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The Planet Mars: Scientific Findings & Conjectures

A newly-published analysis of Mars surface imagery strongly suggests the valleys long attributed to flowing streams and a warm climate can largely (if not exclusively) be the result of sub-glacial water flows and a colder climate.
New Findings Throw Cold Water on Ancient Mars Hypothesis

Early Mars was covered in ice sheets, not flowing rivers.

A large number of the valley networks scarring Mars’s surface were carved by water melting beneath glacial ice, not by free-flowing rivers as previously thought, according to new UBC research published today (August 3, 2020) in Nature Geoscience. The findings effectively throw cold water on the dominant “warm and wet ancient Mars” hypothesis, which postulates that rivers, rainfall, and oceans once existed on the red planet.

To reach this conclusion, lead author Anna Grau Galofre, former PhD student in the department of earth, ocean and atmospheric sciences, developed and used new techniques to examine thousands of Martian valleys. She and her co-authors also compared the Martian valleys to the subglacial channels in the Canadian Arctic Archipelago and uncovered striking similarities.

“For the last 40 years, since Mars’s valleys were first discovered, the assumption was that rivers once flowed on Mars, eroding and originating all of these valleys,” says Grau Galofre. “But there are hundreds of valleys on Mars, and they look very different from each other. If you look at Earth from a satellite you see a lot of valleys: some of them made by rivers, some made by glaciers, some made by other processes, and each type has a distinctive shape. Mars is similar, in that valleys look very different from each other, suggesting that many processes were at play to carve them.” ...
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FULL STORY: https://scitechdaily.com/new-findings-throw-cold-water-on-ancient-mars-hypothesis/
 
Here are the bibliographic details and abstract from the Mars valley formation paper ...

Grau Galofre, A., Jellinek, A.M. & Osinski, G.R.
Valley formation on early Mars by subglacial and fluvial erosion.
Nat. Geosci. (2020).
https://doi.org/10.1038/s41561-020-0618-x
Abstract
The southern highlands of Mars are dissected by hundreds of valley networks, which are evidence that water once sculpted the surface. Characterizing the mechanisms of valley incision may constrain early Mars climate and the search for ancient life. Previous interpretations of the geological record require precipitation and surface water runoff to form the valley networks, in contradiction with climate simulations that predict a cold, icy ancient Mars. Here we present a global comparative study of valley network morphometry, using a principal-component-based analysis with physical models of fluvial, groundwater sapping and glacial and subglacial erosion. We found that valley formation involved all these processes, but that subglacial and fluvial erosion are the predominant mechanisms. This is supported by predictions from models of steady-state erosion and geomorphological comparisons to terrestrial analogues. The inference of subglacial channels among the valley networks supports the presence of ice sheets that covered the southern highlands during the time of valley network emplacement.
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SOURCE: https://www.nature.com/articles/s41561-020-0618-x#citeas
 
New depths revealed.

Two years ago, NASA’s InSight spacecraft alighted on the surface of Mars, aiming to glean clues to the planet’s interior from the shaking of distant earthquakes and deep heat leaking from its soil.

Mars, it turned out, had other ideas. Its sticky soil has thwarted InSight’s heat probe, and in recent months howling winds have deafened its sensitive seismometers. Most mysteriously, the planet hasn’t been rattled by the large marsquakes that could vividly illuminate its depths.

Despite these hurdles, a precious clutch of small-but-clear quakes has enabled the InSight team to see hints of boundaries in the rock, tens and hundreds of kilometers below. They are clues to the planet’s formation billions of years ago, when it was a hot ball of magma and heavier elements like iron sank to form a core, while lighter rocks rose up out of the mantle to form a capping lid of crust.

