't it? Gravitational force would be unconnected with mass, and would be repulsive half the time?

In fact, real objects do have charge imbalances- something which is well understood and easily measured. But it has no connection with gravity.

[Nereid]

Thank you all for your replies about the possible separations of atomic ions and electrons. You sort of connected most of the strings of knowledge for me about this subject.

You're most welcome.

I have always wondered whether a conglomeration of particles that we call a mass always has some minute, statistically, equivalent (with respect to its mass) imbalance of charge that creates gravitational attraction.

From what I've read, on many internet discussion fora, over several years, this kind of idea is quite common; for example, quite a few physics undergrads - and even senior high schoolers - come up with it, independently (and you'll find some crackpots seriously proposing it too).

Of course, with larger masses such as our Sun or planet, the imbalance of charge would be proportionately larger creating the gravity and tides on earth as we know it. This possibility could easily resolve the unified force theory.

Actually, it couldn't; at least, certainly not easily.

In any case, a series of experiments done at the University of Washington - the Eot-Wash experiments - pretty much rule out a great many classes of such theories.

At a more simple level, a lump of iron placed on a scale should 'weigh less' inside a Faraday cage, if this 'charge separation/electromagnetism is the fundamental cause of gravity' were valid - can you see why? As far as I know, there is no measurable drop in the weight of an object, when it's inside a Faraday cage, compared with when it's not.

[dougettinger]

It is as certain as anything can be that this is not the cause of gravity. The forces are completely different ones. If electrical charges were somehow involved, you'd expect the mass of a charged object to change, wouldn't you? Or if you have some other definition of mass, the weight would change with charge and the mass and weight would be unrelated. The force required to accelerate an object would depend on charge, wouldn't it? Gravitational force would be unconnected with mass, and would be repulsive half the time?
In fact, real objects do have charge imbalances- something which is well understood and easily measured. But it has no connection with gravity.

I am not making any claims; this discussion is only for talking purposes. Let's say the any mass no matter what its size had an imbalance of electrons. Then let's say the imbalance created a field outside each and every envelop of matter that attracted positive charges from other envelops of matter. Of course, the positive charges are married already to electrons in their respective pieces of matter. However, the attraction of these lost electrons in each conglomeration of matter would act like gravity and be a monopole attraction. No repulsion of different pieces of matter would exist. The universal constant of G is simply determined by the statistical averaging of charge imbalances found in typical pieces of matter that we utilize in the lab.

I am really interested in the claim that real objects have charge imbalances. How are these imbalances measured ? I presume that static surface charge is neglected.

[Nereid]

It is as certain as anything can be that this is not the cause of gravity. The forces are completely different ones. If electrical charges were somehow involved, you'd expect the mass of a charged object to change, wouldn't you? Or if you have some other definition of mass, the weight would change with charge and the mass and weight would be unrelated. The force required to accelerate an object would depend on charge, wouldn't it? Gravitational force would be unconnected with mass, and would be repulsive half the time?
In fact, real objects do have charge imbalances- something which is well understood and easily measured. But it has no connection with gravity.

I am not making any claims; this discussion is only for talking purposes. Let's say the any mass no matter what its size had an imbalance of electrons. Then let's say the imbalance created a field outside each and every envelop of matter that attracted positive charges from other envelops of matter. Of course, the positive charges are married already to electrons in their respective pieces of matter. However, the attraction of these lost electrons in each conglomeration of matter would act like gravity and be a monopole attraction. No repulsion of different pieces of matter would exist.

What happens if you reverse this:

Let's say the any mass no matter what its size had an imbalance of positive ions. Then let's say the imbalance created a field outside each and every envelop of matter that attracted negative charges (electrons) from other envelops of matter. Of course, the electrons are married already to positive charges in their respective pieces of matter. However, the attraction of these lost positive ions in each conglomeration of matter would act like gravity and be a monopole attraction. No repulsion of different pieces of matter would exist.

Is that correct? Or is it this:

Let's say the any mass no matter what its size had an imbalance of electrons. Then let's say the imbalance created a field outside each and every envelop of matter that repelled electrons from other envelops of matter. Of course, there are positive charges married already to electrons in their respective pieces of matter. However, the repulsion of these lost electrons in each conglomeration of matter would act like anti-gravity and be a monopole repulsion. No attraction of different pieces of matter would exist.

And then what follows?

The universal constant of G is simply determined by the statistical averaging of charge imbalances found in typical pieces of matter that we utilize in the lab.

And if the statistically averaged charge imbalance is zero, then ...?

I am really interested in the claim that real objects have charge imbalances.

Real objects do have charge imbalances. In fact, that's how the charge on the electron was first measured, in the famous Millikan oil drop experiment.

How are these imbalances measured ? I presume that static surface charge is neglected.

If the piece of matter is a conductor, and if the charges are mobile, then they will always appear as static surface charges (do you know why?). In fact, even if the charges are not mobile, and even if the piece of matter is a poor conductor, any charge imbalance will likely end up as a static surface charge.

Left by themselves, static surface charges don't last long, on the surface of the Earth. Why? Because there is a natural process by which charge is constantly being moved around, on all objects down here (actually, more than one process). Can you guess what it is (they are)?

[dougettinger]

Nereid, excess electrons move to "ground" such as those inside lightning. They become shared with the matter on the surface of the earth. I am not sure that I answered your question.

You produced counter arguments to my idea of an imbalance of electrons inside each envelop of matter. I certainly appreciate your interest. May a further expand my idea with you. I repeat that no claims are made.

