Mars has two permanent polar ice caps. During a pole's winter, it lies in continuous darkness, chilling the surface and causing the deposition of 25–30% of the atmosphere into slabs of CO ice (dry ice). When the poles are again exposed to sunlight, the frozen CO sublimes. These seasonal actions transport large amounts of dust and water vapor, giving rise to Earth-like frost and large cirrus clouds. Clouds of water-ice were photographed by the "Opportunity" rover in 2004. The caps at both poles consist primarily (70%) of water ice. Frozen carbon dioxide accumulates as a comparatively thin layer about one metre thick on the north cap in the northern winter only, whereas the south cap has a permanent dry ice cover about eight metres thick.
Polar caps
Mars
Mars | Polar caps
The caps at both poles consist primarily (70%) of water ice; frozen carbon dioxide layer is in northern cap and south cap has a permanent dry ice cover Frozen carbon dioxide accumulates as a comparatively thin layer about one metre thick on the north cap in the northern winter only, whereas the south cap has a permanent dry ice cover about eight metres thick. The caps at both poles consist primarily (70%) of water ice. The caps at both poles consist primarily of water ice.
what is the location of mars in the solar system
user
Mars is the fourth planet from the Sun
assistant
is it known by any other names?
user
Yes, "Red Planet" in English
assistant
are there any volcanoes there?
user
Yes, Olympus Mons
assistant
who named it?
user
Named after observations made by Mariner 9
assistant
what was that?
user
From Nix Olympica; a volcano. Astronomers adopted the name "Olympus Mons" for the albedo feature known as Nix Olympica
assistant
was that a spaceship that made the observations?
user
It was a robotic space probe
assistant
have any other space probes landed on the planet discussed above?
user
Yes, "Mariner 4", "Viking 1", etc
assistant
did the first one land on the planet or was it just a fly by?
user
A flyby mode
assistant
how did it meet its end?
user
The gas supply in the attitude control system was exhausted, and between December 10 and 11, a total of 83 micrometeoroid hits perturbation of the spacecraft's attitude and degradation of the signal strength
assistant
what is found at the polar regions of the planet?
user
In other words, areas with more of the rougher frost are warmer. Research, published in April 2011, described a large deposit of frozen carbon dioxide near the south pole. Most of this deposit probably enters Mars' atmosphere when the planet's tilt increases. When this occurs, the atmosphere thickens, winds get stronger, and larger areas on the surface can support liquid water. A large field of eskers exist around the south pole, called the Dorsa Argentea Formation, it is believed to be the remains of a giant ice sheet. This large polar ice sheet is believed to have covered about 1.5 million square kilometers.
Martian polar ice caps | South polar cap
Chasma Australe, a major valley, cuts across the layered deposits in the South Polar cap. On the 90 E side, the deposits rest on a major basin, called Prometheus. Some of the layers in the south pole also show polygonal fracturing in the form of rectangles. It is thought that the fractures were caused by the expansion and contraction of water ice below the surface.
Martian polar ice caps | Layers
Together, the volume of ice present in the Martian north and south polar ice caps is similar to that of the Greenland ice sheet. An even larger ice sheet on south polar region sheet is suspected to have retreated in ancient times (Hesperian period), that may have contained 20 million km of water ice, which is equivalent to a layer 137 m deep over the entire planet. Both polar caps reveal abundant internal layers of ice and dust when examined with images of the spiral-shaped troughs that cut through their volume, and the subsurface radar measurements showed that these layers extend continuously across the ice sheets.
Water on Mars | Polar ice caps
The polar regions, also called the frigid zones, of Earth are the regions of the planet that surround its geographical poles (the North and South Poles), lying within the polar circles. These high latitudes are dominated by floating sea ice covering much of the Arctic ocean in the north, and by the Antarctic ice sheet on the continent of Antarctica in the South.
Polar regions of Earth | Introduction
That area is twice the area of the state of Texas. In July 2018 ESA discovered indications of liquid salt water buried under layers of ice and dust by analyzing the reflection of radar pulses generated by Mars Express.
Martian polar ice caps | South polar cap
Research based on slight changes in the orbits of spacecraft around Mars over 16 years found that each winter, approximately 3 trillion to 4 trillion tons of carbon dioxide freezes out of the atmosphere onto the winter hemisphere polar cap. This represents 12 to 16 percent of the mass of the entire Martian atmosphere. These observations support predictions from the Mars Global Reference Atmospheric Model—2010.
Martian polar ice caps | Freezing of atmosphere
Scientists have even measured tiny changes in the gravity field of Mars due to the movement of carbon dioxide. The ice cap in the north is of a lower altitude (base at -5000 m, top at -2000 m) than the one in the south (base at 1000 m, top at 3500 m). It is also warmer, so all the frozen carbon dioxide disappears each summer. The part of the cap that survives the summer is called the north residual cap and is made of water ice. This water ice is believed to be as much as three kilometers thick. The much thinner seasonal cap starts to form in the late summer to early fall when a variety of clouds form.
Martian polar ice caps | North polar cap
In addition to Earth, the planet Mars also has polar ice caps. They consist of primarily water-ice with a few percent dust. Frozen carbon dioxide makes up a small permanent portion of the Planum Australe or the South Polar Layered Deposits. In both hemispheres a seasonal carbon dioxide frost deposits in the winter and sublimes during the spring. Data collected in 2001 from NASA missions to Mars show that the southern residual ice cap undergoes sublimation inter-annually. The most widely accepted explanation is that fluctuations in the planet's orbit are causing the changes.
Polar ice cap | Mars
For some time, scientists have thought that the location of the poles of Mars have shifted due to the great mass of volcanic material in the Tharsis dome which includes Olympus Mons, the highest volcano in the solar system. A study published in "Nature" supports this idea. For a period early in the history of Mars, the poles were about 20 degrees away from their present positions. At that time ice was deposited in a region called Dorsa Argentea Formation. Also, the Martian dichotomy was aligned along the equator. A band of rivers formed at around 25 degrees south carried water from the southern highlands to the northern lowlands.