The results, some debuting this month at an online meeting of the American Geophysical Union (AGU), show the planet’s crust is surprisingly thin, its mantle cooler than expected, and its large iron core still molten. The findings suggest that in its infancy, Mars efficiently shed heat—perhaps through a pattern of upwelling mantle rock and subducting crust similar to plate tectonics on Earth. “This may be evidence for a far more dynamic crust formation in Mars’s early days,” says Stephen Mojzsis, a planetary scientist at the University of Colorado, Boulder, who is unaffiliated with the mission.

https://www.sciencemag.org/news/202...ath-surface-offering-clues-planet-s-formation
 
Wibbley Wobbley Mars.

The Red Planet is wiggling and wobbling as it spins, research in the journal Geophysical Research Letters confirms, and astronomers have no idea why.

Like a toy top that teeters as it loses speed, the poles of Mars are wandering ever-so-slightly away from the planet's axis of rotation, moving about 4 inches (10 centimeters) off-center every 200 days or so, researchers reported in a study published Oct. 13, 2020. That makes Mars only the second known planet in the universe to exhibit this phenomenon — known as the Chandler wobble — with Earth being the first, according to the American Geophysical Union's (AGU) news blog, Eos.org.

This wobble — named for astronomer Seth Carlo Chandler, who discovered the phenomenon more than a century ago — is an effect seen in planets that aren't perfectly round, science writer Jack Lee wrote at Eos. On Earth, the wobble is much more pronounced: Our planet's poles wander roughly 30 feet (9 m) from its axis of rotation, wobbling in a circular pattern that repeats every 433 days or so.

This wonky wobble has negligible effect on our planet, according to Eos, but still presents a puzzle. Scientists have calculated that the wobble should naturally die down within a century of its origin, but our planet's current wobble has been going strong for much longer than that. Something — perhaps a combination of pressure changes in the atmosphere and oceans, one 2001 study proposed — seems to be perpetually reigniting the wobble, though the exact mechanism is still unknown.

The Mars wobble is just as puzzling. The authors of the new study detected the wobble using 18 years of data collected by three satellites orbiting the Red Planet: Mars Odyssey, ...

https://www.space.com/mars-chandler-wobble
 
Will that make it difficult to stand on if we ever get there? I say "we"...
 
This could fit in a few threads but seeing as the discovery helps to solve a Martian mystery I'll post it here.

Researchers have discovered a common martian mineral deep within an ice core from Antarctica.

The find suggests the mineral—a brittle, yellow-brown substance known as jarosite—was forged the same way on both Earth and Mars: from dust trapped within ancient ice deposits. It also reveals how important these glaciers were on the Red Planet: Not only did they carve valleys, the researchers say, but they also helped create the very stuff Mars is made of.

Jarosite was first spotted on Mars in 2004, when the NASA Opportunity rover rolled over fine-grained layers of it. The discovery made headlines because jarosite needs water to form, along with iron, sulfate, potassium, and acidic conditions.

These requirements aren’t easily satisfied on Mars, and scientists began to theorize how the mineral could have become so abundant. Some thought it may have been left behind by the evaporation of small amounts of salty, acidic water. But the alkaline basalt rocks in Mars’s crust would have neutralized the acidic moisture, says Giovanni Baccolo, a geologist at the University of Milan-Bicocca and lead author on the new study. ...


https://www.sciencemag.org/news/2021/01/substance-found-antarctic-ice-may-solve-martian-mystery
 
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Mars: Vast amount of water may be locked up on planet

It's a longstanding mystery: how Mars lost the water that flowed across its surface billions of years ago.

Scientists now think they have an answer: much of it became trapped in the planet's outer layer - its crust.

More than four billion years ago, Mars was warmer and wetter - possibly with a thicker atmosphere. Water coursed through rivers, cutting channels in the rock, and pooled in impact craters.

The Red Planet could have held enough water to cover its entire surface in a layer measuring between 100m and one kilometre deep.

Dr Grindrod, from London's Natural History Museum, told BBC News: "We already know from studies of the atmosphere of Mars that some of that water was lost to space, and ice deposits on and just below the surface tell us that some water became frozen."

