Starship Asterisk*

by **Bad Buoys** » Sat Oct 04, 2008 5:13 am

henk,

The common assumption is that the core is cool because there is no magnetic field. But if it were solely silica heated by uranium I don't believe that would set up a field either. I think you need an iron core for magnetism. And even if it does have a hot, iron core; if it were turning with the planet after all these eons, then again there would be no field. Given its further distance from the sun, Mars would have radiated heat faster than Earth and an iron core, though still hot and molten, could have cooled with the increased viscosity accelerating it's match to the crust's motion.

But the geothermal currents I speak of are in water such as Yellowstone with geysers and hot springs. That doesn't require a hot core per se, but could be water that circulates through local, deep structures which are heated by their own nuclear concentrations. If such a case exists on Mars then liquid water could exist under my assumed ice. Additionally if the ice were thick enough and exerted enough pressure on the lake no heat would be needed given the STP curve and again there would be liquid at depths. Matter of fact, those frost ridges around the edge may even be water coming up around the edge of the ice and freezing.

Fascinating area.

by **bystander** » Thu Oct 02, 2008 5:44 pm

loquin wrote:On an almost entirely unrelated side-note, a meteor impacting the earth is known as a meteorite. What about a meteor impacting another planet?

I don't think it matters which planet you are on.

meteoroid
- A relatively small (sand- to boulder-sized) fragment of debris in a solar system that produces a meteor when it hits the atmosphere.
meteor
- A fast moving streak of light in the night sky caused by the entry of external matter into a planet's atmosphere.
meteorite
- A metallic or stony object or body that is the remains of a meteor.

by **bystander** » Thu Oct 02, 2008 5:43 pm

by **loquin** » Thu Oct 02, 2008 5:27 pm

Given the juxtaposition of the impact crater to the slump, it would appear that meteor impact was responsible for the slump. If this is the case, would you think that the impact shock wave caused the slump directly, or, it was indirectly caused by residual heat from the impact, melting ice at the canyon edge (and thus providing lubrication for 'avalanching.')

Or, possibly, a combination?

On an almost entirely unrelated side-note, a meteor impacting the earth is known as a meteorite. What about a meteor impacting another planet?

by **henk21cm** » Mon Jul 28, 2008 9:21 pm

Bad Buoys wrote:If it is ice, its thickness would be very important. How do Mars' internal temps look? Wouldn't any geothermal heat set up massive currents, such as in our magma, under the frozen surface?

If geothermal currents would (still) exist on Mars, then

plate tectonics must be still present. Marsquakes are AFAIK not reported.
due to differential rotation of the hot (magma) core a global magnetic field would be present. The global magnetic field of Mars is extremely weak or is not existent.

Since neither of these two effects are currently present, any hot core is presently cooled down. That does not exclude that both did not exist in the far past, or in other words: "it might have been possible".

Note that the ripples found in the image of the Chasma apodman kindly brought to our attention do not irrefutably proove the existence of flowing water. Flowing air can generate simular patterns. You could analysis the direction of all flow in the Chasma and see if there is a strange pattern, which excludes aeolian influence. Wind equally as water follow a valey.

It is tempting to compare the cliffs with e.g. Niagara falls, or the Victoria falls. These Arean cliffs can be shaped by dry flows (blowing sand/ash) as well.

by **Bad Buoys** » Mon Jul 28, 2008 7:36 pm

henk21cm wrote:There is one major aspect that breaks the similarity between Mars and earth: the difference between the freezing temperature of water and the respective average surface temperatures. On Mars the average surface temperature is an odd 30 K lower than on earth. Here on earth a decrease of 10 K in average tempreature will trigger an ice age. On Mars the average temperature is thought to be too low to allow for a "thaw age".