True polar wander on Mars | Introduction
Triton's south polar region is covered by a highly reflective cap of frozen nitrogen and methane sprinkled by impact craters and openings of geysers. Little is known about the north pole because it was on the night side during the "Voyager 2" encounter, but it is thought that Triton must also have a north polar ice cap. The high plains found on Triton's eastern hemisphere, such as Cipango Planum, cover over and blot out older features, and are therefore almost certainly the result of icy lava washing over the previous landscape. The plains are dotted with pits, such as Leviathan Patera, which are probably the vents from which this lava emerged.
Triton (moon) | Polar cap, plains and ridges
There is much evidence for a large ice sheet that existed in the south polar region of the planet. A large number of eskers which form under ice are found there. The field of eskers make up the Dorsa Argentea Formation. The ice sheet had an area twice that of the state of Texas.
Glaciers on Mars | Ice sheet
Both polar caps show spiral troughs, which were initially thought to form as a result of differential solar heating, coupled with the sublimation of ice and condensation of water vapor. Recent analysis of ice penetrating radar data from SHARAD has demonstrated that the spiral troughs are formed from a unique situation in which high density katabatic winds descend from the polar high to transport ice and create large wavelength bedforms. The spiral shape comes from Coriolis effect forcing of the winds, much like winds on earth spiral to form a hurricane. The troughs did not form with either ice cap, instead they began to form between 2.4 million and 500,000 years ago, after three fourths of the ice cap was in place.
Climate of Mars | Polar caps
Mars has ice caps at its north pole and south pole, which mainly consist of water ice; however, there is frozen carbon dioxide (dry ice) present on their surfaces. Dry ice accumulates in the north polar region (Planum Boreum) in winter only, subliming completely in summer, while the south polar region additionally has a permanent dry ice cover up to eight meters (25 feet) thick. This difference is due to the higher elevation of the south pole. So much of the atmosphere can condense at the winter pole that the atmospheric pressure can vary by up to a third of its mean value.
Climate of Mars | Polar caps
The SHARAD radar penetrated the north polar layered ice deposits of Mars and revealed a relatively small (about 100 meter) maximum deflection of the underlying rock, which suggests a strong lithosphere greater than 300 kilometers thick. Radar results consistent with massive deposits of water ice in middle latitudes support a debris-covered glacier hypothesis. On November 22, 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region of Mars using SHARAD. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior. The calculations for the volume of water ice in the region were based on measurements from SHARAD, the ground-penetrating radar instrument on the "Mars Reconnaissance Orbiter" (MRO).
SHARAD | Findings
The northern polar cap has a diameter of about 1000 km during the northern Mars summer, and contains about 1.6 million cubic km of ice, which if spread evenly on the cap would be 2 km thick. (This compares to a volume of 2.85 million cubic km (km) for the Greenland ice sheet.) The southern polar cap has a diameter of 350 km and a thickness of 3 km. The total volume of ice in the south polar cap plus the adjacent layered deposits has also been estimated at 1.6 million cubic km. Both polar caps show spiral troughs, which recent analysis of SHARAD ice penetrating radar has shown are a result of roughly perpendicular katabatic winds that spiral due to the Coriolis Effect.
Martian polar ice caps | Introduction
The target landing zone was a region near the south pole of Mars, called "Ultimi Scopuli", because it featured a large number of scopuli (lobate or irregular scarps).
Mars Polar Lander | Landing zone
Colaprete et al. conducted simulations with the Mars General Circulation Model which show that the local climate around the Martian south pole may currently be in an unstable period. The simulated instability is rooted in the geography of the region, leading the authors to speculate that the sublimation of the polar ice is a local phenomenon rather than a global one. The researchers showed that even with a constant solar luminosity the poles were capable of jumping between states of depositing or losing ice. The trigger for a change of states could be either increased dust loading in the atmosphere or an albedo change due to deposition of water ice on the polar cap.
Climate of Mars | Polar changes
The polar ice caps are well-known telescopic features of Mars, first identified by Christiaan Huygens in 1672. Since the 1960s, we have known that the seasonal caps (those seen in the telescope to grow and wane seasonally) are composed of carbon dioxide (CO) ice that condenses out of the atmosphere as temperatures fall to 148 K, the frost point of CO, during the polar wintertime. In the north, the CO ice completely dissipates (sublimes) in summer, leaving behind a residual cap of water (HO) ice. At the south pole, a small residual cap of CO ice remains in summer. Both residual ice caps overlie thick layered deposits of interbedded ice and dust.
Geology of Mars | Ice caps
After the polar shift, the location of the dichotomy boundary and the band of river valleys shifted. Dorsa Argentea was no longer at the pole. To produce the change in the pole location, the tilt of the planet remained unchanged, rather the crust and mantle moved. They rotated around the core. This new study suggests that the volcanoes and the movement of the poles occurred at about the same time. Volcanoes were erupting when the rivers were flowing with water. Perhaps the volcanoes supplied much water to the atmosphere, as well as carbon dioxide to warm the atmosphere; these effects would provide water for the rivers.
True polar wander on Mars | Introduction
This permanent dry ice cover at the south pole is peppered by flat floored, shallow, roughly circular pits, which repeat imaging shows are expanding by meters per year; this suggests that the permanent CO cover over the south pole water ice is degrading over time. The northern polar cap has a diameter of about during the northern Mars summer, and contains about of ice, which, if spread evenly on the cap, would be thick. (This compares to a volume of for the Greenland ice sheet.) The southern polar cap has a diameter of and a thickness of . The total volume of ice in the south polar cap plus the adjacent layered deposits has been estimated at 1.6 million cubic km.
Mars | Polar caps
VIMS also detected simple organic (carbon-containing) compounds in the tiger stripes, chemistry not found anywhere else on Enceladus thus far. One of these areas of "blue" ice in the south polar region was observed at high resolution during the July 14, 2005 flyby, revealing an area of extreme tectonic deformation and blocky terrain, with some areas covered in boulders 10–100 m across. The boundary of the south polar region is marked by a pattern of parallel, Y- and V-shaped ridges and valleys. The shape, orientation, and location of these features suggest they are caused by changes in the overall shape of Enceladus.