Earth has a magnetic shield, or magnetosphere, that helps prevent the atmosphere from escaping. But Mars' magnetic shield is weak and could have allowed elemental components of water to escape from the planet.

But the rate at which hydrogen - one chemical constituent of water - escapes from that atmosphere today suggests this can't be the whole story.

If it's assumed that the current loss rate for hydrogen was the same in the past, "it's a pretty small amount of water that you would have lost through this escape process",

In other words, most of the water must have gone elsewhere.

The results of the team's computer modelling work show that between 30% and 99% of Mars' initial water was incorporated into minerals and buried in the planet's crust.

The authors suggest that most of the water was lost between about 4.1 and 3.7 billion years ago
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more at link.
 
Scientists at NASA have reported an exciting detection by its Insight lander on Mars - mysterious rumblings coming from the interior of the planet.

skynews-mars-nasa-planet-red_4546119.jpg


The researchers believe the seismic events may be caused by a sudden release of energy from the planet's interior, but the nature of that release remains unknown and puzzling.

skynews-mars-insight-seismometer_4792734.jpg


The dome-covered instrument recently detected the rumblings

Intriguingly, the new rumblings are believed to have originated in a location on Mars called Cerberus Fossae, where two other previous candidate events are believed to have originated.

Although these rumblings have sometimes been called "Marsquakes" the planet is not believed to have a similarly active tectonic system like Earth's that causes earthquakes.

https://news.sky.com/story/mysterious-rumblings-from-inside-of-mars-detected-by-nasa-lander-12263691

maximus otter
 
Newly reported observations suggest Mars remains volcanically active and remained more amenable to habitation more recently than previously believed.
There's Evidence Volcanoes Are Active on Mars, Raising Chances of Recent Habitability

Evidence seems to be mounting for a geologically and volcanically active Mars.

A new, close study of volcanic features on the surface of the red planet has found that a lava deposit on the Elysium Planitia appears to be very recent indeed - as in, within the last 50,000 years.

On geological timescales, that's shockingly short. And it could mean that Mars was potentially habitable just as recently, with parts of it similar to regions of volcanic activity in glacial areas such as Iceland, where various forms of extremophile bacteria thrive.

"This may be the youngest volcanic deposit yet documented on Mars. If we were to compress Mars geologic history into a single day, this would have occurred in the very last second," said astronomer David Horvath ...
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FULL STORY: https://www.sciencealert.com/volcan...ve-raising-the-chances-of-recent-habitability
 
Cumulative data gathered by the Insight Lander has allowed scientists to create an initial model of Mars' interior structure.
Scientists mapped the mysterious interior of Mars for the first time ever

Mars' core takes up about half of the planet's interior — much larger than scientists expected. ...

Like a bruised peach sliced apart to reveal an enormous yellow pit, Mars shares its inner mysteries in the first-ever map of an alien planet's interior — released as part of three new studies published July 22 in the journal Science.

This premiere look at the Martian interior is the culmination of two years of research (and decades of planning) with NASA's InSight lander ...

"Unlike Earth, Mars has no tectonic plates; its crust is instead like one giant plate," NASA researchers wrote in a statement. "But faults, or rock fractures, still form in the Martian crust due to stresses caused by the slight shrinking of the planet as it continues to cool."

These fractures can result in seismic vibrations — and over the last two years, InSight has detected 733 of them. Using 35 of the largest marsquakes (each measuring between magnitude 3.0 and 4.0 ), NASA researchers calculated how fast and how far seismic waves were traveling within the planet, allowing them to map its interior structures. ...
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FULL STORY: https://www.livescience.com/mars-interior-first-map.html
 
Analysis of surface features imaged from orbit suggests there was substantial flowing water on Mars' surface as recently as 2 billion years ago - a billion years later than previously believed.
Water on Mars may have flowed for a billion years longer than thought

Observations by a long-running Mars mission suggest that liquid water may have flowed on the Red Planet as little as 2 billion years ago, much later than scientists once thought.

