Mars is the fourth planet from the sun and our second closest neighbour. Mars is one of the four terrestrial planets within the solar system and the most explored planet apart from our own where we have sent mechanical rovers to explore the surface.
Mars was named after the Roman god of war by the ancient Romans due to its red colour which resembled blood, while Egyptians name it “Her Desher” which means “The red one” and even today, it is called the red planet.
Mars was first explored in 1965 by Mariner 4, which was launched in 1964, after the failed attempt of Mariner 3, which took 7.5 months to get to Mars. The Mariner 4 probe took photos through close-up fly-bys which were then transmitted back to Earth. The mission lasted for 3 years and then communication was terminated.
Details:
Mars was named after the Roman god of war by the ancient Romans due to its red colour which resembled blood, while Egyptians name it “Her Desher” which means “The red one” and even today, it is called the red planet.
Mars was first explored in 1965 by Mariner 4, which was launched in 1964, after the failed attempt of Mariner 3, which took 7.5 months to get to Mars. The Mariner 4 probe took photos through close-up fly-bys which were then transmitted back to Earth. The mission lasted for 3 years and then communication was terminated.
Details:
- Two moons
- Phobos
- Deimos
- Orbit time around the sun - 687 Days
- Day cycle – 1 Earth day 39 mins
- Average distance from the Sun – 142million miles/ 227.9 million Km
- 1.5 AU from the Sun
- Tilt – 25 degrees
- Planet Radius – 2110.3 miles (3396km)
- Gravity – 0.3794g
- Temperature
- Min – -110c/-166F
- Mean - -60c/ -80F.
- Max – +35c/ 95F
- atmosphere
- 95% Carbon Dioxide, CO2 (the 2 is a subscript in this equation)
- 0.174% Oxygen, O
- 2.6% Nitrogen, N
- 1.9% Argon, Ar
- Trace levels of water vapour (H2O (the 2 is a subscript in this equation)), Carbon Monoxide (CO), Hydrogen (H), and noble gases
Atmosphere
Mars lost its Magnetosphere roughly 4 billion years ago through possible asteroids and solar wind stripping atoms from the outer layer and lowering the atmospheric density. Two probes from the USA and European Space Agency have both detected ionised atmospheric particles trailing behind the planet.
Studies suggest the atmosphere was much thicker in the past and the planet was able to hold water at the surface. During the winter period at the poles, the temperature drops low enough for CO2 to become dry ice which can form about 1-2m thick. During the summer, CO2 undergoes sublimation, releasing the CO2 back into the atmosphere. Because of this, the Atmospheric pressure varies about 25%. Furthermore, Mars has low greenhouse effects due to the low concentration of water vapour and low atmospheric pressure. If the CO2 wasn’t replenished, it would lose all the Co2 in about 3500 years due to the reaction with photons known as Photodissociation. Co2 + h(v) (λ=225nm) -> CO + O This along with the photodissociation of water vapour (plus others) can convert carbon monoxide back to CO2 in the following cycle: CO + OH -> CO2 + H H+O2 +m -> HO2 + m HO2 + O -> OH + O2 Net: CO + O -> CO2 m being the mixing stages by bringing O CO and O2 down from the upper atmosphere |
Methane
Methane is a volcanic and biogenic compound and is of interest to Geologists and Astrobiologists alike. The concentration of methane in the atmosphere varies between 0.24 ppb to 0.65 ppb between winter and summer.
Methane’s presence indicates that an active source of the gas must be present which is potentially produced by a non-biological process such as serpentinization (involving water, Carbon dioxide and the mineral Olivine).
Nitrogen
In the atmosphere of Mars, N2 is the second most prevalent gas. It has a 2.6% mean volume ratio. Numerous measurements revealed enrichment in 15N in the Martian atmosphere. The enrichment of nitrogen's heavy isotopes may be brought on by mass-selective escape processes.
Argon
The third most prevalent gas in the Martian atmosphere is argon. It has a 1.9% mean volume ratio. Mars has a higher concentration of 38Ar than 36Ar in terms of stable isotopes, which can be attributed to hydrodynamic escape.
40Ar, an isotope of argon, is created through the radioactive decay of 40K. 36Ar, on the other hand, is primordial since it was already in the atmosphere when Mars first formed. According to observations, Mars is more abundant in 40Ar than in 36Ar, which rules out mass-selective loss mechanisms as the cause. A proposed explanation for the enrichment is that during the early history of Mars, a sizeable portion of the primordial atmosphere, including 36Ar, was lost due to impact erosion, whereas 40Ar was released into the atmosphere following the impact.
Sulphur Dioxide
An indication of current volcanic activity would be the presence of sulphur dioxide (SO2) in the atmosphere. Due to the ongoing debate concerning the presence of methane on Mars, it has acquired particular interest. It would be expected to detect SO2 and methane in the current Martian atmosphere if volcanoes had been active recently on Mars. With a sensitivity upper limit set at 0.2 ppb, no SO2 has been found in the atmosphere. But in March 2013, a group of researchers at NASA Goddard Space Flight Centre reported finding SO2 in Rocknest soil samples examined by the Curiosity rover.
Methane is a volcanic and biogenic compound and is of interest to Geologists and Astrobiologists alike. The concentration of methane in the atmosphere varies between 0.24 ppb to 0.65 ppb between winter and summer.
