Static electricity may transport dust across airless planetary bodies

Static electricity may transport dust across airless planetary bodies
Credit: NASA

A NASA-funded research team, led by Mihaly Horanyi at the University of Colorado-Boulder (CU-Bolder), has conducted laboratory experiments to bring closure to a long-standing issue of electrostatic dust transport, explaining a variety of unusual phenomena on the surfaces of airless planetary bodies, including observations from the Apollo era to the recent Rosetta comet mission. The research being done at the Institute for Modeling Plasma, Atmospheres and Cosmic Dust (IMPACT) was recently published in the journal Geophysical Research Letters, and explains how dust may be transporting across vast regions above the lunar surface and rings of Saturn, without winds or flowing water.

"Electrostatic dust processes have been hypothesized to explain these space observations. However, no theories until now were able to support these explanations," said Mihaly Horanyi, principal investigator of IMPACT research team.

The team recorded micron-sized dust particles jumping several centimeters high under ultraviolet (UV) radiation or exposure to plasmas. On the moon, these dust particles would have been lofted more than 10 cm above the lunar surface, leading researchers to conclude that the moon's "horizon glow," seen in images taken by Surveyor 5, 6, and 7 five decades ago, may have been caused in part by sunlight scattering in a cloud of electrostatically lofted dust particles.

Vaguely similar to the way dragging your feet across the carpet can generate an electric charge, the movement of electrons in the tiny spaces between dust particles can generate surprisingly large charges and forces, which can lift and move dust particles off the ground. 

In addition to single particles, clusters of dust were lofted, which showed that electrostatic processes may be responsible for the Rosetta detection of fluffy released from the surface of Comet 67P.

These laboratory observations reveal that dusty surfaces can become smooth due to dust mobilization and could help explain the formation of the " ponds" like those seen on asteroid Eros and comet 67P, and the unexpectedly smooth surface on Saturn's icy satellite Atlas.


Explore further

Study shows Moon engulfed in permanent, lopsided dust cloud

More information: For more information about SSERVI and the IMPACT research team, visit sservi.nasa.gov/
Journal information: Geophysical Research Letters

Provided by NASA
Citation: Static electricity may transport dust across airless planetary bodies (2016, July 1) retrieved 23 May 2019 from https://phys.org/news/2016-07-static-electricity-airless-planetary-bodies.html
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Jul 01, 2016
Whaaatt? You mean "electric woo" can happen on planetary bodies? This guy must be some kind of crank to suggest such a thing.

Jul 01, 2016
what? no hat tip to Arthur C Clarke or Doctor Asimov (both said as much 60 years ago)?

Jul 01, 2016
Levitating dust was photographed by an Apollo crewman.
http://www.lpi.us...7321.jpg
http://www.lpi.us...7324.jpg

Jul 01, 2016
Whaaatt? You mean "electric woo" can happen on planetary bodies?


Woo has only been found on the planet Earth, so far.

While it's possible that Woo might exist on other planets, it appears to require some degree of intelligence as a precursor, in addition to a little knowledge. Until extra-terrestrial intelligences are discovered, it's probably best to study our own earthbound Woo until then.

Jul 01, 2016
Not quite sure what they mean by "no theory"?

http://science.na...untains/

http://science.na...nstorms/

Seems to me the "theory" has been around for at least a decade or more... Guess it depends how one defines "theory." 'Idea' vs. 'hard data / understanding.' Clearly, the "idea" has been around for a while. Whether or not anybody had followed up on it with actual tests/measurements is another question, perhaps...

Jul 01, 2016
Yeah, "no theory" was perhaps a bit hyperbolic. What they meant was no hard evidence that ultraviolet light could make dust do that. They should have said "no experiment."

The first link is very definitely a hypothesis by the formal definition, and a theory by mathematical physics definition. However, they now have a much more detailed mathematical description (a numeric simulation), as well as evidence that it really does that. So I guess we can forgive a little hyperbole.

The link to the paper is kinda hard to find: http://onlinelibr...abstract
For that matter so is the NASA article, NASA is always fooling around with their site so ya better look quick before they move it: http://sservi.nas...-bodies/

Jul 02, 2016
Whaaatt? You mean "electric woo" can happen on planetary bodies?


Woo has only been found on the planet Earth, so far.