Scientists charted the presence of chloride salt deposits left behind by flowing water using years of data from NASA's Mars Reconnaissance Orbiter (MRO), which has been orbiting the Red Planet since 2006.

By studying dozens of images of salt deposits taken by the spacecraft's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), the scientists interpreted a younger age for the salt deposits using a method "crater counting." The younger a region is, the fewer craters it should have, with adjustments for aspects such as a planet's atmosphere, allowing scientists to estimate its age. ...

The new results push forward the existence of water on Mars from 3 billion years ago to as little as 2 billion years ago, based on the observations, which could have implications for life on Mars and more broadly, the planet's geological history. ...
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FULL STORY: https://www.livescience.com/water-on-mars-billion-years-longer

PUBLISHED RESEARCH REPORT: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2021AV000534
 
Interesting analysis of the Arsia Mons Elongated Cloud (AMEC) here.

Arsia_Mons_Elongated_Cloud_Mars_Express_HRSC_ESA_DLR_FUBerlin_Justin_Cowart.jpg


A recurring, immense cloud, streaming away from the 20km tall Arsia Mons volcano.
With the possible exception of Elysium Planitia, where younger volcanic features may have been observed, Arsia Mons, like all Martian volcanos, is thought to have been extinct for millions of years.
Although appearing to indicate volcanic activity, the article analyses the cloud as orographic, meaning that it is likely formed by warm, humid air flowing up a mountain's slopes.
The mystery remains however why other Martian volcanoes in the vicinity do not have similar cloud features.

https://www.theweathernetwork.com/c...-cloud-revealed-by-esa-mars-express-satellite
 
Greenhouse warming caused by carbon dioxide had been the most popular explanation for why Mars had been warm enough to host flowing surface water for a few billion years. New analyses of extinct river courses combined with simulations of atmospheric processes surprisingly found no evidence for blaming CO2.
Why Did Mars Dry Out? Mystery Deepens As New Study Points to Unusual Answers

Mars once ran red with rivers. The telltale tracks of past rivers, streams, and lakes are still visible today all over the planet. But about three billion years ago, they all dried up—and no one knows why.

“People have put forward different ideas, but we’re not sure what caused the climate to change so dramatically,” said University of Chicago geophysical scientist Edwin Kite. “We’d really like to understand, especially because it’s the only planet we definitely know changed from habitable to uninhabitable.”

Kite is the first author of a new research study that examines the tracks of Martian rivers to see what they can reveal about the history of the planet’s water and atmosphere.

Many scientists had previously assumed that losing carbon dioxide from the atmosphere, which helped to keep Mars warm, caused the trouble. But the new research findings, published on May 25, 2022, in the journal Science Advances, suggest that the change was caused by the loss of some other important ingredient that maintained the planet warm enough for running water. ...

Since Mars doesn’t have tectonic plates to shift and bury the rock over time, ancient river tracks still lie on the surface like evidence abandoned in a hurry.

This allowed Kite and his collaborators ... to analyze maps based on thousands of pictures taken from orbit by satellites. Based on which tracks overlap which, and how weathered they are, the team pieced together a timeline of how river activity changed in elevation and latitude over billions of years.

Then they could combine that with simulations of different climate conditions, and see which matched best. ...

Kite and his collaborators ran many different combinations of these factors in their simulations, looking for conditions that could cause the planet to be warm enough for at least some liquid water to exist in rivers for more than billion years—but then abruptly lose it.

But as they compared different simulations, they saw something surprising. Changing the amount of carbon dioxide in the atmosphere didn’t change the outcome. That is, the driving force of the change didn’t seem to be carbon dioxide. ...

There are several alternative options. The new evidence fits nicely with a scenario, suggested in a 2021 study from Kite, where a layer of thin, icy clouds high in Mars’ atmosphere acts like translucent greenhouse glass, trapping heat. Other scientists have suggested that if hydrogen was released from the planet’s interior, it could have interacted with carbon dioxide in the atmosphere to absorb infrared light and warm the planet.

