Astronomy

Is there permanent dry ice on Mars?

Is there permanent dry ice on Mars?


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Are there any places featuring permanent dry ice (carbon dioxide ice) on Mars?

Is there dry ice at the poles?


Yes.

The Southern polar ice cap has a covering of $mathrm{CO_2}$ about 8 m thick that doesn't completely disappear in summer. It remains in "pits" of up to about 1km in diameter. The thinner dry ice layer in the North sublimes completely into the atmosphere in summer. [source]


How did Mars get its polar ice caps?

It’s a fairly dry and dusty world, so how did Mars get its frosty poles?

The existence of the Red Planet’s poles support the theory that Mars once had a wet and warm history. Image Credit: NASA

The average temperature on Mars is around -60 degrees Celsius (-76 degrees Fahrenheit) and can get even colder at the poles. This gives Mars permanent polar ice caps consisting primarily of water ice.

Like on Earth, there is seasonal variation on Mars which causes annual changes of the Martian ice caps. During the Red Planet’s winter, a pole will exist in extended periods of darkness. This makes it cold enough to allow layers of carbon dioxide to freeze, building up the ice caps. During the summer this carbon dioxide ice sublimes and the polar ice cap shrinks. The existence of these poles support the theory that Mars once had a wet and warm history on its surface.

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Gullies on Mars sculpted by dry ice rather than liquid water?

Examples of Martian gullies. Until recently they were thought to have been sculpted by flowing liquid water, but they may result from defrosting dry ice processes at the end of winter. Above, gullies on dunes in Russel Crater (54.3°S, 12.9°E) are partially covered by CO2 ice. Below, sinous gullies in a crater in Newton Basin (41°S, 202°E). Image credits: NASA/JPL/University of Arizona. Since 2000, the cameras in orbit around Mars have transmitted numerous images of small valleys cut into slopes, similar in shape to gullies formed by flowing water on Earth. The gullies seem less than a few million years old &mdash and sometimes less than a few years old. This suggested that significant volumes of liquid water may form on Mars today.

This scenario has recently been questioned by frequent monitoring of the Martian surface by the HiRISE camera aboard NASA Mars Reconnaissance Orbiter. This revealed that gully formation is ongoing on present-day Mars, at seasons when the surface environment of Mars is much too cold for liquid water to flow. However, the observed gully activity seems to occur when CO2 ice (condensed from the atmosphere during winter) is defrosting on the Martian surface. Can the two phenomena be related? If so, how could a thin seasonal dry ice layer deposited above the regolith trigger the formation of decametre-scale debris flows behaving as if they were lubricated by liquid?

To better understand the interaction between the CO2 frost and the surface materials, Cédric Pilorget, researcher at the Institut d’Astrophysique Spatiale (CNRS/Université Paris-Sud) and François Forget, CNRS scientist at the Laboratoire de météorologie dynamique (UPMC/ ENS Paris /CNRS/Ecole polytechnique) have developed a numerical model to simulate the environment on a slope. From the underlying regolith to the atmosphere above, the model takes into account the energy exchanges due to radiation, thermal conduction or induced by CO2 phase changes.

A key characteristic of the locations where CO2 ice condenses is that there is always a permafrost layer composed of water ice-cemented grains a few centimetres below the surface. Thus, when CO2 condenses on the surface in winter, the air present in the porous near-subsurface is trapped between the impermeable permafrost layer below and the CO2 ice layer above. How debris-flows looking like water-sculpted gullies can be triggered by dry ice processes on Martian slopes. Image credit: Cédric Pilorget, François Forget, et al. In such conditions, the numerical simulations carried out by Cedric Pilorget and François Forget have revealed a surprising behaviour. At the end of winter or in spring, the solar light penetrates into the translucent CO2 ice layer and heats it from below. The CO2 ice does not melt, but “sublimes” (it passes directly to the vapour state). This gas diffuses down through the near surface porous soil. A fraction can recondense there, while the rest of the gas accumulates in the porous volume. This can considerably increase the near-subsurface pressure, up to several times the atmospheric pressure value. The CO2 ice layer eventually ruptures, inducing a violent decompression. Within a few seconds and up to a few minutes, several cubic meters of gas (and possibly several tens of cubic meters around the vents) have then to flow up through the soil. Such fluxes are able to destabilise the soil grains to form granular flows. Moreover, they can also fluidise the avalanche which may behave like a viscous fluid.

