Welcome to the Darkness!
Compare tosol's hazcam with the previous location.

This navcam is downright spooky looking:
http://qt.exploratorium.edu/mars/opportuni...IBP0642R0M1.JPG

...clearly depositional. You can barely see the evidence of blueberries underneath the dark dust.

Thank you very much Cosmic Rocker! That montage was excellent!

IMHO it appears that the WHITE streaks or rays around Victoria are depositional.

The apron around Victoria is composed of blueberries and dark dust. The dark dust is mostly in the NE quadrant, and blueberries seem to be of the same concentration everywhere.

After the initial apron formation - which would have been darker in the NE, the winds have blown lighter toned material on top of the darker area. Except in a few places where the winds were stronger due to local topography (deep crater bays). There you see that the light stuff was not deposited, so we see the underlying blueberries and dark (presumably heavier) dust.

Look closely at the attached image. How come there are no dark streaks in the middle two shallower bays? If dark dust is being deposited, there should be some dark dust lifted out of the crater and deposited beyond these two bays.

Instead, we see lighter colored material.

-Mike

(a hand goes up hesitatantly at the back of the class)

Seems to me that there might be a mass of darker material just beneath the apron to the upper right here... maybe as bays erode they eventually eat into this subsurface layer and the dark streaks are blown out...? Thought about this after noting how, if you look at the bays which are the sources of the dark streaks, they all go back to a line I've marked in blue on the pic... the two streak-free bays haven't reached that far back yet... maybe when they do, through more erosion, they'll produce their own streaks, too...?



Click to view attachment

[Lecturer's eyes glaze over, turns and stares at the blackboard, realizes alternate hypothesis fits observations. Shrugs resigningly as wave of desperation washes over him.]

Yup. That seems also to be a possibility.

I'm thinkin' a couple of wheel scuffs by Opportunity with an MI inspection would be nail it.

-Mike

Here is what might be a sequence of events leading to what we observe (need to click to enlarge, sorry!):

-Mike

Why wouldn't I say the same thing about the "clean sweep" theory? If there are winds sweeping out of the bays and cleaning the ground, why not in those two bays?

The answer is the same in both cases. The walls of those bays are much steeper than the ones with streaks.

Those in the clean sweep camp... Can someone explain to me how these tiny little bays are creating these powerful dust-cleaning jets?

If the bay was acting as a nozzle, it should (at least initially) shoot straight out along the center line of the bay. It doesn't. As soon as it enters the wind stream, it is swept down wind. There is very little difference in the vector of the wind leaving the bay and the wind stream itself.

If we suppose that the bay is instead causing turbulance, there should be some kind of swirling pattern. That clearly doesn't exist. As further evidence that this is not formed by turbulence, the streaks form at the tips of the bays. Turbulance would form at the tips of the capes and flow down wind. The capes that would form the most turbulance are the ones that extend perpendicular to the wind flow. The darkest streaks form off capes that are almost parallel to the wind flow.

I look forward to more lively debate on this subject. For those who think this will resolve with MI images, I am skeptical...

What type of experiment/observation do you think would be required to provide evidence?

What would the result be for "clean sweep" theory support?
Then what would be the result expected for the "dust deposition" theory?

-Mike

Deposition should be easily apparent, shoudnt it? we should see less blooberries and darker dust burying many of them, we should be able to scruff a wheel and get an MI to determine a depth of the depositional layer.

As for clean sweep, we should see more blueberries (even though bloobs are darker!) since they should be forming more of a desert pavement, if indeed there is soil removal going on and everywhere else we see blueberries at the top. there's no reason to assume differing blueberry concentrations in the initial apron deposits before these dark streak patterns emerged. Again a wheel scruff and MI will presumably be done and we'd be able to tell whats going on under the surface, if anything.

While we wait for MIs, here are two hazcam views, from sol 1134 (between streaks) and 1137 (on the darkest streak). The local times of the images differed by only 5 minutes, so the lighting is identical, and the rover was pointing in almost the same direction in both. The exposures appear to be quite similar, based on the sky and rover parts, but of course they're not calibrated.
Off streak:
Click to view attachment
On streak:
Click to view attachment
On streak is of course darker, but to my eye the berries look less distinct on streak as well. It's possible this is due to a coating of dust, but I could easily be wrong. I think the difference in coatings (extra light dust off streak or dark dust on streak) would be very thin, so I think we really need the MIs.

