According to rawid.exe :
Acquisition time (Mars): Sol 433 15:01:56
Current local time (Mars): Sol 434 02:52:23
Elapsed time since acquisition: 0 days, 11:39:09

As I noted within the last week, here, it looks from the orbital images like there are two different types of terrain between here an Victoria -- the true etched terrain (which features outcrops of evaporite) and a stretch of duned ground that appears to incorporate both dark and light sand/dust in the regolith and duning, but no evaporite outcrops. It's that second type of terrain, which only includes lighter sand in the regolith, that we're crossing now -- in fact, we don't really get to any of the "true" etched terrain until after we pass Erebus (unless we want to make a detour to the west of Erebus, which doesn't appear likely).

I think we're seeing the first examples of eroded evaporite dust mixed in with the broken-up concretion materials that make up the dark regolith out on the dark plains. And if that's the case, since the evaporites are primarily salt-cake rock, it would make sense for the lighter sand to compress into a shinier surface under the wheels -- just like salt-rich soil has been doing at Gusev.

So far, my theory looks pretty good... *grin*...

-the other Doug

Well, it's either a small meteor crater (not unlikely, considering the thin Martian atmosphere, that an impactor the size of a grain of sand would hit and make a tiny crater) or it's a small sinkhole.

It's not at all difficult to imagine voids and gaps in the evaporite layer -- after all, subsidence around organized voids probably formed Anatolia and the other cracks we see out in the plains. But this crater, situated halfway up the crest of a dune, looks a lot more like a tiny impact crater.

As such, it would only display the constituents of the sand in the dune... and therefore wouldn't be all that interesting to Oppy's remote sensors. Right?

-the other Doug

Consider also a martian Myrmeleon Formicarius pitfall ......

.. should be ant-lion in english.

As far as what sol an image was taken on, that info is shown in the title bar. I will try to include a Image Info window with information comparable to rawid.exe in the next version.

I think I can say with a fair degree of certainty that insects did *not* cause this pit.

-the other Doug

Are there any good images from orbit for the "true" etched terrain? I have had some difficulty finding this...

Thanks,

Steve

I'm absolutely agree with you, Doug! I prefer non-meteoric explaination, also because small crater should be rapidly canceled from wind/sand
erosion (think to Vostok)... anyway, should be explored deeply by Oppy!

An image of it with pancam would be nice...but they'll probably drive past it.

.........Anyone seen the classic 50's sci-fi moovie "Invaders from Mars" ? Where the Martians are hiding underground - the sand opens up and the victims fall through? That's what it reminded me of LOL.

The Martians arrive:


http://www.geocities.com/Hollywood/Hills/3411/images.htm

I already posted yesterday, but I don't find...
On sol 410, Opportunity already encountered other structures similar to this; here a mosaic of four Navcam subframes:

Based on this, I think meteoric origin should be excluded...

Why should be excluded?
It may be :-) A bigger impactor hit somewhere and lifted tiny pieces of rock in the air recently (a couple of years ago?), which made such small craterlets.
Look at the Oppy's trails, they still can be seen from orbit, and after exiting Endurance, there were very small differences in the trails left behind 6 months ago.So even in the windy Meridiani, dust deposition process is slow. And this "craterlet" seems with very round edges, so it is not impossible to have been formed years ago and not still been completly erased.

And sorry for my bad english, feel free to correct me anytime :-), I'd appreciate it :-).

I'd like to say (after some thinking), it MUST have been an impact. As far as i can see (but this must be confirmed with pancam or MI) there's an elevated rim around the feature. This can't be there due to a pit caused by a void underneath. There must have been energy acting from inside out / up.

Your explanation of a secundairy impact makes sense to me. Primairy impacts are either some meters at least, or the meteorite burns up completely and doesn't reach the surface. A primairy impact caused by a meteorite the size of a pea that has made it all the way through the atmosphere without burning up completely seems too rare to me to be witnessed by us now. Especially when you consider the wind action, that wipes out this small craters within decades, i would eat my shoe (dutch) if this is a primairy impact.....

If a primairy impact wasn't rare....the plains should be peppered by them (or are they filled up more easy compared to the bigger craters ?) Statistical analyses of crater density (also on the moon and mercury) show, that the smaller the impact, the more frequent they occur (that is, on an atmosphere free body). Then why are there more 5+ meter craters at Meridiani than smaller ones like these ? Maybe it's the wind action that fills them, or it is the fact that meterorites below a certain dimension simply don't make it trough the atmosphere....