Although this process has no exact analogue on Earth, it can be related to terrestrial pyroclastic flows, which are gas–particle mixtures generated during volcanic eruptions. Such flows can travel several kilometres even on very moderate slopes. They can transport metre-sized rocks, and have been found to exhibit side “levees” which are very similar in size to the ones observed on the side of Mars’ gullies. As on Earth, where debris flows triggered by rain or melting snow are rare events, it is likely that an uncommon combination of conditions are required to destabilise the slopes.

The model created by the two French scientists can also explain why Mars’s gullies are located mostly in the 30°–60° latitude range &mdash with a few spots at higher latitudes &mdash and why most gullies are found on poleward facing slopes between 30° and 45° latitude. The CO2 induced pressurisation and fluidisation is predicted to occur precisely where gullies are observed.

All these findings suggest that the solar heating of the seasonal dry ice deposited in winter on Martian slopes is at the origin of a fraction &mdash and possibly all &mdash of the gullies observed on planet Mars. This process has no terrestrial analogues and do not require liquid water. According to this study, the gullies area may not provide potential habitable environments in Mars’ recent past.


Signs of Spring on Mars

A Martian orbiter has spotted seasonal footprints ofspring creeping up on the red planet.

Seasonal polar caps formed from carbon dioxide have begunvaporizing or changing directly from solid ice to gas, and have kicked off achain of events detected by NASA's MarsReconnaissance Orbiter (MRO).

"Spring on Mars is quite different from spring onEarth because Mars has not just permanent ice caps, but also seasonal polarcaps of carbon dioxide, familiar to us on Earth as dry ice," said CandiceHansen-Koharcheck, an MRO scientist at the NASA Jet Propulsion Laboratory inPasadena, Calif.

Ice caps form each Martian winter as carbon dioxidechanges directly to frost and builds dry ice layers more than three feet thick.The arrival of warmer spring temperatures thaws the solid carbon dioxide andthins the ice cap from both top and bottom.

The carbon dioxide gas beneaththe ice cap often flows in the same places each year, eventually creatingchannels or troughs in the planet's surface. MRO has spotted many such spiderynetworks of cracks that remain even after the ice caps have vanished.

Pressure from the newly thawed gas also builds up beneaththe thinning ice cap, which can lead to puffs of escaping gas and dust wherethe ice cap has cracked.

"What happens on Mars, we think, is that as theseasonal ice cap thins from the bottom, gas underneath the cap builds uppressure," Hansen-Koharcheck said. "And where gas under the ice findsa weak spot or a crack, it will flow out of the opening, often carrying alittle dust from the surface below."

That dust ends up swirling about in the wind beforesettling in fan-like or starburst patterns, pointingin the direction of the prevailing wind at the time. Each patternrepresents a jet of gas that was active at one time.

The Martian process differs from springtime thaws onEarth, where frozen water melts from solid to liquid and becomes runoff. Scientistshave yet to spot flowing water on the Martian surface, though some suspectliquids may lie beneath the surface or even insidea volcano.


#55 2021-03-31 08:30:55

Re: Dry ice pneumatic tool

Google found this discussion when I asked about a stationary boiler that runs on propane

Re: Small Propane cylinder boiler
Quote
Post  by Fender » Sun Dec 05, 2010 9:16 pm

Timothy,
A propane tank is too thin to make a proper boiler out of. It is also likely made of the wrong alloy steel. These tanks are not subject to the heat and corrosion a boiler experiences. A boiler will have a "corrosion allowance", meaning that even if the boiler shell loses some of its thickness, it will still be safe to operate. Also, the boiler steel must be very ductile so that it can flex and take the repeated thermal cycles without cracking. Building a boiler is a lot of work, and you need to use the right materials from the start.
If your engine is truly small, a copper boiler may be a good way to go.

This discussion reminded me that Dayton Engineer is quite knowledgeable about gas powered engines ca 1870-1920, and his fund of knowledge includes some overlap with steam boiler driven engines. 

Edit#1:Here's a view of the top end of the field .

