New Mars Forums

very cool, thanks for finding that. i guess thats the best picture from the ground (so far). Pretty amazing nonetheless...

Its hard to say how big it is since the false color might only be showing part of it. They dont say whether the one that was detected by the weather instruments is the same one pictured when it was farther away, probably not...

Today's http://www.spacedaily.com/news/mars-dus … ml]article on Martian dust devils implies that Pathfinder took some photos! ? ! ?  hmmm? anybody know about this?

I havent spent much time thinking about Venus until i read this thread, ive got to admit im pretty ignorant of basic Venus facts and ask the following newbie questions:

- Does anybody know why venus rotates as slowly as it does? is it just that all the other planets happened to get whacked early on by planetoids which imparted the spin in the first place. A Venus day is 243 Earth-days and, get this, it spins backwards compared to the rest of the planets. a Venus year is 225 earth days. if it didnt spin at all then its day would be 243 days since the full orbit would mimic one day. whats up with that?

- Do the clouds transport heat really quickly around the planet? I'd expect the dark side of venus to get pretty cold, with tons of snow and ice forming as the atmosphere comes streaming in to fill the gradient, the greenhouse effect cant be that efficiently insulating can it? i'd expect the poles to be somewhat protected from the heat as well, are the winds belted like on the gas giants or just swirling around everywhere to make venus pretty uniform temperature? id expect some pretty steep temp gradients in a world like this. its really intriguing.

- where does the present day vulcanism come from? Earth has a moon and plate tectonics to account for most of its vulcanism, Venus has no such "stirring" mechanism, perhaps its just residual heat from formation released during brief and rare "plume" episodes. Is there a magnetic field? if so, it would suggest a lively convecting core, if not, where could the vulcanism-driving heat come from?

jeez, i thought theyd be little more sensible and go check out a few interesting things before relegating the rover to this very uncertain fate!  Scenes http://www.lyle.org/mars/imagery/1N1396 … .html]such as this dont look too steep, but consider the tough time it had trying to get up the even flatter Eagle crater. Im hoping that they may be able to shimmy it out eventually and trek on south to the "etched terrain".

Things to check out first:
- the heatshield impact site, probably only a day's drive away!
- <insert your suggestion here>

excellent article, some interesting highlights:

- 53 kilometers up, where the temperature is a mere 110°F, atmospheric pressure is less than Earth's at sea level, and there is a soup of chemical compounds and plenty of light to facilitate the extraction of energy from the soup.

- Venus likely had oceans in its early years, for a few hundred million to a couple of billion years, back when the sun was 30 percent less hot. If you want to think about the best place, 4 billion years ago, to start life (in) this solar system, it would probably be Venus, then, as the sun grew more intense, carbon dioxide and water vapor trapped the heat, conditions spun out of control, the seas boiled off.

- 700 million years ago a cataclysm occurred: Fissures opened all across the planet's crust, and lava covered everything: a global resurfacing event. To this day, lava flows regularly scorch the planet's surface.

- An organism could get energy from the Venusian atmosphere by a multi-step process which uses sulfur dioxide and carbon monoxide to create formaldehyde, sulfur, and energy. Those reactions would explain the low concentration of carbon monoxide on Venus. Intriguingly, this sulfur nutrient cycle could also provide insight into why some forms of sulfur persist when they should have reacted away long ago—an imbalance, a disequilibrium, that indicates that something is injecting energy into the system.

- anomalous Y- and C-shaped bands in Venus' atmosphere. The structures were first clearly observed 60 to 70 kilometers above the surface of Venus by Mariner 10 during a 1974 flyby, and, for some reason astronomers can't explain, absorb ultraviolet light. microbes in the Venusian clouds may have found a way to photosynthesize using UV light instead of the gentle visible bands found on Earth. If this were true, it would help explain another eccentricity of Venus. While the planet turns at an agonizingly slow pace—a full day/night cycle on Venus takes 243 Earth days, a long time for a life-form to wait for the next dawn—its upper atmosphere swirls round in a mere four Earth days, more than 60 times faster. These UV-absorbing microbes would not only explain the high-altitude bands in the atmosphere, but might explain the atmospheric superrotation as well. UV-absorbing microbes could generate distinct hot and cold fronts. These fronts in turn would create a convection cycle, the intense pressure gradients fueling an extra-speedy atmospheric rotation.

Do you buy into the "concretion" theory?

It seems to make the most sense to me, but I'm not aware of any such places on Earth where you have concretions very much like these especially in such abundance, you'd expect such simple features to abundant on earth since the conditions necessary to create them dont seem that different. Or maybe they do exist on Earth and I just dont know it. Or maybe they dont last very long in watery environments like Earth, even though it required water to create them...

In a more fanciful vein they could also be diagenesis formations in vacancies left by fungi like someone else in this forum was suggesting...

That sounds like it could get pretty expesive fast with all those separate units needing to be developed. I think our existing MER rover design could be reused and sent every launch window and i'd expect the cost to be much lower than the current mission, given that all the hard work has been done already...