While it's possible that Woo might exist on other planets, it appears to require some degree of intelligence as a precursor, in addition to a little knowledge. Until extra-terrestrial intelligences are discovered, it's probably best to study our own earthbound Woo until then.

John Woo - Movie director...

Jul 02, 2016
As others have said, there has been plenty of theory, but these are results from experiment. See, for instance: "Surface charging and electrostatic dust acceleration at the nucleus of comet 67P during periods of low activity."
http://www.scienc...1500238X

Again, this is not observation, but an extrapolation of something that has been thought to be possible/ probable for some decades.

Jul 02, 2016
But Jones Dumb you said electric discharge is not possible on comets. Try to get your story straight.

Jul 02, 2016
While it's possible that Woo might exist on other planets, it appears to require some degree of intelligence as a precursor, in addition to a little knowledge. Until extra-terrestrial intelligences are discovered, it's probably best to study our own earthbound Woo until then
So this must mean that woo is a quantum phenomenon.
https://en.wikipe...ysticism

Which begs the question - is quantum mysticism woo or does it merely describe the phenomenon?

Sam Harris vs woo
https://youtu.be/hU6TkfCGlX8

Jul 02, 2016
Oh right, it's not electric discharge, it's "electric discharge"...

Jul 02, 2016
But Jones Dumb you said electric discharge is not possible on comets. Try to get your story straight.

Not on a Grand Canyon making level, no.

Jul 02, 2016
Not on a Grand Canyon making level, no.

Other than your limited imagination, please give an explanation as to why there is this limit to electric discharge. Also, please quantify the limitations of electric discharge you are claiming. We know electric discharge occurs on doorknobs and at much smaller scales. We also know lightning occurs on Earth and is up to at least a thousand times more powerful on Jupiter. We can also see the obvious plasma arc discharge that occurs on stars at much much larger scales. Why do you suppose electric discharge cannot occur on the planetary scale necessary to create canyons and/or craters?

Jul 02, 2016
Not on a Grand Canyon making level, no.

Other than your limited imagination, please give an explanation as to why there is this limit to electric discharge. Also, please quantify the limitations of electric discharge you are claiming. We know electric discharge occurs on doorknobs and at much smaller scales. We also know lightning occurs on Earth and is up to at least a thousand times more powerful on Jupiter. We can also see the obvious plasma arc discharge that occurs on stars at much much larger scales. Why do you suppose electric discharge cannot occur on the planetary scale necessary to create canyons and/or craters?

Ummm - it's a comet?
(as a start)

Jul 02, 2016
Not on a Grand Canyon making level, no.

Other than your limited imagination,

My imagination is just fine, thanks. Like all things it requires control to be useful.
please give an explanation as to why there is this limit to electric discharge.

One word - mass. Volume, composition and density (of charge xmission medium - matter).
Also, please quantify the limitations of electric discharge you are claiming.

See https://en.wikipe...ightning for figures on earth size lightning. Do your own calculating for larger or smaller bodies...
We know electric discharge occurs on doorknobs and at much smaller scales.

Ever see a crater in your finger from it?
We also know lightning occurs on Earth and is up to at least a thousand times more powerful on Jupiter.

Well, Duh. Jupiter is prob'ly around a thousand times larger than Earth... That much more mass/matter to absorb and disperse a charge...
(cont)

Jul 02, 2016
(Cont)
We can also see the obvious plasma arc discharge that occurs on stars at much much larger scales.

Magic word, scale. How many Jupiters would fit in Sol?
Why do you suppose electric discharge cannot occur on the planetary scale necessary to create canyons and/or craters?

Once again - mass. That charge you see on Jupiter? Would't get that big here (for example).
Because there is insufficient mass (electrolytic) to hold an equal opposite charge. It's kinda like a battery - once it gets to a certain charge balance, it doesn't take any more.

Jul 02, 2016
This comment has been removed by a moderator.

Jul 03, 2016
@cd - No discharges are mentioned, either in this PO article, or in the paper to which the article refers. The only mention of "discharge" is in your posts.

Obviously your ignorance and malice blinds you, two rambling posts of you declaring how stupid you are. Do you even know what electric discharge is?

"Electric discharge describes any flow of electric charge through a gas, liquid or solid."

https://en.wikipe...ischarge

Electric charge + movement = electric discharge. Got it now?

