The Electric Comet theory

[DeiRenDopa]

Hmmmmm, could I just maybe know what I'm talking about here?
seattlecentral.edu/faculty/mvillarba/CHEM139/Chapter08.pdf
pg. 9

In the case of the comet, we're dealing with a gaseous solution instead of an aqueous one, but the chemistry remains the same as it's only H⁺ and OH^- (from the mineral base) that are involved in the reaction.

As I understand chemical reactions, the energetics have to work out too.

For example, fire a stream of relativistic protons into a cloud containing lots of OH radicals, and you don't get any water!

Further, densities matter (pardon the pun); the proton-OH radical reaction rate in a low density gas (or plasma) will likely be extremely low (unless there are special circumstances), and IIRC the density in a comet's coma would make it a very good terrestrial vacuum.

The next reaction in the chain is the electro-chemical reaction between the mineral salts and H₂O




That's one key reaction chain. I see several others that could apply to comets as well, in the above pdf., primarily the H₂O produced by a Hydrogen - Oxygen reaction either thermally induced (burning in the heat of the discharge on the surface) or catalytically (analogous to the catalytic reaction in a hydrogen fuel cell).

See above.

I suspect data on reaction rates vs density would be relatively easy to find.

There's also temperature to consider.

I have confirmed the proposed composition of a semi-conducting rock via comparison with the material analyzed in the stardust mission and all of the necessary materials are present.

I have analyzed and presented citations confirming the chemical/electro-chemical reaction chains.

But not - yet - shown what sort of rates these would proceed at, given the specific environments of comet comas.

Right?

I have reviewed the measured EM environment ( of one comet at least ) and compared it to laboratory research involving multiple double layers, ion-drag effects, as well as radius and thickness of the DL sheaths.

You reminded me; your posts with materials on this are waiting for me to read and understand ...

I'll hopefully get around to doing the math as applies to comets, but I'm afraid that insufficient data is available for some critical variables so I'm going to have to make some educated guesses, I suppose.

Yep ... but you should be able to constrain things quite nicely, by bounded estimates (e.g. highly unlikely to be greater than x, equally unlikely to be less than y).

But hey, it's just an "idea"...right?

Yes; it advances from that status once you've done back-of-the-envelope calculations, and can show consistency and quantitative plausibility (within a factor of 100 should suffice).

 

[solrey]

realitycheck,
Most of the articles on the EC/EU related sites are written for laypeople, to be understood by a variety of knowledge levels, same as most science interest sites, or print mags, cater towards a general audience.
There is a section in the forum as a repository for scientific papers for those who wish to dig deeper into more details.
Many of us are waaayyy beyond the comprehension level required for the general articles, some are not.
Personally, I'm also pretty good at applying theory to function.
Sometimes I screw up the terminology, or muddle through some of the details, I admittedly am missing the particular "pedigrees", and I welcome constructive criticism and feedback and try to respond with appreciation.

 

[DeiRenDopa]

An old question, solrey, which goes to consistency: why are comets different?

For example: why don't all those (electro-)chemical reactions happen on the Moon? or Eros? or the MESSENGER spaceprobe?

 

[Reality Check]

realitycheck, have you reviewed my comments regarding Main Belt Comets and localized perturbations to their EM/chemical environment initiating a cometary phase or display? Or remember that I've been saying that all densities are valid within the EC?

Just for the sake of discussion, to consider a comet of ~ 0.6 g/cm³, of similar material as revealed in Stardust, fits easily within EC, as a factor of porosity.
It's that simple.

It's not worth dwelling on, really.

Tomaytow, tomahhtow...whaddya do?

The EC authors have stated that comets are asteroids. This makes density an issue because comets do not have the density of asteroids.

All you have to do is cite where this part of the EC idea has been retracted. It's that simple.

The fact that this is part of the EC "model" makes it worth dwelling on.

If you want to change the EC idea from "comets are asteriods" to "comets are dustballs" then you should get the web site updated. After that you will have to show that dustballs can have the porosity that comet densities require. My impression is that in the scientific model it is dust combined with a bit of ice that allows the porosity of comets to be so high.

