Something else strikes me about this rock even more strongly.

Those are zap pits!

There are at least five features visible on that rock that look exactly like microcraters. They aren't vesicles -- several have raised rims, and one appears to have a glassy blob in the center.

They seem to be in varying states of degradation, with some nearly smoothed out and others very sharp. And these features appear on a wind-flattened side of the rock, indicating that the pitting of the rock has continued at some unguessable rate for the millennia that rock has sat there slowly being wind-carved.

How in the great wide universe does a rock on the surface of Mars get microcraters, when such tiny impactors can't survive a passage through even that thin atmosphere?

Or are my eyes playing tricks on me...?

-the other Doug

Like, wow, man...

Seriously, Ed's photomanipulation, while almost psychedelic in appearance, does contain some very interesting information. Anything that brings out such low-contrast features and shows movement with time is a valuable tool -- even if it looks like you had to take acid to figure it out...

-the other Doug

Wait a second -- that's the Jupiter II from the Lost in Space TV show!



I guess they're not lost anymore...

-the other Doug

To heck with that -- I want some imaging of the giant cat!

Anyone know if RADAR will have enough resolution to be able to tell if it's a long-hair or a short-hair cat?

And is there any relationship between this giant cat and the giant rabbit that keeps Chang-Oh company on the Moon?

-the other Doug

Totally agreed. If you'll recall, back when I picked Sol 479 for Oppy's un-stuck date (OK, so I was five days' worth of optimistic), I also predicted we'd spend several days investigating the dune in which we got stuck before we'd move on towards Erebus.

OK, so I forgot to add the three days of celebration the MER Team would (deservedly) partake in before they got back to working...

-the other Doug

That brings up a question -- just what is the resolution of the TES on board MGS, anyway? Or is it even still working? My thought is that if we can get high-resolution TES readings of the site from orbit, we can follow the hematite signature (and thereby follow the blueberries) to find safe routes.

Somehow, I doubt the TES resolution is fine enough to use it for that purpose, though.

-the other Doug

Careful, though -- it could also be an empty lakebed filled with the same sort of "mud" that Huygens landed on. It's hard to say.

Will RADAR reflect off the surface of an ethane or methane lake, or will it penetrate right to the solid icy surface underneath? In other words, will a RADAR pass tell us if that depression is filled with liquid, or not?

-the other Doug

I noticed it, but I was assiduously trying to avoid saying anything about it, having had to deal with that particular maligning of my own name for pretty much my whole life...



-the other Doug

We've all been assuming that the evaporite that once contained the blueberries that now pave the surface throughout most of the plains units was eroded away by winds. And that makes sense, winds have been the primary erosional process on Mars for millions and millions of years.

However -- I'm still mystified as to where all the evaporite dust went, and how winds could erode away more than the very top layer of evaporite, leaving an extremely thin layer of blueberries. That's not what we see -- the plains seem to be mantled in a fairly thick (at least 10 to 20 cm) layer of blueberries and blueberry dust (with an admixture of the Martian dust that gets transported globally by the frequent dust storms).

How can wind erode evaporite that's covered by a thin layer of blueberries?

Maybe it wasn't wind.

These plains appear to have been inundated by water cyclically, according to the evaporite record we saw in Endurance. And the chemical content of the water that evaporated, forming the evaporite layers, changed significantly from one flooding event to the next.

Perhaps the final series of floodings were composed of water of a chemical nature that it eroded the uppermost third-to-half meter of the previously deposited evaporite, and then drained or evaporated at a level below the thus-exposed layer of blueberries? If you think about water dissolving the soft, salty evaporite rock but leaving the blueberry concretions that had formed within it undissolved, you get something that leads to the conditions we see today -- a layer of "loose" blueberries sitting on top of many layers of evaporite.

The only problem with this theory is that it would have been the only time in the long history of flooding and evaporation that a new flooding would have liberated a layer of loose blueberries. We don't see any layers of blueberries/blueberry-derived soils between any of the layers of evaporite. So either 1) a final flooding that was capable of dissolving blueberries out of the top layers of evaporite would have to have featured a *very* different set of chemical properties than all of the previous floodings (or maybe was a glaciation and not a flooding?), or 2) all of the floodings dissolved prior evaporite layers, but the blueberries didn't concrete within the evaporite layers until quite late in the process, just before the final flooding events. Either way, the water-erosion theory requires some major change in conditions between a large number of early flooding events and the final flooding event(s) prior to Mars' Great Freeze and Dry-Out.

I hate theories that require you to plug somewhere into the equation a clause that semantically resembles the phrase "...and then a miracle occurs..." And that's sort of what that last little glitch in my theory feels like... *sigh*...

I dunno, what do y'all think of a glaciation as opposed to a late flooding to explain the blueberry paving? That could have mechanically torn the soft evaporite into dust, leaving the harder, more-resistant blueberries to pave the resulting plains after the glaciers retreated? Which do you think might be more likely?

-the other Doug

I really think many of these issues would be easier to resolve if we could get RADAR imaging of some of these areas, especially the polar regions and the area of the "smile". And, of course, the Huygens landing site.

