I had a nice little American Thanksgiving and the time off with the family was great!
I was going over some of the images I have not seen lately and I found this little mystery.
On Sol 2072 the Pancam picked up this 'glint' (or flare) in the neighborhood.

Here is 2072 right, filter 6 - - - - - - - - - - - - - - - 2072 left, filter 4
Click to view attachmentClick to view attachment

Every time we have seen this in the past it was the sun glinting off a highly reflective surface.

This little flash might be a very interesting little side trip when we finish up here.
(speculation mode: shiny iron, or an old coca-cola can..)

Cheers

What color does the filter make it? Gold??

I'm guessing it's just a cosmic ray strike or something. I can't see anything obvious that would cause the glint./

None of the cosmic ray strikes I've seen thus far deposited enough energy to overload so many adjacent pixels, while that's been common for specular reflections of light. I go with a polished surface of some kind.

Steve M

If it's real, Stu will be ecstatic...almost certainly another metallic meteorite!

Unfortunately that glint isn't visible in any of the other L (or R) frames taken of that scene. So that pretty much proves it's a cosmic ray hit. Anything out there that was that bright would show up in neighbouring filters.

Never mind, I'm sure there are plenty more meteorites between us and Endeavour!

Colour view of recent RATting...

Click to view attachment

I had a dream last night... it was the day we rolled up to the foothills of Endeavour, and there was a single, huge, weathered boulder sitting on the ground ahead of us, looking like a martian version of the Sphinx. Very impressive.

Here is a right filter, false color, composite image showing the recently brushed area on Marquette, sol 2075. The brushed rock surface displays very different colors compared to the unbrushed surface. We can apparently see some individual mineral grains as different colors. This RGB composite uses R=R1/R2, G=R1, and B=R5/R7.
Click to view attachment

What do you make of the 'yellow' rind, Tom? An ablation crust?

There were 14 images shot that sol, of that region.
They are taken at approximately 20.5 secs apart.

1) 11:15.36 no glint
2) 11:15:57 no glint
3) 11:16:17 GLINT ----------------
4) 11:16:38 no glint

-etc for 10 more images

It is quite possible that an edge of something shiny could glint for a few seconds between the 40 seconds between the 2nd and 4th image. The smaller the object (or rounder and/or tilted), then it will take less time for it to exactly line up between the camera and the sun. The number of adjacent pixels involved in the 'flare' does not have the signature of a cosmic ray event; which usually shows up has a couple of hot pixels or three or ten... in a very straight line. I am not ruling out a cosmic ray event (in fact that was my first thought), but the width and length of the flare indicates (to me) that this is a very real reflection.

Dear Mr. Squyres, lets rover over and take a peek and then move onward onto Endeavor.

So...I do not think this glint 'proves' it is a cosmic ray hit.
Your mileage may definitely vary (!)

Cheers

I'm not sure, but it could simply be what the dusty surface of the rock looks like under certain lighting conditions. See, for example, another similar image I made from an earlier sol.

FWIW, PD, I agree.
We have only seen similar, specular reflections at this distance from metallic structures of the spacecraft (lander, heat shield). Glints from rocks (like the one in front of us, and also Comanche) have mainly been obvious in MIs. But a bright glint like this doesn't require a boulder. A crystalline surface a centimeter or so square could account for it, as part of a rock not much bigger. There are lots of small rocks around here. I hope this area will get further examination.

One idea would be that different faces of MI likely have different thicknesses of dust, due to the direction of prevailing winds and the slope of the surface. Considering how different the real brushed surface of MI looks compared with the dusty surface, I could see how thinner dust could look quite different from thicker dust. Combine that with Tom's point about lighting, and that could account for the differences. It would be nice if they could brush that "rind" area, though.

Sol 2078 (Sat 28 Nov) Pancams. These more than normally pronounced 'channels' almost look like they could have been made by Oppy - They look fascinating. If any of you geologists find them interesting enough, what do you think?

- do not attach an image to a thread that is freely viewable on a server elsewhere - simply link to it, and attach a thumbnail.

Point taken!