 

[Reality Check]

realitycheck,
Most of the articles on the EC/EU related sites are written for laypeople, to be understood by a variety of knowledge levels, same as most science interest sites, or print mags, cater towards a general audience.
There is a section in the forum as a repository for scientific papers for those who wish to dig deeper into more details.

Can you give a link to the section in the forum used as a repository for scientific papers?
Maybe a list of the scientific papers published on the EC idea?

My guess is that the scientific papers are similiar to the ones you have been citing, i.e. papers with no menton at all of the EC idea.
This means that you have to show how these papers apply to the EC idea. That is impossible without an actual EC model other then "electricity did it".

 

[DeiRenDopa]

solrey, I've started going through the material I hadn't read before, and the question I keep asking is "how is this relevant to comets?"

To take just one example, at random: you quote from a document on the types of discharges, in which glow discharges are characterised as occurring in low density plasmas (pressure of ~1 mbar, IIRC) ... but the density of the solar wind is way, way, way lower, and the density at the surface of Mercury, the Moon, ... essentially the same.

So if you are interesting in claiming that there are glow discharges on comets (whether of the magnetron variety or not), surely you need to show that the parameter space in which glow discharges have been observed overlaps with that of comets, don't you? And, as far as I can see, so far you haven't.

Also, the MESSENGER diagram refers to a magnetosphere, which plasma structure the Earth, Jupiter, ... also possesses, by virtue of their intrinsic magnetic fields. But in one post you stated, apparently quite clearly, that comets do not have intrinsic magnetic fields! If so, why do you expect the same plasma processes to occur in comets' comas?

I stress that this is just a random sample of questions, from a fairly cursory read of the material you have presented; however, I think it gives you an idea of the sorts of things you would need to address in order to move on from idea (well, some anyway; there is other stuff too).

 

[tusenfem]

Tusenfem, It's my understanding that the DL sheaths are perpendicular to the direction of particle flow. Introducing a magnetic field affects the direction of particle flow, thus the orientation of the sheaths. In the case of the comet, the particle flow is perpendicular to the surface therefore the sheaths will be perpendicular to this flow, thus parallel to the surface.

It all depends on what kind of DL you are looking at (just using an ideal situation for simplicity). At the boundary of two different plasmas the "two charge layers" are parallel to the boundary. In a current carrying DL the "two charge layers" are perpendicular to the current direction.

I have no idea what you mean with "perpendicular to the particle flow." Just a particle flow (even when charged) will not generate a DL.

The solar wind draping around the comet will have plasma flow along it, and thus "parallel to the surface of the comet" Here is a figure showing the draped field (at venus). So, how do you put a DL in that picture? Also, the paper by Laakso says that The electric field component measured by the double probe antenna is almost parallel to y and is larger than the vxB electric field. Such strong fields cannot be supported near a comet and the reason such a large field is measure is because of photo emission, dust impact. The variations in the DC field that are measured correlate well with the measured ion fluxes.

So, we can see that the electric field is "in the flow direction" however this is most likely just the co-moving electric field of the solar wind. This layer where there is this electric field also has a current layer (which one would expect, in order to slow down the field as it drapes around the comet). The total potential drop that is estimated it large over the region but the region itself is also very large. However, this is a radial distance, which means perpendicular to the magnetic field. A double layer thus does not come into the picture as the 10000 km size of the layer is way to large for a DL (10 to 25 times the Debye length, see Alfvén). And there is the problem that it is unclear how this DL should be created, perpendicular to the magnetic field.

Ah, questions questions.

 

[tusenfem]

Note the qualifier, would, which I used intentionally. Not IS.
Regardless, the answer is that a DC electric field has been measured, as related below, but I don't have numbers on the exact strength of that field.

You could always have asked for a copy of the paper.
The total potential drop over that layer was 50 kV according to Laakso.
Hardly your expected "orders of magnitude higher than 10⁹ V."

 

[solrey]

Yep, relating the orientation of the DL to the direction of particle flow was not a good description. DL's around an electrode will generally be parallel to the surface, though.

Tusenfem, would you be so kind as to provide a link to that paper on the electric field?