Methane’s presence indicates that an active source of the gas must be present which is potentially produced by a non-biological process such as serpentinization (involving water, Carbon dioxide and the mineral Olivine).
Nitrogen
In the atmosphere of Mars, N2 is the second most prevalent gas. It has a 2.6% mean volume ratio. Numerous measurements revealed enrichment in 15N in the Martian atmosphere. The enrichment of nitrogen's heavy isotopes may be brought on by mass-selective escape processes.
Argon
The third most prevalent gas in the Martian atmosphere is argon. It has a 1.9% mean volume ratio. Mars has a higher concentration of 38Ar than 36Ar in terms of stable isotopes, which can be attributed to hydrodynamic escape.
40Ar, an isotope of argon, is created through the radioactive decay of 40K. 36Ar, on the other hand, is primordial since it was already in the atmosphere when Mars first formed. According to observations, Mars is more abundant in 40Ar than in 36Ar, which rules out mass-selective loss mechanisms as the cause. A proposed explanation for the enrichment is that during the early history of Mars, a sizeable portion of the primordial atmosphere, including 36Ar, was lost due to impact erosion, whereas 40Ar was released into the atmosphere following the impact.
Sulphur Dioxide
An indication of current volcanic activity would be the presence of sulphur dioxide (SO2) in the atmosphere. Due to the ongoing debate concerning the presence of methane on Mars, it has acquired particular interest. It would be expected to detect SO2 and methane in the current Martian atmosphere if volcanoes had been active recently on Mars. With a sensitivity upper limit set at 0.2 ppb, no SO2 has been found in the atmosphere. But in March 2013, a group of researchers at NASA Goddard Space Flight Centre reported finding SO2 in Rocknest soil samples examined by the Curiosity rover.
Oxygen and ozone
Molecular oxygen (O2) makes up about 0.174% of the Martian atmosphere, according to estimates. It is a by-product of the photolysis of ozone (O3), water vapour, and carbon dioxide (CO2). It can re-form ozone (O3) when combined with atomic oxygen (O). The Herschel Space Observatory discovered a molecule of oxygen on Mars in 2010.
Atomic oxygen is created in the high atmosphere by the photolysis of CO2, and it can leave the environment through ion pickup or dissociative recombination. Since the Viking and Mariner missions in the 1970s, atomic oxygen had not been discovered in the atmosphere of Mars until it was discovered in early 2016 by the Stratospheric Observatory for Infrared Astronomy (SOFIA).
The amount of oxygen in the Martian atmosphere increased by 30% in the spring and summer, according to research conducted by NASA scientists on the Curiosity rover mission in 2019.
The ozone that exists in the Martian atmosphere can be destroyed by catalytic cycles involving strange hydrogen species, just like the stratospheric ozone in the Earth's atmosphere can.
H + 03 -> OH + O2
O + OH -> H + O2
Net: O + O3 -> 2O2
Ozone is typically found in greater abundance in areas with less water vapour since water is a major source of these unusual hydrogen species. Measurements revealed that in the winter and spring when the air is chilly and has a low water saturation ratio, the total column of ozone can reach 2-30 um around the poles. The heterogeneous reactions that occur in water-ice clouds may further confound the real reactions between ozone and strange hydrogen molecules.
Molecular oxygen (O2) makes up about 0.174% of the Martian atmosphere, according to estimates. It is a by-product of the photolysis of ozone (O3), water vapour, and carbon dioxide (CO2). It can re-form ozone (O3) when combined with atomic oxygen (O). The Herschel Space Observatory discovered a molecule of oxygen on Mars in 2010.
Atomic oxygen is created in the high atmosphere by the photolysis of CO2, and it can leave the environment through ion pickup or dissociative recombination. Since the Viking and Mariner missions in the 1970s, atomic oxygen had not been discovered in the atmosphere of Mars until it was discovered in early 2016 by the Stratospheric Observatory for Infrared Astronomy (SOFIA).
The amount of oxygen in the Martian atmosphere increased by 30% in the spring and summer, according to research conducted by NASA scientists on the Curiosity rover mission in 2019.
The ozone that exists in the Martian atmosphere can be destroyed by catalytic cycles involving strange hydrogen species, just like the stratospheric ozone in the Earth's atmosphere can.
H + 03 -> OH + O2
O + OH -> H + O2
Net: O + O3 -> 2O2
Ozone is typically found in greater abundance in areas with less water vapour since water is a major source of these unusual hydrogen species. Measurements revealed that in the winter and spring when the air is chilly and has a low water saturation ratio, the total column of ozone can reach 2-30 um around the poles. The heterogeneous reactions that occur in water-ice clouds may further confound the real reactions between ozone and strange hydrogen molecules.
Habitability and search for life
In the astronomical community, it was widely believed in the late nineteenth century that Mars had elements necessary for life, such as water and oxygen. While studying the planet in 1894 at Lick Observatory, W. W. Campbell discovered that "if water vapour or oxygen occur in the atmosphere of Mars, it is in quantities too small to be detected by spectroscopes at that time." This observation was not widely recognised because it defied many of the measurements used at the time. The investigation was repeated by Campbell and V. M. Slipher in 1909 using improved tools and the same outcomes.
