Graphic of how the solar wind flows over the Moon.  Credit: NLSI

Shocking! Lunar Craters May Be Electrified

Article Updated: 24 Dec , 2015

by

The Moon keeps getting more interesting all the time! But now comes “shocking” news that exploring polar craters could be much harder and more dangerous than originally thought. New research shows that as the solar wind flows over natural obstructions on the moon, such as the rims of craters at the poles, the craters could be charged to hundreds of volts. “In a nutshell, what we’re finding is that the polar craters are very unusual electrical environments, and in particular there can be large surface charging at the bottom of these craters,” said William Farrell from Goddard Space Flight Center, lead author of a new research on the Moon’s environment.

The moon’s orientation to the sun keeps the bottoms of polar craters in permanent shadow, allowing temperatures there to plunge below minus 400 degrees Fahrenheit, cold enough to store volatile material like water for billions of years. And of course, any resources that may lie in those craters are of interest for any future explorers, should astronauts ever return to the Moon.
[/caption]
“However, our research suggests that, in addition to the wicked cold, explorers and robots at the bottoms of polar lunar craters may have to contend with a complex electrical environment as well, which can affect surface chemistry, static discharge, and dust cling,” said Farrell, who is part of a lunar Dream Team — the Lunar Science Institute’s Dynamic Response of the Environment at the moon (DREAM) project, which is also part of NASA’s Lunar Science Institute.

Solar wind inflow into craters can erode the surface, which affects recently discovered water molecules. Static discharge could short out sensitive equipment, while the sticky and extremely abrasive lunar dust could wear out spacesuits and may be hazardous if tracked inside spacecraft and inhaled over long periods.

The solar wind is a thin gas of electrically charged components of atoms – negatively charged electrons and positively charged ions — that is constantly blowing from the surface of the sun into space. Since the moon is only slightly tilted compared to the sun, the solar wind flows almost horizontally over the lunar surface at the poles and along the region where day transitions to night, called the terminator.

The researchers created computer simulations to discover what happens when the solar wind flows over the rims of polar craters. They discovered that in some ways, the solar wind behaves like wind on Earth — flowing into deep polar valleys and crater floors. Unlike wind on Earth, the dual electron-ion composition of the solar wind may create an unusual electric charge on the side of the mountain or crater wall; that is, on the inside of the rim directly below the solar wind flow.

Since electrons are over 1,000 times lighter than ions, the lighter electrons in the solar wind rush into a lunar crater or valley ahead of the heavy ions, creating a negatively charged region inside the crater. The ions eventually catch up, but rain into the crater at consistently lower concentrations than that of the electrons. This imbalance in the crater makes the inside walls and floor acquire a negative electric charge. The calculations reveal that the electron/ion separation effect is most extreme on a crater’s leeward edge – along the inside crater wall and at the crater floor nearest the solar wind flow. Along this inner edge, the heavy ions have the greatest difficulty getting to the surface. Compared to the electrons, they act like a tractor-trailer struggling to follow a motorcycle; they just can’t make as sharp a turn over the mountain top as the electrons.

“The electrons build up an electron cloud on this leeward edge of the crater wall and floor, which can create an unusually large negative charge of a few hundred Volts relative to the dense solar wind flowing over the top,” said Farrell.

The negative charge along this leeward edge won’t build up indefinitely. Eventually, the attraction between the negatively charged region and positive ions in the solar wind will cause some other unusual electric current to flow. The team believes one possible source for this current could be negatively charged dust that is repelled by the negatively charged surface, gets levitated and flows away from this highly charged region. “The Apollo astronauts in the orbiting Command Module saw faint rays on the lunar horizon during sunrise that might have been scattered light from electrically lofted dust,” said Farrell. “Additionally, the Apollo 17 mission landed at a site similar to a crater environment – the Taurus-Littrow valley. The Lunar Ejecta and Meteorite Experiment left by the Apollo 17 astronauts detected impacts from dust at terminator crossings where the solar wind is nearly-horizontal flowing, similar to the situation over polar craters.”