It would be interesting to see some sort of itemized cost analysis breakdown of the MER project.
Where was the most money spent?
- The boosters to get them to Mars might perhaps be the most expensive non-reducable cost.
- The R&D costs are already spent, sending slightly modified copies should be relatively cheap
- The mission control costs probably wont change that much regardless of the mission, even if through advanced AI the probes could become self-suficient.
- the raw materials and construction of the probes should be cheaper if we reuse the design and fabrication methods. Very little of the materials and expertise are "off-the-shelf" so its probably pretty expensive on a per-mission basis.

Sending multiple simplified lander packages (such as the NetLanders proposal or those DeepSpace impactors on the ill-fated MPL mission) is probably the cheapest way to get probes into all the very dangerous and varying terrains cheaply because you can afford to produce a lot of simple single-purpose probes that can be sent on one booster and dispatched en-masse to a lot of different landing sites on one mission, but unfortunately they wont be able to rove around without increasing the weight and limiting to one probe per booster, and so the cost goes up signifficantly.

I think the theory was that Callisto hasnt had anything change its terrain since it was formed, so the craters are all built up on top of each other from time immemorable, whereas Europa's surface, being a layer of ice on its sea, is somewhat plastic and is always relatively young, since any crater impacts are assimilated and disappear over a relatively short timescale.

Callisto would be a good place to drill and get good core samples chronicling the last few billion years.

lol
i guess it only makes sense that Martian kids are the only ones in the solar sytem that eat their peas, being green and all... -but of course they dont like those Earth-colored blueberries one bit!

The same thing struck me, and its perplexing that there is even much variation in the surface at all considering this area has had so much time to reach erosional equilibrium. here's a guess:

- The "streambeds": one possibility is that the surface expands/contracts perhaps ice is freezign/thawing under the surface and cracks open up to take a gulp of berries and close up again when conditions change. If this is true, then the rover should be able to dig these areas and find concentrations of berries just under the surface of these streambeds. Either that or the cracks were just the result of dryout and they swalled the berries and have since been filled in by dust. in that case these crack features are extremely old and the net loss of topsoil in this area is not very substantial. However, I assume the loss of topsoils here due to wind erosion to be at least a meter since these deposits were laid down in order to get the concentration of berries that we see littered at the surface as compared to their apparent relatively low concentration in the undersoil. Once the berries reach a certain concentration at the surface this erosion is slowed and any crack formation can proceed onward for ages, unerased by erosion.

- There were also many areas such as "first base" i think it was, that looked like a "divet" with a flat rock at the bottom: maybe there was a layer of bedrock atop all of what we see that was *much" softer. this layer has since almost compeltely eroded away. the areas where we see flat rock surfaces at the same level of the soil might perhaps be the current remnant of this layer or a similarly soft layer that was below it. anywhere there were large chunks of this layer thrown about by cratering and more impacts subsequently partially burried these debris, these chunks would eventually dissolve faster than the current soil line to go below the soil line leaving "divets" that have a flat rock surface at the bottom that is still eroding downward, slowly deepening/widening the divet.

thanks for that link Cindy,

heres an interesting http://www.sundog.clara.co.uk/halo/owmars.htm]article on Martian halos

and here's pics of sun pillars on Earth: an http://www.weather-photography.com/Phot … 1-22]upper pillar and a http://www.meteoros.de/arten/ee09e.htm]lower pillar.

on second thought, frost accumulation and subsequent warm-period meltouts i think would tend not to create such long and consistent channels as the ones we see here (in my off-hand non-hydrologist intuitive judgement at least).

The length and even width of these channels seem to require a *sustained* outflow, even if its sporadic. The idea of warm air dripping and melting the ice pack i think would only create small runs of channels that would concentrate at the alcove of the channel and not go very far before the water gets soaked up or evaporated or frozen. we just wouldnt see the long channels. There must be some other characteristic at work here to explain this mystery...

It cant be an aquifer source since the water source is in the crater rim and is above the surrounding terrain. there can be no water table this high in such a case.

...maybe the water freezes as it goes downhill and is insulated by a blanket of ice so it keeps running, but the probelm is then why would it melt in the first place if its cold enough to freeze it?

...maybe the water drips out and erodes some debris that is responsible for carving the channels as it runs down the slope. but are solid debris capable of forming such features? i thought no, anyone?

...maybe the http://science.nasa.gov/headlines/y2003 … hristensen hypotheis had a run here, in that there was once an insulating blanket of snow/ice over these channels that acted as a greenhouse, the sunlight being absorbed as deep as 15 centimeters and melting the subsurface snow and perhaps once it melts the water picks up some salts from the soil which melts still more ice, accelerating the process. this would allow the melt to run long and consistently enough to form these channels underneath the protective blanket of ice.

in this case, i guess the large part of these channels wouldnt be forming today (althought there might be some erosion due to frost build-up and melt), but they would still be young geologically speaking.