“We don’t know what this factor is, but we need a lot of it to have existed to explain the results,” Kite said. ...
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FULL STORY: https://scitechdaily.com/why-did-ma...epens-as-new-study-points-to-unusual-answers/

PUBLISHED RESEARCH REPORT: https://www.science.org/doi/10.1126/sciadv.abo5894
 
https://www.cnn.com/2022/06/30/china/china-tianwen-1-mars-images-intl-hnk-scn/index.html

China's Mars probe has photographed the entire red planet​

By Jessie Yeung, CNN
(CNN)After more than a year on the surface of Mars, China's Tianwen-1 probe has taken images covering the entire red planet, the country's space agency announced Wednesday.
Tianwen-1, which means "quest for heavenly truth," was launched in 2020 and landed on Mars last May, when the Zhurong rover on board started its mission of patrolling and exploring the planet while the orbiter spun overhead.
In a statement, China's National Space Agency (CNSA) said the probe has now completed all its assigned tasks, including taking medium-resolution images covering the entire planet.
The images, posted by the space agency on social media, show the Martian landscape's rugged terrain: dusty red dunes, shield volcanoes, impact craters, the south pole ice sheet, and the cliffs and ridges of the Valles Marineris canyons -- one of the largest canyons in our solar system.
The images were taken by the probe's orbiter, which circled Mars 1,344 times, capturing images of the planet from every angle, while the rover explored the surface, CNSA said.
The six-wheeled rover carried scientific instruments on its journey, gathering information about Mars' geological structure, atmosphere, environment and soil. The probe has collected 1,040 gigabytes of raw scientific data, which has been processed by scientists on Earth and handed to research teams for further study, the agency said.
CNSA said it had shared the orbiter's flight information with NASA and the European Space Agency (ESA), and the scientific data will be available to international scientists "at an appropriate time."
With temperatures dropping during the Martian winter, as well as poor sand and dust conditions, the rover entered a dormant mode on May 18 that will last through the harsh season before its expected awakening in December -- when the landing area will enter early spring, bringing better weather.
The orbiter will continue conducting tests and preparing for future tasks, the space agency said.
Prior to China's success with Tianwen-1, only the United States and the former Soviet Union had landed a spacecraft on the surface of Mars -- but India, the ESA, and the United Arab Emirates have sent spacecraft to enter the planet's orbit.
With Tianwen-1, China was the first nation to attempt sending both an orbiter and a rover on its first homegrown Mars mission. NASA, for instance, sent multiple orbiters to Mars before ever attempting a landing.
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And:
https://petapixel.com/2022/06/29/detailed-photos-of-mars-captured-by-chinas-tianwen-1-probe/
 

Volcanic eruption created extremely rare mineral found on Mars​


A chunk of the "extremely rare" mineral tridymite unexpectedly found at the bottom of Gale Crater on Mars may have been created by a volcanic eruption more than three billion years ago.

The discovery of tridymite, a high-temperature and low-pressure form of quartz, perplexed scientists when it was discovered by NASA's Curiosity rover in 2016 because the mineral is normally associated with volcanic activity on Earth where it is already considered very rare.

Gale Crater, where the sample was taken, had been selected as the landing site for the rover because of the likelihood it once contained liquid water.

The tridymite was discovered in a larger rock sample taken from lake-formed mudstone that also contained feldspar, cristobalite and opaline silica.

https://www.upi.com/Science_News/20...ridymite-found-mars-curiousity/2711658766177/

maximus otter
 
Meteoroid shock waves help scientists locate new craters on Mars.

Findings will help build more accurate picture of how often space rocks crash into red planet.

Researchers have located fresh craters on Mars using shock waves caused by lumps of space rock as they tear through the sky and slam into the ground.