It's tough, fredk. The hazcams, navcams, and then pancams all seem to leave us with the same lousy resolution of the critical details at their respective distances. More MI's will be nice, but so will pancam closeups.

atomoid: Unless it's something exotic, it should become apparent if we get the appropriate resolutions in a variety of filters aimed downward. We're right in the middle of the darkest swath according to the map.

I agree both that the MIs will help AND that it looks like in the streak there is a dust coating on everything including the berries. This is kind of the opposite of the clean sweep idea, which suggested that the berries themselves provided the darker shade.

I don't necessarily consider berries as the source of the darkness. When I threw my vote into the clean sweep camp, I simply took the position that the underlying layer of the apron is dark, with lighter dust on top of it. Whether the winds are keeping these areas dark, or the winds are depositing light dust everywhere but these areas, it amounts to the same thing. Light material on top of a dark apron is my clean sweep position.

If I was in the depositional camp, I would be arguing that the apron has a light base, with dark material being deposited on top of that in these areas. I'm beginning to think this position might be correct. The wheel tracks seem to show lighter areas, as if the wheels were picking up the dark deposits revealing the lighter base beneath. However, I'll stick with my original vote and wait to see how JPL calls it.

Maybe it's more complicated than either position suggests.

Brian

It looks like the blueberry count is approximately the same in either the dark or light zones around Victoria.

So either the coating (light or dark) is very thin and draping over the already present blueberries or the blueberries themselves are also being wind deposited at the same uniform rate all around Victoria. I have a really tough time understanding how the wind could be able to sort light and dark sands yet not be able to sort the larger and heavier blueberries.

To do list for Oppy:

1) Look at MI of surface in dark zone.
2) Scuff soil at this location: take another MI.
3) Move to light area (just over the "border" with the dark zone).
4) Look at MI of surface in light zone
5) Scuff soil at this light zone: take another MI


Hypothesis: White streak deposition (light overlaying dark):
Expected observations:
MI dark surface: blueberries + dark material
MI dark scuff: blueberries + dark material
MI light surface: blueberries + light material
MI light scuff: blueberries + dark material

Hypothesis: Dark dust depostion (dark overlaying light)
Expected observations:
MI dark surface: blueberries + dark material
MI dark scuff: blueberries + light material
MI light surface: blueberries + light material
MI light scuff: blueberries + light material

Hypothesis: Side by side depostion (Stu's hypothesis):
Expected observations:
MI dark surface: blueberries + dark material
MI dark scuff: blueberries + dark material
MI light surface: blueberries + light material
MI light scuff: blueberries + light material

It is assumed that the MI concentrations of blueberries would remain constant, both on the surface and after scuffing. If blueberry concentration varies significantly in either area (when scuffed), then that implies differential depostion of blueberries as well and the overall picture becomes a little more complicated.

From the Pancam image from fredk's post, it initially appears that the blueberries in the dark zone image have a thin coating of dark dust. So I would have to politely leave the "clean sweep" camp and cross over to the Dark Side. At least until MI results come in, at which point I reserve the right to waffle further.

-Mike

BrianL: Yeah, I think the berries are mostly light in many of the filters, and that the clean-sweep hypothesis is best understood as the exposure of the dark, underlying apron soil. But there is the "berry shadow factor" which would play a variable role.

I was looking for some HRSC imagery that might show some changes over time. The resolution of what I found was not impressive, and the changes might be more related to lighting, atmospheric conditions, or something else; but there are large differences between the two images in this animated gif. The image from orbit 1183 was taken on December 19, 2004, and that from orbit 2064 was captured on August 23, 2005. I'm not sure that these help us understand very much, though.

One thing I found interesting about these was the variable location of lat/long between the two. I locked the animation on Victoria, and you can see a slight shift in the longitude axis and a more noticeable shift in the latitude axis.
Click to view attachment

Just to clarify my own thoughts here...

What I think is happening is that as the crater erodes away there comes a point where a buried layer of darker material <very fine-grained, powdery material, laid down in this region of Meridiani in the distant past. This material could be either 1) particles excavated from beneath the surface by an impact that created one of the very large craters in Victoria's area, or 2) fine, dark dust grains dumped nearby during a long ago large dust storm> - is suddenly exposed to the air and therefore to the winds that move across the crater and/or whip up out of it. This material is then blown away from Victoria, falling back to the surface to leave dark streaks that cover the existing "apron" material.