See these crops - both around 15K

Click to view attachment ..... Click to view attachment

Links to source
http://qt.exploratorium.edu/mars/opportuni...R5P2271L2M1.JPG
http://qt.exploratorium.edu/mars/opportuni...R5P2271L2M1.JPG

Sorry, was in a bit of a hurry early morning today - Is there an issue with bandwidth costs? In fact, I sent a donation to Doug about a week ago to help with server costs and I'm happy to chuck in every year - so perhaps I should have been more mindful!!!

Well dang. You got me. I'm not a geologist, but I did take a lot of courses and later made a hobby of it.

I'm going to suggest that it is related to a subsurface fracture of some kind. How far are we from the fresh crater? I would imagine that a jigsaw puzzle like this Meridiani substrate gets nudged around a bit when there are impacts.

> How far are we from the fresh crater?

Less then 350m.

Colour view of the interesting surface feature imaged by Oppy...

http://twitpic.com/rg6w0

Stu, great job! That really is an interesting patch of real estate . . . and there are our Meridiani layers peeking through, as reliable as ever.

There is a red clay jogging track near where I live here in Taipei. In August when the ants are migrating, they engineer little roads across the track that look very much like the one Stu has colorized. The end product really looks uncannily similar, but of course if Opportunity were out there on my jogging track she would have seen the little critters in action, not merely their accomplishments. Are we really sure that the rover itself did not somehow leave a scuff mark?

Couple of 3D views of Oppy herself... careful, that antenna (1st pic) will have yer eye out...!

http://twitpic.com/rijcd

http://twitpic.com/rij8t

In the latest Planetary report, it's reported that the team has concluded that MI is not a meteorite:

Suggestion: Oppy drove over a slightly loose plate of rock and it tilted enough to shift the dust along its edge.

We've actually seen countless examples of things like this along the way. Nothing very special about it.

Phil

Another tidbit from the latest report:



and

It seems like a no-brainer to save the RAT for the soft clays at Endeavour. Why waste it on a hard basalt? What could we possibly learn that would be worth it?

MarkG, take a bow -- olivine!

If we knew what we were going to learn - then we wouldn't be doing ANY of this, would we?



If it's actually a piece of primordial crust, as suggest by Squyres, then studying it is important. It's quite likely that the rock out at Endeavour will be the same exceptionally soft rock we've been used to at Eagle, Endurance and Victoria - which consumes almost no RAT bit at all.

Post#733:"Phenocrysts? A healed fracture? Peridotite (or gabbro)? "

Olivine: The brushed areas of M.I. just had the "look" of coarse-grained olivine, the way the crystal surfaces look and the non-red semi-translucent look. The sharper edged grains are likely pyroxene and feldspar.

I hope more areas of the rock get brushed before (and if) a grind site is chosen. I see veins and inclusions that merit a clear look.

The coarseness of grain and high olivine content definitely imply that this rock came from significant depth -- the coarse grain size implies slow crystallization (and slow cooling) far from the surface, and the veins imply shear and rework at depth (the filled in veins are as hard as the surrounding rock -- it did not fragment along the veins).

It took a pretty good impact to excavate this rock, perhaps a 100-km or much more sized crater would be left behind. Which crater would it be? The recent-ness (relative to the Meridiani surface) of the debris of this rock and it shards might cut the potential source list down to a short list. However, it is also possible that a smaller impact "recently" excavated this rock from the rim debris of the original big crater. Even that impact had to be big enough to "gently" throw this rock's parent debris clump on a sub-orbital trajectory. By gently, I mean an non-shock acceleration, since the rock is still intact.

Well, maybe this helps folks understand why this rock is so interesting.

I'm no geologist but olivine would mean this rock was never in contact with water so i suppose that this rock should be older than meridiani.It would be interesting to note whether any olivine was detected at the bottom of deep craters in Meridiani representing an older geological layer prior to the water history in this region..assuming that this olivne rock originated from Meridiani and not from an another region.Any suggestions guys?

I understood that the reason for going to Endeavour was to examine rocks that are different from the usual Meridiani rocks we've been seeing. The uplifted Endeavour rim rocks presumably predate the Meridiani plains we've been travelling on.