Have you reviewed the papers I cited regarding Debye length, specifically this one?
Relationship Between the DC Bias and Debye Length in a Complex Plasma.
arxiv.org/pdf/astro-ph/0701063

 

[solrey]

Mercury like a comet? This is not just my opinion.

Mercury has a comet-like gas tail.

What about the atmosphere?

MESSENGER Scientists "Astonished" to Find Water in Mercury's Thin Atmosphere

Well, not really water. Water related ions, like OH^-.

The surprising result is the detection of water-related ions like O+, OH-, and H2O+. Credit: NASA / JHUAPL / U. Michigan

How could there be water on Mercury? Zurburchen listed three possibilities, which are not mutually exclusive. Firstly, it has long been theorized (but not yet proved) from Earth-based radar observations that there may be reservoirs of water ice in small areas of Mercury's poles where local topography creates permanently shadowed spots in crater walls that might trap water over the age of the solar system. Second, the water could come from comets. Third, the process of chemical sputtering could create water where none existed before from the ingredients of solar wind and Mercury rock, as Zurburchen explains.

"The solar wind is highly ionized. Those are radicals -- they want to make connections with everything that they can. Imagine a solar wind hydrogen showing up and hitting the surface. It weathers whatever the mineral is, and steals an oxygen. If you do that, you get something like OH^-, for example." OH^-, also known as a hydroxyl group, would produce a peak at atomic mass 17 on the FIPS spectrum. "You can do it in reverse -- an oxygen from the solar wind can steal a hydrogen. The process is called chemical sputtering."

I think I've mentioned chemical sputtering as a way to produce OH^-. Sodium is abundant, and the water related ions were surprisingly abundant, given the data on "magnetic tornado's", a.k.a. "flux transfer events", or a "discharge vortex" implies a Townsend dark discharge which could be another process for producing OH^- as I've previously described. Was this overlooked, or was this discounted, or even feasible?

In an acid-base neutralization reaction,
– H+ from acid reacts with the OH– from base → water, H2O
– The cation (M+) from base combines with anion from acid (X–) → the salt

HX(aq) + BOH(aq) → H2O(l) + BX(aq)
acid base water salt
Note: -An acid will always react with a base to produce water and a salt.
– It does not matter if the salt produced is soluble or insoluble since water always forming means a reaction always occurs.

The next reaction that would occur is when that water then reacts with free electrons, liberated from the surface, within the electric field of the discharge current. Mineral salts in the dust and flakes etched from the surface are probably involved in this reaction. The cathode reaction is:
2H2O + 2e- -> 2OH- + H2

The reaction chain would result in a certain ratio of leftover sodium, likely a factor of the strength of the discharge.

In September 1985, the International Cometary Explorer (ICE) Spacecraft passed through the plasma tail of Comet Giacobini–Zinner at a distance of 7800 km downstream from the nucleus. The relative velocity between comet and spacecraft was 21 km/s, and instruments aboard the spacecraft made magnetic field, energetic particle, and ion composition measurements. The composition measurements showed the presence of water group and CO+ions, as well as an appreciable, but localized flux of ions havingM/Q= 24 ± 1 adjacent to the edges of the plasma tail. These ions were tentatively identified by M. A. Coplanet al.(1987,J. Geophys. Res.92, 39–46) as either C+2or Na+. Motivated by recent observations of neutral sodium in the tail of Comet Hale–Bopp (G. Cremoneseet al., 1997,Astrophys. J. Lett.490, L199), the Giacobini–Zinner composition data have been reexamined, particularly with regard to the spatial distribution of theM/Q= 24 ± 1 ions, now identified as Na+. This conclusion along with other observations of neutral sodium in comets clearly show that there are a variety of sources of sodium in comets.

 

[DeiRenDopa]

Mercury like a comet? This is not just my opinion.

Mercury has a comet-like gas tail.

At that level, the Moon has one too (IIRC), as does Io (sorta), ... but 'a comet-like gas tail' does not a comet make.

From that article - which is not a paper, so one needs to take what it says with the appropriate caution - it seems the 'like' is limited to a shape and a linear dimension ... certainly the composition is different, etc.