The operative word is 'surface'. Considering Mars' lower atmospheric pressure water would remain solid even longer. But we've seen much evidence of water events on Mars with some, such as the Chasma cliffs, being on a massive scale. So the surface must have been much warmer at some period [Apex of Martian Warming with a period of intense volcanic activity?]
And that dark surface layer seen spilling over the cliff's edge may evidence recent, major volcanic activity which, covering the icy surface have aided a temporary thaw; at which time the ash would have settled to the bottom while the surface began a refreeze era.

If it is ice, its thickness would be very important. How do Mars' internal temps look? Wouldn't any geothermal heat set up massive currents, such as in our magma, under the frozen surface? Are there any IR images of the Chasma?

by **henk21cm** » Sun Jul 27, 2008 8:12 pm

Bad Buoys wrote:JPG should never be used for analysis if possible. It is the only compression scheme which actually changes elements in the picture.

I could not agree more. JPEGs DCT ruins the quality of derivatives. I prefer PNG or lossless TIFF. Unfortunately JPG is mostly available on the web. There are exceptions, the Hubble site and the Phoenix site sometimes provide TIFF. Image processing which uses large scale structures -i.e. low frequency correlation- is possible on JPG, if the JPG quality is 75% or better. Such images or rather image sequences allow for the determination of displacements of the order of 1/20 of a pixel, on a ROI of 16x16 pixels.

by **apodman** » Sun Jul 27, 2008 1:34 pm

Bad Buoys wrote:... if you shrink and display the whole image ...

Are you sure the problems are due to jpg compression? Just shrinking the picture causes loss of resolution and "screen door" dithering. When I view this picture full size as intended, it looks pretty good. What you say about loss of information and quality in jpgs, especially after repeated "saves", is true - I just don't see it here.

Like henk21cm, I scrolled around the full size image several times looking unsuccessfully for the location of the APOD photo. But there was a lot of detail (ripples, etc.) to contemplate while I was looking.

by **Bad Buoys** » Sun Jul 27, 2008 6:31 am

That image, especially if you shrink and display the whole image, appears to have been stored and transmitted as a .jpg too many times. It is beginning to appear as shot through a screen door. JPG should never be used for analysis if possible. It is the only compression scheme which actually changes elements in the picture.

by **henk21cm** » Sat Jul 26, 2008 9:06 pm

apodman wrote:Here's a nice picture of Echus Chasma:

Huge image

Indeed, a very interesting image. Unfortunately i can not recognize the area on the apod of 20080723so i can not say whether this image shows the same area and so whether it is characteristic for the Echus Chasma. What i see in huge image, is a pattern filled with ripples. These are characteristic for a sandy bottom in a river, beach or tidal area. The English wikipedia explanation of ripples is very brief, the Dutch explanation is somewhat longer, the German explanation is excellent. I'll translate some of it, since (my assumption) you will not understand German.

Translated from http://de.wikipedia.org/wiki/Rippelmarke

Ripples are formed in a wet sandy environment, where the water velocity exceeds the critical velocity slightly. When the critical velocity for the movement of grains of sand is reached, the grains start to move and cluster in small groups. This creates irregularities in the sedimentary surface, being a few grains thick. This influence the flow in the boundary layer (added: between turbulent flow and laminar flow along the bottom). These irregularities lead to small hills. At the top of these hills the flow lines are closer together and the flow velocity increases. The sedimentary grains are transported upward, on to the top of the hill, at the windward side. Their movement is called saltating: rolling and jumping. The grains accumulate at the top of the hill. If too many grains are deposited at the top, the slope of the hill becomes instable and the grains slide down at the lee side of the hill and form a sediment. These thin layers of grains are called foresets and they form natural slopes of about 30–35°.

This process repeats itself and hill after hill is build, separated and laminated by deposits of intermediary layers of fine sediment, raining out of suspension. This leads to the gradual formation of ripples. At the top of the hills or dunes the flow is split. Part of the flow follows the interface between water and sand. The other part flows further and forms turbulent eddies at the lee side and as a consequence the flow hits the surface of the sediment, where, due to the enhanced turbulence, further erosion is generated, forming and deepening the troughs between the hills. Part of the eroded grains may be transported backwards to the foot of the slope at the lee side and are deposited as a thin layer. The other part is again brought into suspension or is transported to the windward side of the hill.

