Monthly Archives: January 2024

Over 15 years ago, ESAs Mars Express spacecraft studied the Medusae Fossae Formation, revealing enigmatic deposits up to 2.5 km deep. From those early observations, it was unclear what the deposits were made of, but the new research has an answer.

This image shows a height map of the Martian surface, with lowest land in blue and highest in white. Image credit: ESA.

The Medusae Fossae Formation (MFF) a massive, unusual deposit of soft rock near Mars equator is about one-fifth as large as the continental United States and 100 times more massive than the largest explosive volcanic deposit on Earth.

It consists of several wind-sculpted features measuring hundreds of km across and several km high.

Found at the boundary between the Martian highlands and lowlands, the features are possibly the biggest single source of dust on Mars.

Initial observations from ESAs Mars Express spacecraft showed the MFF to be relatively transparent to radar and low in density, both characteristics wed see from icy deposits.

However, planetary scientists couldnt rule out a drier possibility: that the features are actually giant accumulations of windblown dust, volcanic ash or sediment.

Weve explored the MFF again using newer data from Mars Express MARSIS radar, and found the deposits to be even thicker than we thought: up to 3.7 km thick, said Dr. Thomas Watters, a planetary researcher at Smithsonian Institution.

Excitingly, the radar signals match what wed expect to see from layered ice, and are similar to the signals we see from Mars polar caps, which we know to be very ice rich.

If melted, the ice locked up in the MFF would cover the entire planet in a layer of water 1.5 to 2.7 m deep: the most water ever found in this part of Mars, and enough to fill Earths Red Sea.

Heres where the new radar data comes in! Given how deep it is, if the MFF was simply a giant pile of dust, wed expect it to become compacted under its own weight, said Dr. Andrea Cicchetti, a researcher at the National Institute for Astrophysics in Italy.

This would create something far denser than what we actually see with MARSIS.

And when we modeled how different ice-free materials would behave, nothing reproduced the properties of the MFF we need ice.

The new results instead suggest layers of dust and ice, all topped by a protective layer of dry dust or ash several hundred meters thick.

In this image, the white line on Mars surface (top) shows a stretch of land that was scanned by Mars Express MARSIS radar. The graph below shows the shape of the land and the structure of the subsurface, with the layer of dry sediments (likely dust or volcanic ash) in brown and the layer of suspected ice-rich deposits in blue. The graph shows that the ice deposit is thousands of meters high and hundreds of km wide. If all the suspected water ice in the MFF melted, it would cover Mars in an ocean of water up to 2.7 m deep. Image credit: CReSIS / KU / Smithsonian Institution.

This latest analysis challenges our understanding of the MFF, and raises as many questions as answers, said Dr. Colin Wilson, ESA project scientist for Mars Express and the ESA ExoMars Trace Gas Orbiter.

How long ago did these ice deposits form, and what was Mars like at that time?

If confirmed to be water ice, these massive deposits would change our understanding of Mars climate history.

Any reservoir of ancient water would be a fascinating target for human or robotic exploration.

The results will be published in the journal Geophysical Research Letters.

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Thomas Watters et al. 2024. Evidence of Ice-Rich Layered Deposits in the Medusae Fossae Formation of Mars. Geophysical Research Letters, in press;

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Mars Express Finds New Evidence for Ice-Rich Layered Deposits in Medusae Fossae - Sci.News

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Researchers have taken the first steps toward finding liquid solvents that may someday help extract critical building materials from lunar and Martian rock dust.

Extracting these materials is an important piece in making long-term space travel possible.

Using machine learning and computational modeling, the researchers found about half a dozen good candidates for solvents that can extract materials on the moon and Mars usable in 3D printing. The powerful solvents, called ionic liquids, are salts that are in a liquid state.

The machine learning work brought us down from the 20,000-foot to the 1,000-foot level, says Soumik Banerjee, associate professor in the School of Mechanical and Materials Engineering at Washington State University.

We were able to down select a lot of ionic liquids very quickly, and then we could also scientifically understand the most important factors that determine whether a solvent is able to dissolve the material or not.

As part of its Artemis mission, NASA, which funded Banerjees work, wants to send humans back to the moon and then to deeper space to Mars and beyond. But to make such long-term missions possible, astronauts will have to use the materials and resources in those extraterrestrial environments, using 3D printing to make structures, tools, or parts from essential elements extracted from lunar or Martian soil.

In situ resource utilization is a big deal over the next couple of decades for NASA, says Banerjee. Otherwise, we would need a terribly high payload of materials to carry from Earth.