Surely this can have relevance only if you can show - quantitatively (at the back-of-envelope level) - that your proposed 'generate gas tails' processes produce results which match the data (in this case, comets and Mercury)?

What about the atmosphere?

MESSENGER Scientists "Astonished" to Find Water in Mercury's Thin Atmosphere

Well, not really water. Water related ions, like OH^-.





I think I've mentioned chemical sputtering as a way to produce OH^-. Sodium is abundant, and the water related ions were surprisingly abundant, given the data on "magnetic tornado's", a.k.a. "flux transfer events", or a "discharge vortex" implies a Townsend dark discharge which could be another process for producing OH^- as I've previously described. Was this overlooked, or was this discounted, or even feasible?

Who knows?

One thing that is known is that Mercury has an intrinsic dipole magnetic field, of strength x, and comets don't.

Unless and until you start crunching some numbers, it's all just disconnected ideas buzzing around, isn't it?

Oh, and once again, a popsci article is not a paper (who knows; perhaps most of what's here would never appear in a peer-reviewed paper, if only because it's too speculative?)

The reaction chain would result in a certain ratio of leftover sodium, likely a factor of the strength of the discharge.

Same comments as above ... time to roll up your sleeves and start making some serious estimates?

Oh, and what is the source of the last two quotes? It's always a good idea to provide details of your sources ...

 

[solrey]

From Science News, August 1985

The relative abundance of sodium in Mercury's atmosphere invites comparison with Jupiter's satellite Io, which also has a lot of sodium. In Io's case sodium appears to be sputtered off the satellite's surface by energetic particles in Jupiter's magnetosphere . In Mercury's case the solar wind solar wind, probably does the sputtering (Sputtering, A popular method for adhering thin films onto a substrate. Sputtering is done by bombarding a target material with a charged gas (typically argon) which releases atoms in the target that coats the nearby substrate. It all takes place inside a magnetron vacuum chamber under low pressure.) The hydrogen and helium seem to come directly from the solar wind. the solar wind can also take sodium from the atmosphere of Mercury, but bombardment of the planet by meteors could provide a replacement supply to maintain a steady amount. All in all, Potter and Morgan say, the atmosphere of Mercury resembles the coma of a comet more than it does the atmosphere of a planet like earth.

That was way back in '85, long before MESSENGER detected other gases on Mercury also associated with comets, such as OH^-.
It would seem that we have direct evidence relating to sputtering in at least two distinct envrionments.
The magnetron chamber in the industrial process of sputtering is basically a magnetron glow discharge. On a comet, instead of a substrate to coat, the material is instead stretched out by the solar plasma stream via ion drag.

What I've been saying is that there is a combination of surface sputtering and focused magnetron glow discharge, producing the "atmosphere" of gas and dust, in the coma and tail of a comet.
A comet also has two seperate types of tails, dust tails and an ion tails. The ion tails are "field aligned", separating the flow of high velocity ions from the lower velocity surrounding dust and neutrals.

In a more energetic discharge that etches abundant material from the surface, there is more material for free sodium to recombine with, after being accelerated out of the zone where the discharge impinges on the surface away from the bulk of the most energetic electro-chemical reactions. Less material available, more free sodium.
That's how I see it working out in a logical process.

 

[DeiRenDopa]

From Science News, August 1985




That was way back in '85, long before MESSENGER detected other gases on Mercury also associated with comets, such as OH^-.
It would seem that we have direct evidence relating to sputtering in at least two distinct envrionments.
The magnetron chamber in the industrial process of sputtering is basically a magnetron glow discharge. On a comet, instead of a substrate to coat, the material is instead stretched out by the solar plasma stream via ion drag.

What I've been saying is that there is a combination of surface sputtering and focused magnetron glow discharge, producing the "atmosphere" of gas and dust, in the coma and tail of a comet.
A comet also has two seperate types of tails, dust tails and an ion tails. The ion tails are "field aligned", separating the flow of high velocity ions from the lower velocity surrounding dust and neutrals.

In a more energetic discharge that etches abundant material from the surface, there is more material for free sodium to recombine with, after being accelerated out of the zone where the discharge impinges on the surface away from the bulk of the most energetic electro-chemical reactions. Less material available, more free sodium.
That's how I see it working out in a logical process.

