- 3750 - MARS - is it a dead planet? Earth is between two planets Venus and Mars. We have just begun to explore close enough to learn if these planets could have ever sustained live? Researchers that seismic signals indicate vulcanism still plays an active role in shaping the Martian surface. So it is not totally dead. Let’s start with Mars first:
--------------------- 3750 - MARS - is it a dead planet?
- See Review 3751 to learn about Venus and Review 3752 to learn about Phobos the satellite of Mars.
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- Since 2018, the NASA InSight Mission deployed the SEIS seismometer on the surface of Mars, seismologists have been listening to the seismic pings of more than 1,300 marsquakes.
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- A detailed analysis of the quakes’ location and spectral character brought a surprise. With epicenters originating in the vicinity of the “Cerberus Fossae‘, a region consisting of a series of rifts or ‘graben“, these quakes tell a new story. A story that suggests vulcanism still plays an active role in shaping the Martian surface.
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- Researchers analyzed a cluster of more than 20 recent marsquakes that originated in the Cerberus Fossae graben system. From the seismic data, scientists concluded that the low-frequency quakes indicate a potentially warm source that could be explained by present day molten lava, magma at that depth, and volcanic activity on Mars.
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- When they scanned observational orbital images of the same area, they noticed that the epicenters were located very close to a structure that has previously been described as a “young volcanic fissure.” Darker deposits of dust around this fissure are present not only in the dominant direction of the wind, but in all directions surrounding the “Cerberus Fossae Mantling Unit“.
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- The darker shade of the dust signifies geological evidence of more recent volcanic activity, within the past 50,000 years, relatively young, in geological terms.
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- Mars is the only planet, other than Earth, in which scientists have ground-based rovers, landers, and now even drones that transmit data. All other planetary exploration, so far, has relied on orbital imagery.
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- “ InSight’s SEIS” is the most sensitive seismometer ever installed on another planet.
Mars is important for understanding similar geological processes on Earth. The red planet is the only one we know of, so far, that has a core composition of iron, nickel, and sulphur that might have once supported a magnetic field.
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- Topographical evidence also indicates that Mars once held vast expanses of water and possibly a denser atmosphere. Even today, scientists have learned that frozen water, although possibly mostly dry ice, still exists on its polar caps.
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- 3.6 billion years ago Mars was very much alive, at least in a geophysical sense. It spewed volcanic debris for a long enough time to give rise to “Tharsis Montes region“, the largest volcanic system in our solar system and the “Olympus Mons“, a volcano nearly three times the elevation of Mount Everest.
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- The quakes coming from “Cerberus Fossae” suggest that Mars is not quite dead yet. Here the weight of the volcanic region is sinking and forming parallel graben (or rifts) that pull the crust of Mars apart. What we are seeing are the last remnants of this once active volcanic region or that the magma is right now moving eastward to the next location of eruption.
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- “Mars Express” satellite has revealed that Mars churns up surprisingly Earth-like cloud patterns that are reminiscent of those in our planet’s tropical regions. Earth and Mars have vastly different atmospheres. The dry, cold atmosphere of Mars is composed almost entirely of carbon dioxide while Earth’s is rich in nitrogen and oxygen. Its atmospheric density is less than one fiftieth of Earth’s atmosphere, equivalent to the density found at about 35 kilometers above Earth’s surface.
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- Despite being wildly different, their cloud patterns have been found to be surprisingly Earth-like, pointing to similar formation processes. A new study dives deeper into two dust storms that occurred near the martian North Pole in 2019. Two cameras on board Mars Express, the Visual Monitoring Camera (VMC) and the High Resolution Stereo Camera (HRSC), together with the MARCI camera on board NASA’s Mars Reconnaissance Orbiter, imaged the storms from orbit.
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- The sequence of VMC images shows that the storms appear to grow and disappear in repeated cycles over a period of days, exhibiting common features and shapes. Spiral shapes are notably visible in the wider views of the HRSC images. The spirals are between 1,000 and 2,000 km in length, and their origin is the same as that of the extra-tropical cyclones observed in Earth's mid-latitudes and polar latitudes.