Is there any source that can give us an idea of the planned RADAR coverage areas on Titan during the primary mission? I know it's impossible to say what might be engineered for the extended mission(s), but can anyone tell us what parts of Titan will definitely be RADAR-imaged?

-the other Doug

Compaction of soft, fluffy powder. Not hard to explain at all. And the material lower in the drift kicks out quite nicely, so it's already more compacted.

There is similar dust and sand drifting all over the planet. I seriously doubt it was all created in one big global snowstorm three billion years ago, back when snow was possible on Mars. You have to remember, it has been eons since Mars' atmosphere was thick enough to support precipitation like that. These are classic windblown drifts -- there's no reason to postulate precipitation when none has occurred for at *least* millions of years. Besides, we've seen minor changes in the drifts (outside of Endurance) in the time Oppy has been at Meridiani. No, these drifts are still in the process of creation/deflation, and I feel pretty confident in saying they're all simple aeolian features.

First, I bet there's a hard blueberry-paved surface under these drifts. Second, the facies don't change without reason -- we just don't see the reasons at first glance. In this case, the difference is probably as simple as wind erosion shifting from eroding the blueberry paving to eroding a greater percentage of evaporite outcrop, resulting in different grain size and mass. Which creates drifts of different composition and structure. Add to that the windbreaks caused by the low rims of Erebus and its fellow ancient craters (making up the ancient crater cluster that lies to the west of Victoria), and voila! you have all the reasons needed for the change in the facies.

-the other Doug

All of this is my best guess -- after all, I'm not an Areologist. But it seems to me that the east-west trending "ridge" is indeed the remnants of the northern rim of an ancient impact crater that has been filled in, its rim almost entirely obscured. The question is not so much whether the "dark patch" north of Erebus is an ancient crater (which I t hink it almost definitely is), the question is how and when was it filled.

If it was just filled by windblown dust, it could be a huge pit of soft powder that will act as a rover trap. But I don't think that's how it got filled.

I think this crater was made *before* Mars dried out and froze up, and that the ancient sea filled it. That would mean it's filled with sediments from the ancient sea, which means that it's filled with more evaporite and sandstone. Which ought to provide good, solid footing under the drifts.

I also don't think there is anything like duricrust on the drift surface that was "broken through" when Oppy got stuck. I think that Oppy got stuck because the drifts are more and more powdery in the white-ish fish-scale drift arcs and it managed to get itself in a position where it had three wheels on one side of the drift crest and three wheels on the other side, causing each side to try and slide in opposite ways. Since the rover can't slide to both sides at once, instead, it dug into the powder rather than riding on top of it. Yes, there is some kind of cementation process that occurs to the soils over a lot of Mars' surface, and yes, there are layers in these drifts that demonstrate varying compositions of the dust that makes them up. But these drifts formed a *long* time after there was rain on Mars, I think -- I don't think that groundwater or precipitation has caused the drift surfaces to become cemented.

In the long run, what I *don't* want to see is the MER Team lose its courage and fret about rover traps over every hill and beneath every drift. The whole purpose of the MERs is to see what's over the next ridge, and as long as we have a fair degree of confidence that we can dig out of soft sands when necessary, I say we should try and visit as many of the landforms here as we can. The darker "fill" inside the ancient crater north of Erebus looks like a slightly different landform, and without any ground-truth that arguies for that fill being unsafe, I'd say go for it...

-the other Doug

Looks like an impact crater that's been half-covered (or half-erased) by some process(es) yet unknown. But the half that remains really has the classic form of a crater.

Of course, that's just what it looks like to me. Could be a bunch of things. But impacts are one of the few ways (and by far and away the most common way) in which nature makes such big circular features, and the half that we see looks like a perfect half-circle.

Now, if it *is* an impact crater, and the northern half has bene submerged or overridden by some resurfacing process, maybe it's the resurfacing process, and not the remnant crater form, that's causing the redspot. The crater wall might just be controlling the extent of the redspot "condition" geographically -- for example, if there's a cryovolcanic "flow" encroaching into a crater, gasses emitted at the flow front could continue along the same direction, hit the far crater wall, and be ducted upwards into an upwelling that results in the redspot condition we're seeing.

-the other Doug

I believe I disagree entirely. We have ground truth as to what the current terrain is like -- that scalloped, fish-scale pattern of light markings are high drifts of very soft material. The first time Oppy tried to drive through the center of the lightest portion of one of those scalloped features, it got stuck in very soft powder.

To the east (right), there is nothing but more of this fish-scale patterning. We know that this is going to be more of the rover-trap soft-powder dunes.

The darker area, on the other hand, looks like it's back to the blueberry pavement with low (10cm or less) drifts. It looks like far safer and faster driving than going to the east.

In fact, I'd head southwest to get to this darker unit as fast as possible, and then straighten out to the south and head for the rim of Erebus. Now, getting from Erebus to Victoria could be dicey, since there are a lot of obvious tall drifts and serious dunes crossing the rim and extending to the east -- just the direction you want to go to reach Victoria...