Ripples are divided into three groups or classes, according to their size:

Ripples, 3-5cm high, wavelength: 4-60 cm
Large ripples, 6cm - 1.5 m high, wavelength: 0.6-30 m
Giant or Mega ripples, 1-8 m high, wavelength larger than 30m.

The large and giant ripples are generated when the particle size of the sand is larger than 0.6-0.7 mm. The giant ripples are stationary, the other migrate or 'walk' . This imageshows a ripple pattern. (end of translation).

When studying the image apodman brought to our attention, two things are remarkable. The first is the fact that the ripple patterns are not parallel. There are parts where the angles differ 90º. If the origin of the ripples is aeolian, like the wind blown sand dunes (Giant ripples) in the Sahara dessert, then on a scale of 50 km the predominant wind would have been blowing from completely different directions, even perpendicular.

The second is the scale of the ripples, or rather their wavelength. I rotated the image by 97º, it is then horizontal. In the mid section the wavelength of the ripples is about 10 m (20 ripples in 234 pixels = 234 m). At the right side the wavelength has decreased to about 6 m (33 ripples in 235 pixels = 235 m). If one considers the flow as mildly turbulent, gravity plays hardly any role. The mere fact that the acceleration of gravity on Mars differs from that on earth, is under the assumption of mildly turbulent flow of no importance, and thus the values as on earth, can be used.

by **apodman** » Sat Jul 26, 2008 4:14 pm

Here's a nice picture of Echus Chasma:

(Link)

redorbit.com wrote:Eroding Material over Flows in Echus Chasma

Image PSP_001430_1815 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on November 15, 2006. The complete image is centered at 1.6 degrees latitude, 278.9 degrees East longitude. The range to the target site was 265.2 km (165.8 miles). At this distance the image scale ranges from 53.1 cm/pixel (with 2 x 2 binning) to 106.1 cm/pixel (with 4 x 4 binning). The image shown here has been map-projected to 50 cm/pixel and north is up. The image was taken at a local Mars time of 3:30 PM and the scene is illuminated from the west with a solar incidence angle of 54 degrees, thus the sun was about 36 degrees above the horizon. At a solar longitude of 136.0 degrees, the season on Mars is Northern Summer. Posted on: 07 Feb, 2007

The quote above describes the linked image and is found at:

(Link)

I duplicated the text here because it's a big web page that may take some people forever to load.

by **apodman** » Sat Jul 26, 2008 3:58 pm

Andy Wade wrote:"I found my thrill,
Onnnnnn blueberry grey..."

Nah, doesn't work.

... apologies

Hematite's grey, dilly dilly, blueberry's blue
Meridiani Planum has spherules for you ...

(further apologies)

by **Andy Wade** » Sat Jul 26, 2008 2:14 pm

apodman wrote:
neufer wrote:
apodman wrote:According to http://www.space.com/scienceastronomy/h ... 40319.html ...

"blueberries" ... are, for the record, gray in color
<<... Yellow, orange and red create a "warm grey". Green, blue, or purple, create a "cool grey". When there is no cast at all, it is referred to as "neutral grey". ...>>
Surely you've heard of "blueberry grey".

"I found my thrill,
Onnnnnn blueberry grey..."

Nah, doesn't work.

(Sincere apologies to Mr Domino)

by **henk21cm** » Sat Jul 26, 2008 10:25 am

Bad Buoys wrote:I think water on Mars is going to be found to be much more prevalent than we've ever thought. And an ice surface would also show craters. That is unless Mars also goes through global warming and cooling cycles much as the Earth such that liquid water occurs every tens of thousand years and thus this surface is remade. Our Earthly cycles are dependent upon precessions of our orbit and pole declination. Atmospherics only modify this base cycle.