Because this underlying layer of darker material is not uniform, but is clumped and has areas of greater density etc embedded within it, the erosion of the crater occasionally exposes patches of much denser material which then creates much darker streaks: if conditions are right - strong winds in the right direction, a dense patch of dark material exposed - then a very dark streak can be produced. At other times, when there's not so much dark material being exposed, the streaks are less dramatic looking, or vanish altogether.

Just thinking aloud...

Dark streak MIs are in: http://qt.exploratorium.edu/mars/opportuni...ger/2007-04-08/
It's not clear to me what's going on, though the berries look quite clean on the dark streak. We may have to wait for official word on this.

OK it's official (IMHO)! The Clean Streakers rule! Shiny, glossy concretions and well sorted, coarse sand.
QED

Boy, it really is hard to tell from these two MIs, isn't it? I notice a strong specular reflection from the concretions in the sunlight, which I don't recall seeing (at least not in such a pronounced fashion) on blueberries in other areas.

I wonder if perhaps that wouldn't indicate that the berries have been sandblasted here, by very small-grained dust particles? Polished, as it were? I find it hard to believe that the relative darkening of the berries (if that is, indeed, what we're seeing) is due to a dust coating. That would have to be *awfully* fine dust, to simply darken the surface of the concretions without any individual grains being visible.

Some of the concretions also seem to sit in shallow bowls of the fine-grained soil. I would think that would be indicative to deflation rather than deposition, but I could be wrong...

-the other Doug

Hold onto your hat, Oppy, so it doesn't blow away!

I think it is deposition. Unlike most other MI (I have gone back to sol 750) the blue berries seem to be almost alone in the fine sand without lots of small light colored fragments. For example, compare this MI from the dark stripe with this from another area. Seems like more dark fine grain material burying light color fragments.

Floyd

Floyd scooped me, I was just about to post this image, comparing between-streak (top) and on-streak (bottom):
Click to view attachment
Clearly, as he says, there are much fewer small berry-like fragments visible on streak. It looks to me like deposition of dark sand/dust which has buried the small fragments, but somehow the dark deposit doesn't stick to the large berries or has blown off due to wind.

Also, dvandorn, I don't think most of the darkening on streak is due to darker berries. Looking at the hazcams I posted yesterday, I think the darkening is between berries. That's consistent with what we're seeing here.

It's like this, guys, dusty surfaces scatter incident light in a wide ~hemispherical arc. So significant light reaches the eye regardless of the viewing or illumination angle. Shiny surfaces (like a mirror) reflect most of the light in one direction which matches the incident angle. So the bright (specular) reflection reaches an eye at the same angle as the source of illumination, but almost no light reaches eyes at other viewing angles, so the surface generally looks dark (at least much darker than a dusty surface). So a surface of clean concretions and clean rounded sand grains will look darker than a dusty one, even if the material composing the substrate has the same albedo as the dust. In this case the hematite concretions and basalt sandgrains may actually be darker (lower albedo) than the oxidized, pink dust, which accentuates the effect. There may also be a higher density of the berries in the streaks, though I haven't yet seen clear evidence that there is a significant difference. Someone needs to do the patient counting.
Basically, the clean, rounded sand grains at El Dorado were dark from high viewing angles (and from orbit) for the same reasons. Clean Martian sand dunes look dark, dusty ones look lighter.
Trust me.

I don't think anyone can argue with the fact that a dusty coating can lighten the surface. But we also know that dark dust can certainly exist. So the issue has to be settled by observation, not by a priori arguments.
Looking at the MIs I posted two messages up, there are clearly fewer berries visible on streak, not more, and it's the smallest ones that are lacking. How do you explain this with the removal of light dust on the streaks?

Sorry, Freddo, it will take a lot more data than that to convince me that there is any significant difference in the size-frequency distribution of berries and berry fragments inside vs outside of streaks. Keep counting.

Thanks for this, Cosmic! I think I'm more optimistic than you, though. If you look at these two images, the two MOC images I posted earlier, and the Hirise images, I think there is a pattern:

My first and your second frames were both taken during southern summer, and the streaks in the NNE of Victoria are not very dark in these frames relative to other features. My second, your first, and the Hirise images were all taken during southern winter, and all show the NNE streaks as very dark.

My picture is that during southern autumn or winter, winds blow towards the NNW, and gather dark sand/dust from inside the NE rim and deposit it outside in the few darkest streaks. Then in southern spring/summer, winds blow towards the SE, and the darkest streaks are coated with the ubiquitous light dust.