Enceladus | South polar region
Following the Mars flyby of the Mariner 4 spacecraft in 1966, scientists concluded that Mars' polar caps consist entirely of dry ice. However, findings made in 2003 by researchers at the California Institute of Technology have shown that Mars' polar caps are almost completely made of water ice, and that dry ice only forms a thin surface layer that thickens and thins seasonally. A phenomenon named dry ice storms was proposed to occur over the polar regions of Mars. They are comparable to Earth's thunderstorms, with crystalline CO taking the place of water in the clouds. Dry ice is also proposed as a mechanism for Geysers on Mars.
Dry ice | Extraterrestrial occurrence
Scientists have even measured tiny changes in the gravity field of Mars due to the movement of carbon dioxide. In other words, the winter buildup of ice changes the gravity of the planet. Mars has seasons that are similar to Earth's because its rotational axis has a tilt close to our own Earth's (25.19° for Mars, 23.45° for Earth). The south polar cap is higher in altitude and colder than the one in the north. The residual southern ice cap is displaced; that is, it is not centered on the south pole. However, the south seasonal cap is centered near the geographic pole.
Martian polar ice caps | South polar cap
They probably all contain ice-rich material. Many of these features are found in the Northern hemisphere in parts of a boundary called the Martian dichotomy, mostly between 0 and 70 E longitudes. Near this area are regions that are named from ancient places: Deuteronilus Mensae, Protonilus Mensae, and Nilosyrtis Mensae.
Brain terrain | Introduction
Tharsis is found in the Amazonis quadrangle and the Tharsis quadrangle.
True polar wander on Mars | Introduction
Polar regions receive less intense solar radiation than the other parts of Earth because the sun's energy arrives at an oblique angle, spreading over a larger area, and also travels a longer distance through the Earth's atmosphere in which it may be absorbed, scattered or reflected, which is the same thing that causes winters to be colder than the rest of the year in temperate areas. The axial tilt of the Earth has a major effect on climate of the polar regions. However, since the polar regions are the farthest from the equator, they receive the weakest solar radiation and are therefore generally frigid year round due to the earth's axial tilt of 23.5° not being enough to create a high maximum midday declination to sufficiently strengthen the sun's rays even in summer, except for relatively brief periods in peripheral areas near the polar circles.
Polar regions of Earth | Climate
The gas rushing underneath a slab to the site of a geyser carves a spiderweb-like pattern of radial channels under the ice, the process being the inverted equivalent of an erosion network formed by water draining through a single plughole.
Mars | Polar caps
SHARAD radar data when combined to form a 3D model reveal buried craters in the north polar cap. These may be used to date certain layers.
SHARAD | Findings
Charon's north polar region, Mordor Macula, is considerably darker and more reddish than the rest of its surface. The favored explanation for this phenomenon is that it was formed by condensation of gases that escaped from Pluto's atmosphere. In winter, the temperature is −258 °C, and these gases, which include nitrogen, carbon monoxide, and methane, condense into their solid forms; when these ices are subjected to solar radiation, they chemically react to form various reddish tholins. Later, when the area is again heated by the Sun as Charon's seasons change, the temperature at the pole rises to −213 °C, resulting in the volatiles sublimating and escaping Charon, leaving only the tholins behind.
Geology of Charon | Polar regions
Both polar caps show spiral troughs, which recent analysis of SHARAD ice penetrating radar has shown are a result of katabatic winds that spiral due to the Coriolis Effect. The seasonal frosting of areas near the southern ice cap results in the formation of transparent 1-metre-thick slabs of dry ice above the ground. With the arrival of spring, sunlight warms the subsurface and pressure from subliming CO builds up under a slab, elevating and ultimately rupturing it. This leads to geyser-like eruptions of CO gas mixed with dark basaltic sand or dust. This process is rapid, observed happening in the space of a few days, weeks or months, a rate of change rather unusual in geology – especially for Mars.
Mars | Polar caps
Called the polar hood, the clouds drop precipitation which thickens the cap. The north polar cap is symmetrical around the pole and covers the surface down to about 60 degrees latitude. High resolution images taken with NASA's Mars Global Surveyor show that the northern polar cap is covered mainly by pits, cracks, small bumps and knobs that give it a cottage cheese look. The pits are spaced close together relative to the very different depressions in the south polar cap.
Martian polar ice caps | North polar cap
Because the Borealis basin covers 40% of the surface of Mars, and much of the Northern Hemisphere, many currently recognized regions of Mars lie within it:
North Polar Basin (Mars) | Large regions within the Borealis Basin
Mars has two permanent polar ice caps. During a pole's winter, it lies in continuous darkness, chilling the surface and causing the deposition of 25–30% of the atmosphere into slabs of CO ice (dry ice). When the poles are again exposed to sunlight, the frozen CO sublimes. These seasonal actions transport large amounts of dust and water vapor, giving rise to Earth-like frost and large cirrus clouds. Clouds of water-ice were photographed by the "Opportunity" rover in 2004. The caps at both poles consist primarily (70%) of water ice. Frozen carbon dioxide accumulates as a comparatively thin layer about one metre thick on the north cap in the northern winter only, whereas the south cap has a permanent dry ice cover about eight metres thick.
Mars | Polar caps
Liquid water cannot exist on the surface of Mars due to low atmospheric pressure, which is less than 1% that of Earth's, except at the lowest elevations for short periods. The two polar ice caps appear to be made largely of water. The volume of water ice in the south polar ice cap, if melted, would be sufficient to cover the entire planetary surface to a depth of . A permafrost mantle stretches from the pole to latitudes of about 60°. Large quantities of ice are thought to be trapped within the thick cryosphere of Mars. Radar data from "Mars Express" and the "Mars Reconnaissance Orbiter" (MRO) show large quantities of ice at both poles (July 2005) and at middle latitudes (November 2008).
Mars | Hydrology
The polar ice caps of Mars show geologic evidence of glacial deposits. The south polar cap is especially comparable to glaciers on Earth. Topographical features and computer models indicate the existence of more glaciers in Mars' past. At mid-latitudes, between 35° and 65° north or south, Martian glaciers are affected by the thin Martian atmosphere. Because of the low atmospheric pressure, ablation near the surface is solely caused by sublimation, not melting. As on Earth, many glaciers are covered with a layer of rocks which insulates the ice. A radar instrument on board the Mars Reconnaissance Orbiter found ice under a thin layer of rocks in formations called lobate debris aprons (LDAs).