Acquiring those building materials must be done in an environmentally friendly and energy efficient way. The method to mine the elements also cant use water, which isnt available on the moon.

Ionic liquids, which Banerjees group has been studying for more than a decade for use in batteries, could be the answer.

Testing each ionic liquid candidate in a lab is expensive and time consuming, however, so the researchers used machine learning and modeling at the level of atoms to narrow down from hundreds of thousands of candidates. They looked for those that might digest lunar and Martian materials, extract important elements such as aluminum, magnesium, and iron, regenerate themselves, and perhaps produce oxygen or water as a byproduct to help provide life-support.

Identifying superior qualities that the solvents will need, the researchers were able to find about half a dozen very strong candidates. Important factors for success included the size of the molecular ions that make up the salts, its surface charge density, which is the charge per unit area of the ions, and the mobility of the ions in the liquids.

Working with researchers at the University of Colorado in a separate study, the researchers tested a few ionic liquids in the lab for their ability to dissolve compounds. They hope to eventually build a lab-scale or pilot-scale reactor and test good candidate solvents with lunar regolith-type materials.

The new study appears in the Journal of Physical Chemistry B.

Source: Washington State

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Solvents may pave way for building on Mars and the moon - Futurity: Research News

The surface of Mars may appear barren and lifeless, but it seems the red planet is keeping quite a few secrets hidden from prying human eyes.

Luckily, we have technology and a new radar survey of the Medusae Fossae Formation region on the Martian equator has revealed what appears to be giant layered slabs of buried water ice, several kilometers thick.

It's the most water ever found around Mars' middle, and suggests the dry old dustball isn't quite as devoid of the stuff as we thought.

There's as much water buried there, scientists say, as can be found in Earth's Red Sea; if it were brought to the surface and melted, it would cover Mars in a shallow ocean between 1.5 to 2.7 meters (4.9 to 8.9 feet) deep.

Hints of the buried deposits were first detected in 2007, up to a depth of 2.5 kilometers (1.6 miles), but scientists didn't know what they were. New data, and new tools for analyzing that data, have revealed much more about the deposits than expected.

"We've explored the Medusae Fossae Formation again using newer data from Mars Express's MARSIS radar, and found the deposits to be even thicker than we thought: up to 3.7 kilometers (2.3 miles) thick," says geologist Thomas Watters of the Smithsonian Institution.

"Excitingly, the radar signals match what we'd expect to see from layered ice, and are similar to the signals we see from Mars's polar caps, which we know to be very ice rich."

The Medusae Fossae Formation is a collection of huge deposits that extends for some 5,000 kilometers (3,107 miles) along the equator of Mars, marking the boundary between the lowlands in the northern hemisphere, and the cratered highlands in the south.

It's not known what created the deposits, but they're huge, standing several kilometers high, sculpted by the wild winds that scour the surface of Mars.

Because the region is so poorly understood, scientists are naturally keen to learn more about it. In 2007, Watters and his team collected radar data that showed the clear presence of something, buried beneath the ground.

What wasn't clear was the nature of that something. Given how dusty the Medusae Fossae Formation is, the deposits could have consisted of buried dust. They could also have been volcanic material, sediment from wetter eons past, or intriguingly water ice.

So the researchers collected new radar observations of the region, analyzed the results, and performed modeling to try to figure out what is buried under the windswept dust and stone. And the only thing that fit the data well was water ice.

"Given how deep it is, if the MFF was simply a giant pile of dust, we'd expect it to become compacted under its own weight," says physicist Andrea Cicchetti of the National Institute for Astrophysics in Italy.

"This would create something far denser than what we actually see with MARSIS. And when we modeled how different ice-free materials would behave, nothing reproduced the properties of the MFF we need ice."

In the last few decades, as Mars exploration has grown, our previous understanding of the dead dust-ball has changed dramatically. Everywhere we look, Mars shows evidence of water long ago, running over the surface in rivers, or pooling in lakes or oceans.

There's no liquid water on Mars now, that we know of. Where all that water went remains a mystery: did it disappear into space as vapor, or is it sequestered inside the planet, locked away where we can't see it? The Medusae Fossae Formation may hold some answers to this question.

Scientists want to know where to find water on Mars for another, practical reason. When humans are eventually sent to the red planet, they're going to need water for survival. If there's water there already, that will minimize the amount they need to take with them.

Unfortunately, the Medusae Fossae Formation water is off-limits: It's buried beneath several hundred meters of Martian dust, beyond our ability to access.