It wasn't until 1925 when W. S. Adams confirmed the findings, that the myth of Mars' ability to support life similarly to that of Earth was completely dispelled. The seasonal fluctuations on Mars were explained by factors other than life, yet papers on Martian biology were still published in the 1960s. As late as 1962, comprehensive simulations of a functioning ecosystem's metabolism and chemical cycles were being published.
The ability of a planet to establish climatic circumstances beneficial to the origin of life is known as planetary habitability, and it currently favours planets with liquid water on their surface. Most frequently, this requires that a planet's orbit fall inside the habitable zone, which for the Sun is thought to extend from within Earth's orbit to around Mars' orbit. Mars dips into this zone during perihelion, but its thin (low-pressure) atmosphere prohibits liquid water from lingering for very long there. The planet's capacity for habitability is demonstrated by the flow of liquid water in the past. Recent data suggests that any surface water on Mars may have been too acidic and salty to support typical terrestrial life.
Since Mars lacks a magnetosphere, it has poor protection against solar wind bombardment and insufficient atmospheric pressure to keep water in a liquid state (water instead sublimes to a gaseous state), all of which make it difficult to support organic life. Mars also has little heat transfer across its surface. The cessation of volcanic activity appears to have halted the recycling of chemicals and minerals between the surface and the interior of the planet, rendering Mars largely, or possibly completely, geologically dead.
The Viking landers, Spirit and Opportunity rovers, Phoenix landers, and Curiosity rovers have all conducted in-situ research on Mars. Although there is evidence that the planet was once much more habitable than it is now, it is still unknown whether there have ever been any living things there. At their various landing sites, the Viking probes of the mid-1970s conducted studies to identify microorganisms in Martian soil, and the results were encouraging, including a brief rise in CO2 generation in response to water and nutrients. Scientists eventually refuted this evidence of life, sparking a discussion that is still going on now. NASA scientist Gilbert Levin claims that Vikings may have discovered life.
The soil has an alkaline pH and includes magnesium, sodium, potassium, and chloride, according to tests by the Phoenix Mars lander. Life could be able to survive on the soil's nutrients, but it would still need protection from the strong ultraviolet light. Chlorate, perchlorate, and nitrate ions were discovered in 2014 during a study of the Martian meteorite EETA79001, indicating that they are likely common on Mars. Chlorate and perchlorate ions would be transformed into additional, more reactive oxychloride by UV and X-ray radiation, indicating that any organic molecules would need to be buried below the surface to survive. The average radiation level on the surface is 0.64 millisieverts per day, which is much less than the radiation level of 1.84 millisieverts per day or 22 millirads per day during the flight to and from Mars.
In Low Earth Orbit, where Earth's space stations orbit, the radiation levels are roughly 0.5 millisieverts per day. With lava tubes southwest of Hadriacus Mons that may have radiation levels as low as 0.064 millisieverts per day, Hellas Planitia has the lowest surface radiation at about 0.342 millisieverts per day.
Carbonate globules discovered in meteorite ALH84001, which is assumed to have come from Mars, have been theorised to be fossilised bacteria that were present there when the meteorite was blasted from the Martian surface by a meteor strike some 15 million years ago. A wholly inorganic origin for the shapes has been suggested in response to scepticism about this proposal. Both methane and formaldehyde, which are found in trace amounts by Mars orbiters, are thought to be probable signs of life because they would decompose swiftly in the atmosphere of Mars.
These substances could also be renewed through volcanic activity or other geological processes, like serpentinite. On the surface of impact craters on Mars, impact glass has been discovered. On Earth, impact glass can preserve indications of life. Similarly, if there had been life at the location, the glass in impact craters on Mars might have retained indications of it.
In the astronomical community, it was widely believed in the late nineteenth century that Mars had elements necessary for life, such as water and oxygen. While studying the planet in 1894 at Lick Observatory, W. W. Campbell discovered that "if water vapour or oxygen occur in the atmosphere of Mars, it is in quantities too small to be detected by spectroscopes at that time." This observation was not widely recognised because it defied many of the measurements used at the time. The investigation was repeated by Campbell and V. M. Slipher in 1909 using improved tools and the same outcomes.
It wasn't until 1925 when W. S. Adams confirmed the findings, that the myth of Mars' ability to support life similarly to that of Earth was completely dispelled. The seasonal fluctuations on Mars were explained by factors other than life, yet papers on Martian biology were still published in the 1960s. As late as 1962, comprehensive simulations of a functioning ecosystem's metabolism and chemical cycles were being published.
The ability of a planet to establish climatic circumstances beneficial to the origin of life is known as planetary habitability, and it currently favours planets with liquid water on their surface. Most frequently, this requires that a planet's orbit fall inside the habitable zone, which for the Sun is thought to extend from within Earth's orbit to around Mars' orbit. Mars dips into this zone during perihelion, but its thin (low-pressure) atmosphere prohibits liquid water from lingering for very long there. The planet's capacity for habitability is demonstrated by the flow of liquid water in the past. Recent data suggests that any surface water on Mars may have been too acidic and salty to support typical terrestrial life.