Glacier | On Mars
Over millions of years, the residual tholin builds up thick layers, obscuring the icy crust. The south polar region is also dark, and was imaged by New Horizons using sunlight reflected off Pluto.
Geology of Charon | Polar regions
This condensation and evaporation will cause the proportion of the noncondensable gases in the atmosphere to change inversely. The eccentricity of Mars' orbit affects this cycle, as well as other factors. In the spring and autumn wind due to the carbon dioxide sublimation process is so strong that it can be a cause of the global dust storms mentioned above. The northern polar cap has a diameter of approximately 1,000 km during the northern Mars summer, and contains about 1.6 million cubic kilometres of ice, which if spread evenly on the cap would be 2 km thick. (This compares to a volume of 2.85 million cubic kilometres for the Greenland ice sheet.) The southern polar cap has a diameter of 350 km and a maximum thickness of 3 km.
Climate of Mars | Polar caps
Planum Australe (Latin: "the southern plain") is the southern polar plain on Mars. It extends southward of roughly 75°S and is centered at . The geology of this region was to be explored by the failed NASA mission Mars Polar Lander, which lost contact on entry into the Martian atmosphere. In July 2018, scientists reported the discovery, based on MARSIS radar studies, of a subglacial lake on Mars, below the southern polar ice cap, and extending sideways about , the first known stable body of water on the planet.
Planum Australe | Introduction
The planet Mars has two permanent polar ice caps. During a pole's winter, it lies in continuous darkness, chilling the surface and causing the deposition of 25–30% of the atmosphere into slabs of CO ice (dry ice). When the poles are again exposed to sunlight, the frozen CO sublimes. These seasonal actions transport large amounts of dust and water vapor, giving rise to Earth-like frost and large cirrus clouds. The caps at both poles consist primarily of water ice. Frozen carbon dioxide accumulates as a comparatively thin layer about one metre thick on the north cap in the northern winter, while the south cap has a permanent dry ice cover about 8 m thick.
Martian polar ice caps | Introduction
The south polar permanent cap is much smaller than the one in the north. It is 400 km in diameter, as compared to the 1100 km diameter of the northern cap. Each southern winter, the ice cap covers the surface to a latitude of 50°. Part of the ice cap consists of dry ice, solid carbon dioxide. Each winter the ice cap grows by adding 1.5 to 2 meters of dry ice from precipitation from a polar-hood of clouds. In summer, the dry ice sublimates (goes directly from a solid to a gas) into the atmosphere. During each year on Mars as much as a third of Mars' thin carbon dioxide (CO) atmosphere "freezes out" during the winter in the northern and southern hemispheres.
Martian polar ice caps | South polar cap
Atmospheric water vapor varies in abundance seasonally, with the greatest abundances in each hemisphere's summer after the seasonal polar caps have sublimated into the atmosphere. During winter, both water and carbon dioxide frost and ices form on Mars' surface. These ices form the seasonal and residual polar caps. The seasonal caps - which form each autumn and sublimate each spring - are dominated by carbon dioxide ice. The residual caps - which persist year after year - consist mostly of water ice at the north pole and water ice with a thin veneer (a few 10's of meters thick) of carbon dioxide ice at the south pole.
Compact Reconnaissance Imaging Spectrometer for Mars | Modern climates
While the north polar cap of Mars has a flat, pitted surface resembling cottage cheese, the south polar cap has larger pits, troughs and flat mesas that give it a Swiss cheese appearance. The upper layer of the Martian south polar residual cap has been eroded into flat-topped mesas with circular depressions. Observations made by Mars Orbiter Camera in 2001 have shown that the scarps and pit walls of the south polar cap had retreated at an average rate of about 3 meters (10 feet) since 1999. In other words, they were retreating 3 meters per Mars year. In some places on the cap, the scarps retreat less than 3 meters a Mars year, and in others it can retreat as much as 8 meters (26 feet) per Martian year.
Martian polar ice caps | Swiss cheese appearance
Research based on slight changes in the orbits of spacecraft around Mars over 16 years found that when one hemisphere experiences winter, approximately 3 trillion to 4 trillion tons of carbon dioxide freezes out of the atmosphere onto the northern and southern polar caps. This represents 12 to 16 percent of the mass of the entire Martian atmosphere. These observation support predictions from the Mars Global Reference Atmospheric Model—2010.
Mare Boreum quadrangle | Freezing of atmosphere
The Arctic has various definitions, including the region north of the Arctic Circle (currently Epoch 2010 at 66°33'44" N), or the region north of 60° north latitude, or the region from the North Pole south to the timberline. The Antarctic is usually defined as south of 60° south latitude, or the continent of Antarctica. The 1959 Antarctic Treaty uses the former definition. The two polar regions are distinguished from the other two climatic and biomatic belts of Earth, a tropics belt near the equator, and two middle latitude regions located between the tropics and "polar regions".
Polar regions of Earth | Definitions
Over time, south polar pits merge to become plains, mesas turn into buttes, and buttes vanish forever. The round shape is probably aided in its formation by the angle of the sun. In the summer, the sun moves around the sky, sometimes for 24 hours each day, just above the horizon. As a result, the walls of a round depression will receive more intense sunlight than the floor; the wall will melt far more than the floor. The walls melt and recede, while the floor remains the same. Later research with the powerful HiRISE showed that the pits are in a 1-10 meter thick layer of dry ice that is sitting on a much larger water ice cap.
Martian polar ice caps | Swiss cheese appearance
There are many settlements in Earth's north polar region. Countries with claims to Arctic regions are: the United States (Alaska), Canada (Yukon, the Northwest Territories and Nunavut), Denmark (Greenland), Norway, Finland, Sweden, Iceland, and Russia. Arctic circumpolar populations often share more in common with each other than with other populations within their national boundaries. As such, the northern polar region is diverse in human settlements and cultures.
Polar regions of Earth | Circumpolar Arctic region
Images taken by "Cassini" during the flyby on July 14, 2005, revealed a distinctive, tectonically deformed region surrounding Enceladus's south pole. This area, reaching as far north as 60° south latitude, is covered in tectonic fractures and ridges. The area has few sizable impact craters, suggesting that it is the youngest surface on Enceladus and on any of the mid-sized icy satellites; modeling of the cratering rate suggests that some regions of the south polar terrain are possibly as young as 500,000 years or less. Near the center of this terrain are four fractures bounded by ridges, unofficially called "tiger stripes".