I deduce from the ongoing success/sales of this company there is a significant demand for steam power on Earth in 2021.

India is still (to the best of my knowledge) still running steam equipment on many of their railroads.

Edit#2: There is a YouTube channel set up by MyFordBoy to offer instruction on shop practice

There is a set of four videos that shows how to make a small copper boiler to drive a model steam engine.

The process involved use of a lathe, hacksaw, scribe, hammer, file, torch (for annealing), drill press and various other tools.


Ancient Lakes

The rovers (Spirit, Opportunity, and Curiosity) that have operated on the surface of Mars have been used to hunt for additional evidence of water. They could not reach the most interesting sites, such as the gullies, which are located on steep slopes. Instead, they explored sites that might be dried-out lake beds, dating back to a time when the climate on Mars was warmer and the atmosphere thicker—allowing water to be liquid on the surface.

Spirit was specifically targeted to explore what looked like an ancient lake-bed in Gusev crater, with an outflow channel emptying into it. However, when the spacecraft landed, it found that the former lakebed had been covered by thin lava flows, blocking the rover from access to the sedimentary rocks it had hoped to find. However, Opportunity had better luck. Peering at the walls of a small crater, it detected layered sedimentary rock. These rocks contained chemical evidence of evaporation, suggesting there had been a shallow salty lake in that location. In these sedimentary rocks were also small spheres that were rich in the mineral hematite, which forms only in watery environments. Apparently this very large basin had once been underwater.

The Curiosity rover landed inside Gale crater, where photos taken from orbit also suggested past water erosion. It discovered numerous sedimentary rocks, some in the form of mudstones from an ancient lakebed it also found indications of rocks formed by the action of shallow water at the time the sediment formed (Figure 10.30).

Figure 10.30. (a) This scene, photographed by the Curiosity rover, shows an ancient lakebed of cracked mudstones. (b) Geologists working with the Curiosity rover interpret this image of cross-bedded sandstone in Gale crater as evidence of liquid water passing over a loose bed of sediment at the time this rock formed. (credit a: modification of work by NASA/JPL-Caltech/MSSS credit b: modification of work by NASA/JPL-Caltech/MSSS)

People like human faces. We humans have developed great skill in recognizing people and interpreting facial expressions. We also have a tendency to see faces in many natural formations, from clouds to the man in the Moon. One of the curiosities that emerged from the Viking orbiters’ global mapping of Mars was the discovery of a strangely shaped mesa in the Cydonia region that resembled a human face. Despite later rumors of a cover-up, the “Face on Mars” was, in fact, recognized by Viking scientists and included in one of the early mission press releases. At the low resolution and oblique lighting under which the Viking image was obtained, the mile-wide mesa had something of a Sphinx-like appearance.

Unfortunately, a small band of individuals decided that this formation was an artificial, carved sculpture of a human face placed on Mars by an ancient civilization that thrived there hundreds of thousands of years ago. A band of “true believers” grew around the face and tried to deduce the nature of the “sculptors” who made it. This group also linked the face to a variety of other pseudoscientific phenomena such as crop circles (patterns in fields of grain, mostly in Britain, now known to be the work of pranksters).

Members of this group accused NASA of covering up evidence of intelligent life on Mars, and they received a great deal of help in publicizing their perspective from tabloid media. Some of the believers picketed the Jet Propulsion Laboratory at the time of the failure of the Mars Observer spacecraft, circulating stories that the “failure” of the Mars Observer was itself a fake, and that its true (secret) mission was to photograph the face.

The high-resolution Mars Observer camera (MOC) was reflown on the Mars Global Surveyor mission, which arrived at Mars in 1997. On April 5, 1998, in Orbit 220, the MOC obtained an oblique image of the face at a resolution of 4 meters per pixel, a factor-of-10 improvement in resolution over the Viking image. Another image in 2001 had even higher resolution. Immediately released by NASA, the new images showed a low mesa-like hill cut crossways by several roughly linear ridges and depressions, which were misidentified in the 1976 photo as the eyes and mouth of a face. Only with an enormous dose of imagination can any resemblance to a face be seen in the new images, demonstrating how dramatically our interpretation of geology can change with large improvements in resolution. The original and the higher resolution images can be seen in Figure 10.31.