Since Mars lacks a magnetosphere, it has poor protection against solar wind bombardment and insufficient atmospheric pressure to keep water in a liquid state (water instead sublimes to a gaseous state), all of which make it difficult to support organic life. Mars also has little heat transfer across its surface. The cessation of volcanic activity appears to have halted the recycling of chemicals and minerals between the surface and the interior of the planet, rendering Mars largely, or possibly completely, geologically dead.
The Viking landers, Spirit and Opportunity rovers, Phoenix landers, and Curiosity rovers have all conducted in-situ research on Mars. Although there is evidence that the planet was once much more habitable than it is now, it is still unknown whether there have ever been any living things there. At their various landing sites, the Viking probes of the mid-1970s conducted studies to identify microorganisms in Martian soil, and the results were encouraging, including a brief rise in CO2 generation in response to water and nutrients. Scientists eventually refuted this evidence of life, sparking a discussion that is still going on now. NASA scientist Gilbert Levin claims that Vikings may have discovered life.
The soil has an alkaline pH and includes magnesium, sodium, potassium, and chloride, according to tests by the Phoenix Mars lander. Life could be able to survive on the soil's nutrients, but it would still need protection from the strong ultraviolet light. Chlorate, perchlorate, and nitrate ions were discovered in 2014 during a study of the Martian meteorite EETA79001, indicating that they are likely common on Mars. Chlorate and perchlorate ions would be transformed into additional, more reactive oxychloride by UV and X-ray radiation, indicating that any organic molecules would need to be buried below the surface to survive. The average radiation level on the surface is 0.64 millisieverts per day, which is much less than the radiation level of 1.84 millisieverts per day or 22 millirads per day during the flight to and from Mars.
In Low Earth Orbit, where Earth's space stations orbit, the radiation levels are roughly 0.5 millisieverts per day. With lava tubes southwest of Hadriacus Mons that may have radiation levels as low as 0.064 millisieverts per day, Hellas Planitia has the lowest surface radiation at about 0.342 millisieverts per day.
Carbonate globules discovered in meteorite ALH84001, which is assumed to have come from Mars, have been theorised to be fossilised bacteria that were present there when the meteorite was blasted from the Martian surface by a meteor strike some 15 million years ago. A wholly inorganic origin for the shapes has been suggested in response to scepticism about this proposal. Both methane and formaldehyde, which are found in trace amounts by Mars orbiters, are thought to be probable signs of life because they would decompose swiftly in the atmosphere of Mars.
These substances could also be renewed through volcanic activity or other geological processes, like serpentinite. On the surface of impact craters on Mars, impact glass has been discovered. On Earth, impact glass can preserve indications of life. Similarly, if there had been life at the location, the glass in impact craters on Mars might have retained indications of it.
Geology
The topography and physiography of Mars' northern and southern hemispheres differ noticeably from one another. A key worldwide geologic feature of the earth is this dichotomy. A sizable topographic depression can be found in the northern region. The elevation of around one-third of the surface is 3-6 km lower than that of the other two-thirds of the surface, especially in the northern hemisphere. The variation in elevation between the continents and ocean basins of Earth is comparable to this first-order relief feature. As a disparity in impact crater density and crustal thickness between the two hemispheres, as well as these other two ways of expressing the dichotomy. The hemisphere south of the dichotomy border, also known as the southern highlands or uplands, is extremely ancient and extensively cratered, with rough surfaces that date back to the age of tremendous bombardment.
In contrast, the lowlands to the north of the dichotomy border are remarkably smooth and level, have fewer big craters, and have other traits that suggest considerable resurfacing has taken place since the formation of the southern highlands. The thickness of the crust is the third difference between the two hemispheres. The crust in the southern highlands "peaks" at around 58 km (36 mi) in thickness, while the crust in the northern lowlands "peaks" at about 32 km (20 mi) in thickness, according to topographic and geophysical gravity data. Depending on which of the three physical manifestations of the dichotomy is being taken into consideration, the dichotomy border can be found at different latitudes across Mars.
The topography and physiography of Mars' northern and southern hemispheres differ noticeably from one another. A key worldwide geologic feature of the earth is this dichotomy. A sizable topographic depression can be found in the northern region. The elevation of around one-third of the surface is 3-6 km lower than that of the other two-thirds of the surface, especially in the northern hemisphere. The variation in elevation between the continents and ocean basins of Earth is comparable to this first-order relief feature. As a disparity in impact crater density and crustal thickness between the two hemispheres, as well as these other two ways of expressing the dichotomy. The hemisphere south of the dichotomy border, also known as the southern highlands or uplands, is extremely ancient and extensively cratered, with rough surfaces that date back to the age of tremendous bombardment.
In contrast, the lowlands to the north of the dichotomy border are remarkably smooth and level, have fewer big craters, and have other traits that suggest considerable resurfacing has taken place since the formation of the southern highlands. The thickness of the crust is the third difference between the two hemispheres. The crust in the southern highlands "peaks" at around 58 km (36 mi) in thickness, while the crust in the northern lowlands "peaks" at about 32 km (20 mi) in thickness, according to topographic and geophysical gravity data. Depending on which of the three physical manifestations of the dichotomy is being taken into consideration, the dichotomy border can be found at different latitudes across Mars.