As fas as i understand, you base your idea that the Echus Chasma is filled with frozen water on the similarity between ice sheets in the arctic and the surface of the Chasma. I do agree on your remark that a surface of ice can have craters, the craters on the Jovian moon Europa confirm that hypothesis.

About the glacial ages, the inclination of Mars' rotational axis is similar to that of earth, although the excentricity of Mars' orbit is more than that of our planet. Since the distance between Mars and the sun is larger than between earth and the sun, Mars' precession period is considerably longer than for earth: 170 kyear (25.8 kyear for earth). Glacial cycles -if any- will last longer.

Next the influence of the sun on Mars is less than on earth. As a result the temperatures at Mars are considerbly lower than on earth. Moreover the climatological influence, which in your vision is of less importance, is according to paleogeologists, e.g. Oerlemans, a major factor. The much debated and cursed 'greenhouse effect' is the key player in the initiation and ending of glacial periods. Without the greenhouse effect the temperature on earth would have been considerably lower, only allowing (the currently known) vegetation in the tropics.

Before us humans started to use fossil fuels for our work (we have used wood and coal for heating purposes for ages), the amount of greenhouse gases was predominantly controled by vulcanic activity. About 0.5 Gyear and 1 Gyear ago our planet was completely frozen: commonly known as "snowball earth". Since the feedback mechanism: absorption of CO2 by the tiny creatures (like plankton and foraminifera) in the ocean was no longer possible or substantially hampered, while volcanoes continued spewing CO2 gas, the level of CO2 rose to an astonishing value: between 1 and 10% (compared to the current 0.035%). That ended the snowball earth periods. Similarly the greenhouse mechanism is thought to be co-responsible for the ending of the latest glacial periods, about 100 kyears ago.

On Mars some volcanoes have been identified, notably Olympus Mons. The smoking gun of recent volcanic activity is however lacking, nor did i read news about recent volcanic activity on Mars, in contrast to Io. A reasonable assumption might be that volcanic activity on Mars is low, or the lads at NASA have been picking their noses in stead of analyzing images.

So far, most ingredients for glacial cycles are present, although not all active. Your idea might be feasible so far. There is one major aspect that breaks the similarity between Mars and earth: the difference between the freezing temperature of water and the respective average surface temperatures. On Mars the average surface temperature is an odd 30 K lower than on earth. Here on earth a decrease of 10 K in average tempreature will trigger an ice age. On Mars the average temperature is thought to be too low to allow for a "thaw age".

I do agree with you that high counts of impact craters in the bottom of the Echus Chasma are lacking, which suggests a recent (in geologicals terms so to say) origin.

by **Bad Buoys** » Fri Jul 25, 2008 11:46 pm

Nope. I feel that the chasma is filled with water even more. It may be covered deeper with insulating soil than that which we saw under the lander but look at that surface. Those look like leads which have opened at some time in the past and refrozen; just as they do in the Arctic. And with experts thinking the cliffs were formed by water, it makes even more sense for the valley to be full of the same. At minimum there must be a deep sedimentary layer from so much water having carved those cliffs in the past. I think water on Mars is going to be found to be much more prevalent than we've ever thought.

And an ice surface would also show craters. That is unless Mars also goes through global warming and cooling cycles much as the Earth such that liquid water occurs every tens of thousand years and thus this surface is remade. Our Earthly cycles are dependent upon precessions of our orbit and pole declination. Atmospherics only modify this base cycle. Mars and the other planets are probably similar though we haven't even started any measurement to track these unpopulated planets. After all, look how little we know of our own.

by **ta152h0** » Thu Jul 24, 2008 11:54 pm

I would love to see some guys in a UFO bring their photo album. Before you flame me, I am a regular guy having some fun here, not drunk. And no, i don't believe those things, until I see one, and photograph it clearly, not fuzzy. I saw a movie ( in outer limits I think ) that starred an airplane going thru a time continuun, trying to find LaGuardia airport, and intead circling a jungle replete with dinosaurs.

by **henk21cm** » Thu Jul 24, 2008 9:07 pm

NoelC wrote:Why is it a given that the base of the chasm was covered in Lava?