Very interesting finding Oppy ! We should take a closer look !

Weird.........theyve moved back a bit

http://qt.exploratorium.edu/mars/opportuni...05P1214R0M1.JPG

My guess is, there *are* more small craters than 5+ meter ones. The only thing is, all "larger" craters within a certain area can be counted on satellite images. Dish-sized craters must be stumbled upon accidentally by Oppy before they are taken into account. So the sampling is skewed.

Resemble this hole not a bullet hole similar that would a bullet causes? Therefore I think it was rather a small meteorite that recently has fallen.

Have maybe anybody a picture of such a bullet hole in sand-like ground that he/she could post?

I understand what you mean. This certainly is an aspect that has to be taken into account. But the fact that it really is the first one in 5 km's of driving.....makes me think the smaller ones are the minority.

We need an updated rout map from Pando

http://www.geocities.com/vladimorka/MerView.zip
Simple image name decoder - you can browse your downloaded images or just paste any image name in the editbox and click 'decode' to have it decoded.

And I don't think oppy has moved much farther than Voyager - there aren't any significant nav images since sunday.

Talking about stumbling randomly I was looking at some old sol 95 images from Oppy and saw this dish shaped depression on the rim of endurance, Dish-sized crater or wind action?

I have gone to the trouble of making a stero pair which i have attached but can't figure out if it will pop correctly in the post.
Click to view attachment

Looks really fresh, though, doesn't it?

I think what we're seeing is the intersection of two surface-altering processes. The first is impact -- since Mars has a very thin atmosphere, the lower size limit of impactors that reach the surface is a lot smaller than here on Earth. But it's a lot larger than what would reach the lunar surface, for example. So, you get more craters from 6 cm on up than you do on Earth, but a lot less than you see on the Moon.

The second process is aeolian weathering. Over the course of just a few years, decades at most, this small little dimple crater will probably be covered over by sand and dust. Which means it's probably quite fresh -- a few years at most. Unlike on the Moon, where the most numerous craters are the zap pits made by grains of dust measured in microns, and where there are no other weathering processes happening, Mars doesn't retain craters of this size all that long. Because of aeolian weathering.

So, the impact flux of such particles must be pretty slow, or else we would see a bunch of these little dimples all over Meridiani in varying stages of obliteration. And we don't. In simple terms, aeolian erosion is happening a lot faster than tiny impacts are happening -- but both appear to be happening.

Seeing as this looks to be a very, very recent cratering event, let's bring up the topic of another thread, shall we? Perhaps this dimple was caused by a stray bolt, or fleck of metal, that separated from Oppy's cruise stage when it broke up and impacted at about a thousand KPH? I mean, going back to the Venn diagrams we did in grade school , there *is* an intersection of the sets "tiny craters made by very small impactors within the last few years" and "space debris that might have broken into some very small fragments that we *know* impacted close to here within the last few years."

I'm not saying this tiny dimple was caused by a tiny piece of Oppy's cruise stage -- but the timing and the size could well be correct. And it seems a bit coincidental that a really, really fresh crater should show up within what must be only several km of the debris footprint of Oppy's cruise stage...

-the other Doug

Check out the last post from Pertinax in the Cruise stage impact thread.

That's the thread I was talking about. Seems to me the cruise stage had to have broken up into a few pieces, and the mass/drag ratio on a bolt would probably be more weighted towards mass than that of a bigger chunk of the CS, with more exposed surface area. So it might make sense that the dark splotch is the crater from a large, "junkier" piece of the CS and this little tiny dimple is from a much smaller piece that shot out a little further.

It's possible that this is a tiny secondary from the larger CS impact, but to tell the truth, this looks like a primary -- most especially because the impact was likely at a pretty sharp angle and the crater remains circular. At slower speeds, as you see in secondaries from small craters, craters made by low-angle impactors become elliptical. But beyond a certain speed, even low-angle impactors make perfectly circular craters.

-the other Doug

Well, as long as we're not going anywhere, at least they took pancams of the mini-craters.

http://qt.exploratorium.edu/mars/opportuni...21P2592L7M1.JPG

http://qt.exploratorium.edu/mars/opportuni...21P2593L7M1.JPG

Maybe they are not craters!?

Maybe something beneath the ground evaporated.

They are most likely craters. They have elevated rims.