Mars does not now appear to have a structured global magnetic field, but observations do indicate that the planet's crust includes magnetic regions and that its dipole field has seen past alternating polarity reversals. The alternating bands observed on the ocean floors of Earth have many characteristics with the paleomagnetism of magnetically sensitive minerals. One argument is that these bands show plate tectonics on Mars four billion years ago, before the planetary dynamo stopped working and the planet's magnetic field went away. It was first proposed in 1999 and reexamined in October 2005 (with the aid of the Mars Global Surveyor). http://planetary-science.org/mars-research/surface-geology-of-mars/
The volcanic provinces Tharsis and Elysium
The Tharsis area or Tharsis bulge is a vast volcano-tectonic province that spans the dichotomy barrier in Mars' western hemisphere. This enormous, raised structure has a circumference of thousands of kilometres and may take up as much as 25% of the planet's surface. Tharsis has the greatest heights on the planet and the largest known volcanoes in the Solar System; it is typically 7–10 km above datum (Martian "sea" level). The Tharsis Montes, which consist of three massive volcanoes named Ascraeus Mons, Pavonis Mons, and Arsia Mons, are positioned NE-SW along the bulge's crest. The northern section of the area is occupied by the enormous Alba Mons (formerly known as Alba Patera). At the western extremity of the province, off the main bulge, is the enormous shield volcano Olympus Mons.
The lithosphere of the planet has undergone severe strains as a result of Tharsis' high mass. The upshot is that from Tharsis, enormous extensional cracks (grabens and rift valleys) stretch outward, encircling the globe.
Several thousand kilometres to the west of Tharsis, Elysium, is a minor volcanic centre. Three major volcanoes—Elysium Mons, Hecates Tholus, and Albor Tholus—make up the 2,000-kilometer-diameter Elysium volcanic complex. It is believed that the Elysium group of volcanoes differs somewhat from the Tharsis Montes in that the former's formation involved both lavas and pyroclastic rocks.
The Tharsis area or Tharsis bulge is a vast volcano-tectonic province that spans the dichotomy barrier in Mars' western hemisphere. This enormous, raised structure has a circumference of thousands of kilometres and may take up as much as 25% of the planet's surface. Tharsis has the greatest heights on the planet and the largest known volcanoes in the Solar System; it is typically 7–10 km above datum (Martian "sea" level). The Tharsis Montes, which consist of three massive volcanoes named Ascraeus Mons, Pavonis Mons, and Arsia Mons, are positioned NE-SW along the bulge's crest. The northern section of the area is occupied by the enormous Alba Mons (formerly known as Alba Patera). At the western extremity of the province, off the main bulge, is the enormous shield volcano Olympus Mons.
The lithosphere of the planet has undergone severe strains as a result of Tharsis' high mass. The upshot is that from Tharsis, enormous extensional cracks (grabens and rift valleys) stretch outward, encircling the globe.
Several thousand kilometres to the west of Tharsis, Elysium, is a minor volcanic centre. Three major volcanoes—Elysium Mons, Hecates Tholus, and Albor Tholus—make up the 2,000-kilometer-diameter Elysium volcanic complex. It is believed that the Elysium group of volcanoes differs somewhat from the Tharsis Montes in that the former's formation involved both lavas and pyroclastic rocks.
Impact basins
On Mars, there are several large, circular impact basins. The Hellas basin, which is in the southern hemisphere, is the largest one that is clearly visible. With a centre at roughly 64°E longitude and 40°S latitude, it is the second-largest confirmed impact structure on the globe. Its 1,800 km-diameter Hellas Planitia centre is ringed by a large, severely eroded annular rim structure with sparsely spaced rough irregular mountains (massifs), which most likely are uplifted, jostled chunks of the old pre-basin crust. On the northwest and southwest corners of the rim, there are old, low-relief volcanic structures. The sedimentary strata on the basin floor are thick, structurally intricate, and have a lengthy geologic history of deposition, erosion, and internal deformation. The Hellas basin contains the lowest heights on earth, with certain regions of the basin floor plunging more than 8 km below the datum.
The Argyre and Isidis basins are the planet's other two significant impact features. Argyre (800 km in diameter), like Hellas, is situated in the southern highlands and is encircled by a substantial ring of mountains. Charitum Montes, a group of mountains on the southern part of the rim, may have been eroded at some point in Mars' past by valley glaciers and ice sheets. On the dichotomy boundary, at around 87°E longitude, is the Isidis basin, which has a diameter of about 1,000 km. The basin has a semi-circular shape since the northern-eastern portion of its rim has been eroded and is currently covered by deposits from the northern plains. Arcuate grabens that surround the basin's northwest rim are what give it its distinctive appearance. Deposits from the northern plains entirely engulf another sizable basin called Utopia. Only the altimetry data can plainly see its contour. The vast basins on Mars are all very ancient and originated from the final intense bombardment. They are believed to be similar in age to the Moon's Imbrium and Orientale basins.