Of course that's not to say that the Endeavour rocks won't be soft, which is the point you were trying to make. Just (hopefully) different.

With both MRO and Odyssey contending with safe mode resets, etc., we must be sipping data from both MER's through a very long and thin straw -- direct-to-Earth transmission.
What effect is this having on the missions and the day-to-day choices? How is DSN time/schedule affected?

DSN schedules still contain almost constant coverage for MODY and MRO.
Over the next two weeks...lots of two-way passes with both MERs.

The Endeavour area is lower in the Meridiani sequence, but by no means the basal unit. Marquette is clearly from a deeper igneous unit (a gabbro is a magma that has cooled slowly at depth, a basalt is magma that has reached the surface and cooled quickly. Cools slowly, larger crystals are able to form; cools quickly, no time to form large crystals).

--Bill

So what does that tell us about how far away is Marquette's source? If Endeavour is the deepest crater in the area, is Marquette from farther still?

As I understand it, Endeavour existed before the Meridiani layers were laid down. The reason that Marquette can not be from Endeavour is because all the ejecta from that impact is covered by the 100 plus meters of the Meridiani layers. The exception to this is the rim of Endeavour which is formed of pre-Meridiani layer material. Couldn't Marquette be ejecta from an impact on Endeavour's rim? Or is there reason to believe Endeavour's rim does not contain that type of material?

I guess one question is from exactly how deep did MI come? Is there a direct grain size - formation depth relationship? There are largish and relatively fresh-looking craters within 100 km or so of us, in particular Bopolu - it's in the lower left of the image in this post. But Bopolu is only around 20 km across.


It was a very clear explanation - thanks!

Maybe I missed something. Has the long holiday in space idea been ruled out?

I haven't heard that MI coming from a "space holiday" is ruled out. But the odds have got to be in favour of it being local ejecta.

So it crystallised slowly deep inside a rocky world and the odds are that world was Mars and it never achieved escape velocity. Fair enough. The odds could change though if there is no suitable crater of the right age. I have another question. Can the MER instruments unambiguously identify such a rock as originally Martian as opposed to (say) Lunar or Mercurian? Or does the statement about Martian origin arise merely from this being the most likely possibility among several?

Could we tell if Marquette had been blasted into orbit and then fell back to Mars after that orbit decayed? If that is the case, then Marquette could have come from anywhere on Mars.

It doesn't have much in the way of re-entry symptoms (fusion crust etc)

I don't know. Way back when we were approaching the area I drew attention to a very bright rock that I hoped we'd stop at, but we didn't. It was pointed out that a lot of the fragments lying around seemed to be showing bright glints. Since we came up close I have been noticing strangely flat surfaces on several fragments. These surfaces show up greenish in the colour images and Marquette itself seems to have some of that surface left in places. I know I should refer back to all the relevant posts but, heck, they're all in this thread and fairly recent. I think Shaka was the first to pose a direct question about the 'rind'.

A rock ejected from a large impact doesn't have to go into a stable orbit that subsequently decays to end up almost anywhere on a planet. A lot of the ejected rocks go into very excentric "orbits" with a perigeum (or periwhatever) below the surface of the planet and therefore re-enters after less than one orbit.
This can occur almost anywhere since the planet rotates while the rock is in orbit. Computer modelling usually shows a marked concentration of re-entries near the antipodal point of the impact with a westward "trail" (if the planet rotates eastwards) but some rocks will impact almost anywhere on the globe.

Periareion. I knew Ares would be in there because they always use the greek name, but I had to look up how to concatenate all those vowels.

A good point there, tty, but a sub-orbital spaceflight is no advance on an inside-the-atmosphere hop for solving the long term storage problem. The options for that seem to be either storage on Mars involving two widely spaced impact events or storage in space.

Read today's posting on Emily's Planetary Society blog about Mercury to see a good illustration of this point.

Here's Marquette seen by the navcam from a different angle after today's drive. Pancams tomorrow.
Click to view attachment

Farewell Marquette Island...

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... and welcome to Endeavour Crater !