It may be a good idea to clarify exactly what is meant by the term "sputtering".

As I understand it, the process is essentially mechanical: a particle with a high kinetic energy collides with a (solid) surface, and part of the kinetic energy goes into breaking the (chemical?) bonds of an atom, part into the kinetic energy of the liberated atom(s), part into heating the solid. The particle doing the bombarding is usually an ion, but doesn't have to be. Here on Earth, in factories, sputtering is nearly always done with ions whose kinetic energy comes from the fields in magnetrons (or similar devices); on surfaces such as Mercury or the Moon (or the surface of a spacecraft), the ions doing the bombarding are already present in the solar wind (though various processes associated with planetary magnetic fields may create a population of ions with enhanced energy).

Re "focused magnetron glow discharge": I asked you this before, but I don't think you answered: how can there be such a thing, on a comet, if it has no intrinsic magnetic field? Also, why is there no such glow discharge on the Moon, Eros, ... and the surfaces of various spacecraft?

 

[Reality Check]

At last - something that may have some relevance to comets from solrey .
Sputtering

Sputtering is a process whereby atoms are ejected from a solid target material due to bombardment of the target by energetic ions. It is commonly used for thin-film deposition, etching and analytical techniques (see below).

I can see this possibly happening on a comet's leading surface as the solar wind hits it. It would be a contribution to the heating of the comet, e.g. the temperature distribution that was measured for Tempel 1.
But this is bad news for the EC idea.

No hot spots are seen in thermal maps of Tempel 1

 

[Tim Thompson]

Why are Electric Comets Better?

A confession of bias up front: I pretty much abandoned the thread, having plenty of other useful things to do, on the grounds that in my opinion the entire topic of electric comets is far too stupid to bother with.

Now, that said, a question if I may, for any electric comet proponent who chooses to answer: Why is the "electric comet" paradigm superior to the standard comet models used by mainstream scientists? Can anyone cite an intolerable conflict between the observed behavior of comets and the mainstream physics that purports to explain comet behavior, such that the mainstream must be abandoned in favor of the new idea?

 

[tusenfem]

Yep, relating the orientation of the DL to the direction of particle flow was not a good description. DL's around an electrode will generally be parallel to the surface, though.

Yes, but perpendicular to the current flow.

Tusenfem, would you be so kind as to provide a link to that paper on the electric field?

http://esoads.eso.org/abs/1991JGR....96.7731L

Have you reviewed the papers I cited regarding Debye length, specifically this one?
Relationship Between the DC Bias and Debye Length in a Complex Plasma.
arxiv.org/pdf/astro-ph/0701063

Not have, quickly scanned this paper I do, interesting it is, maybe later read I, conclusion bring.

 

[tusenfem]

At last - something that may have some relevance to comets from solrey .
Sputtering

I can see this possibly happening on a comet's leading surface as the solar wind hits it. It would be a contribution to the heating of the comet, e.g. the temperature distribution that was measured for Tempel 1.
But this is bad news for the EC idea.

Sputtering is indeed a "universal process" which is happening a great deal e.g. at the Galilean satellites (except for Ganymede which has its own internal magnetic field, where the energetic particles cannot reach the surface). In planetary physics, it is indeed the hitting of the surface by energetic particles. Once more at Jupiter, it is the plasma that corotates with the Jovian magnetosphere, which is faster than the orbital velocity of e.g. Europa, and you find that the impact onto the atmosphere/surface will lead to ejection of particles that used to be part of the atmosphere/surface.

Sputtering is rather hampered by an internal magnetosphere, as the particles that do the work are usually ions, and thus are constricted in their motion by the magnetic field. This does not mean that it does not happen.

Now, color me wrong, but were those "magnetic tornados" not observed in the tail? Here is the popsci paper with the drawing, so no they are also up front. The FTE can indeed let the solar wind get into the magnetosphere and let it do the sputtering. Unfortunately, it is not said how many of these FTEs were found. Methinks it could just be one as it was just a flyby of Mercury. Making things prettier in a popsci paper (e.g. to saveguard your funding) is not unusual. However, it would be nice if the popsci article would also say where the science is being published.