Equatorial canyonThe Valles Marineris is a vast network of deep, linked canyons and troughs in the western hemisphere that is located close to the equator. Nearly a fifth of the planet's circumference, or over 4,000 km, of the canyon system, is located east of Tharsis. Valles Marineris would be as wide as North America if it were placed on Earth. The canyons are up to 300 km broad and 10 km deep in certain areas. The Valles Marineris, which is sometimes compared to Earth's Grand Canyon, has a totally different genesis than its smaller, so-called equivalent on Earth. Water erosion is largely responsible for creating the Grand Canyon. The Martian equatorial canyons were generated mostly by faulting and were of tectonic origin. They might resemble the rift valleys of East Africa. The canyons are the surface manifestation of the Martian crust's strong extensional strain, which is most likely the result of stress from the Tharsis bulge.
terrain and outflow channelsThe eastern end of the Valles Marineris has a landscape that descends into a dense jumble of low, rounded hills that appear to have been created by the collapse of upland surfaces to create wide, rubble-filled hollows. These regions are known as chaotic terrain, and they serve as the heads of enormous outflow channels that fully emerge from the chaotic terrain and empty (debouch) into Chryse Planitia to the north. The channels were most likely created by catastrophic releases of water from aquifers or the melting of underlying ice, as indicated by the presence of streamlined islands and other geomorphic characteristics. These features could, however, potentially have been created by several volcanic lava flows that originated in Tharsis.
By terrestrial standards, the channels, which include Ares, Shalbatana, Simud, and Tiu Valles, are vast, and the flows that created them were also tremendous. For instance, it is estimated that a peak discharge of 14 million cubic metres (500 million cu ft) per second, or more than ten thousand times the Mississippi River's typical discharge, was needed to carve the 28-km-wide Ares Vallis.
Ice caps
Christiaan Huygens first recognised the polar ice caps as telescopic features of Mars in 1672. Since the 1960s, we have known that during the polar winter, when temperatures drop to 148 K, the CO2 frost threshold, CO2 ice condenses out of the atmosphere, forming the seasonal caps (those observed in the telescope to grow and wane seasonally). In the north, the CO2 ice sublimates (totally melts) in the summer, leaving a capped remnant of water (H2O) ice. A modest CO2 ice cover is still present at the south pole during the summer.
Both remaining ice caps are covered by thick stratified deposits of ice and dust that are intertwined. The stratified deposits in the north create the 3 km high and 1,000 km wide Planum Boreum plateau. Planum Australe, a similar kilometre-thick plateau, is located to the south. Although both plana (the Latin plural of planum) and polar ice caps are commonly used interchangeably, the permanent ice actually only forms a thin mantle on top of the stratified deposits. The stratified layers most likely represent alternating cycles of dust and ice deposition brought on by climatic modifications associated with changes in the planet's orbital parameters over time. Some of the youngest geologic units on Mars can be found in the polar layered deposits.
Christiaan Huygens first recognised the polar ice caps as telescopic features of Mars in 1672. Since the 1960s, we have known that during the polar winter, when temperatures drop to 148 K, the CO2 frost threshold, CO2 ice condenses out of the atmosphere, forming the seasonal caps (those observed in the telescope to grow and wane seasonally). In the north, the CO2 ice sublimates (totally melts) in the summer, leaving a capped remnant of water (H2O) ice. A modest CO2 ice cover is still present at the south pole during the summer.
Both remaining ice caps are covered by thick stratified deposits of ice and dust that are intertwined. The stratified deposits in the north create the 3 km high and 1,000 km wide Planum Boreum plateau. Planum Australe, a similar kilometre-thick plateau, is located to the south. Although both plana (the Latin plural of planum) and polar ice caps are commonly used interchangeably, the permanent ice actually only forms a thin mantle on top of the stratified deposits. The stratified layers most likely represent alternating cycles of dust and ice deposition brought on by climatic modifications associated with changes in the planet's orbital parameters over time. Some of the youngest geologic units on Mars can be found in the polar layered deposits.
Volcanism
Large sections of the Martian landscape are covered in volcanic landforms and structures. Tharsis and Elysium are home to Mars' two most noticeable volcanoes. Because Mars has fewer tectonic boundaries than Earth does, geologists believe this is one of the reasons Mars' volcanoes have been able to grow so huge. Lava from a stationary hot spot could build up at the same spot on the surface for many hundreds of millions of years.
On the surface of Mars, no active volcano eruption has ever been observed by scientists. In the past ten years, searches for thermal signatures and surface alterations have not turned up any proof of active volcanism.
The first Martian soil X-ray diffraction analysis was carried out on October 17, 2012, by the Curiosity rover at "Rocknest" on Mars. The presence of many minerals, including feldspar, pyroxenes, and olivine, as detected by the rover's CheMin analyzer suggested that the Martian soil in the sample was comparable to the "weathered basaltic soils" of Hawaiian volcanoes. Tridymite was discovered in a rock sample from Gale Crater by the same rover in July 2015, which led researchers to hypothesise that silicic volcanism may have been significantly more frequent than previously believed in the planet's volcanic history.
Large sections of the Martian landscape are covered in volcanic landforms and structures. Tharsis and Elysium are home to Mars' two most noticeable volcanoes. Because Mars has fewer tectonic boundaries than Earth does, geologists believe this is one of the reasons Mars' volcanoes have been able to grow so huge. Lava from a stationary hot spot could build up at the same spot on the surface for many hundreds of millions of years.
On the surface of Mars, no active volcano eruption has ever been observed by scientists. In the past ten years, searches for thermal signatures and surface alterations have not turned up any proof of active volcanism.