The new scars on the face of the planet are the first impact craters ever traced from the bang and crash of hurtling meteoroids bombarding another planet. The findings will help scientists build a more accurate picture of how often Mars is battered by the solar system’s rocky detritus and refine their understanding of the deep internal structure of our planetary neighbour.

“This is the first time we have felt and heard an impact on another planet,” said Prof Raphael Garcia, a planetary seismologist at the Higher Institute of Aeronautics and Space at the University of Toulouse.

To see if they could find craters produced by incoming meteoroids on Mars, the researchers examined seismic waves recorded by Nasa’s InSight lander between May 2020 and September 2021. The probe touched down in the barren expanse of Elysium Planitia in November 2018 on a mission to investigate the planet’s structure, crust and impact activity.
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(C) The Guardian. '22.

No Martians yet, but new craters.
 
Newly published modeling and simulation work suggests Mars could have generated widespread sub-surface microbial life in its distant past. However, their most likely metabolic organization would have involved methane production sufficient to trigger global cooling and drive the microbial life either farther underground or - more probably - extinct.
Underground microbes may have swarmed ancient Mars

Ancient Mars may have had an environment capable of harboring an underground world teeming with microscopic organisms, French scientists reported Monday.

But if they existed, these simple life forms would have altered the atmosphere so profoundly that they triggered a Martian Ice Age and snuffed themselves out, the researchers concluded.

The findings provide a bleak view of the ways of the cosmos. Life — even simple life like microbes — “might actually commonly cause its own demise,” said the study’s lead author, Boris Sauterey, now a post-doctoral researcher at Sorbonne University.

The results “are a bit gloomy, but I think they are also very stimulating.,” he said in an email. “They challenge us to rethink the way a biosphere and its planet interact.” ...
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FULL STORY: https://apnews.com/article/astronom...-environment-4036e0d097f98628cc662ee7cb50b59a
 
Here are the bibliographic details and abstract from the published research report.

Sauterey, B., Charnay, B., Affholder, A. et al.
Early Mars habitability and global cooling by H2-based methanogens.
Nat Astron (2022).
https://doi.org/10.1038/s41550-022-01786-w

Abstract
During the Noachian, Mars’ crust may have provided a favourable environment for microbial life1,2. The porous brine-saturated regolith3,4,5 would have created a physical space sheltered from ultraviolet and cosmic radiation and provided a solvent, whereas the below-ground temperature2 and diffusion6,7 of a dense, reduced atmosphere8,9 may have supported simple microbial organisms that consumed H2 and CO2 as energy and carbon sources and produced methane as a waste. On Earth, hydrogenotrophic methanogenesis was among the earliest metabolisms10,11, but its viability on early Mars has never been quantitatively evaluated. Here we present a probabilistic assessment of Mars’ Noachian habitability to H2-based methanogens and quantify their biological feedback on Mars’ atmosphere and climate. We find that subsurface habitability was very likely, and limited mainly by the extent of surface ice coverage. Biomass productivity could have been as high as in the early Earth’s ocean. However, the predicted atmospheric composition shift caused by methanogenesis would have triggered a global cooling event, ending potential early warm conditions, compromising surface habitability and forcing the biosphere deep into the Martian crust. Spatial projections of our predictions point to lowland sites at low-to-medium latitudes as good candidates to uncover traces of this early life at or near the surface.

SOURCE: https://www.nature.com/articles/s41550-022-01786-w
 
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EnolaGaia said:
Newly published modeling and simulation work suggests Mars could have generated widespread sub-surface microbial life in its distant past. However, their most likely metabolic organization would have involved methane production sufficient to trigger global cooling and drive the microbial life either farther underground or - more probably - extinct.

FULL STORY: https://apnews.com/article/astronom...-environment-4036e0d097f98628cc662ee7cb50b59a
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Maybe that's why the atmosphere is mostly CO2?
Methane breaks down over time to become CO2.
 