Jul 03, 2016
There is no FLOW of electric charge described in the paper. Got that now?

LOL!

From the article;
The research being done at the Institute for Modeling Plasma, Atmospheres and Cosmic Dust (IMPACT) was recently published in the journal Geophysical Research Letters, and explains how dust may be transporting across vast regions above the lunar surface and rings of Saturn, without winds or flowing water.

Hmmmmm....
may have been caused in part by sunlight scattering in a cloud of electrostatically lofted dust particles.

Mmmhuh...
In addition to single particles, clusters of dust were lofted,

How exactly do the charges get from the surface to being "lofted"? Do we need to discuss what "flowing" means?

Jul 03, 2016
"Electric discharge describes any flow of electric charge through a gas, liquid or solid."

https://en.wikipe...ischarge

Electric charge + movement = electric discharge. Got it now?

However, there is not necessarily any discharge occurring - only opposite charges being attracted to each other. Movement of mass by electrical charge differential does not require discharge. Just low gravity and low density...(and something about surface area, but I don't know the specifics, so...)
Rub a balloon on your head. Electrostatic charge builds attraction and the balloon sticks to your head. What's missing? Discharge.
edit - just saw FSC's explanation. Better wording than mine...:-) (dangit)

Jul 03, 2016
What is wanted is an explanation of where the locally unbalanced charge that causes the dust grains to leap comes from, and the answer is the solar wind and the solar radiation.

The solar wind consists of mixed protons, electrons, and alpha particles. Depending on the exact dynamics of how they were ejected, these particles can form charge moieties consisting of more protons, more electrons, or more alpha particles, or mixes of two or three. Overall (over the extent of the Solar System, more or less) they are about evenly mixed for no net charge. But in any given location, all three states- positive, neutral, and negative- can be seen over time.

The silliness here is imagining that the Sun is very simple. It is not. It has weather just like every other body we have studied up close. But the surface area of the Sun is so huge that it is almost unimaginably complex. Nevertheless, it is driven- on average- by escaping heat and by enormous magnetic fields.
[contd]

Jul 03, 2016
[contd]
Believing that such a chaotic environment would produce a smooth solar wind is ludicrous.

Then there's the radiation. Ultraviolet radiation is strong enough to knock electrons out of molecules and atoms. There is no transport of charge here. What happens is that the electrons fly away; and if enough UV photons hit a particle in a small enough time, then it becomes strongly charged for a little while, until it attracts enough electrons to cancel its charge. Since all the nearby particles among the multitude are undergoing similar events, there is a net positive charge; furthermore, the initial momentum of the electrons is net toward the interior (think which direction the photons can come from and you will see why) and this causes net separation of charges resulting in the dramatic leaps some of these particles show.

Over time, the electrons migrate back and the charge is cancelled.
[contd]

Jul 03, 2016
[contd]
And finally, what happens when the net momentum of the UV photons strikes the edge of the Moon (or whatever other body that has dust and no atmosphere)? The momentum is across the ground. In this case, the electrons are thrown into open space above the surface, very much farther away. This makes the net charge developed even stronger, resulting in a "storm" of leaping dust particles, preceded by a "storm" of electrons which charge anything standing to the opposite charge from the leaping dust particles, which are attracted and neutralized, and adhere.

So we are looking at three different effects:
1. Solar wind charge moieties that can temporarily charge areas of anything they hit.
2. UV radiation pushing electrons away from dust grains deeper into the soil, causing a separation of charge and consequent effects, and
3. UV radiation pushing electrons away from dust grains into space above the surface, causing an even greater separation of charge.

[contd]

Jul 03, 2016
[contd]
It's a long process, but it's had billions of years to work. So we find dust has migrated from the impacts where it was formed to the rest of the surface of the Moon (or whatever other body) and it naturally has accumulated in the low places.

And this is exactly what we see when we send spacecraft to check.

Gee, looks like all those simulations work just fine according to observation. So the theory is solid. And now we have experiments to test all of the assumptions, and they all say the theory is solid too.

This is called "science." How it works is nicely demonstrated here, a combination of observation, conjecture to hypothesis to theory, and experiment. A good job by all concerned.

@FSC,
Hey @WG - the more, the merrier!
Sure glad you said that. ;)

Jul 03, 2016
Um - yeah...
What he said...