Enceladus | South polar region
Evidence that Mars once had enough water to create a global ocean at least 137 m deep has been obtained from measurement of the HDO to HO ratio over the north polar cap. In March 2015, a team of scientists published results showing that the polar cap ice is about eight times as enriched with deuterium, heavy hydrogen, as water in Earth's oceans. This means that Mars has lost a volume of water 6.5 times as large as that stored in today's polar caps. The water for a time may have formed an ocean in the low-lying Vastitas Borealis and adjacent lowlands (Acidalia, Arcadia and Utopia planitiae).
Martian polar ice caps | Polar ice cap deuterium enrichment
Research based on slight changes in the orbits of spacecraft around Mars over 16 years found that when one hemisphere experiences winter, approximately 3 trillion to 4 trillion tons of carbon dioxide freezes out of the atmosphere onto the northern and southern polar caps. This represents 12 to 16 percent of the mass of the entire Martian atmosphere. These observation support predictions from the Mars Global Reference Atmospheric Model—2010.
Mare Australe quadrangle | Freezing of atmosphere
The large amount of ice and snow also reflects a large part of what weak sunlight the Polar regions receive, contributing to the cold. Polar regions are characterized by extremely cold temperatures, heavy glaciation wherever there is sufficient precipitation to form permanent ice, and extreme variations in daylight hours, with twenty-four hours of daylight in summer, and complete darkness at mid-winter.
Polar regions of Earth | Climate
Micrometeorites found in polar sediments are much less weathered than those found in other terrestrial environments, as evidenced by little etching of interstitial glass, and the presence of large numbers of glass spherules and unmelted micrometeorites, particle types that are rare or absent in deep-sea samples. The MMs found in polar regions have been collected from Greenland snow, Greenland cryoconite, Antarctic blue ice Antarctic aeolian (wind-driven) debris, ice cores, the bottom of the South Pole water well, Antarctic sediment traps and present day Antarctic snow.
Micrometeorite | Polar depositions
On 29 April 2015, NASA stated that its New Horizons missions had discovered a feature thought to be a polar ice cap on the dwarf planet Pluto. The probe's flyby of Pluto in July 2015 allowed the "Alice" ultraviolet imaging spectrometer to confirm that the feature was in fact an ice cap composed of methane and nitrogen ices.
Polar ice cap | Pluto
In 2018, it was announced that a subglacial lake was discovered below the south polar ice cap of Mars. The lake was detected by "Mars Express" orbiter, and is long, lying under ca. of glacial cover, with water temperature estimated to be , and having an extremely salty brine. In September 2020, scientists confirmed the existence of several large saltwater lakes under the ice in the south polar region of the planet Mars. According to one of the researchers, “We identified the same body of water [as suggested earlier in a preliminary initial detection], but we also found three other bodies of water around the main one ...
Lakes on Mars | Southern polar cap subglacial lake
In the north, the layered deposits form a 3 km-high, 1,000 km-diameter plateau called Planum Boreum. A similar kilometers-thick plateau, Planum Australe, lies in the south. Both plana (the Latin plural of planum) are sometimes treated as synonymous with the polar ice caps, but the permanent ice (seen as the high albedo, white surfaces in images) forms only a relatively thin mantle on top of the layered deposits. The layered deposits probably represent alternating cycles of dust and ice deposition caused by climate changes related to variations in the planet's orbital parameters over time (see also Milankovitch cycles). The polar layered deposits are some of the youngest geologic units on Mars.
Geology of Mars | Ice caps
The Dorsa Argentea Formation (DAF) is thought to be a large system of eskers that were under an ancient ice cap in the south polar region of Mars. This large polar ice sheet is believed to have covered about 1.5 million square kilometers. That area is twice the area of the state of Texas. The ice sheet formed near the boundary of the Noachian-Hesperian era and receded in the early Hesperian era. A thick ice sheet was able to be formed more easily in the south polar region than in the North pole because the south pole is higher in altitude.
Mare Australe quadrangle | Dorsa Argentea Formation
A polar ice cap or polar cap is a high-latitude region of a planet, dwarf planet, or natural satellite that is covered in ice. There are no requirements with respect to size or composition for a body of ice to be termed a polar ice cap, nor any geological requirement for it to be over land, but only that it must be a body of solid phase matter in the polar region. This causes the term "polar ice cap" to be something of a misnomer, as the term ice cap itself is applied more narrowly to bodies that are over land, and cover less than 50,000 km: larger bodies are referred to as ice sheets.
Polar ice cap | Introduction
See list of craters on Mars. Mars has two permanent polar ice caps, the northern one located at Planum Boreum and the southern one at Planum Australe.
Geography of Mars | Topography
The bulk of the northern ice cap consists of water ice; it also has a thin seasonal veneer of dry ice, solid carbon dioxide. Each winter the ice cap grows by adding 1.5 to 2 m of dry ice. In summer, the dry ice sublimates (goes directly from a solid to a gas) into the atmosphere. Mars has seasons that are similar to Earth's, because its rotational axis has a tilt close to our own Earth's (25.19° for Mars, 23.44° for Earth). During each year on Mars as much as a third of Mars' thin carbon dioxide (CO) atmosphere "freezes out" during the winter in the northern and southern hemispheres.
Martian polar ice caps | North polar cap
This extremely rough terrain is suggestive of young, ʻaʻā lava flows. A 200-km-long band of low to zero radar albedo ("stealth" region) cuts across the southwest Tharsis. The region corresponds to the location of the Medusa Fossae Formation, which consists of thick layers of unconsolidated materials, perhaps volcanic ash or loess. Ground-penetrating radar instruments on the Mars Express orbiter (MARSIS) and the Mars Reconnaissance Orbiter (SHARAD) are currently providing stunning echo-return data on subsurface materials and structures to depths of up to 5 km. Results have shown that the polar layered deposits are composed of almost pure ice, with no more than 10% dust by volume and that fretted valleys in Deuteronilus Mensae contain thick glaciers covered by a mantle of rocky debris.