If this is anything like correct, we're lucky we got here in time since we're now well into southern spring and the dark streaks may be getting covered in light dust. This may help explain why the first streak appeared less distinct from the ground than we may have expected, though viewing geometry was probably the biggest factor.

A windsock, a windsock, my kingdom for a windsock!

That's interesting, fredk. I meant to eventually compare them carefully, but I got caught up in this new project. It would be interesting to verify which direction the seasonal winds blow. I could swear I found that information once. I'll try to chase it down again. Unfortunately, it seems that those directions work just as well for the dust cleaning hypothesis.

Here's another montage using MIs from sols 924 to 1139. I tried to choose the best focused ones. They are reduced to 50% of their size to make this thing manageable, so you might want to look at the full-sized images for the best clarity.

I think most would agree that the MIs from sols 924 and 1069 are noticeably dusty. They are from areas well away from the main dark streaks. The images from sols 1103, 1135, and 1139 all appear to show significantly less dust. They are all from the general area of streaks, and even though two are from inter-streak locations, one might expect them to be cleaner than areas where no or faint streaks occur. That observation fits well with the clean-streak idea. I'm pretty convinced that the sol 1139 MIs are the least dusty of all. The very well sorted sand in those really clinched it for me.
Click to view attachment 1001 KB

The next best thing to a windsock is our trusty RAT; the grindings are sometimes blown out in a dust trail. So I would propose a sampling program as follows: (Of course, our PIs may well dismiss the streak issue as trivial and non-controversial, and so be unwilling to spend the time.)
1. Make at least 2 more MIs at different spots here.
2. Make at least 2 overhead PANs for counting berries and fragments.
3. Then proceed to another location (or two) in mid-streak to repeat the MI and PAN routine,
4. Proceed to the area of exposed rock close to the rim and do a RAT, observing the dust plume.
5. Eventually repeat steps 1 and 2 at locations outside of the streak to the east.
That should provide statistically conclusive evidence to resolve the issue for even the most devout Depositionist.

Thanks again, CR! I think though that it is tough to compare dust levels from these images, especially when some have bad focus or are taken under very different lighting conditions (crucially, sol 1139 is under full sunlight). I am much more confident that 1139 contains many fewer small berry pieces than 1135, and given those two sols' proximity, and surface homogeneity on metre scales based on hazcam and pancam navcam imagery, this observation carries much more weight.

I have to ask you though what exactly do you mean by "the very well sorted sand in those really clinched it for me" - how does the sorted character support sweep vs deposit? If the darkness is deposited, then as the air jet emerging from the bay moves northward out over the plain and slows down, it should drop the heaviest dark particles first, and then lighter and lighter. Couldn't that lead to the "well sorted sand"? How would sweep give you sorted sand?

Given the drive we've taken out here solely for the purpose of examining the Darkness, I think they can't dismiss this issue as trivial! I'd sure love to know their thoughts on this now, though. Remember too that they've got more to work with (minites etc).

I had thought the MIs might conclusively settle this, but it seems that both devout Depositionists and Sweepers are maintaining their positions! The fun continues...

I agree with fredk--I think it is deposition and that the ratio of sand to berries is critical. But it is even more complex. Both light dust and dark material from Victoria are being deposited as well as removed (possibly at different times of year).
If
dark deposition rate = dd/dt
light deposition rate = ld/dt
dark sweeping rate = ds/dt
light sweeping rate = ls/dt
You get a dark band when dd/dt+ls/dt > ld/dt+ds/dt
but if dd/dt much bigger than all the others, then you get a buildup of dark sand covering the little light fragments and all the dust---just what we see in 1139

In all fairness, Shaka was the first to note the well sorted appearance of the surface grains. If this doesn't pan out in the end, I'll blame it on him. I might have difficulty expressing this efficiently, but here goes.

You could come up with a dark depositional scenario that employs well sorted grains, but we really haven't seen evidence of sand grains of the the size that are apparent in the sol 1139 MIs that have undergone much transport recently. That sand was blown to where it now is a long time ago, and it seems to not be affected much by modern winds. That sand, along with the berries and other larger fragments aren't going anywhere these days, and I see them as comprising the base soil or surface regolith here, and it has usually been been darker in appearance when we've seen it elsewhere.