Still, the discovery raises hopes that there's water hiding elsewhere on Mars. It also gives scientists new information in the hunt to uncover Mars' enigmatic history, and transformation to its present state.

"This latest analysis challenges our understanding of the Medusae Fossae Formation, and raises as many questions as answers," says planetary scientist Colin Wilson of the European Space Agency.

"How long ago did these ice deposits form, and what was Mars like at that time? If confirmed to be water ice, these massive deposits would change our understanding of Mars climate history. Any reservoir of ancient water would be a fascinating target for human or robotic exploration."

The research has been published in Geophysical Research Letters.

Excerpt from:

A Massive Amount of Water Ice Has Been Found on Mars, Lurking Beneath The Equator - ScienceAlert

After a short period of worrying silence, NASA said on Saturday night that it was able to regain contact with the Ingenuity helicopter. The autonomous aircraft unexpectedly ceased communications with the Perseverance rover, which relays all transmissions between Ingenuity and Earth, on Thursday during its 72nd flight on Mars. It had already been acting up prior to this, having cut its previous flight short for an unknown reason, and NASA intended to do a systems check during the latest ascent.

The space agency said in an update posted on X that its now reviewing the data from Ingenuity to understand what happened. Perseverance picked up its signal after the team instructed it to perform long-duration listening sessions. Ingenuity has experienced blackouts before, as recently as last year, and was able to return to flight. But its too early to say if that will be the case this time. The mini helicopter is already running well past the original timeline of its mission.

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NASA says it's reestablished contact with the Ingenuity Mars helicopter - Engadget

The potential discovery suggests that Mars once looked very different from how it appears today and could once have sustained life.

Scientists operating Europe's Mars Express orbiter say it may have spotted huge ice water deposits below the surface of Mars.

Its estimated that the deposits are around 3.7 kilometres thick, meaning that they could fill Earth's Red Sea if melted or cover the entirety of Mars in a layer of water about two metres deep.

The new findings suggest that Mars once looked very different to how it appears today, with glaciers, lakes, and river channels, according to scientists.

"We've seen evidence of glaciers, extinct glaciers which are no longer there, but also some glaciers covered with dust. Most of the water ice we've seen on Mars today is at higher latitudes, where the temperatures are colder and so the ice can be stable," said Colin Wilson, a project scientist at ESA.

"It's a testament to how much water there would have been on Mars in the past to amass piles of water ice several kilometres thick. That's a vast amount of water. So, we've seen the evidence of lots of water on the Martian surface in other places," Wilson added.

ESAs Mars Express orbiter first confirmed the presence of ice on the Red Planet in 2004.

It discovered the deposits in 2007, but it wasnt clear what they were made of -- perhaps giant accumulations of dust, volcanic ash or sediment.

In 2015, NASA also said Mars appears to have flowing streams of salty water.

"Today, we're revolutionising our understanding of this planet. Our rovers are finding that there's a lot more humidity in the air than we ever imagined," said Jim Green, NASAs Director of Planetary Science, at a press conference.

Now, 15 years later, Mars Express new data suggests the deposits are actually layers of dust and ice.

The ice water is located at its equator, not at its poles, which surprised scientists.

"We don't expect to see a polar ice cap at the equator," said Wilson.

"It's as ludicrous on Mars as it would be on Earth, but that's what the data are telling us, saying it does look like that".

This excited scientists about the potential of human exploration missions.

Given that Mars is a cold planet, between 20C and -153C, according to NASA, finding water ice in low latitudes instead of polar regions would have made human exploration missions easier.

"One of the reasons we were excited about finding water ice at low latitudes is that that is where future exploration missions, in particular human exploration missions, are going to have to land for reasons of orbital mechanics and also power availability," said Wilson.

The layers of dust and ice are topped with a protective layer of dust or ash several hundred metres thick.

"However, if it's 300 metres down, that's not very helpful for exploration goals. Unfortunately, this probably won't be the answer to our human exploration needs," Wilson added.

Europe's Mars Express probe departed Earth in June 2003 and arrived at Mars in December 2003. It recently marked two decades studying the Red Planet.

For more on this story, watch the video in the media player above.

Video editor Roselyne Min

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ESA's Mars Express orbiter discovers ice water deposits at the Red Planet's equator - Euronews

Confectionery giant Mars has opened a new snacking research and development hub at its Goose Island campus in Chicago.

The new 44,000-square-foot hub is one of the seven global innovation centres operated by Mars around the world, the company noted.

The company has invested $42 million (38.6 million) in this facility dedicated to chocolate and nut testing, research and innovation.