(As DS knocks another one WAY out of the park...)


Jul 03, 2016
First, as stated in the article;
On the moon, these dust particles would have been lofted more than 10 cm above the lunar surface

To be lofted 10cm off the surface, that electrically charged dust particle must have a force imposed upon it to move (Newton's 1st Law). I ask, what force is being applied to move that charge. I do believe that is an electrostatic force. An electrostatic force moved a charged particle and this can be measured, defined as electricity. The transport of those charges to "low places" (i.e. areas less charged by the solar winds) is also measurable, in other words a "flow". The fact of the matter is, what is described here is absolutely an electric discharge.

Jul 03, 2016
But I digress, it's not an electric discharge, it's an "electric discharge"....

Jul 03, 2016
What among all the diverse phenomena I mentioned are you referring to, exactly, when you say electric discharge, @CD? I see at least five candidates there.

Jul 03, 2016
Magic word, scale.

Yep, and EDM is scalable. Let's use that imagination, without the constraints imposed by priori beliefs.

For discussion sake, let's pontificate on a theoretical event.

Let's take two similar sized bodies from two different regions of space. Say an Earth and Mars interaction for familiarity sake. Let's also assume they both have magnetic fields and they are on course for a collision of sorts. I ask, what will happen when those two magnetic fields collide with each other? Being from two different regions of space, the likelihood of equal potential is small. From what I understand and equalization process will ensue. The energy levels required to create canyons and craters is adequately accounted for.

Jul 03, 2016
Let's also assume they both have magnetic fields
How strong are these magnetic fields according to you?

and they are on course for a collision of sorts.
Big assumption. We know enough about their current orbits that we know this cannot have happened for a very, very long time- billions of years in fact. The signature of such an encounter would still be present in their orbits. Very, very unlikely assumption, in fact, given the evidence.

I ask, what will happen when those two magnetic fields collide with each other?
Not much. Magnetic fields don't "collide." The sum of the field determines its intensity and vector at each point; as the fields change, due to the movements of their sources, the intensity and vector sums change.
[contd]

Jul 03, 2016
[contd]
But the sum of the force of, to take your example, Earth's and Mars' EM fields' actions on one another's cores (because that's what the action is upon) by the EM field of each (because that's what's acting) is minuscule compared to the actions of their gravity fields. So again, not much. Two different reasons. <-pretty darn good evidence

Being from two different regions of space, the likelihood of equal potential is small.
What's "equal" mean? How close do you expect them to be? C'mon, now, you can't make claims like this without quantifying them. Let's see what you think you're talking about here. Otherwise this is just handwaving.

From what I understand and equalization process will ensue.
True enough, but how quickly? And from what? Once again, how big do you think the difference is between Earth's and Mars' charges? Do you have any data to back this up? You know we've measured this, right?

[contd]

Jul 03, 2016
[contd]
The energy levels required to create canyons and craters is adequately accounted for.
No, they're not. Accounting implies numbers, and you haven't given any.

You have no observations of the charges of planets. You have no evidence to back up your claim of the orbits of the planets having brought the inner rocky planets close to one another. You have a claim of magnetic fields "colliding," a complete misunderstanding of the real dynamics of the situation. Basically a bunch of wild claims stacked on top of each other in a tottering tower of assumptions. And not a single quantified prediction among them.

Do better. Evidence, quantified evidence. Not more handwaving. Not more new claims to cover up the fact you didn't answer the previous ones (AKA "Gish Gallop" in its purest form). Numbers, and papers that report them.

Jul 03, 2016
What among all the diverse phenomena I mentioned are you referring to, exactly, when you say electric discharge, @CD? I see at least five candidates there.

By definition;

"Electric discharge describes any flow of electric charge through a gas, liquid or solid."

Any flow of electric charge. The solar wind is, in itself, an electric discharge. Just about any plasma interaction is an electric discharge.

Jul 03, 2016
By definition;

"Electric discharge describes any flow of electric charge through a gas, liquid or solid."

Any flow of electric charge. The solar wind is, in itself, an electric discharge. Just about any plasma interaction is an electric discharge.
OK, so now show that the effects of the solar wind can account for these jumping dust motes.

Meanwhile the experiment reported above shows them jumping from UV. Not solar wind. UV is photons, and photons have no charge. No flowing charge there, and solar photons outnumber solar wind particles by billions if not trillions to one.