Martian surface | Radar Investigations
On Earth, the only continent where the ice cap polar climate is predominant is Antarctica. All but a few isolated coastal areas on the island of Greenland also have the ice cap climate. Coastal regions of Greenland that do not have permanent ice sheets have the less extreme tundra climates. The northernmost part of the Eurasian land mass, from the extreme northeastern coast of Scandinavia and eastwards to the Bering Strait, large areas of northern Siberia and northern Iceland have tundra climate as well. Large areas in northern Canada and northern Alaska have tundra climate, changing to ice cap climate in the most northern parts of Canada.
Polar climate | Locations
Data obtained by the Mars Express satellite, made it possible in 2004 to confirm that the southern polar cap has an average of thick slab of CO ice with varying contents of frozen water, depending on its latitude: the bright polar cap itself, is a mixture of 85% CO ice and 15% water ice. The second part comprises steep slopes known as 'scarps', made almost entirely of water ice, that fall away from the polar cap to the surrounding plains. This transition area between the scarps and the permafrost is the 'cryptic region', where clusters of geysers are located. This model explores the possibility of active water-driven erosive structures, where soil and water derived from the shallow sub-surface layer is expelled up by CO gas through fissures eroding joints to create spider-like radiating tributaries capped with mud-like material and/or ice.
Geysers on Mars | Water-driven erosion
Had the water ever all been liquid and on the surface, it would have covered 20% of the planet and in places would have been almost a mile deep. This international team used ESO’s Very Large Telescope, along with instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility, to map out different isotopic forms of water in Mars’s atmosphere over a six-year period.
Martian polar ice caps | Polar ice cap deuterium enrichment
This suggests that a climatic shift allowed for their onset. Both polar caps shrink and regrow following the temperature fluctuation of the Martian seasons; there are also longer-term trends that are better understood in the modern era.
Climate of Mars | Polar caps
There are fissures, plains, corrugated terrain and other crustal deformations. Several additional regions of young terrain were discovered in areas not well-imaged by either "Voyager" spacecraft, such as the bizarre terrain near the south pole. All of this indicates that Enceladus's interior is liquid today, even though it should have been frozen long ago.
Enceladus | Surface features
Several fossils of insects and crustaceans are known from South Polar Cretaceous sediments of New Zealand. The Late Cretaceous Mangaotanean Monro Conglomerate was situated at 68°S and provided fossils of "Helastia sp.", and the crab "Hemioon novozelandicum" was found in the Swale Siltstone, located at 76°S during the late Albian. Several specimens of insects were also found in the Tupuangi Formation of the Chatham Islands at a latitude of 79°S during the Cenomanian to Turonian.
South Polar region of the Cretaceous | Invertebrates
The composition of the lava is unknown, although a mixture of ammonia and water is suspected. Four roughly circular "walled plains" have been identified on Triton. They are the flattest regions so far discovered, with a variance in altitude of less than 200 m. They are thought to have formed from eruption of icy lava. The plains near Triton's eastern limb are dotted with black spots, the "maculae". Some maculae are simple dark spots with diffuse boundaries, and others comprise a dark central patch surrounded by a white halo with sharp boundaries. The maculae typically have diameters of about 100 km and widths of the halos of between 20 and 30 km.
Triton (moon) | Polar cap, plains and ridges
Polar lows were first identified on the meteorological satellite imagery that became available in the 1960s, which revealed many small-scale cloud vortices at high latitudes. The most active polar lows are found over certain ice-free maritime areas in or near the Arctic during the winter, such as the Norwegian Sea, Barents Sea, Labrador Sea and Gulf of Alaska; however, polar lows also have been found in the Sea of Japan and the Sea of Okhotsk. Polar lows dissipate rapidly when they make landfall. Antarctic systems tend to be weaker than their northern counterparts since the air-sea temperature differences around the continent are generally smaller.
Polar low | History
Much of the surface of Mars is covered by a thick smooth mantle that is thought to be a mixture of ice and dust. This ice-rich mantle, a few yards thick, smoothes the land. Because there are few craters on this mantle, the mantle is relatively young. Changes in Mars's orbit and tilt cause significant changes in the distribution of water ice from polar regions down to latitudes equivalent to Texas. During certain climate periods water vapor leaves polar ice and enters the atmosphere. The water returns to the ground at lower latitudes as deposits of frost or snow mixed with dust.
Diacria quadrangle | Latitude dependent mantle
Changes in Mars's orbit and tilt cause significant changes in the distribution of water ice from polar regions down to latitudes equivalent to Texas. During certain climate periods water vapor leaves polar ice and enters the atmosphere. The water comes back to ground at lower latitudes as deposits of frost or snow mixed generously with dust. The atmosphere of Mars contains a great deal of fine dust particles. Water vapor will condense on the particles, then fall down to the ground due to the additional weight of the water coating. When ice at the top of the mantling layer goes back into the atmosphere, it leaves behind dust, which insulating the remaining ice.
Gorgonum Chaos | Gullies
During the flyby of July 14, 2005, the Composite Infrared Spectrometer (CIRS) found a warm region near the south pole. Temperatures in this region ranged from 85–90 K, with small areas showing as high as , much too warm to be explained by solar heating, indicating that parts of the south polar region are heated from the interior of Enceladus. The presence of a subsurface ocean under the south polar region is now accepted, but it cannot explain the source of the heat, with an estimated heat flux of 200 mW/m, which is about 10 times higher than that from radiogenic heating alone.
Enceladus | Possible heat sources
HiRISE images taken under the HiWish program found triangular shaped depressions in Milankovic Crater that researchers found contain vast amounts of ice that are found under only 1–2 meters of soil. These depressions contain water ice in the straight wall that faces the pole, according to the study published in the journal Science. Eight sites were found with Milankovic Crater being the only one in the northern hemisphere. Research was conducted with instruments on board the Mars Reconnaissance Orbiter (MRO). The following images are ones referred to in this study of subsurface ice sheets. These triangular depressions are similar to those in scalloped terrain.