-the other Doug

I think you're right. Even the color TV cameras on the Apollo missions were color-wheel systems, in which a wheel of R-G-B filters spun in front of a monochrome vidicon tube. When the image was received back on Earth, it was passed electronically through a set of video generators that combined each tri-color triplet into a single colored TV frame.

I believe the shuttle and ISS are now both equipped with TV cameras that send color frames, and I know they have been using digital color still-picture cameras on shuttle and ISS flights, so MSL won't be the first spacecraft of any type to transmit single-frame color pictures. But I think you're right, it will be the first lunar or planetary probe to do so.

-the other Doug

How about this:

"To the MER Team -- when Opportunity needed to be dug out, they dug in!"

-the other Doug

Sounds like a song cue for a Hope-Crosby road picture -- "Ohhh, we're off on the highway to Erebus. You never know when we'll get stuck! Yes, as we salley fore, we'll see some dunes and more -- the odds are even we'll run into Dorothy Lamour!"

-the other Doug

As I understand it, the rovers can be programmed to do auto-nav sequences in which the height of obstacles to be avoided is a variable. In other words, until we get out of potentially dangerous drift territory, Oppy's autonav could (conceivably) be set to avoid any object higher than, say, 20cm above its current position. That would naturally lead it to follow interdunal areas.

It would be slow, but steady (10 to 20 m per day, maybe) but it would get us out of this landform, where we can drive faster again...

-the other Doug

I have a very important reason for quoting the original post, pic and all.

You see, the amount of time it takes to make an exposure like this means the picture just isn't going to come out well.

The problem here is obvious. The reason the Earth isn't as distinct as it could be is obvious.

Somebody moved.

-the other Doug

The other real difference between potential Martian and Europan life is that Martian life, if it exists today, is likely to be very, very simple -- bacteria at best. Whereas if Europa has developed life, there are fewer reasons to believe that it would *have* to be very simple. With an aquatic environment and enough heat from within the moon's rocky core, Europan life has no greater obvious evolutionary limits than Earth's sea life does.

As much as finding fossilized bacteria, or even live bacteria, on Mars would prove a point and be interesting in and of itself, it wouldn't give us a whole lot of data on how life might develop outside of Earth's influence. Multi-cellular organisms (or their equivalent) in Europa's oceans would demonstrate how life might be able to organize itself in different ways to those we see on Earth. For example, would genetic encoding be DNA-based? Or has Europan life found different ways to organize, evolve and propogate?

I think the most boring thing we could possibly find on Europa would be -- fish. Regular old fish, with scales and gills and DNA and everything. But it would sure hint at some common ancestor to life on both worlds, wouldn't it?

My bets are on truly alien life forms swimming in Europa's oceans, whether they look like fish or not.

-the other Doug

I've heard some rumors recently of a new theory of Jupiter's relative position in the solar system -- something about its having formed well outside of the orbit of Saturn and having migrated in to its current position.

First, I guess I'd like to know what, if anything, y'all have heard about this theory. And are there any hard facts supporting it (such as analysis of isotopic abundances, etc.)?

I have to admit, the Saturn system shows a lot of effects of high gravity gradients occurring at some time in the past. What makes me wonder about Jupiter's pasage being responsible is that we don't see the same effects on the Jovian moons that we see on Saturn's.

I guess the question is, how would a Jovian passage so obviously disrupt the Saturn system (tearing moons apart, flinging some completely out of its orbit, placing others in far different orbits than they started in), while the four major moons of Jupiter show no such effects?

-the other Doug

This event deserves its own thread.

To quote the illustrious Dr. King -- "Free at last, free at last, thank God Almighty, we're free at last!

So, how much y'all want to bet we'll stay here for a few sols, looking very carefully at the tracks and waiting for the MER Team to figure out how to proceed from here?

-the other Doug

Doug, is there any way you can include a diskette or something that includes the names of all the people here on the Forum? So the MER Team knows how much we were *all* pulling for them?

-the other Doug

Well... *if* the theory is correct that Tycho ejecta caused the landslide at the Taurus-Littrow landing site (a quarter of the way around the moon from Tycho), and *if* the dating of the slide is accurate, then we know exactly how old the regolith is at the Surveyor VII site. Something around 109 million years old.

I'm one of the guys who thinks Surveyor I would have been a better target than Surveyor III, by the way. It sits on a much younger lava flow than anywhere else visited by any terrestrial probe, and the regolith there might indeed be thinner than a meter -- I've heard estimates of perhaps only 30 to 60 cm regolith depth for the Flamsteed site. And an age of perhaps less then a billion years.

-the other Doug

I guess a mare is a mare is a mare, but it realy strikes me how closely Surveyor V's patch of the Sea of Tranquility resembles Apollo 11's patch.

Of course, Surveyor V's horizon is a bit closer than that of Tranquility Base, since it's sitting in a shallow crater. I know they refired the verniers on Surveyor V, but didn't try a hop like they did on Surveyor VI (I think because they had a power issue that ensured it wouldn't survive more than about the length of the lunar day). But wouldn't it have been cool if a Surveyor could have hopped itself out of a shallow crater and improve its viewpoint?

-the other Doug