Finally, the evidence says that the solar wind is net uncharged. So overall, it's actually wrong to describe it as a "flow of electric charge."

And to put a cherry on top, a net flow of electric charge out of the Sun would either quickly charge the Sun so much that it could no longer happen, or else violate conservation of electric charge.

We done here?

Jul 03, 2016
To be lofted 10cm off the surface, that electrically charged dust particle must have a force imposed upon it to move (Newton's 1st Law). I ask, what force is being applied to move that charge. I do believe that is an electrostatic force.

"Coulomb force, also called electrostatic force or Coulomb interaction, attraction or repulsion of particles or objects because of their electric charge."
Actually - their DIFFERENCE in charge. Being large enough to out force gravitational force and EM binding (to other proximate particles).
An electrostatic force moved a charged particle and this can be measured, defined as electricity.

No. Electricity (flow) is sequential electron charge transfer (discharge). Lack of sufficiently immediate proximity to those larger (or smaller) charges prevent this.
Edit - Shoot. Spent too much time thinking about this response. Look at all that has occurred since!

Jul 03, 2016
"Coulomb force, also called electrostatic force or Coulomb interaction, attraction or repulsion of particles or objects because of their electric charge."
Actually - their DIFFERENCE in charge.
Careful- remember like charges repel.

Being large enough to out force gravitational force and EM binding (to other proximate particles).
This part you've got right, but remember that because there is no antigravity, gravity always wins in the limit of size. There simply aren't that many processes happening that segregate charges in large enough moieties to affect astrophysical processes.

Jul 03, 2016

Meanwhile the experiment reported above shows them jumping from UV. Not solar wind. UV is photons, and photons have no charge.

Did you miss this part?
The team recorded micron-sized dust particles jumping several centimeters high under ultraviolet (UV) radiation or exposure to plasmas.

OR plasmas...

Jul 03, 2016
Yes, as a matter of fact I did. Thanks, @CD.

Jul 03, 2016
"Coulomb force, also called electrostatic force or Coulomb interaction, attraction or repulsion of particles or objects because of their electric charge."
Actually - their DIFFERENCE in charge.
Careful- remember like charges repel.

Well aware. I know +/-, but I see the point you are making.
Being large enough to out force gravitational force and EM binding (to other proximate particles).
This part you've got right, but remember that because there is no antigravity,
Why I used outforce instead of negate. It's always a matter of ratio.
gravity always wins in the limit of size. There simply aren't that many processes happening that segregate charges in large enough moieties to affect astrophysical processes.

Understood.

Jul 03, 2016
One other thing, DS.
You keep using moieties.
Makes me wonder when you're gonna start using larrieties or curlieties...

Jul 03, 2016
oops. double

Jul 03, 2016
Heh, it's a habit I picked up from a professor. It's particularly apt when talking about a group of particles that share a characteristic that are part of a much larger group that is, overall, homogeneous, though locally heterogeneous.

Jul 03, 2016
Only a couple of very favored ones. ;)

Jul 03, 2016
Well done, @FSC.

Jul 03, 2016
So, photoelectrons under UV radiation, or secondary electrons caused by impinging electrons (as e.g. in the solar wind), were found to be responsible for the lofting of dust particles. Not plasmas.

DS and FSC.
Thanks for not treating CD (or me) as raving idiots in this thread. Really appreciate the info you 2 have provided that improves my "portrait" of the process. Hopefully, it was good for CD, too.
BTW, would UV excitation of particles work anyway similar in modality to "Rayleigh scattering"?

Jul 04, 2016
(1) a cavity-side surface patch can collect unexpectedly large negative charge due to the absorption of a photoelectron and/or secondary electron emitted from the neighboring particles, which magnitude can be much larger than the charge on a sheath-side surface patch due to direct exposure to UV and/or plasma, and (2) the particle-particle repulsive force can become the dominant electrostatic force, far exceeding the sheath electric field force, in [being] responsible for dust mobilization and lofting.