“This important work by Dr. Farrell and his team is further evidence that our view on the moon has changed dramatically in recent years,” said Gregory Schmidt, deputy director of the NASA Lunar Science Institute at NASA’s Ames Research Center, Moffett Field, Calif. “It has a dynamic and fascinating environment that we are only beginning to understand.”

Next steps for the team include more complex computer models. “We want to develop a fully three-dimensional model to examine the effects of solar wind expansion around the edges of a mountain. We now examine the vertical expansion, but we want to also know what happens horizontally,” said Farrell. As early as 2012, NASA will launch the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission that will orbit the moon and could look for the dust flows predicted by the team’s research.

The research was published March 24 in the Journal of Geophysical Research.

Source: NLSI

,



42 Responses

  1. IVAN3MAN_AT_LARGE says:

    “I guess that we would expect [cats] to be affected in a similar manner?” 😉

  2. Aqua says:

    I see mortars lofting a conductive doped carbon fibre netting, which expands to fill the basin of a charged crater’s floor. The netting continually collects the negatively charged electrons from the Sun which are used to generate power and a magnetic field strong enough to ward off most incoming radiation.. the field surrounds the habitat and close environs.
    This might be used on the Moon AND Mars?

  3. Torbjorn Larsson OM says:

    So the usual wisdom is that ambipolar drift acts to keep plasma neutral. But here there are surface effects around flow blockages.

    Seems like a Star Treck future up ahead, add craters as good subjects for field “shields” besides radiation protection. Set them up over the area those ~ 100 s before entering, and let the dust equalize instead.

    [Or perhaps a hydrogen ion spray gun would be easier – and funnier!]

  4. Torbjorn Larsson OM says:

    D’oh! “Star Treck” – Star Trek. (I swear I had water with dinner! But what was in it, that was some doofy spelling…)

  5. SteveZodiac says:

    so, there’s water and power …..

  6. Olaf says:

    Is it such a big danger?
    It is not like 1 meter difference will zap you with 100 volt.

  7. Aqua says:

    @iantresman – The Moon’s surface is exposed to +/-1,370 watts per square meter in the solar wind. There is a temperature difference of 275 degrees F between sunlight and dark. As the terminator processes across the surface the solar wind abruptly starts or stops energizing the regolith as the temperature simultaneously rises or falls. It has been recently speculated that rolling dust storms of thermal or triboelectrically levitated dust and gas particles proceed along with the terminator on the Moon as an artifact of those temperature and energy density oscillations. It is possible that this ‘terminator energy’ field is circumlunar and interacts with the cold sink electrons?

  8. Aqua says:

    BuzzzzZAP! A way to make and transport water vapor on the Moon?

  9. PrometheusOnTheLoose says:

    Brinf a few mirrors and set the up downwind of the solar wind, to reflect into the crater. . . . warm it up and reduce the charging at the same time.

  10. vagueofgodalming says:

    Lunar Craters May Be Electrified

    I agree. Time to dispense with those polluting diesel and coal-fired craters.

  11. IVAN3MAN_AT_LARGE says:

    Aqua:

    The Moon’s surface is exposed to +/-1,370 watts per square meter in the solar wind.

    Dude, I think that you’ve confused protons in the solar wind with photons — it is light energy from the Sun that is equivalent to ~1368 W/m² at a distance of 1 AU.

  12. Lawrence B. Crowell says:

    The low conductivity of the lunar regolith is what permits this charge build up to grow. The sun charges this up as a sort of natural Leyden jar. This is rather unexpected.

    LC

  13. Hon. Salacious B. Crumb says:

    I, for one, do believe it. I’ll wait for the evidence thank you.

    What is the conductive of the regolith here, eh?

  14. Torbjorn Larsson OM says:

    It is not like 1 meter difference will zap you with 100 volt.

    Well, if the discharge time is on the order of 100 s, you will collect more of a charge difference traveling in and out of these “Leyden” craters.

    Sure, I would wait for evidence before crying “charge!” But seeing the dust effects already observed, it is a compelling model.

  15. Olaf says:

    @Torbjorn Larsson
    “Well, if the discharge time is on the order of 100 s, you will collect more of a charge difference traveling in and out of these “Leyden” craters.”

    Yes you collect more charge if you move to one side but you lose the charge step but step when you jump to the other side. (Assuming you have a conducting suit)

    It is a big story if you would jump 100 meters. Or have a long conducting cable and then touch it.

