On The Road Again! - Page 22

pk, after a few more hundered meters southwest a super 3D image would be able to sort out what's what.

I don't favor the Lazu peak because it is 45 km distant vs 20 km distant for an Endeavor peak.

That means - all other things being equal - that the Lazu peak is 2.25 times higher than the Endeavour peak to be seen above it. I haven't done the math, but I think that the 190 meter difference in height would put the Lazu peak below the Endeavour peak. I have to go out for the rest of the afternoon but will do the math this evening.

Also, because of the extra distance the Lazu peak should be even less clear than the Endurance East rim - which is clearly ( to my eye ) less distinct than the near rim peaks.

Just did the math...

using a small angle distance to horizon approximation...

D = Sqrt( 2Rh ), where

h is height above the ground and D is distance to the horizon and R is the radius of the Planet...

For the MER rover

h=1.5 m and R = 3,400,000 m

so h = 3,200 meters.

NOW, we solve for h for the Endeavour peak:

The distance to the rover horizon from the Endeavour peak is 20-3.2 = 16.8 km, so

h=16.8 * 16.8 /( 2 * 3400 ) = 0.041 km = 41 meters.

The distance to the rover horizon from the Lazu peak is 45-3.2 = 41.8 km, so,

h=41.8 * 41.8 / ( 2 * 3400 ) = 0.257 km = 257 meters.

Thus the Lazu peak would have to be 257-41 = 216 meters higher than the Endeavour peak.

190

Stupid comment parser ate my final sentence:

The actual difference in height of 190 meters is less than the 216 meter difference required for the Lazu peak to appear higher than the Endeavour peak - so the Lazu peak is below the Endeavour peak.

Horton: Nice analysis.

I was referring to a nearer Iazu peak, not the really high far-rim Iazu peak that is 45km away.
I have annotated the two in the image below.

If you mouse over the area I have circled in blue in Google Mars, you will see that there is a peak there. It is -1251m high, and apparently 59m higher than the far rim of Endeavour (-1310m). Both these points are equidistant (33km) from Opportunity's current position.
If one is visible, the other one should be too.
Well, perhaps on a clear day.

The far side is about 33 km from Opportunity and at that distance 1 pixel = 9 meters.

The far side highest point is about 6 pixels above the horizon - 54 m.

The height difference between Lazu spur ( -1251 ) and the Endeavout highest point ( -1310 ) is 59 meters - which is about 6 pixels lower.

The spur peak is just on the horizon at 33 km distance.

BTW, the highest far peak is thus about 130 + 6*9 = 184 +/- 9 meters above the rover's position height.

Aaand - we're back:

about 3 meters closer to Resolution crater.

Now, what was all that about?

Perhaps the goal was to put Opportunity a few meters higher to see further?

IF the rover got, say, two meters higher by climbing the dunes then the horizon would then be 4.9 km vs 3.2 km.

More importantly, the intermediate dunes would be lower than the horizon and would not interfere with peeking at the, er, peaks of Endeavour.

Notice that there seems to be a truly flat horizon in this view.

Horton,
Re.
The height difference between Lazu spur ( -1251 ) and the Endeavout highest point ( -1310 ) is 59 meters - which is about 6 pixels lower.

Shouldn't it be six pixels higher? -1251 > -1310.

Perhaps we are seeing the Iazu spur in the blue forum here.

Er, yes. Those "unnatural" negative numbers fool me all the time...

Here is a Google Mars 3D of Lazu:

The first thing I noticed was that the Lazu plateau is almost as high as the highest Endeavour peaks! Furthermore, the plateau is over 20 degrees wide from the current Opportunity position!!

So where is Lazu in the panorama???

Well, it may be there - but so diffuse that it is invisible! ( Sure would like a crack at the original data - assuming it is not compressed. )

Notice that the sides of the Lazu plateau - including the peaks, are dark - so that they would be less visible than the bright rim peaks of Endeavour.

One feature that puzzled me in the vertical 4x horizon pan was the little "step up" just before whait I thought was the west rim. Perhaps in fact it is the srart of the Lazu Plateau.

I originally thought that all the complexity to the west was caused by nearby dunes - but perhaps not all of it!

I shoourre would like a peek at the original data...

Mars. Damn queer place.

Here is Endeavour and Lazu together in 3D.

Hello brother Hort,

This is a simple question in regard to cross-eyed 3D of witch I am a big fan. It is obvious the image is exaggerated. That makes me wonder what else is exaggerated.