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- The martian dust storms are made up of regularly spaced smaller cloud cells, arranged like grains or pebbles. The same texture is also seen in clouds in Earth’s atmosphere. The familiar textures are formed by convection, whereby hot air rises because it is less dense than the cooler air around it.
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- The type of convection observed here is called “closed-cell convection“, when air rises in the center of small cloud pockets, or cells. The gaps of sky around the cloud cells are the pathways for cooler air to sink below the hot rising air.
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- On Earth, the rising air contains water which condenses to form clouds. The dust clouds on Mars Express show the same process, but on Mars the rising air columns contain dust rather than water. The Sun heats dust-laden air causing it to rise and form dusty cells. The cells are surrounded by areas of sinking air which have less dust. This gives rise to the granular pattern also seen in the image of clouds on Earth.
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- By tracking the movement of cells in the sequence of images, the wind speed can be measured. Wind blows over the cloud features at speeds of up to 140 kilometers / hour, causing the shape of the cells to elongate in the direction of the wind. Despite the chaotic and dynamic atmospheres of Mars and Earth, nature creates these orderly patterns. One key insight made possible with the VMC images is the measurement of the altitude of dust clouds.
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- The length of the shadows they cast are measured and combined with knowledge of the Sun’s position to measure the height of the clouds above the martian surface. Results revealed that dust can reach approximately 6 to 11 kilometers above the ground and the cells have typical horizontal sizes of 20 to 40 km.
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- Despite the unpredictable behavior of dust storms on Mars and the strong wind gusts that accompany them, we have seen that within their complexity, organized structures such as fronts and cellular convection patterns can emerge.
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- Such organized cellular convection is not unique to Earth and Mars; observations of the Venusian atmosphere by Venus Express show similar patterns. Mars dry convection is a further example of the value of comparative studies of similar phenomena occurring in planetary atmospheres in order to better understand the mechanisms underlying them under different conditions and environments.
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- Understanding dust storms is relevant for future missions to Mars. In extreme cases, dust storms can block much of the light from the Sun from reaching the solar cells of rovers on the surface of the Red Planet.
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- In 2018, a planetary-scale dust storm not only blocked sunlight reaching the surface, but also covered the solar panels of NASA’s Opportunity rover with dust. Both of these factors led to the rover losing electrical power, ending the mission. Monitoring the evolution of dust storms is crucial for helping protect future solar-powered missions and eventually crewed missions to the planet against such powerful phenomena.
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- When Mars was a young planet, it was bombarded by ice asteroids delivering water and organic molecules necessary for life to emerge. Mars is called the “red planet“. But once, it was actually blue and covered in water, bringing us closer to finding out if Mars had ever harbored life.
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- Some 4.5 billion years ago, there was enough water for the entire planet to be covered in a 300-meter-deep ocean. This as when Mars was bombarded with asteroids filled with ice. It happened in the first 100 million years of the planet's evolution. The asteroids also carried organic molecules that are biologically important for life.
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- The icy asteroids also brought biologically relevant molecules such as amino acids to the Red Planet. Amino acids are used when DNA and RNA form bases that contain everything a cell needs.
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- The oceans that covered the entire planet in water were at least 300 meters deep, but they may have been up to one kilometer deep. In comparison, there is actually very little water on Earth.
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- This happened within Mars’s first 100 million years. After this period, something catastrophic happened for potential life on Earth. It is believed that there was a gigantic collision between the Earth and another Mars-sized planet. It was an energetic collision that formed the Earth-Moon system and, as the same time, wiped out all potential life on Earth.
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- Conditions allowing the emergence of life were present on Mars long before Earth. It was by means of a meteorite that is billions of years old that the researchers have been able to look into Mars’s past history. The meteorite was once part of Mars’s original crust and offers a unique insight into what happened at the time when the solar system was formed.