The first Martian soil X-ray diffraction analysis was carried out on October 17, 2012, by the Curiosity rover at "Rocknest" on Mars. The presence of many minerals, including feldspar, pyroxenes, and olivine, as detected by the rover's CheMin analyzer suggested that the Martian soil in the sample was comparable to the "weathered basaltic soils" of Hawaiian volcanoes. Tridymite was discovered in a rock sample from Gale Crater by the same rover in July 2015, which led researchers to hypothesise that silicic volcanism may have been significantly more frequent than previously believed in the planet's volcanic history.
Sedimentology
Throughout its history, especially on ancient Mars, flowing water seems to have been widespread on Mars' surface. Numerous of these rivers cut out the terrain, creating networks of valleys and depositing silt. Many different wet settings, such as alluvial fans, meandering channels, deltas, lakes, and possibly even oceans, have seen the re-deposition of this silt.
Gravity is connected to the deposition and transit processes. Martian landscapes were shaped by many environmental factors due to gravity and related variations in water flows and flow speeds, deduced from grain size distributions. However, there are additional methods for determining how much water was present on ancient Mars. Several different sedimentary minerals, including clays, sulphates, and hematite, have been formed and transported as a result of groundwater's role in cementing Aeolian sediments.
The wind has been a significant geomorphic force on dry surfaces. Mega ripples and dunes, two types of wind-driven sand bodies, are very frequent on the current Martian surface, and Opportunity has found a lot of Aeolian sandstones while travelling across the planet. Jake Matijevic (rock) and Ventifacts are both examples of Aeolian landforms on the Martian surface.
Locally on Mars, a wide range of additional sedimentological facies are also present, including cryogenic and periglacial material, glacial deposits, hot springs, dry mass movement deposits (particularly landslides), and dry mass movement deposits. At Meridiani Planum and Gale Crater, rovers have found signs of ancient rivers, a lake, and dunes in the strata that have been preserved.
Groundwater on Mars
One group of scientists suggested that groundwater rising to the surface in several locations, notably inside craters, may have contributed to the formation of some of the strata on Mars. The idea holds that dissolved mineral-containing groundwater that rose to the surface in, and later surrounding craters contributed to the formation of strata by cementing sediments and adding minerals, particularly sulphate. An area-wide discovery of sulphates and a groundwater model both lend credence to this notion. First, scientists found that groundwater had repeatedly risen and deposited sulphates by using Opportunity Rover to examine surface minerals. Later investigations using equipment from the Mars Reconnaissance Orbiter revealed that the same kind of compounds exist across a wide region, including Arabia.
Throughout its history, especially on ancient Mars, flowing water seems to have been widespread on Mars' surface. Numerous of these rivers cut out the terrain, creating networks of valleys and depositing silt. Many different wet settings, such as alluvial fans, meandering channels, deltas, lakes, and possibly even oceans, have seen the re-deposition of this silt.
Gravity is connected to the deposition and transit processes. Martian landscapes were shaped by many environmental factors due to gravity and related variations in water flows and flow speeds, deduced from grain size distributions. However, there are additional methods for determining how much water was present on ancient Mars. Several different sedimentary minerals, including clays, sulphates, and hematite, have been formed and transported as a result of groundwater's role in cementing Aeolian sediments.
The wind has been a significant geomorphic force on dry surfaces. Mega ripples and dunes, two types of wind-driven sand bodies, are very frequent on the current Martian surface, and Opportunity has found a lot of Aeolian sandstones while travelling across the planet. Jake Matijevic (rock) and Ventifacts are both examples of Aeolian landforms on the Martian surface.
Locally on Mars, a wide range of additional sedimentological facies are also present, including cryogenic and periglacial material, glacial deposits, hot springs, dry mass movement deposits (particularly landslides), and dry mass movement deposits. At Meridiani Planum and Gale Crater, rovers have found signs of ancient rivers, a lake, and dunes in the strata that have been preserved.
Groundwater on Mars
One group of scientists suggested that groundwater rising to the surface in several locations, notably inside craters, may have contributed to the formation of some of the strata on Mars. The idea holds that dissolved mineral-containing groundwater that rose to the surface in, and later surrounding craters contributed to the formation of strata by cementing sediments and adding minerals, particularly sulphate. An area-wide discovery of sulphates and a groundwater model both lend credence to this notion. First, scientists found that groundwater had repeatedly risen and deposited sulphates by using Opportunity Rover to examine surface minerals. Later investigations using equipment from the Mars Reconnaissance Orbiter revealed that the same kind of compounds exist across a wide region, including Arabia.
Exploration
Remote exploration of Mars began in the late 20th century, probes launched from Earth have greatly increased our understanding of the Martian system, with a particular emphasis on its geology and prospects for habitability. Engineering interplanetary travel is challenging, and attempts to explore Mars have failed frequently, particularly in the beginning. Approximately 60% of all Mars-bound spacecraft failed before completing their missions, and some failed even before they could start their observations. Some missions have seen unexpected success, like the Mars Exploration Rovers Spirit and Opportunity, which continued to function well into their intended lifespan.