My idea only applies to electrons and not positive ions. I assume that all protons and neutrons are married to electrons. Due to asymmetry more electrons were produced in the beginning universe than what was needed by atomic nuclei. These excess electrons become fairly evenly distributed as matter was being produced. These almost massless particles became locked inside the crystalline structure of molecules. As a combined attractive force inside any matter these electrons seek other protons and neutrons outside the given crystalline structure in which they are trapped. This seeking creates a force field that we call gravity. As a column of matter increases in length, more gravity force is created above the column due to the increase in trapped electrons.

The protons and neutrons and their appointed electrons that make-up matter are happy. It is the excess electrons that are unhappy and keep trying to become paired with another compatible particle. This unhappiness creates gravity fields for all sizes of agglomerations of particles such as little steel balls and large stars.

The free electrons of static charge, electricity, and lightning bolts are a separate and distinct phenomenon from what is being discussed.

[Chris Peterson]

Nereid, excess electrons move to "ground" such as those inside lightning. They become shared with the matter on the surface of the earth.

To be clear... electrons in lightning can move either up or down, depending on the direction of the field. And the actual distance any one electron travels is very small- a fraction of an inch. No electrons at one end of a lightning bolt travel to the other end. There are very few free electrons, and those that are free only remain so a very short time and distance.

My idea only applies to electrons and not positive ions. I assume that all protons and neutrons are married to electrons. Due to asymmetry more electrons were produced in the beginning universe than what was needed by atomic nuclei. These excess electrons become fairly evenly distributed as matter was being produced. These almost massless particles became locked inside the crystalline structure of molecules. As a combined attractive force inside any matter these electrons seek other protons and neutrons outside the given crystalline structure in which they are trapped. This seeking creates a force field that we call gravity. As a column of matter increases in length, more gravity force is created above the column due to the increase in trapped electrons.

Aside from numerous theoretical problems, there is the simple observational problem that we can detect and measure charge, even at the atomic level. We could directly observe electrons trapped in atoms or molecules but not associated with the normal valence electrons found in atoms. And we don't.

[dougettinger]

Chris, that posted observation would certainly eliminate my idea. I do wonder how a trapped electron may be detected. I would think the very act of breaking apart molecules would affect any excess electrons since they are now mobile enough to avoid detection. The mere observation itself could possibly disturb the experiment's outcome. I am not well versed in the details of particle physics experiments. And chemical experiments should not be able to reveal the observation you speak of.

Again, it must repeat that I make no claims and wish not to be dismissed as a crackpot. I am certainly looking for some cracks in scientific thinking.

[dougettinger]

Thank you all for your replies about the possible separations of atomic ions and electrons. You sort of connected most of the strings of knowledge for me about this subject.

You're most welcome.

In any case, a series of experiments done at the University of Washington - the Eot-Wash experiments - pretty much rule out a great many classes of such theories.

At a more simple level, a lump of iron placed on a scale should 'weigh less' inside a Faraday cage, if this 'charge separation/electromagnetism is the fundamental cause of gravity' were valid - can you see why? As far as I know, there is no measurable drop in the weight of an object, when it's inside a Faraday cage, compared with when it's not.

I read about the Faraday cages. I do not really see the connection of why a lump of iron would weigh more or less inside a Faraday cage. As I have proposed, some excess electrons are locked inside the crystalline structure of matter. The Faraday cage whether it was charged externally or not should have no affect of the locked electrons inside the lump of iron. Electrons will certainly re-arrange themselves on the surface of the cage to produce no electrical field inside the cage when being exposed to an external static charge or electrical field. The excess electrons cannot arrange themselves except for any existing free electrons on the surface of the lump of iron. These trapped, excess electrons can only create a field known as gravity and the pull of gravity (weight) remains unchanged. Make sure that you understand - I make no claims.

[Nereid]

Thank you all for your replies about the possible separations of atomic ions and electrons. You sort of connected most of the strings of knowledge for me about this subject.

You're most welcome.

In any case, a series of experiments done at the University of Washington - the Eot-Wash experiments - pretty much rule out a great many classes of such theories.

At a more simple level, a lump of iron placed on a scale should 'weigh less' inside a Faraday cage, if this 'charge separation/electromagnetism is the fundamental cause of gravity' were valid - can you see why? As far as I know, there is no measurable drop in the weight of an object, when it's inside a Faraday cage, compared with when it's not.

I read about the Faraday cages. I do not really see the connection of why a lump of iron would weigh more or less inside a Faraday cage.

A Faraday cage acts as a shield; external electric and magnetic fields cannot penetrate inside (well, sorta; any significant residual fields can be made trivial by creating a set of nested Faraday cages).

If gravity is nothing more than an electrostatic field, caused by imbalanced charges frozen into all ordinary matter, then inside a Faraday cage the only gravity would be that from the imbalanced charges frozen into the material of which the cage is made (and the lump of iron itself); the bazillion tonnes of matter which make up the Earth would count for nothing.

As I have proposed, some excess electrons are locked inside the crystalline structure of matter. The Faraday cage whether it was charged externally or not should have no affect of the locked electrons inside the lump of iron.

Right.

The effect would be on the electric field created by the excess electrons locked inside the matter comprising the Earth.

Electrons will certainly re-arrange themselves on the surface of the cage to produce no electrical field inside the cage when being exposed to an external static charge or electrical field. The excess electrons cannot arrange themselves except for any existing free electrons on the surface of the lump of iron. These trapped, excess electrons can only create a field known as gravity and the pull of gravity (weight) remains unchanged.

But if gravity is nothing but an electric field, the cage will exclude it (well, almost all of it).

Or am I missing something from your explanation?