THAT is interesting addition and makes much sense. I wonder if heat plays a part in the process, as well...?
And thanks for confirming my general thought on the scattering question. Wasn't all that sure, so I asked...

yep
Jul 04, 2016
So, photoelectrons under UV radiation, or secondary electrons caused by impinging electrons (as e.g. in the solar wind), were found to be responsible for the lofting of dust particles. Not plasmas.
Well done from Da Schneib

So plasma from the sun does not create uv light?
Brilliant! You guys are silly!!
So here are the beginnings of the larger picture a more holistic view in its infancy. Hopefully you will appreciate it even if it is not all agreeable.http://www.nap.ed...ter/5#65
To understand flow remebering fundamentals is key.
Conductance
Admittance
Susceptance
Inductance
Reactance
Impendence
Resistance

yep
Jul 04, 2016
Sorry, here it us from the top of the chapter.
http://www.nap.ed...hapter/5

Jul 04, 2016
@FSC, you're on fire!

Jul 04, 2016
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Jul 04, 2016
@cd Hey, good buddy. Liked seeing you at Eu '16. Guess we'll meet up again at JW. https://www.mywot...atch.com

I just realized when I farted that it was plasma! That made me think, what if the dinosaurs caused the comet that came back and hit the earth? It also made me think that the early late bombardment means life was already here. We clearly were further out in the solar system in recent times. I've found a Native American guide to hygiene that references rings around Uranus that weren't discovered for hundreds of years, and then only with remote probes. I'm going to send one to check out my plasma now.

Okay...
That was sorta dumb - but it made me chuckle, so...:-)

Jul 04, 2016
@FSC, you're on fire!

AHA!!
You confirm heat DOES play a part in the process...:-)

Jul 05, 2016
But Jones Dumb you said electric discharge is not possible on comets. Try to get your story straight.


Not of the sort or of the magnitude the idiot Thornhill prattles on about. I suggest reading the paper I
linked and actually trying to understand it. That nutjob would have us believe the jets coming from comets (which have been spectroscopically shown to be H20, CO2 etc) are electric discharges. If you want dumb, then that is dumb, as anybody who has bothered to keep up with the literature over the last decade or so would know.
And the paper I linked is not observation, just hypothesis. Based on well known physics. And only at periods of low activity, because, as we have seen, the solar wind is getting nowhere near the comet at periods of higher activity. If it makes you feel better to call it a "discharge", so be it. Nobody in the literature is.
This chap has written papers on the 67P mission; from 1986; http://onlinelibr...10.1029/


Jul 05, 2016
Not of the sort or of the magnitude the idiot Thornhill prattles on about.

Like I said, it's not electric discharge, it's "electric discharge".....

Jul 05, 2016
@CD, are you seriously proposing that comet tails are from "electric discharge?"

Both of them?

Pointing in different directions?

Really?

Jul 05, 2016
Just in case there are questions, see the following diagram: http://www.univer...gram.jpg

Jul 05, 2016
@WG
I wonder if heat plays a part in the process, as well...?

It is an interesting question and since nobody dared an answer on it, I will give it a shot.

This lunar static charge build-up produced by solar photons is indeed a thermodynamic process. As soon as temperature gets over 0 kelvin there is some probability to find free electrons. This probability gets higher and higher as temperature climbs. For those who remember vacuum tubes for example, an electron cloud was generated by a heating element.

tbc

Jul 05, 2016
...

But in the phenomenon described in this article, you need more than some free surface electrons; you got to hit them hard enough to send them flying in space. That is where the U.V. part of the solar spectrum plays a role in this process. As electrons gets dislodge the surface of the moon facing the sun becomes electro-positive so much that the surface dust particles repels each other's and gives rise to this spectacle.
BTW, would UV excitation of particles work anyway similar in modality to "Rayleigh scattering"?

Scattering hun? Since your questioning revolved around thermalization, it would be appropriate to direct you toward Compton scattering. If you understand it well, you will know how a surface exposed to intense light radiates in the IR spectrum https://www.youtu...7acYIxhw

Jul 06, 2016
Hey FSC!
You're trying real hard @TC to put yourself forward as some kind of physics expert, but the reality is that you have a very poor grasp of the subject. My advice: give it up, or go and do the hard thing: learn physic!

Unlike you, I will not make any judgement on your knowledge base. But I will not hold back to tell you that your social skills do not fly very high. As I am a bit ticklish on this aspect, you just found a fast way to my ignore list. For the rest of your concerns, I will let users who appreciate my participation on PO be the judge of that.

Jul 13, 2016
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Aug 08, 2016
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