The Curiosity and Perseverance rovers, both controlled by the American space agency NASA, as well as the Zhurong rover, a component of the Tianwen-1 mission by the China National Space Administration (CNSA), are the three operating rovers on the surface of Mars as of December 2022. The planet is being surveyed by seven orbiters, including Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, MAVEN, the Trace Gas Orbiter, the Hope Mars Mission, and the Tianwen-1 orbiter. These orbiters have collected a tonne of data on Mars. There are several planned Mars sample return missions, such as the NASA-ESA Mars Sample Return, that will pick up the samples that the Perseverance rover is currently gathering. In 2021 11 probes were exploring Mars, including the Ingenuity chopper that is assessing potential study locations for Perseverance.
The Soviet Union undertook several missions to Mars beginning in 1960, including the first flybys and hard (impact) landings (Mars 1962B). NASA's Mariner 4 made the first successful flyby of Mars on July 14-15, 1965. When Mariner 9 began orbiting Mars on November 14, 1971, it made history as the first space probe to do so. As technology advanced, the amount of data that probes returned drastically grew.
Two Soviet probes were the first to make contact with the surface: the Mars 2 lander on November 27 and the Mars 3 lander on December 2, 1971. Mars 2 crashed during descent, while Mars 3 made contact with the surface roughly 20 seconds after the first soft landing on Mars. In 1974, Mars 6 was unsuccessful during descent but did send back some garbled atmospheric data. Two orbiters carrying a lander each that made a successful soft landing in 1976 were launched as part of the Viking programme by NASA in 1975. Vikings 1 and 2 were in use for six and three years, respectively. The first colour images of Mars were transmitted by the Viking landers.
In 1988, the Soviet Union dispatched Phobos 1 and Phobos 2 to Mars to research Mars and its two moons, with a special emphasis on Phobos. While travelling to Mars, Phobos 1 lost touch. Phobos 2 photographed Mars and Phobos satisfactorily, but it malfunctioned just before it was supposed to send two landers to the surface of Phobos.
Mars has a reputation for being a challenging space exploration target; just 25 of 55 attempts, or 45.5%, have been totally successful as of 2019, with three more missions being partially successful and partially unsuccessful. However, eight of the sixteen missions since 2001 are still in operation.
Remote exploration of Mars began in the late 20th century, probes launched from Earth have greatly increased our understanding of the Martian system, with a particular emphasis on its geology and prospects for habitability. Engineering interplanetary travel is challenging, and attempts to explore Mars have failed frequently, particularly in the beginning. Approximately 60% of all Mars-bound spacecraft failed before completing their missions, and some failed even before they could start their observations. Some missions have seen unexpected success, like the Mars Exploration Rovers Spirit and Opportunity, which continued to function well into their intended lifespan.
The Curiosity and Perseverance rovers, both controlled by the American space agency NASA, as well as the Zhurong rover, a component of the Tianwen-1 mission by the China National Space Administration (CNSA), are the three operating rovers on the surface of Mars as of December 2022. The planet is being surveyed by seven orbiters, including Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, MAVEN, the Trace Gas Orbiter, the Hope Mars Mission, and the Tianwen-1 orbiter. These orbiters have collected a tonne of data on Mars. There are several planned Mars sample return missions, such as the NASA-ESA Mars Sample Return, that will pick up the samples that the Perseverance rover is currently gathering. In 2021 11 probes were exploring Mars, including the Ingenuity chopper that is assessing potential study locations for Perseverance.
The Soviet Union undertook several missions to Mars beginning in 1960, including the first flybys and hard (impact) landings (Mars 1962B). NASA's Mariner 4 made the first successful flyby of Mars on July 14-15, 1965. When Mariner 9 began orbiting Mars on November 14, 1971, it made history as the first space probe to do so. As technology advanced, the amount of data that probes returned drastically grew.
Two Soviet probes were the first to make contact with the surface: the Mars 2 lander on November 27 and the Mars 3 lander on December 2, 1971. Mars 2 crashed during descent, while Mars 3 made contact with the surface roughly 20 seconds after the first soft landing on Mars. In 1974, Mars 6 was unsuccessful during descent but did send back some garbled atmospheric data. Two orbiters carrying a lander each that made a successful soft landing in 1976 were launched as part of the Viking programme by NASA in 1975. Vikings 1 and 2 were in use for six and three years, respectively. The first colour images of Mars were transmitted by the Viking landers.
In 1988, the Soviet Union dispatched Phobos 1 and Phobos 2 to Mars to research Mars and its two moons, with a special emphasis on Phobos. While travelling to Mars, Phobos 1 lost touch. Phobos 2 photographed Mars and Phobos satisfactorily, but it malfunctioned just before it was supposed to send two landers to the surface of Phobos.
Mars has a reputation for being a challenging space exploration target; just 25 of 55 attempts, or 45.5%, have been totally successful as of 2019, with three more missions being partially successful and partially unsuccessful. However, eight of the sixteen missions since 2001 are still in operation.
This image of "Vera Rubin Ridge" was taken by NASA's Curiosity Mars rover roughly two weeks before to the rover beginning its ascent of this treacherous slope on lower Mount Sharp.
The view was created by combining 13 photos acquired on August 19, 2017, with the right-eye telephoto lens of the Mastcam.
https://www.nasa.gov/image-feature/jpl/pia21851/looking-up-at-layers-of-vera-rubin-ridge-on-sol-1790