  16. Aodhhan says:

    iantresman… nice job finding and posting the research info.
    It is somewhat interesting information. I don’t think there is any direct danger to astronauts on the surface. Although there is the capability to build up volts… from this information anyhow… I don’t see an amperage threat. However, the damage it could do to electronics is obvious. Just like many other instruments on Earth, have to ensure they are grounded when used.

    All in all, I think there is probably more of a threat on Mars, where any piece of equipment in a dust storm will begin to collect a charge.

    If you could think of a way to collect & store this energy to a point where it is as efficient as a solar cell… then you have something! Since it could be used just about anywhere there is solar wind.

  17. Aqua says:

    IVAN3MAN_AT_LARGE

    The solar wind is made of Hydrogen (95%) and Helium (4%) and Carbon, Nitrogen, Oxygen, Neon, Magnesium, Silicon and Iron (~1%). These atoms are all in the form of positive ions which means they have lost electrons because the temperature is so hot. So really, solar wind is positive ions and the electrons these ions have lost. We call this plasma.

    How does this plasma effect the lunar surface?

    Scott M. Auerbach, a theoretical chemist at the University of Massachusetts at Amherst offers a more detailed answer:

    “Light from the sun excites electrons in the atoms which constitute the brick wall. How does that electronic energy get converted to heat, you ask. The key is ‘radiationless transitions.’ Here’s how it works: the atoms of the brick are perpetually vibrating. Some of those atoms vibrate sufficiently vigorously that their vibrational energy is roughly equal to the electronic energy (photons) absorbed from the sun–in essence, they are in resonance with the solar energy. Those atoms then make a quantum transition from ‘electronically excited’ to ‘vibrationally excited,’ meaning that the energy causes the whole atom to move. We feel that motion as “heat.” The atoms which make the jump to vibrational excitation soon collide into neighboring atoms, dissipating their vibrational energy throughout the entire brick, making the brick hot throughout.

    Now… if all that electric heat energy connects from the terminator plasma wall to the cold sink electrons stored n the polar craters, you’ve got a circuit!

  18. Hannes says:

    Is there any possibility that this build-up of negative charge somehow has influenced the signature traces of the imaging spectrometers from Chandrayaan-1 and others?

  19. Aqua says:

    “The electrons build up an electron cloud on this leeward edge of the crater wall and floor, which can create an unusually large negative charge of a few hundred Volts relative to the dense solar wind flowing over the top,” said Farrell.

    The negative charge along this leeward edge won’t build up indefinitely. Eventually, the attraction between the negatively charged region and positive ions in the solar wind will cause some other unusual electric current to flow. The team believes one possible source for this current could be negatively charged dust that is repelled by the negatively charged surface, gets levitated and flows away from this highly charged region.”

    The key words here are “…can create an unusually large negative charge of a few hundred Volts…” and “…the attraction between the negatively charged region and positive ions in the solar wind will cause some other unusual electric current to flow…”

    MY SUGGESTION was that thermally induced triboelectrically levitated (Positively charged) dust plasma’s at the terminator could complete a circuit to the cold sinks in a rolling wave of current… as part of a very LARGE collection area!

  20. Hannes says:

    I mean hydroxyl groups are negatively charged. And there is water on the moon, presumably…

  21. Olaf says:

    @Aqua
    The solar wind has equal negative and positive charge. So it is is electrical neutral.

    The only difference is that the electrons land on a different part on the rim than the positive charge creating a difference in charge because the moon dust is no-conductive.

  22. Olaf says:

    @iantresman
    No both positive and negative charge will get absorbed by space dust making it neutral.

  23. Olaf says:

    @iantresman
    The therm space-charge has nothing to do with “space” in your reference.

    Also this is a laboratory experiment in your refernce they force a magnetic field that is pretty strong across 2 electrodes. This is not what happens in real space. The magnetic field differential is very very very very very very and did I mention very(?) low in real space. Also dust particles rotates, losing the charge build up at one side.

  24. IVAN3MAN_AT_LARGE says:

    Aqua:

    [I]f all that electric heat energy connects from the terminator plasma wall to the cold sink electrons stored n the polar craters, you’ve got a circuit!