The question is, are all cross eyed 3D’s exaggerated and to what degree. Is it 2:1 or what.
BTW, nice image of the peaks ahead. Glad to be on the bus with you, pass the windex please.

Fred

The vertical relief in the Google Mars 3D is exaggurated by 3X and the eye separation is about 20 km, which means it's like looking at a 1 meter scale model of Mars with 3X vertical scale exagguration about 10 cm from the model.

In fact, all the rover images have exaggurated 3D separation. The Navcam and Pancam cameras are about 300 mm apart vs a normal eye separation of about 65mm - so that has the effect of making things seem like models about 20% of normal size.

See the article How 3-D Works: Mars Revealed by Human-Like Eyes for a more detailed explanation.

Sol 1823-1824 bedrock montage:

Oppy moved about 3.6 meters onto bedrock near Resolution crater that for all the world ( Earth world that is ) looks like cracked and peeling mud in a dried up shallow lake.

Looks like a little science is in store for the weekend.

All; Hort's comment about the cracks is right on.
Google "mud cracks" and you will see examples which are very similar.

sol 1823 L257 of dark dunes west of Resolution crater:

with links to location and 3Ds.

About 21 months ago Oppy was almost silenced by a major dust storm.

But here we see that in many places the fine redish dust has already moved out of the dune troughs onto the crests.

Are constant winds blowing from the east? ( maybe northeast? )

So maybe the dark bands indicate periods of strong wind and few dust storms which move the larger dark particles towards the crest - and the lighter bands are weaker winds and lots of redish dust deposited from dust storms?

Any other ideas?

Re 433/434,
Yes, dried cracked mud - a feature that, due to erosion, would have a fleeting existence on Earth. How has this possible Martian example remained fresh-appearing despite the evidence of erosion all around?
Perhaps we are seeing, the effects of distinct Martian time-epochs. The putative 'dried mud' was formed in a period of great geologic activity, and has been preserved by the present quiescence.
James

re 435:
It could be that the main body of the dune is 'fossilized,' inactive; and, over who knows how many centuries, a surface 'crust' has formed over the motionless dune. The red dust we see is sort of a faint flicker of the past (and perhaps the future, if Mars indeed undergoes huge climatic swings). Meteorite impacts and the rover tracks break through this crust and allow the pliable inner material to be quickly affected by the present vanishingly weak winds.
James

James; Maybe in the future when Mars history is finally unravelled it will consist of periods such as bombardment, glacial , wet, warm dry, windy, etc.

Hey gang, you know my interests usually lie with theories that employ the climates we have seen on Mars rather than any climate that we can imagine. Maybe I'm this way because it makes thinking about Mars a better game for me if the possibilities are restricted in some non-arbitrary way. Anyway, Occam's Razor gives me all the justification I need for trying to use the known processes first.

There is a paradox that Horton referred to in a recent post: a few weeks of dust storm at Gusev completely obscured rover tracks, but these aeolian ripples at Meridiani have impact craters that suggest they haven't been completely rebuilt for a long long time, up to millions of years. I think that the paradox might be solved if we try to use the most obvious, active and proven process on the planet - the dust cycle - to account for the formation of ripples and dunes, and at the same time hypothesize that larger particles never saltate to explain the low rate of erosion and very slow rate of change of ripples and dunes.

I keep coming back to the small changes that have cleaned up the mess after small impacts, returning the disturbed surfaces to a condition similar to the surroundings. I suppose one could argue that even these small changes have required superstorms capable of tearing up the crusted, granule-coated surface layer of soil, but to me nothing about the ripples looks like the aftermath of a violent storm. The soil surfaces look like they've been developing slowly for a long time. I wonder if the copious dust movements combined with very gradually acting soil processes like temperature cycling and the weak water cycle we see today could grow and change these ripples over geologic time. Maybe the superstorms aren't necessary. The hardest fact to account for without superstorms is the presence of the granule-sized particles surfacing the ripples.

sol 1826 ( Mar 14, 2009 ) MI panorama:

with links to 3D and location.

OK, I think I finally see the internal contradiction of the "blueberries as concretions" hypothesis:

IF these cracks are mud cracks then they were formed on the surface of a soft lake bottom when it dried up.

BUT that means that the blueberries on the surface were NOT recently exposed by erosion from a thicker bedrock! A conconcretion can not concrete on a rock surface!

Of course, the counter argument is that since the blueberries are concretions then the cracks are not mud cracks!

BUT if they are not mud cracks - then what mechanism formed them?

Anyone? Anyone?