Actually I just found it (I think) in Science (to which I have no access online).

 

[solrey]

Tim Thompson:
Now, that said, a question if I may, for any electric comet proponent who chooses to answer: Why is the "electric comet" paradigm superior to the standard comet models used by mainstream scientists? Can anyone cite an intolerable conflict between the observed behavior of comets and the mainstream physics that purports to explain comet behavior, such that the mainstream must be abandoned in favor of the new idea?

Greetings Tim Thompson. That's a bit of a loaded question, actually. How about something like; What evidence causes one to believe that the "electric comet" paradigm might be the next step in the evolution of our understanding of comets?


As we probe deeper into the environs of the comet, we have discovered a dynamic plasma environment within organized, complex electro-magnetic fields. A magnetosphere has been detected around Comet Halley.

The region of the magnetic barrier in front of the contact surface is shown to be an electric load for the MHD generator arising as a result of the solar wind interaction with a comet.

I have been using the data from Mercury's MESSENGER mission to illustrate the analogues to comets regarding chemical sputtering, and Flux Transfer Events inducing electro-chemical reactions, and noting the by-products of those reactions and the similarities to comets, including why comets have a lower ratio of sodium due to binding with abundant dust particles, of which Mercury produces very few, if any.
Comet samples have been found to be surprisingly asteroid-like. Even the amino acid glycine that was recently found in the Stardust samples can be produced in the presence of an electric field, with the right ingredients, as illustrated in the Miller-Urey experiments. Not saying that's the only explanation for the glycine, just a possible one.

The "dirty snowball" idea has been around since ~1950 and as more details are uncovered, we're discovering that comets aren't fitting the paradigm very well. A couple of examples are comas the size of Jupiter, or even the Sun, and some comets displaying coma's and tails much further from the Sun than they should.


Tusenfem, I believe the link I provided about the FTE's on Mercury was from NASA, actually. The illustration is from:

NASA/Goddard Space Flight Center/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

Not exactly popsci.

 

[DeiRenDopa]

Greetings Tim Thompson. That's a bit of a loaded question, actually. How about something like; What evidence causes one to believe that the "electric comet" paradigm might be the next step in the evolution of our understanding of comets?


As we probe deeper into the environs of the comet, we have discovered a dynamic plasma environment within organized, complex electro-magnetic fields. A magnetosphere has been detected around Comet Halley.

I have been using the data from Mercury's MESSENGER mission to illustrate the analogues to comets regarding chemical sputtering, and Flux Transfer Events inducing electro-chemical reactions, and noting the by-products of those reactions and the similarities to comets, including why comets have a lower ratio of sodium due to binding with abundant dust particles, of which Mercury produces very few, if any.
Comet samples have been found to be surprisingly asteroid-like. Even the amino acid glycine that was recently found in the Stardust samples can be produced in the presence of an electric field, with the right ingredients, as illustrated in the Miller-Urey experiments. Not saying that's the only explanation for the glycine, just a possible one.

The "dirty snowball" idea has been around since ~1950 and as more details are uncovered, we're discovering that comets aren't fitting the paradigm very well. A couple of examples are comas the size of Jupiter, or even the Sun, and some comets displaying coma's and tails much further from the Sun than they should.


Tusenfem, I believe the link I provided about the FTE's on Mercury was from NASA, actually. The illustration is from:

Not exactly popsci.

You might like to consider outlining, for TT if no one else:

* what your next planned steps are, wrt developing this idea

* what you consider to be the most critical tests of the idea (i.e. the ones which will mostly likely, and most certainly, distinguish it from various null hypotheses)

... and so on.

 

[Reality Check]

The "dirty snowball" idea has been around since ~1950 and as more details are uncovered, we're discovering that comets aren't fitting the paradigm very well. A couple of examples are comas the size of Jupiter, or even the Sun, and some comets displaying coma's and tails much further from the Sun than they should.

Can you give citations to the sources that describe how these observations impact on the "dirty snowball" scientific theory (i.e. Whimple's model)?

As far as I can see they just confirm the snowball part of the model and that comets have a wide variety - from the original "dirty snowball" to the "icy dustball" that is Tempel 1.