Couldn't the flat bottom be explained by millions (billions?) of years of dust accumulation?

Good question. When you compare the plateau with the chasma, you will notice little or no impact craters. That suggests a relative young surface. Even fine dust will show impact craters, although influence of wind will erode an maybe erase those craters partly. Storms might even blow the chasma clean from dust. You might remember vast dust storms in the early 70-ties, compromising the explorations of Mars.

The absense of impact craters does neither proove nor reject Bretts remark that the bottom of the chasma was filled by the top layer, e.g. when a caldeira collapsed. The rilles at the top of the cliffs suggest flow of material, either dry or wet. The pattern of the darker material to the right of the central crater at the plateau suggests either a collapse of the plateau or a slow gradual flow of the dark material.

A lot of suggests: "It could have happened". We need more certainty. How? The caldeira at Yellowstone national park suffered a huge collaps, an odd 600 kyears ago. Vegetation will hide some of its key features. Maybe someone of us has (geological) images of the results of that collaps, showing similar symptoms.

by **MSpanke** » Thu Jul 24, 2008 4:54 am

The parallel chasms can also be explained by a deep underground crack in the crust. What caused the crust to seperate can be explained by a number of geological acivities. As sand seeps into the crack the avalanches on the cliff sides widen the trench. No water is needed to explain the larger feature here.

by **NoelC** » Thu Jul 24, 2008 4:41 am

Why is it a given that the base of the chasm was covered in Lava?

Couldn't the flat bottom be explained by millions (billions?) of years of dust accumulation?

-Noel

by **Baggins** » Thu Jul 24, 2008 3:52 am

Hi all,

I've been collecting APODs for about a year now but did not know that there was a community forum to discuss these kinds of things and comment about the APODs. I'm not scientifically educated only interested in our solar system and universe.

With that said, the general concensus by scientists and even the caption suggests that this chasm once contained a vast amount of water and/or lava. By the looks of it to me............it seems to be more of a huge crevice opening up beneath the top layers of soil and all the material just dropping vertically down into the hole. There doesn't seem to be the lateral movement of the material down the trench that water typically does to soil in liquid. The different color material (whether red or blueish) on the surface looks like it just fell vertically and stayed there.

Am I looking at this correctly or should I just stick to what I know. Some pictures that I've seen of the closeups of the surface of Mars seem to show water weathered rock but I honestly don't see anything "wet" happening in this chasm recently or eons ago.

Thanks for the interesting discussion. I'll be back!

Regards,

Brett Bagley

by **henk21cm** » Wed Jul 23, 2008 9:18 pm

iamlucky13 wrote:On that side [Phoenix] note, they're still having trouble with the oven doors on the TEGA instrument.

Yes, read about that on the JPL site. These scraping tests gave me the impression that the acquisition of a decent sample was a lot harder than anticipated, which is strange, since NASA will not likely send a lander to Mars without a decent test with frozen soil, if such is anticipated or at least the joyful expectation of the scientists involved.

iamlucky13 wrote:What program do you use for all those color composite manipulations you do?

That is called Matlab. It is a kind of programming language specially meant for visualization of data, images included. For clarity, the program i wrote is listed below in the code section. It is very straight forward.