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- The whole secret is hiding in the way Mars’s surface has been created because it is a surface that does not move. On Earth it is opposite. The tectonic plates are in perpetual motion and recycled in the planet’s interior.
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- Plate tectonics on Earth erased all evidence of what happened in the first 500 million years of our planet’s history. The plates constantly move and are recycled back and destroyed into the interior of our planet. In contrast, Mars does not have plate tectonics such that planet’s surface preserves a record of the earliest history of the planet.
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“Mars Express” space probe has revealed that Mars churns up surprisingly Earth-like cloud patterns that are reminiscent of those in our planet’s tropical regions. Earth and Mars have vastly different atmospheres. The dry, cold atmosphere of Mars is composed almost entirely of carbon dioxide while Earth’s is rich in nitrogen and oxygen.
-
- Its atmospheric density is less than one fiftieth of Earth’s atmosphere, equivalent to the density found at about 35 km above Earth’s surface. Despite being wildly different, their cloud patterns have been found to be surprisingly Earth-like, pointing to similar formation processes.
-
- The sequence of “Visual Monitoring Camera“, VMC, images shows that the storms appear to grow and disappear in repeated cycles over a period of days, exhibiting common features and shapes. Spiral shapes are notably visible in the wider views of the images. The spirals are between 1,000 and 2,000 km in length, and their origin is the same as that of the extra-tropical cyclones observed in Earth's mid-latitudes and polar latitudes.
-
- The images reveal a particular phenomenon on Mars. They show that the martian dust storms are made up of regularly spaced smaller cloud cells, arranged like grains or pebbles. The texture is also seen in clouds in Earth’s atmosphere.
-
- The familiar textures are formed by convection, whereby hot air rises because it is less dense than the cooler air around it. The type of convection observed here is called “closed-cell convection“, when air rises in the center of small cloud pockets, or cells. The gaps of sky around the cloud cells are the pathways for cooler air to sink below the hot rising air.
-
- On Earth, the rising air contains water which condenses to form clouds. The dust clouds imaged by Mars Express show the same process, but on Mars the rising air columns contain dust rather than water. The Sun heats dust-laden air causing it to rise and form dusty cells. The cells are surrounded by areas of sinking air which have less dust. This gives rise to the granular pattern also seen in the image of clouds on Earth.
-
- The length of the shadows the dust clouds cast are measured and combined with knowledge of the Sun’s position to measure the height of the clouds above the martian surface. Results revealed that dust can reach approximately 6–11 km above the ground and the cells have typical horizontal sizes of 20–40 km.
-
- Despite the unpredictable behavior of dust storms on Mars and the strong wind gusts that accompany them, we have seen that within their complexity, organized structures such as fronts and cellular convection patterns can emerge.
-
- Such organized cellular convection is not unique to Earth and Mars; observations of the Venusian atmosphere by Venus Express arguably show similar patterns. As well as learning more about how planetary atmospheres ‘work’, understanding dust storms is relevant for future missions to Mars.
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- Another interesting angle is that the asteroids also carried organic molecules that are biologically important for life. The icy asteroids brought biologically relevant molecules such as amino acids to the Red Planet. Amino acids are used when DNA and RNA form bases that contain everything a cell needs.
-
- The new study indicates that the oceans that covered the entire planet in water were at least 300 meters deep. They may have been up to one kilometer deep. In comparison, there is actually very little water on Earth.
-
- This happened within Mars’s first 100 million years. After this period, something catastrophic happened for potential life on Earth. It is believed that there was a gigantic collision between the Earth and another Mars-sized planet. It was an energetic collision that formed the Earth-Moon system and, as the same time, wiped out all potential life on Earth.
-
- Therefore, the researchers have really strong evidence that conditions allowing the emergence of life were present on Mars long before Earth. It was by means of a meteorite that is billions of years old that the researchers have been able to look into Mars’s past history. The meteorite was once part of Mars’s original crust and offers a unique insight into what happened at the time when the solar system was formed.