Mythopoeika said:
Maybe that's why the atmosphere is mostly CO2?
Methane breaks down over time to become CO2.
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That's a good point, but I don't know one way or the other. The simulation study was highly speculative. It presumed the emergence of microbial life similar to early life on earth (as far as we think we understand it). The full text of the report isn't accessible, so it's difficult to tell what they took into consideration and how they believed the events developed.
 
Images from orbit have been correlated with InSight seismic data to identify the two largest meteor strikes on Mars' surface since all the bots arrived and began exploring.
Two NASA spacecraft detect biggest meteor strikes at Mars

Two NASA spacecraft at Mars — one on the surface and the other in orbit — have recorded the biggest meteor strikes and impact craters yet.

The high-speed barrages last year sent seismic waves rippling thousands of miles across Mars, the first ever detected near the surface of another planet, and carved out craters nearly 500 feet (150 meters) across, scientists reported Thursday in the journal Science.

The larger of the two strikes churned out boulder-size slabs of ice, which may help researchers look for ways future astronauts can tap into Mars’ natural resources.

The Insight lander measured the seismic shocks, while the Mars Reconnaissance Orbiter provided stunning pictures of the resulting craters. ...

The impact observations come as InSight nears the end of its mission because of dwindling power, its solar panels blanketed by dust storms. InSight landed on the equatorial plains of Mars in 2018 and has since recorded more than 1,300 marsquakes.

“It’s going to be heartbreaking when we finally lose communication with InSight,” said Bruce Banerdt of NASA’s Jet Propulsion Laboratory ...

Banerdt estimated the lander had between four to eight more weeks before power runs out.

The incoming space rocks were between 16 feet and 40 feet (5 meters and 12 meters) in diameter ... The impacts registered about magnitude 4.

The larger of the two struck last December some 2,200 miles (3,500 kilometers) from InSight, creating a crater roughly 70 feet (21 meters) deep. The orbiter’s cameras showed debris hurled up to 25 miles (40 kilometers) from the impact, as well as white patches of ice around the crater, the most frozen water observed at such low latitudes ...
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FULL STORY (With Photos): https://apnews.com/article/astronom...ence-planets-364148721693322f03e008dad34461ea
 
Image analysis has identified evidence for a large ocean's existence on Mars circa 3.5 billiion years ago.
Ancient Traces of a Giant Ocean Have Just Been Discovered on Mars

... cientists have found evidence of a vast ocean existing on the surface of the red planet around 3.5 billion years ago, likely covering hundreds of thousands of square kilometers.

That evidence comes in the form of distinctive shoreline topography, identified through numerous satellite images of the Martian surface. When these images are snapped at slightly different angles, a relief map can be constructed.

Researchers have been able to chart out more than 6,500 kilometers (4,039 miles) of fluvial ridges, apparently carved out by rivers, demonstrating that they are most likely eroded river deltas or submarine-channel belts (channels carved out on the seafloor). ...

All this ties into the search for life on Mars. One of the most fundamental questions scientists are looking at in regards to the red planet is whether it has ever had conditions that are hospitable enough to be able to support life.

"What immediately comes to mind as one the most significant points here is that the existence of an ocean of this size means a higher potential for life," says Cardenas.

"It also tells us about the ancient climate and its evolution. Based on these findings, we know there had to have been a period when it was warm enough and the atmosphere was thick enough to support this much liquid water at one time." ...
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FULL STORY: https://www.sciencealert.com/ancient-traces-of-a-giant-ocean-have-just-been-discovered-on-mars
 

Megatsunami swept over Mars after massive asteroid hit the Red Planet​


A Martian megatsunami — a giant killer wave that may have reached more than 80 stories tall — may have raced across the Red Planet after a cosmic impact similar to the one that likely ended Earth's age of dinosaurs, a new study finds.

pohl-crater-768x563.jpg


Although the surface of Mars is now cold and dry, a great deal of evidence suggests that an ocean's worth of water covered the Red Planet billions of years ago. Previous research found signs that two meteor strikes might have triggered a pair of megatsunamis about 3.4 billion years ago.The older tsunami inundated about 309,000 square miles (800,000 square kilometers), while the more recent one drowned a region of about 386,000 square miles (1 million sq. km).