HiWish program | Exposed Ice Sheets
The south polar seasonal cap has a bizarre variety of bright and dark streaks and spots that appear during spring, as carbon dioxide ice sublimates. Prior to MRO there were various ideas for processes that could form these strange features, a leading model being carbon dioxide geysers. CRISM has watched the dark spots grow during southern spring, and found that bright streaks forming alongside the dark spots are made of fresh, new carbon dioxide frost, pointing like arrows back to their sources - the same sources as the dark spots. The bright streaks probably form by expansion, cooling, and freezing of the carbon dioxide gas, forming a "smoking gun" to support the geyser hypothesis.
Compact Reconnaissance Imaging Spectrometer for Mars | Modern climates
Mars, like Earth, has ice caps at its poles. In addition to frozen water, Mars ice caps also have frozen carbon dioxide, commonly known as dry ice. In addition, Mars has seasons similar to Earth. The North Pole of Mars has a permanent water ice cap and a winter-only dry ice cap. On the south pole, both the water and carbon dioxide are permanently frozen. Europa, a moon of Jupiter, is covered with a permanent sheet of water ice, similar to Antarctica. Scientists theorize that it may have sub-glacial lakes similar to those seen in Antarctica.
Ice cap climate | Extraterrestrial
The Dorsa Argentea Formation (DAF) is thought to be a large system of eskers that were under an ancient ice cap in the south polar region of Mars. The ancient ice cap was at least twice the size of the present ice cap and may have been 1500–2000 meters thick. Later research suggests that the area of this polar ice sheet is believed to have covered about 1.5 million square kilometers, roughly twice the size of France or the American state of Texas. This group of ridges extends from 270–100 E and 70–90 S, around the south pole of Mars.
Dorsa Argentea Formation | Introduction
Mars Odyssey found what appear to be natural caves near the volcano Arsia Mons. It has been speculated that settlers could benefit from the shelter that these or similar structures could provide from radiation and micrometeoroids. Geothermal energy is also suspected in the equatorial regions.
Colonization of Mars | Equatorial regions
Mars does not possess a large moon to keep its tilt stable. Today, ice is concentrated at the poles, with a greater tilt, more ice will exist at mid-latitudes. These climate changes may be able to be measured with study of these layers. These triangular depressions are similar to those in scalloped terrain. However scalloped terrain, displays a gentle equator-facing slope and is rounded.
Hellas quadrangle | Exposed ice sheets
It is believed that large quantities of water and carbon dioxide ices remain frozen within the regolith in the equatorial parts of Mars and on its surface at higher latitudes.
Regolith | Mars
The existence of ice in the Martian northern (Planum Boreum) and southern (Planum Australe) polar caps has been known since the time of Mariner 9 orbiter. However, the amount and purity of this ice were not known until the early 2000s. In 2004, the MARSIS radar sounder on the European "Mars Express" satellite confirmed the existence of relatively clean ice in the south polar ice cap that extends to a depth of below the surface. Similarly, the SHARAD radar sounder on board the "Mars Reconnaissance Orbiter" observed the base of the north polar cap 1.5 – 2 km beneath the surface.
Water on Mars | Polar ice caps
The landscape of the Middle Jurassic polar region has been reconstructed from the remains of forests exposed in New Zealand, which were between 70 and 80°S during the Jurassic. The vegetation was largely made up of conifers, cycads, and other gymnosperms, as well as ferns; on the forest floor grew lycopods, bryophytes, fungi, and algae. It had a temperate climate with heavy rainfall.
South Polar region of the Cretaceous | Jurassic
In addition, radar studies in Deuteronilus Mensae show that all lobate debris aprons examined in that region contain ice. The experiments of the Phoenix lander and the studies of the Mars Odyssey from orbit show that frozen water exists just under the surface of Mars in the far north and south (high latitudes). Most of the ice was deposited as snow when the climate was different. The discovery of water ice in LDAs demonstrates that water is found at even lower latitudes. Future colonists on Mars will be able to tap into these ice deposits, instead of having to travel to much higher latitudes.
Lobate debris apron | Introduction
The large troughs present in each pole, Chasma Boreale and Chasma Australe, have both been argued to have been formed by meltwater release from beneath polar ice, as in a terrestrial jökulhlaup. However, others have argued for an eolian origin, with them induced by katabatic winds blowing down from the poles.
Outflow channels | Polar regions
On Mars, the warming seems to be down to dust blowing around and uncovering big patches of black basaltic rock that heat up in the day."
Climate of Mars | Polar changes
The spacecraft measured 3.6 meters wide and 1.06 meters tall with the legs and solar arrays fully deployed. The base was primarily constructed with an aluminum honeycomb deck, composite graphite–epoxy sheets forming the edge, and three aluminum legs. During landing, the legs were to deploy from stowed position with compression springs and absorb the force of the landing with crushable aluminum honeycomb inserts in each leg. On the deck of the lander, a small thermal Faraday cage enclosure housed the computer, power distribution electronics and batteries, telecommunication electronics, and the capillary pump loop heat pipe (LHP) components, which maintained operable temperature.
Mars Polar Lander | Spacecraft design
Much of the surface of Mars is covered by a thick smooth mantle that is thought to be a mixture of ice and dust. This ice-rich mantle, a few yards thick, makes the surface look very smooth. Because there are few craters on this mantle, the mantle is relatively young. Changes in Mars's orbit and tilt cause significant changes in the distribution of water ice from polar regions down to latitudes equivalent to Texas. During certain climate periods water vapor leaves polar ice and enters the atmosphere. The water returns to the ground at lower latitudes as deposits of frost or snow mixed generously with dust.
Arcadia quadrangle | Latitude dependent mantle
This process may still be happening at present. On November 22, 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region of Mars. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior. The volume of water ice in the region were based on measurements from the ground-penetrating radar instrument on Mars Reconnaissance Orbiter, called SHARAD. From the data obtained from SHARAD, “dielectric permittivity”, or the dielectric constant was determined. The dielectric constant value was consistent with a large concentration of water ice.
Common surface features of Mars | Scalloped topography
The south polar region of the Moon was surveyed by the Lunar Prospector spacecraft and a hydrogen signature was detected. Potential sources for this hydrogen include water deposits from comet or meteorite impacts, the solar wind or out-gassing. This crater is sufficiently large that the temperature within the shaded region is below . This would allow water ice to remain on or near the crater surface for billions of years without sublimating.