I think I see tinier, fluffier dust grains in the MIs from earlier sols that are lying on top of and between the stuff that is too large to move in the current wind regime. They seem to be rarer in the most recent MIs. That is why I described the surface sand as very well sorted. I see fewer smaller grains.

In all fairness, Freddo, it was you who first announced the cleanliness of the berries (post #67). I simply extended your observation to the sand grains. To me the trick is to look for the circular outline of the grains. The more clearly you can resolve them, the more dust-free (i.e. well-sorted) they are.

"Dig we must."

I, like many, saw the dark deposits below the rim and the dark fans
extending from the rim above them and thought: Ah, yes, dark material
from the deposits is being blown out of the crater.

But if, like you say, the dark areas blow Victoria's rim are dark for
the same reason that El Dorado is dark (blown free of light dust). Then
the same wind that blows the patches below the rim clean also blows
the areas above the rim at those spots clean.

Maybe he's referring to this sort of process described by Steve Squyres:
"El Dorado is a spectacular dune field.... We think that, in terms of how this thing got
here, because of the configuration of this terrain with respect to the prevailing winds,
it may be an aeolian cul-de-sac.... What you see in the Microscopic Imager is a sand
that is very well sorted, very well rounded.... This is very clean stuff."
http://www.planetary.org/blog/article/00000497/

Dark areas below Victoria's rim could present this same "cul-de-sac" situation.
Above the rim? Certainly not a cul-de-sac. But still blown clean of light-colored
dust (and fine sand?).

Does anyone know if El Dorado was thought to be deposited dark sand or dark sand swept clean of light dust? "Aeolian cul-de-sac" sounds like a place where winds stagnate and drop deposits, rather than where winds are fast and lift off light dust. If El Dorado is depositional, then that supports the streaks being so too, since the grain size in the streaks is smaller than at El Dorado.

In all four frames that are not on a streak, one can see the outline of the larger berries. One can also see their shadows. On the dark streak frame, no outline - no shadows.

The smaller grains are almost non-existant. One can only see the very top poking out of the soil.

The clear interpretation is that the fine grains are burying the larger ones. How can that be anything but deposition?

The dark streaks are dark grains being deposited on the lighter apron.

Seems like the 1139 berries are more deeply buried. Most seem to be more than half way, which is more rare on other images.

Assuming that the dark fine grains are burying the berries (and presumably overlying any lighter-colored sands) as the initial obervations suggest:

Are the fine particles heavier (denser) or less dense than the lighter-colored "normal" sands?

What does this say about the local wind speed? Is it higher or lower?

How did the dark streak form? What is the sequence of events for the deposition?

-Mike

Here is a side by side comparison of two wheel images as Oppy did a little shuffle in both a dark zone (sol 1137) in a light zone (sol 1126).

Even with the differences in lighting, there is really very little, if any, differences between the two. If I try really hard, I can almost imagine that the lines in the dark zone (1137) images show a little bit more fine structure due to smaller grain size. (The "X marks the spot" part of the wheel tread left a very detailed impression in this picture). But I may be really trying to read the tea leaves here. I would also like to say that there are hints of lighter tracks underneath as well, but that's more wishful thinking.

I desperately want Oppy to do a burnout on Mars and look at the underlayer. I fully expect to see a more "normal" sand grains and coloration.

This would make great sand to write a message with a stick....like "Send more robots" or something like that.

-Mike

Both. It is depositional for large basaltic sand grains, and erosional for smaller, lighter grains of dust. In a past period of strong prevailing winds from a southerly direction, sediment of all sizes (including particles eroded from the vesicular basalts) were blown up against Husband Hill. The wind was strong enough to blow the fines up and over the hill (some got dropped up behind the summit in dunes), but the heavier basalt grains a significant fraction of a millimeter in diameter didn't make it. They blew partly up the hill in gusts and then rolled back, up and back, over and over until they got beautifully round and clean and sculpted into a dune field that could not climb over Husband Hill, and was such an effective light trap that it fooled a guy from Portugal into thinking it was an abyss.

Sure, you can say the Victoria streaks are both depositional and erosional in that sense, as well. Obviously there is sand and concretions in the streak and they had to get there some way. In the past they must have been blown there by some powerful winds - and deposited - but we have been debating why the streaks look darker than other parts of the annulus now. Every Martian year or three dust storms spread light pink dust over everything. The VC streaks are obliterated. They only reappear gradually over subsequent weeks as the prevailing southerly winds (winds less powerful than the storm winds) blow through the crater, circulate in some complex pattern molded by the crater topography, and funnel or rotate up and out through The Valley without Peril and adjacent bays, lifting and carrying the pink dust with them. Thus the streaks reappear through an erosional process, a process that cleans the dust from the underlying berries and sand. This dusty wind polishes the berries to a high sheen.