A 2019 study found what may have been ground zero for the younger megatsunami — Lomonosov Crater, a 75-mile-wide (120 km) hole in the ground in the icy plains of the Martian Arctic. Its large size suggests the cosmic impact that dug the hole itself was big, similar in scale to the one from a 6-mile-wide (10 km) asteroid that struck near what is now the town of Chicxulub in Mexico 66 million years ago, triggering a mass extinction that killed off 75% of Earth's species, including all dinosaurs except birds.

Now the new study finds what may be the origin point of the older megatsunami — 69-mile-wide (111 km) Pohl Crater, which the International Astronomical Union named after science-fiction grandmaster Frederik Pohl in August.

https://www.space.com/mars-megatsunami-massive-asteroid-impact-crater

maximus otter
 
Interactive Zoomable Mars Map

The map is a product of Caltech’s Bruce Murray Laboratory for Planetary Visualization, and took six years and tens of thousands of hours to develop.

‘I wanted something that would be accessible to everyone,’ said Jay Dickson, the image processing scientist who led the project and manages the Murray Lab.

The map allows you to view cliffsides, impact craters, and dust devil tracks, captured in detail in a new mosaic composed of 110,000 images.

To create the new mosaic, Dickson developed an algorithm to match images based on the features they captured. He manually stitched together the remaining 13,000 images that the algorithm couldn’t match.

The remaining gaps in the mosaic represent parts of Mars that hadn’t been imaged by CTX by the time Dickson started working on this project, or areas obscured by clouds or dust.

One of the mosaic’s coolest features highlights impact craters across the entire planet, allowing viewers to see just how scarred Mars is.

‘For 17 years, MRO has been revealing Mars to us as no one had seen it before,’ said the mission’s project scientist, Rich Zurek of JPL. ‘This mosaic is a wonderful new way to explore some of the imagery that we’ve collected.’
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The first fossil evidence pointing to an environment that once could have hosted life on Mars has been reported​


The discovery of hexagonal patterns in ancient Martian mud suggests it once had a cyclical climate with seasons similar to those on Earth.

The detection of distinctive hexagonal patterns on a portion of the Martian terrain has been described as a “major discovery”, made possible with data obtained by NASA’s Curiosity rover.

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A close-up of the panorama taken by Curiosity’s Mastcam at “Pontours” reveals hexagonal patterns – outlined in red in the same image, right – that suggest these mud cracks formed after many wet-dry cycles occurring over years. Credits: NASA/JPL-Caltech/MSSS/IRAP.

The new findings, along with the previous detection of simple organic molecules, offer mounting evidence that the Red Planet once had conditions ideal for the formation of more complex compounds, and possibly even forms of life.

https://thedebrief.org/strange-patt...lizing-new-evidence-for-ancient-life-on-mars/

Abstract of the article in Nature.

maximus otter
 
Green Mars.

Mars might be the Red Planet, but its atmosphere glows green.

Using the European Space Agency's (ESA) ExoMars Trace Gas Orbiter (TGO), scientists have observed Mars' atmosphere glowing green for the first time ever — in the visible light spectrum, that is.

The effect is called airglow (or dayglow or nightglow, depending on the hour), and it occurs on Earth, too. While it shares some similarities with the northern lights (or aurora) here on our planet, it's a different phenomenon with different causes. Nightglow, in particular, "occurs when two oxygen atoms combine to form an oxygen molecule," according to ESA. On Mars, this happens at an altitude of approximately 31 miles (50 km). By comparison, auroras occur when charged particles from the sun collide with Earth's magnetic field.

https://www.livescience.com/space/m...-may-see-a-green-sky-eerie-new-study-suggests
 
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