Code: Select all

function chasm
orig_image = imread('..\images\chasm.jpg'); % Read the image

new_image = orig_image; % Copy the image
%	RGB numbering
r = 1;
g = 2;
b = 3;

%	Exchange red and blue
new_image(:,:, r) = orig_image(:,:,b);
new_image(:,:, b) = orig_image(:,:,r);

figure(1);
image(new_image);   % Visualize it

%	Original image
figure(2);
image(orig_image);

%	Rotate RGB
new_image(:,:,r) = orig_image(:,:,g);
new_image(:,:,g) = orig_image(:,:,b);
new_image(:,:,b) = orig_image(:,:,r);
figure(3);
image(new_image);

%	Permutate BG
new_image(:,:,r) = orig_image(:,:,r);
new_image(:,:,g) = orig_image(:,:,b);
new_image(:,:,b) = orig_image(:,:,g);
figure(4);
image(new_image);


%	Use the blue image    
new_image(:,:,r) = orig_image(:,:,b)-30;	% darker
new_image(:,:,g) = orig_image(:,:,r)-30;	% darker
new_image(:,:,b) = orig_image(:,:,g)/3 + orig_image(:,:,r)/3; % blue1/3 

figure(8);
image(new_image);

%	Grayscale image
figure(7);
image(orig_image(:,:,3));
colormap(gray(256));

%	RG as the Blue image, B less blue
new_image(:,:,r) = orig_image(:,:,b);
new_image(:,:,g) = orig_image(:,:,b);
new_image(:,:,b) = orig_image(:,:,b)-20;
figure(9);
image(new_image);

return;

From what Art Neuendorfer has reported, maybe todays APOD image we are looking at is a real (false) colour image, whereas the former images of Mars are 'heated' grayscale images, with a flavour of brownish orange, which makes us think it is a colour image. That could explain why my images 8 and 9 looked more 'natural' than the other ones.

by **ta152h0** » Wed Jul 23, 2008 9:04 pm

maybe MARS simply shrunk due to a long ago cooling event and this is the location for a weak structure ?

by **apodman** » Wed Jul 23, 2008 8:42 pm

neufer wrote:
apodman wrote:According to http://www.space.com/scienceastronomy/h ... 40319.html ...

"blueberries" ... are, for the record, gray in color
<<... Yellow, orange and red create a "warm grey". Green, blue, or purple, create a "cool grey". When there is no cast at all, it is referred to as "neutral grey". ...>>

Surely you've heard of "blueberry grey".

by **neufer** » Wed Jul 23, 2008 7:39 pm

apodman wrote:According to http://www.space.com/scienceastronomy/h ... 40319.html ...

"blueberries" ... are, for the record, gray in color

<<In the RGB color model used by computer displays, it is created by mixing equal amounts of red, green, and blue light. Images which consist wholly of neutral colors are called monochrome, black-and-white or greyscale. Most grey pigments have a cool or warm cast to them, as the human eye can detect even a minute amount of saturation. Yellow, orange and red create a "warm grey". Green, blue, or purple, create a "cool grey". When there is no cast at all, it is referred to as "neutral grey".>>
http://en.wikipedia.org/wiki/Gray_(color)

by **henk21cm** » Wed Jul 23, 2008 7:06 pm

emc wrote:I found this at ESA... more images of Echus Chasma...

The crater that is prominently visible in todays APOD is not easy to find in the ESA image. The coordinates of three craters in the JPG from ESA are:

The main crater is right on the lower edge: (H, V) = (260, 1495). It is hardly visible. Todays Apod image has been snapped further to the East (below).
The eye of emc's whale: (H,V) = (480, 1360), about 10 km to the NorthWest. (North is to the right)
The crater with the Northern white radial stripes is at (H,V) = (580, 970), about 15 km to the West (distance to the eye)

The area in southern direction (left) has indeed a darker shade of brown than the area to the north. Judging from the shadow, there is a ridge or wall, which separates the dark brown from the light brown. Sorry if it is not brown, colour recognition is not my strongest asset.

Starship Asterisk*

High Cliffs Surrounding Echus Chasma on Mars (23 Jul 2008)

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Re: Ice or soil? That's the question

Re: Ice or soil? That's the question

JPG: no thank you, PNG: yes please!

Ripples

Ice or soil? That's the question

Chasm

Find where the crater is.