[X] My Assistant

[Tman]

What may you estimate? Which direction have they decided for Spirit?

http://www.greuti.ch/spirit/which_route.jpg

Thanks Phil for this map!

I put my money on 3.

This post has been edited by Tman: Jun 2 2005, 07:59 PM

[djellison]

Once again - Steve reads our minds

But after a lot of thought we have finally decided, and the decision is to head up Husband Hill. We're not going to try a frontal assault this time. Instead, we're going to spiral up and to the right, working both upslope and also cross-slope simultaneously. Whether we'll actually reach the summit is an open question at this point. But we're convinced that the route we've chosen offers the quickest path to a view of whatever's on the south side of the hill... and that's what we want to see next.

[Tesheiner]

Ustrax,

It seems that the "pilgrim" will be heading to "Santiago de Compostela".

[Nirgal]

this is great news !

with the following two quotes, a dream (that I've been dreaming ever since it became clear that the rovers are capable of doing really long distance drives) could finally come true:

But after a lot of thought we have finally decided, and the decision is to head up Husband Hill.

this little incident is not going to deter us from continuing our southward exploration. South is where we think the best science is, and we're not going to turn tail and run because of one unfortunate

it's the dream of Spirit and Opportunity taking panoramas from the top of the
Columbia Hills and the great Victora Crater ...

what a great expedition and what exciting prospects for the remaining
life span of the rovers

[djellison]

It sounds like Route 2.75 is about the way we're going - essentially making Clovis, and LL the first two 'tack' points driving up the hill in a big Z

Doug

[wyogold]

It sounds like Route 2.75 is about the way we're going - essentially making Clovis, and LL the first two 'tack' points driving up the hill in a big Z

Doug

I can't wait to see the pan from the top. I am lucky enough to see great views almost every weekend. You can around 60+ miles up the valley and nearly 40 in every direction. The mars images from spirit (even now) lower on the hill allow me to imagine being on Mars as I look out over the valley below on the weekends.

The regular view



same view but.....
imagine being on Mars with the crater walls of Gusev Crater in the distance



thank you everybody that spends time building the programs,pans, movies,theories,maps and everything else. you are all great.

scott

[djellison]

I guess this is backstay

Doug

[Jeff7]

It rather reminds me of Adirondak.

[Bob Shaw]

Looks like a nice lump of basalt! Not a vesicle in sight...

[dilo]

A couple of images showing this rock before and after brush (with MI stitched mosaics):


Interesting fracture visible in bot images, but what hit me is the small conical extrution in the lower part (visible only in the color Pancam images).

[Bill Harris]

Interesting, too, is the pattern of "dust swirls" (and lack of dust) on the rock.

I noticed the "barnicle", too.

--Bill

[dvandorn]

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

[edstrick]

I really doubt those are zap pits, but....

Here's something that's not new, but has never gotten above the press-release dominated media coverage of Mars science.

Current obliquity of Mars spin axis to the orbit is some 23 degrees. Post Viking modeling showed a possible periodic range of obliquity from some 15 deg to some 45 deg. More recent studies using serious number crunching orbit modeling shows the variations are more chaotic, less periodic over the long term.. and (maybe) somewhat smaller. (I'd have to spend some hours in the library to update my fading memory on this.)

When the obliquity is high, the poles get baked, and volatiles are driven toward the equator. That has been discussed recently, as possibly explaining low latitude hydrogen in soils and eolian mantles at lower latitudes.

BUT... When the obliquity is low, the poles get little sunlight all year, and get *COLD*.... and can trap a very large fraction of the atmosphere CO2... Mars's atmosphere may collapse to a Nitrogen/Argon atmosphere with about 5% of the current surface pressure. That's still plenty of atmosphere to stop micrometeoroids, but not golf-ball sized stuff.... If the minimum obliquity is higher, the freezeout may not be as severe.

Mars is *NOT* always the way we see it now, even in geologically recent times.

[Bill Harris]

...range of obliquity from some 15 deg to some 45 deg.

When the obliquity is low, the poles get little sunlight all year, and get *COLD*.... and can trap a very large fraction of the atmosphere CO2...

Wouldn't high obliquity also trap CO2 at one pole, too? For half of the year, you have one very large pole that can be in the dark down to the equator for up to half the year (would "6 months" be valid on Mars?). Seems to me that low obliquity would result in the smallest polar caps and the lowest maximum temperatures and a moderate temperature range.

--Bill

[Bob Shaw]

As with the pits which Opportunity saw, I stand by the good ol' Principle of Conformity: everything we see should be similar to everything else, and out-of-place evidence is probably not the basis for a startling new theory as much as just plain wrong. So, let's turn the picture upside down for a few moments.

The Martian environment has changed radically since the youth of that planet, and may well change again (though, presumably with none of the cyclical retreading of materials which characterises our own planet, or even Venus, so that on Mars a steady loss of volatiles by either locking up or photo-disassociation and loss to space has been the long-term trend). I think that these are hardly likely to be arguable, and that - yes - there are a number of credible mechanisms at work, any or all of which may dominate at different epochs.

OK, so then we turn to impacts. Granted, Mars is covered in craters, so has obviously suffered lots of impacts, and plainly there must have been many more small impacting objects than big ones - that's the whole basis of crater-counting, which is - of course - the primary tool we have for estimating the relative ages of planetary surfaces.

But tiny impacts? How small an impact crater might we see? Iwon't repeat the discussion from the Opportunity thread, but I *do* have the impression that there's been some special pleading going on, which is probably blinding us to some real features of these unearthly landscapes.

The key to sorting out all this is... ...conformity. Seeing *one* crater tells us very little. Seeing a range of craters, with different (or similar) characteristics tells us *everything*. The problem with the mini-crater hypotheses is that we don't see enough of them to make a meaningful analysis possible, as yet.

So, what can we do?

Well, keeping an eye out for pits sounds sensible - but let's not assume that any old lesion in a rock is an impact site, it's about as much help as deciding that every wrinkly thing is a fossil! What we need are *lots* of examples of craters of varying sizes, associated with rocks where at least some of their history may be inferred - and not to jump up and down with excitement over the first hole we find!

[Guest_Edward Schmitz_*]

I agree with bob... to an extent. I like your rationallity and careful approach. But we do have some luxury here that we can avail our selves of. This is informal discussion. Anything goes. If the pits strike Doug as interesting, he should call it to our attention. Having done that, we might all be paying more attention to these features. That, I am sure, is how it works in the war room where they plan the rover activities.

Now, having said that, I agree that it is premature to dive into detailed theories. Especially if it requires restructuring of our understanding of the planet. It seems that those pits could have a large number of explanations. A chemical process seems plausible to me. At meridiani, it was startling to me just how much the chemistry could vary at sub-millimeter resolution.

I just like talking about Mars, in general. I think it is fun to come up hair-brain notions of what is going on. Some of them stick, most of them don't. But it is always fun.

Ed