Andrew Clarke, global president of Mars Snacking said, "This state-of-the-art facility will serve as the epicentre for the kind of groundbreaking research and development that will shape the snacking category for generations to come. Innovation has been at the heart of our success for over 100 years, and this significant investment reaffirms our unwavering commitment to staying ahead of the curve.

"With an assembly of trailblazing associates, pioneering partnerships that ignite our creativity and unparalleled technology at our fingertips, we will continue to push boundaries in our relentless pursuit of delivering extraordinary experiences for our consumers around the world."

The facility will allow its associates in Chicago to create and refine new products for the snacking portfolio before they are scaled at large around the globe.

It will centralise innovation components under one roof while also serving as a testing ground for future-focused, sustainable ingredients, Mars added.

The new hub will also feature a dedicated nut facility to enable next-generation testing, evaluation and application of peanuts and tree nuts within Mars products, such as Snickers, M&M'S and KIND.

The facility, powered with 100% renewable energy, is fossil-fuel-free and covered by renewable energy credits from Mars' wind farm in Ford Ridge, Illinois.

The new hub joins Mars' network of existing global innovation sites in Chicago, Illinois;Guangzhou, China; Huariou,China;Elizabethtown, Pennsylvania; andSlough, United Kingdom.

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Mars Opens Snacking Research And Development Hub In Chicago | ESM Magazine - ESM European Supermarket Magazine

Maybe Mars isnt as dry as we thought. ESAs Mars Express has revealed new details about a region near Mars equator that could contain a massive deposit of water ice several kilometers deep. If it is indeed ice, there is enough of it in this one deposit that if melted, water would cover the entire planet up to 2.7 meters (almost 9 feet) deep.

But ice is just one explanation for the unusual features detected by the orbital spacecraft. Another is that this is a giant pile of dust several kilometers deep although the dust would still need to have some ice mixed in.

Mars Express has been orbiting Mars since December of 2003 and back in 2007, the spacecraft studied the Medusae Fossae Formation (MFF), a large geological formation that includes wind-sculpted ridges and grooves, abrupt mesas, interspersed with smooth and gently undulating areas. The region extends intermittently for more than 5,000 km (3,100 miles) along the equator of Mars, extending from just south of Olympus Mons to Apollinaris Patera, with a smaller additional region closer to Gale Crater, where the Curiosity rover is exploring.

Various spacecraft in addition to Mars Express, such as NASAs Mars Global Surveyor and Mars Odyssey, have also detected subsurface ice, as much as 2.5 km (1.5 miles) deep.

Now, new data from Mars Express suggest layers of water ice stretching even further underground the most water ever found in this part of the planet.

Weve explored the MFF again using newer data from Mars Expresss MARSIS radar, and found the deposits to be even thicker than we thought: up to 3.7 km (2.3 miles) thick, said Thomas Watters of the Smithsonian Institution, USA, lead author of both the new research and the initial 2007 study, in an ESA press release. Excitingly, the radar signals match what wed expect to see from layered ice, and are similar to the signals we see from Marss polar caps, which we know to be very ice rich.

Watters and his team say that if melted, the ice contained within the MFF would cover the entire planet in a layer of water 1.5 to 2.7 m deep, enough to fill Earths Red Sea.

But MFFs windswept landscapes contains one of the most extensive deposits of dust on Mars, which is possibly the biggest single source of dust on Mars. Some studies determined the strange features in this landscape could have been formed by explosive volcanoes.

In the 2007 observations with Mars Express, the radar data showed the MFF to be relatively transparent to radar and low in density two characteristics which would reveal icy deposits. However, scientists couldnt rule out a drier possibility: that the features are actually giant accumulations of windblown dust, volcanic ash or sediment.

But the beauty of long-lasting spacecraft is that it provides the opportunity for multiple observations of a single region on Mars over many years, providing additional follow-up data for study.

Heres where the new radar data comes in! Given how deep it is, if the MFF was simply a giant pile of dust, wed expect it to become compacted under its own weight, said co-author Andrea Cicchetti of the National Institute for Astrophysics, Italy. This would create something far denser than what we actually see with MARSIS. And when we modelled how different ice-free materials would behave, nothing reproduced the properties of the MFF we need ice.

The new results instead suggest layers of dust and ice, all topped by a protective layer of dry dust or ash several hundred meters thick.

We do know that massive stores of ice near the equator could not have formed in the planets present climate.