Cabeus (crater) | Volatiles
This hypothesis was confirmed theoretically by Robert Leighton and Bruce Murray in 1966. Today it is known that the winter caps at both poles are primarily composed of CO ice, but that a permanent (or perennial) cap of water ice remains during the summer at the northern pole. At the southern pole, a small cap of CO ice remains during summer, but this cap too is underlain by water ice. The final piece of the Martian climate puzzle was provided by Mariner 4 in 1965. Grainy television pictures from the spacecraft showed a surface dominated by impact craters, which implied that the surface was very old and had not experienced the level of erosion and tectonic activity seen on Earth.
Water on Mars | Historical background
Vastitas Borealis (Latin 'northern waste') is the largest lowland region of Mars. It is in the northerly latitudes of the planet and encircles the northern polar region. Vastitas Borealis is often simply referred to as the northern plains, northern lowlands or the North polar erg of Mars. The plains lie 4–5 km below the mean radius of the planet, and is centered at . To the north lies Planum Boreum. A small part of Vastitas Borealis lies in the Ismenius Lacus quadrangle. The region was named by Eugene Antoniadi, who noted the distinct albedo feature of the Northern plains in his book "La Planète Mars" (1930).
Vastitas Borealis | Introduction
By chance, both spacecrafts flew over cratered regions and missed both the giant northern volcanoes and the equatorial grand canyon discovered later. Their approach pictures did, however, photograph about 20 percent of the planet's surface, showing the dark features long seen from Earth – in the past, these features had been mistaken for canals by some ground-based astronomers. When Mariner 7 flew over the martian south pole on August 4, 1969, it sent back pictures of ice-filled craters and outlines of the south polar cap. Despite the communication defect suffered by Mariner 7 earlier, these pictures were of better quality than what had been sent by its twin, Mariner 6, a few days earlier when it flew past the martian equator.
Mariner 6 and 7 | Science data and findings
This layering contains a record of past climates on Mars, just how Earth's ice sheets have a record for Earth's climate. Reading this record is not straightforward however, so, many researchers have studied this layering not only to understand the structure, history, and flow properties of the caps, but also to understand the evolution of climate on Mars.
Water on Mars | Polar ice caps
It is possible that dinosaurs, after becoming locally extinct at the equator, more preferred the polar regions.
South Polar region of the Cretaceous | Non-avian
The planned landing site and its alternate site, are located within the polar LQ30 quadrangle. The surface likely consists of impact melt, possibly mantled by ejecta from the massive South Pole–Aitken basin and mixing by subsequent nearby impacts. The nature of the melt is mostly mafic, meaning it is rich in silicate mineral, magnesium and iron. The region could also offer scientifically valuable rocks from the lunar mantle if the basin impactor excavated all the way through the crust.
Pragyan (rover) | Planned landing site
The composition of the ice will vary. For example, Earth's polar caps are mainly water ice, whereas Mars's polar ice caps are a mixture of solid carbon dioxide and water ice.
Polar ice cap | Introduction
There may have been much more water available in the Martian atmosphere when the ice sheet developed. This group of ridges extends from 270–100 E and 70–90 S, around the south pole of Mars. It sits under the Late Amazonian South Polar Layered Deposits (SPLD). The amount of these ridges is huge, one study studied seven different ridge systems which contained almost 4,000 ridges that had a total length 51,000 km. Most eskers are thought to be formed inside ice-walled tunnels by streams which flowed within and under glaciers. After the retaining ice walls melted away, stream deposits remained as long winding ridges.
Mare Australe quadrangle | Dorsa Argentea Formation
The polar bear is found in the Arctic Circle and adjacent land masses as far south as Newfoundland. Due to the absence of human development in its remote habitat, it retains more of its original range than any other extant carnivore. While they are rare north of 88°, there is evidence that they range all the way across the Arctic, and as far south as James Bay in Canada. Their southernmost range is near the boundary between the subarctic and humid continental climate zones. They can occasionally drift widely with the sea ice, and there have been anecdotal sightings as far south as Berlevåg on the Norwegian mainland and the Kuril Islands in the Sea of Okhotsk.
Polar bear | Population and distribution
Many triangular shaped depressions are visible in Milankovič crater. According to a team of researchers, these depression display water ice in the straight wall that faces the pole. Eight sites were found with Milankovic crater being the only one in the northern hemisphere. This discovery is important because the ice lies under only a meter or two of cover. Research was conducted with instruments on board the Mars Reconnaissance Orbiter (MRO). The following images are ones referred to in this study of subsurface ice sheets.
Milankovič (Martian crater) | Exposed ice sheets
A significant number of polar bears are found at Hopen in the winter; moreover, the sub-population of "Ursus maritimus" found here is a genetically distinct taxon of polar bears associated with the Barents Sea region.
Hopen (Svalbard) | Environment
Theory had predicted that ice would be found under a few cm of soil. This mantle layer is called "latitude dependent mantle" because its occurrence is related to the latitude. It is this mantle that cracks and then forms polygonal ground. This cracking of ice-rich ground is predicted based on physical processes.
Common surface features of Mars | <a href="Latitude%20dependent%20mantle">Latitude dependent mantle</a>
They appear to be the youngest features in this region and are surrounded by mint-green-colored (in false color, UV–green–near IR images), coarse-grained water ice, seen elsewhere on the surface within outcrops and fracture walls. Here the "blue" ice is on a flat surface, indicating that the region is young enough not to have been coated by fine-grained water ice from the E ring. Results from the visual and infrared spectrometer (VIMS) instrument suggest that the green-colored material surrounding the tiger stripes is chemically distinct from the rest of the surface of Enceladus. VIMS detected crystalline water ice in the stripes, suggesting that they are quite young (likely less than 1,000 years old) or the surface ice has been thermally altered in the recent past.
Enceladus | South polar region
The spectra of the dust was similar to spectra of bright, low thermal inertia regions like Tharsis and Arabia that have been detected by orbiting satellites. A thin layer of dust, maybe less than one millimeter thick covers all surfaces. Something in it contains a small amount of chemically bound water.
Gusev (Martian crater) | "Spirit" Rover's rocks and minerals discoveries on Mars