This collage of two Pancam images in two channel (R1+R2) show that Opportunity stall occurred not far from Viking/Voyager craters, at the beginning of a more accidentated terrain (note the left track disappearing below a dune, more clear with 3D image!):

So, how far have we made it past Voyager? We haven't seen an updated route map lately. Hopefully, we'll be moving around this wheel somehow. Maybe no 220 meter sols though. I guess the etched terrain wouldn't let us do that anyway.

I'd estimate about 200m south. There was a shortish drive ( about 40 m maybe? ) on leaving it - and a 160odd which then ended with the steering problem

Doug

@dilo,

Maybe this is an FAQ, but:

the color image you posted is from one of those series where
they use 2 filters from different sides each (i.e Right 1, Left 2)
So how do you (and others) align the left/right pictures such that
there is no pixel-offset from the left/right eye perspective in the different color channels ?

(As I've been focused on the "single band-coloring", I
havn't done much multi-band colorizing or stereo-anaglyph related stuff
so far ... )

The Pancam composition of the filters L456 shows somewhat more details of the "bullet hole":

http://www.greuti.ch/oppy/pan-oppy-sol436.jpg

It looks deep. I suggest we disperse carrots in the general area and then lurk to see if Bugs Bunny will dare come out

Squires says we're in the etched terrain. Who is it that posts route maps? Is there an updated one?

In his update he also said they were about half a kilometer from Erebus.

Updated Opportunity Route Map:

It seems to me too much of a coincidence that these tiny, very fresh mini-craters happen to be the area of Oppy. My guess would be that it is a result of the cruise stage breaking up on re-entry.

Wow....not too far to go now

Well, it's quite a ways to Victoria. I'm thinking Erebus will be like Vostok.

This is the view ahead to the Erebus area... pancams from sol 437. At the top of my image I have cropped out the horizon and mosaicked the three frames together with a bit of tonal adjustment. The lower half is the near-horizon section of the above image with about tenfold vertical exaggeration. This is an interesting way to get a better feel for subtle topography near the horizon (I've been doing it for Viking Lander 2, trying to find its exact location, which is still not known exactly... more news on this later!)

So there will to be something to see at Erebus, but it's still hard to match what we see in this image to the MOC images.

Phil

Click to view attachment

Nirgal, I apologize for my late reply...
Image I posted is not a "colorized" one, but was obtained from two couples of subframes (512x512) taken wit PanCam using filters R1 and R2 and stitched by me. I know that these aren't real color filters, but I managed RGB balancing and "color dominance" in order to abtain most realistic results...
Incidentally, also I estimated about 200m distance from Voyager crater based on this picture...

Yes, and the interesting thing is that "grain [of etched terrain] is caused by the very large ripples"...
http://athena1.cornell.edu/news/mubss/
But, hey, nobody noticed that "bluberries" seem disappeared now!!??!!
Yes, we do not have recent microscopic camera pictures, but based on PanCam close-up like this below, now we have finer irregular-shaped objects!

I still see plenty of blueberries in there - but I think they may be becoming less dense, and mainly on one side of each dune.

Doug

Maybe...but wath about shape? It seems unusual to me...

I guess ones that spend their time further from outcropping are generally older and thus more erroded?

Doug

Yep, the blueberries are becoming less and less a percentage of the soils here. I'm still convinced we're seeing the deposition of the erosion products from the evaporite layer. Soil analyses of these lighter-colored dunes will determine that for sure, I imagine.

I'm still thinking that this isn't "true" etched terrain, regardless of what Squyres calls it. This is deposition of lighter-colored sand in the dunes. The "true" etched terrain is south and west of Oppy -- where there are exposed ridges of evaporite sticking out from the sand dunes. Ridges that look to me like they're the remnants of the ejecta "splash" from the ancient crater cluster of which Erebus is a part.

-the other Doug

I put this Pan together from the latest pancam images (I think)... all taken with the L2 filter.

WooHoo! An updated route map. It looks like it's about a half kilometer away, as the man said. It's still hard to say what we will see when we get there, but if the rim outcrops were much taller than the intervening dunes, they'd be more prominent by now. We'll need to be patient for another couple of hundred meters before we can start placing the serious bets.

Either that, or they are just very common in this area. we don't have data from other spots close by, so who knows..

If I didn't know any better I'd day that was taken out in the ocean on a calm day.
An ocean here on Earth by the by

Wonderful image. Thanks

jG

Another "false color" stitching from Sol 442

This is certainly a different way to map Oppy's progress