    Yeah, right(!)… Do you have any idea how tenuous the solar wind really is, and also how long it would take to accumulate sufficient useful ‘charge’ in those “natural Leyden jar” craters to power anything?

  25. Olaf says:

    @iantresman
    “Stubbs et al say that in shadow, plasma electrons tend charge the lunar surface negatively ”

    You are confusing 2 things.
    UV and x-rays light collides with the moon dust at the front side and the ejected electrons end then up at the unlit site. This is dust spead over the size of the moon!.

    Dust in space behaves differently, they can both be charged positive or negative depending on the positive or negative charge that happens to collide on it. Dust in space will rotate so the distribution of positive and negative charge will cancel each other out and also become neutral,

    Fact is solar wind itself is neutral charged, it contains both equal number of positive and negative charges. When it hits the moondust it is electrical neutral. Except for the slightly different orbits at the moon’s poles craters that have a slightly different trajectory.

  26. Lawrence B. Crowell says:

    There seems to be some confusion here. The solar wind consists largely of protons and electrons in a diffuse plasma. Since the proton is 1876 times the mass of the electron a physical influence may cause a charge separation. The different masses means there are different transport properties of the species. In this case the physical interaction involves the crater rim which acts to convert some of the kinetic energy of the solar wind charged particles into an electrostatic potential.

    The solar wind is pretty diffuse, around a few ions or electrons per cubic centimeters.

    LC

  27. IVAN3MAN_AT_LARGE says:

    Lawrence B. Crowell:

    There seems to be some confusion here.

    I think that’s the ulterior motive of “the usual suspects” here. 😉

  28. Olaf says:

    @Aqua

    “The key words here are “…can create an unusually large negative charge of a few hundred Volts…” and “…the attraction between the negatively charged region and positive ions in the solar wind will cause some other unusual electric current to flow…””

    2 different keywords does not mean that there is a connection.

  29. Olaf says:

    @antresman Says:

    “The glass tube does not absorb positive ions from the plasma and become neutral.”

    Why not?

  30. IVAN3MAN_AT_LARGE says:

    Aqua:

    MY SUGGESTION was that thermally induced triboelectrically levitated (Positively charged) dust plasma’s at the terminator could complete a circuit to the cold sinks in a rolling wave of current… as part of a very LARGE collection area!

    MY SUGGESTION is that you show us the mathematics involved for this proposed “LARGE collection area” project!

  31. Hon. Salacious B. Crumb says:

    These guys seem to believe in Mary Poppins, with her levitating umbrella making her casually zooming across the clear blue sky.
    Fictions and reality or two separate things. Pity a spoonful of sugar doesn’t make it so!

  32. Aqua says:

    ‘The proof’ was collected on the spacesuits, especially the legs of lunar explorers..

  33. Hon. Salacious B. Crumb says:

    iantresman said;

    “Lunar dust does charge and levitate. It has been observed and modelled.”

    Does it? Does evidence and measurements of the phenomena been observed on the Moon?

    It might, but you cannot say it “does”!

    Again, you make the same old error and just cannot get past the stumbling block of how science works. These observations LOOK like the phenomena, but that doesn’t mean it IS the phenomena. Sure you can generate a model to explain it, but you need not only to see the phenomena you need to measure it and quantify it.
    The way you speak anyone would think this is the only explanation! (Done and dusted, so to speak.) Really, could it be there might be an alternative explanations?

    If we believe the tosh your saying here, why bother sending and launch at great expense the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission in 2002?

    Just we listen to you,believe it, and we can save a whole heap of money!

    So. Maybe this is the explanation, maybe it is not. Seeing something is one thing, trying to explain it is another, but the third component is to actually measure and watch the behaviour of the phenomena in the lunar environment.

    Suppositions and hunches are the way of pseudo-science. Convincing yourself that something must be true is not science at all.

    Read the article again. It says things like “our research suggests that”, “polar lunar craters may have to contend with a complex electrical environment”, “Static discharge could short out sensitive equipment”, “The team believes one possible source for this current could be negatively charged dust”, “and could look for the dust flows predicted by the team’s research.”