Figure 10.31. The so-called “Face on Mars” is seen (a) in low resolution from Viking (the “face” is in the upper part of the picture) and (b) with 20 times better resolution from the Mars Global Surveyor. (credit a: modification of work NASA/JPL credit b: modification of work by NASA/JPL/MSSS)

After 20 years of promoting pseudoscientific interpretations and various conspiracy theories, can the “Face on Mars” believers now accept reality? Unfortunately, it does not seem so. They have accused NASA of faking the new picture. They also suggest that the secret mission of the Mars Observer included a nuclear bomb used to destroy the face before it could be photographed in greater detail by the Mars Global Surveyor.

Space scientists find these suggestions incredible. NASA is spending increasing sums for research on life in the universe, and a major objective of current and upcoming Mars missions is to search for evidence of past microbial life on Mars. Conclusive evidence of extraterrestrial life would be one of the great discoveries of science and incidentally might well lead to increased funding for NASA. The idea that NASA or other government agencies would (or could) mount a conspiracy to suppress such welcome evidence is truly bizarre.

Alas, the “Face on Mars” story is only one example of a whole series of conspiracy theories that are kept before the public by dedicated believers, by people out to make a fast buck, and by irresponsible media attention. Others include the “urban legend” that the Air Force has the bodies of extraterrestrials at a secret base, the widely circulated report that UFOs crashed near Roswell, New Mexico (actually it was a balloon carrying scientific instruments to find evidence of Soviet nuclear tests), or the notion that alien astronauts helped build the Egyptian pyramids and many other ancient monuments because our ancestors were too stupid to do it alone.

In response to the increase in publicity given to these “fiction science” ideas, a group of scientists, educators, scholars, and magicians (who know a good hoax when they see one) have formed the Committee for Skeptical Inquiry. Two of the original authors of your book are active on the committee. For more information about its work delving into the rational explanations for paranormal claims, see their excellent magazine, The Skeptical Inquirer, or check out their website at www.csicop.org/.


Mars, like the earth, chills or heats up based on its relation to the sun. It too has seasons, growing colder in winter and warmer in summer. As mentioned, Mars also has ice caps, besides gullies that appear to have been created by water. The way the gullies are shaped is a lot like those on earth formed by rivers and floods. Dry ice, though, may be the cause.

As for the ice caps, a solid swathe of ice forms them. In the winter, dry ice rapidly collects over the poles and over the surface of the planet. Scientists at NASA also discovered in 2018 that snowfall exists on Mars, falling only at night but mainly sublimating before it hit the surface. In the spring, the dry ice remaining on the surface from the winter sublimates, tossing up the red sand dunes to unearth (un-mars?) the darker-colored sands beneath.


Dry ice on Mars may help colonize red planet, research says

A new way of generating energy could potentially power human colonies on Mars, a new study claims. This is thanks to nothing more than dry ice, which is abundant on the red planet, according to recent research.

Since man wants to start colonizing the place within the next few decades, we need all the help we can get. This could also have profound implications on planning. For now, we’re only considering one-way trips, owing to huge energy demands. This could change.

The gist of the new energy theory proposed by a team of researchers from Northumbria, Edinburgh and Newcastle universities lies in carbon dioxide. Scientists say the principle is no different to what happens when you observe the effect of a drop of water on a scalding-hot stove. The energy generated by that process, which agitates the drop of water, is similar to the pioneering new approach, outlined in the journal Nature Communications.

Scientists call the principle at the heart of this process the Leidenfrost effect. This happens when a liquid comes into near contact with a much hotter surface. And it fits perfectly with the example of carbon dioxide – or dry ice.

In the case of carbon dioxide, blocks of the material are able to levitate above a hot surface because of protection given by the layer of evaporated gas. Researchers propose harnessing the power of that gas to power engines – the first time anyone has proposed to use the Leidenfrost effect to generate energy.

“By placing water droplets and small blocks of dry ice on top of hot, turbine-like surfaces, we have used the Leidenfrost effect to create rotational motion. The turbines channel the released vapor, whose flow in turn drives the levitating surface above to rotate,” says Dr. Rodrigo Ledesma-Aguilar, co-author on the research in a related article.