Why don't the winds funnel through and clean Bottomless Bay and Bay of Toil as well? Well, they do to a minor degree - you can see faint streaks if you look hard - but the winds probably aren't as strong through the western bays because the crater is higher here (remember Beacon?) or because of some other topographic asymmetry.

Parsimony favors the Clean Streakers because they don't have to postulate a discrete source of dark material being eroded out of the NE cliffs. Where is the source? What is it? I can't see it. I'm still waiting to see a Pancam shot with an arrow pointing to an outcrop of basalt or coal or god-knows-what black stuff. I'm not holding my breath.

How about these...

I spent about two minutes looking for these. There are more and better.

I'm sure you can point to a place near the end of a dark sediment streak where it would be appropriate to go look for an outcrop of basalt or coal or whatever, but none of your arrows actually shows such an outcrop. I would be glad to have Oppy visit some of these locations for a close-up search, but I am very doubtful that she will actually find anything other than more sulfate-rich sandstones. We have looked at a lot of rock on Meridiani Planum, and not seen any such outcrops. I don't see any yet in Victoria.

Is it your assertion that because we haven't seen these layers, the assumtion is they don't exist. The evidence points to some dark deposit in the north northeast part of VC. It may, in fact, have an origin far from VC. But the dark, fine-grained matterial is there now. The orbital shots show these desposits in the crater. The ground frames show that it is mobile. I agree that the frames pointed to earlier may not be a source. But they are clearly not being uncovered. Those deposits high on the wall moved to that location if they did not originate there. The dunes, the deposits on the crater wall and the dark streaks are all too conspicuous to be coinsidence.

I take it the possibility that this dark material might be originally caused by groundwater coming out in a point source fashion has been addressed? Because from your image on the left, that's certainly what it appears like. There's not so much as an outcrop as there is an old flow of dark material from point sources in the wall.

I'm sure this will be eventually settled with closer looks, but my first guess is water borne deposits into the NE section of the crater, and then that material blown up onto the annulus from the winds out of the South.

My big question is _when_ this dark material appeared.

Here's the final query of mine... more of a tease. We've already seen that in at least a couple of places under camera surveillance, groundwater has come to the surface. Say that these dark spots are some indication of old groundwater flows... wouldn't it be neat to think of this happening under our noses?

I'm wondering about the composition of the dark stuff.

Could we get clues via APXS and mini-TES and subtract out the known lighter material background?

Or is the dark layer too thin?

-Mike

That's an interesting picture for the formation of El Dorado, Shaka - do you have references for this or is this your own?I think this is a major weakness with Sweep. I see it as very unparsimonious to postulate an unusual extremely sensitive dependence of wind speed on subtle topography. Yeah, the NW rim is higher, but only by a couple of metres! (Remember we had to stretch those images of the rim during the approach to Vicky by a big factor!) That compares with a total depth of 70 odd metres.I don't think we need an entirely black outcrop as such - as long as it contains the dark material as a component which separates out due to differential erosion. Also remember we can see some difference inside the NE rim, namely the linear "fracture" features. There could be an association.
Still, I think the long arrow in Edward's first image is fairly convincing as a dark piece of outcrop. Of course lighting might be a factor. Here's another view of it from sol 1021:
Click to view attachment
In fact, Shaka, the more I look at this image the more certain I become of this. The dark feature looks, quite incredibly, just like your avatar! I think we can only interpret this as a direct message to you, Shak, to open your eyes and see the Dark!

Click to view attachment

You guys trying to test my religious convictions?
My tiki knows the depths of my devotion.

Seriously, why was I so naive as to imagine one good MI from the streak would settle the argument.
You dirty streakers are nothing if not resilient. I'm sure we could continue the fun into the indefinite future, but I'm tempted to let the issue simmer now until we get at least a little more data from Oppy. I've gotten the uncomfortable feeling, though, that no amount of data will sway some of you. I will at least make the following promise: If Oppy ever discovers a stratum of black material of whatever genesis, in whatever location, I will abjure my tiki, and grovel at the feet of whatever unwashed dieties you all follow.