    Why do they speak like this?

    …and here you are saying definitively that it is all magically true by plasma whatever (again).

    You even said yourself; “I agree that there are many different charging mechanisms.”

    Where are you going to go if they don’t find anything?
    Or if the charge is unexpectedly 0.01V or 10,000 volts?
    It is assumed the regolith is low conductivity, but really is it?
    If water exists, would that not make little difference, and not dramatically effect the electrical conductivity? (It isn’t liquid is it?)

    “Lunar dust does charge and levitate”

    Yeah…and the proof?

    As I said; “I’ll wait for the evidence, thank you.’ and also do some critical thinking too! Really.

  34. Aqua says:

    Dust levitation’s and polar field grounding currents may only occur during CME events WHILE the Moon is in Earth’s magneto tail…. But I’ll wager we’ll eventually find them!

  35. IVAN3MAN_AT_LARGE says:

    Aqua:

    ‘The proof’ was collected on the spacesuits, especially the legs of lunar explorers.

    Yeah, and I get cat hair collecting on my trouser legs, but that’s no ‘proof’ that the pussy is full of plasma!

  36. Hon. Salacious B. Crumb says:

    “I am making no suppositions and hunches. My comments are supported by numerous citations. I have yet to see one citation from you.”

    What. A citation is required just to point out how science works? You have to be kidding me.

    As for; “I never said that lunar dust levitates definitively by being immersed in a plasma, as you pointed out yourself, I said there were several different mechanisms.”

    Good for you, but it is only half-true. Yet your own language here pushes the usual agenda as if it is absolutely true and conveniently just ignores anything else.

    Having an “open mind” is really the point – something that you guys rarely show.

    Note; “Plasma” is any rate effect are minor compared to the near continuous c.1,370 Watts of energy raining down every 14 days or so on the lunar surface. What happens to that energy do you suppose?

  37. Olaf says:

    @iantresman
    “The plasma sometimes has a significant effect, but of course it depends on the phenomena we are interested in, and the timescales.”

    Note the word “sometimes”, like every 10.000 years where all the planets happen to be aligned and a space Alien accidentially sneezes near a black holr.

    I still don’t see why a teeny weeny small effect barely noticable can be proof of something very big. At best you get a electrick shock and the place is discharged for then next million of years or so, it is so tiny.

  38. Hon. Salacious B. Crumb says:

    @iantrsman

    I have to give you some credit here for your general expression of the nature of science after this was pointing out to you. (This is unlike some of the stalwarts who we regularly meet when it comes to such subjects.)

    The caution here was more to do regarding the novice scientists who read this. It is very easy to mislead or construed – especially when it comes down to discriminating real facts and knowledge from either theories and conjectures.

    It will be interesting to see if the probe here finds anything to support these theories, and regardless of what is found, it will certainly provide more detailed knowledge of the lunar environment. On that point, I’m sure we do agree.

  39. ND says:

    “Some say hydrogen (ions), others protons.”
    These things are synonymous. There is no confusion here. A hydrogen ion by definition is a proton. You’re splitting hairs.

    “Some say redshift, some say distance.”
    The evidence is overwhelming that redshift increases with distance. You’re trying to sneak in some EU/PC stuff here that argues against this.

    iantresman, given your history of postings it’s justifiable to say that your sole purpose on Universe Today is to evangelize and promote EU/PC. You’re always trying to divert conversation in that direction.

  40. Olaf says:

    @iantresman
    “My posting can all be corroborated by numerous citations and NASA postings. Blame them if they makes you have evil thoughts.”

    You mean numerous citations that have no connection in common except for some keywords that happen to be the same?

    Like: I can get in my pyjame, my pyjama can get in my suitcase so that is proof that I can get in my suitcase?

  41. ND says:

    Here’s an interesting article on this topic and how the EU people on thunderbolts site have picked up on it.

    http://dealingwithcreationisminastronomy.blogspot.com/2010/04/electric-universe-lunar-electric-fields.html

  42. IVAN3MAN_AT_LARGE says:

    @ ND,

    Yeah, I saw that already, and I’m not surprised that “the usual suspects” are wetting their knickers over that matter!

Comments are closed.