-
- The whole secret is hiding in the way Mars’s surface has been created and of which the meteorite was once a part because it is a surface that does not move. On Earth it is opposite. The tectonic plates are in perpetual motion and recycled in the planet’s interior.
-
- Plate tectonics on Earth erased all evidence of what happened in the first 500 million years of our planet’s history. The plates constantly move and are recycled back and destroyed into the interior of our planet. In contrast, Mars does not have plate tectonics such that planet’s surface preserves a record of the earliest history of the planet,” explains Martin Bizzarro.
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- Scientists have long suspected that Mars was once warm and wet in its ancient past. The “Mars Ocean Hypothesis” says that the planet was home to a large ocean around 4 billion years ago. The ocean filled the Vastitas Borealis basin in the planet’s northern hemisphere. The basin is 2.5–3 miles below Mars’ mean elevation.
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- The “Aeolis Dorsa region” is the shoreline of an ancient ocean. The region contains more than 4,000 miles of ridges and is Mars’ most dense region of “fluvial ridges“. Fluvial ridges are elongated troughs carved by flowing water and are likely eroded river deltas or submarine-channel belts.
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- The topography revealed the presence of a 3.5 billion-year-old shoreline. There are sedimentary deposits over 2,950 feet deep in the region that have since been eroded to different degrees.
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- The topographic map shows definitive evidence of a roughly 3.5-billion-year-old shoreline with substantial sedimentary accumulation, at least 900 meters thick, that covered hundreds of thousands of square kilometers.
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- “Aeolis Dorsa” is a sedimentary basin, and scientists know from studying Earth how much geological information these basins hold. The basins contain a record of sediment deposits over geological time scales, referrd to as ‘stratigraphic succession.’ On Earth, sedimentary basins also hold a lot of resources. Earth’s coal, natural gas, and petroleum are found in these basins. Mars won’t have these resources, but the basins contain stratigraphic records of geological periods.
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- The rocks in Aeolis Dorsa capture some fascinating information about what the ocean was like. It was dynamic. The sea level rose significantly. Rocks were being deposited along its basins at a fast rate. There was a lot of change happening here.
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- “Stratigraphy” played a vital role in this research. Stratigraphy is the geological study of layers of rock. It only makes sense to look for sedimentary basins on Mars for clues on that planet’s history. Water is critical in our quest to understand Mars and its ancient habitability. Stratigraphy is how researchers can understand how all that sediment built up over time as changing water levels caused the shoreline to advance and retreat.
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- By grouping landforms based on stratigraphic position paleoflow directions were reconstructed. They tracked the initial regression and later transgression of a shoreline during at least 900 meters of sea-level rise, a scale consistent with a northern ocean on a warm and wet early Mars.
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- Viking spacecraft found shorelines thousands of kilometers long Orbital data from the “Mars Global Surveyor” found they rose and fell several kilometers in altitude. There’s nothing like that on Earth. Mars’ spin axis has shifted by almost 3,000 km in the past 2 or 3 billion years. That could’ve accounted for the enormous changes in shoreline elevations on Mars.
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- Cells are the building blocks of living things, and they need liquid. Water provides pressure inside cells, which keeps everything inside the cell in the right shape. Without the proper form, the parts of the cell can’t function properly, and there’s no rigidity inside a cell. Without water, it’s all over. In fact, cells are about 70% water by mass.
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- So the search for ancient life on Mars is intertwined with the search for ancient water. Since scientists think that shorelines on Earth were likely where life started, it makes sense to find shorelines on Mars as part of our search for ancient habitability.
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- A major goal for the Mars Curiosity rover missions is to look for signs of life. It’s always been looking for water, for traces of habitable life. This is the biggest one yet. It’s a giant body of water, fed by sediments coming from the highlands, presumably carrying nutrients. If there were tides on ancient Mars, they would have been here, gently bringing in and out water. This is exactly the type of place where ancient Martian life could have evolved.
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- November 20, 2022 MARS - is it a dead planet? 3750
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--------------------- --- Monday, November 21, 2022 ---------------------------
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