If scientists manage to harvest this energy, there is no reason why trips to Mars should be one-way. In 2013, science discovered there were massive deposits of dry ice on Mars.

The gullies observed on Mars were a topic of debate, as scientists searched for evidence of the water that once created them. But recent studies are overwhelmingly in favor of carbon dioxide.

The experts are not quite sure how exactly frozen carbon dioxide can cause gullies to form. This phenomenon isn’t encountered naturally on Earth, so there was nothing to compare the processes on Mars with. One possible mechanism is that soil sublimates frozen carbon dioxide, which allows it to flow. Another is the buildup of frozen gas, which causes steep slopes to slide.

And according to Rodrigo Ledesma-Aguilar’s in the university’s press release:“Carbon dioxide plays a similar role on Mars as water does on Earth. It is a widely available resource, which undergoes cyclic phase changes under the natural Martian temperature variations.”

“Perhaps future power stations on Mars will exploit such a resource to harvest energy as dry-ice blocks evaporate, or to channel the chemical energy extracted from other carbon-based sources, such as methane gas,” he also said, adding that “one thing is certain: our future on other planets depends on our ability to adapt our knowledge to the constraints imposed by strange worlds, and to devise creative ways to exploit natural resources that do not naturally occur here on Earth.”

Harvesting the results, according to the researchers, will be humanity’s biggest challenge in the 21st century.

An engine based on the Leidenfrost effect is different to the steam-based ones we’re used to here on Earth. “The high-pressure vapor layer creates freely rotating rotors whose energy is converted into power without the need of a bearing, thus conferring the new engine with low-friction properties,” says Dr Gary Well, another co-author.

“This is the starting point of an exciting avenue of research in smart materials engineering. In the future, Leidenfrost-based devices could find applications in wide ranging fields, spanning from frictionless transport to outer space exploration,” explains Professor Glen McHale, executive dean for Engineering and Environment at the university.

NASA currently has two robotic rovers operating on Mars, and three orbiting probes. The latest probe arrived in the Martian orbit in September 2014, on a mission to study the planet’s upper atmosphere. The agency is not planning any manned exploration missions until the 2030s at the earliest.


Astronomy Picture of the Day for Sept. 26 – Dry Ice On Mars

Discover the cosmos!Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

Dry Ice Pits on Mars
Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA

Explanation: Part of Mars is defrosting. Around the South Pole of Mars, toward the end of every Martian summer, the warm weather causes a section of the vast carbon-dioxide ice cap to evaporate. Pits begin to appear and expand where the carbon dioxide dry ice sublimates directly into gas. These ice sheet pits may appear to be lined with gold, but the precise composition of the dust that highlights the pit walls actually remains unknown. The circular depressions toward the image center measure about 60 meters across. The HiRISE camera aboard the Mars-orbiting Mars Reconnaissance Orbiter captured the above image in late July. In the next few months, as Mars continues its journey around the Sun, colder seasons will prevail, and the thin air will turn chilly enough not only to stop the defrosting but once again freeze out more layers of solid carbon dioxide.


Life on Mars?

Early Speculations
Even after the rejection of the idea of Martian canals, many scientists thought Mars might harbor simple forms of life. Prior to the 1965 Mariner mission the atmospheric pressure was thought to be 1/10th that of Earth rather than the actual 1/100th. Color changes on a seasonal timetable suggested the possibility of plant life that grew and subsided with the seasons. These color changes were later shown to be due to the deposition and removal of dust on the surface.

Viking Experiments
One of the primary objectives of the Viking missions was to search for signs of life. Three different search techniques were used to look for microorganisms, each based on a different chemical indicator of the presence of life. (1) Gas-Exchange Experiment (2) Labeled-Release Experiment (3) Pyrolitic-Release Experiment

Viking Results
Initially all three experiments seemed to show strong positive results. However, the activity was initially high and declined with time, which would be unusual for a growing lifeform. Also, the onboard gas chromatograph and mass spectrometer found no organic materials in the soil. The explanation turned out to be that the soil was more chemically active than terrestrial soil due to its exposure to UV radiation. The thin Martian atmosphere was unable to block UV radiation from the surface. This radiation breaks down carbon-containing molecules, thus sterilizing the soil, and also produces superoxides in the soil which are highly reactive with water, or even the testing container.