This latest analysis challenges our understanding of the Medusae Fossae Formation, and raises as many questions as answers, says Colin Wilson, ESA project scientist for Mars Express and the ESA ExoMars Trace Gas Orbiter (TGO). How long ago did these ice deposits form, and what was Mars like at that time? If confirmed to be water ice, these massive deposits would change our understanding of Mars climate history. Any reservoir of ancient water would be a fascinating target for human or robotic exploration.

If this does turn out to be large stores of water ice, the MFF deposits would be an incredibly valuable resource for any future human exploration of Mars. These types of missions would need to land near the planets equator, due to landing constraints, and resources like abundant solar power, and more moderate temperatures. The presence of equatorial water ice could provide a steady supply of water for a future base on Mars.

Further reading: ESA

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The Ice Sheet on Mars is Even Thicker Than Previously Believed - Universe Today

New data from the European Space Agency's Mars Express orbiter suggests a massive deposit called the Medusae Fossae Formation (MFF) holds enough water ice to cover the entire planet in an ocean that's anywhere from five to 8.8 feet deep if it were somehow melted, that is.

Scientists had previously held that there was still a chance the deposit was largely made of volcanic ash. But given the latest findings, it's far more likely to be made of water ice, especially given its geographical features that resemble those found at the planet's polar ice caps.

"Dry material, no matter what it is, just doesnt fit," Smithsonian Institution senior scientist Tom Watters, the lead author of a new paper published in the journal Geophysical Research Letters, told New Scientist of the research. "We just cant come up with another material other than water ice that fits the electrical properties, that also has this layering that were finding."

It's a particularly exciting new discovery as it represents the largest deposit of water ice found near the Red Planet's equator, making it an exciting potential location for future explorers to visit.

"Weve explored the MFFagain using newer data from Mars Expresss MARSIS radar, and found the deposits to be even thicker than we thought: up to [2.3 miles] thick," said Watters in an ESA statement about the work. "Excitingly, the radar signals match what wed expect to see from layered ice, and are similar to the signals we see from Marss polar caps, which we know to be very ice rich."

The surface of the formation is made of geographical features that were likely formed by wind, which measure hundreds of miles across and several miles tall.

While initial measurements from back in 2007 suggested the possibility that the region was made of water ice, scientists couldn't rule out that it was a massive accumulation of windblown dust, volcanic ash or sediment instead.

"Given how deep it is, if the MFF was simply a giant pile of dust, wed expect it to become compacted under its own weight," said coauthor Andrea Cicchetti of the National Institute for Astrophysics, Italy, in the statement. "This would create something far denser than what we actually see with MARSIS."

Their conclusion: the MFF is made up of layers of dust and ice.

But there's one big problem: the formation's ice deposits are trapped underneath several hundred feet of dust or ash, making it difficult to reach for any future Mars explorers.

And plenty of questions remain.

"This latest analysis challenges our understanding of the Medusae Fossae Formation, and raises as many questions as answers," said Mars Express project scientist Colin Wilson in the statement. "How long ago did these ice deposits form, and what was Mars like at that time?"

"If confirmed to be water ice, these massive deposits would change our understanding of Mars climate history," he added. "Any reservoir of ancient water would be a fascinating target for human or robotic exploration."

More on Mars water: Chinese Rover Finds Evidence of Liquid Water on Mars

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Scientists Discover Enough Mars Ice to Cover Planet in Water - Futurism

Art by Mars Robinson

Continuing with the BTT series, I felt the need to highlight one of the most criminally underrated and disrespected players ever. Chris Action Jackson, better known as Mahmoud Abdul-Rauf is a 6'1" point guard who has the ability to score not only at will but at an alarming rate. Even at the young age of 54, you can find him torching your favorite veterans and young hoop influencers alike in the Ice Cube-owned BIG 3 league.

Mahmouds illustrious basketball career is the stuff of legend. A star at LSU, Rauf garnered national attention with his shifty and quick style of play. He was very Barry Sanders-like in his fluidity weaving through defenders to create space for his often automatic jump shot. Rauf was your favorite shooters favorite shooter. A career 29.0 PPG at LSU on 47/37/86. Rauf was shooting from the logo before it was even a thing.

Before Steph, Dame, and Trae gave us 40-foot bombs on the regular, Mahmoud gave us spectacle after spectacle with his premier shot-making. After racking up two national Player of the Year awards, Mahmoud would then be drafted third overall in the 1990 NBA Draft by the Denver Nuggets. Mahmoud was a bright spot for a Denver team that saw little to no success while he was there.

During a six-season stint in Denver (14.6 PPG on 44/35/90), Rauf was named to the NBAs All-Rookie Second Team (90'), was the NBAs Most Improved Player (93'), led the league in free throw percentage twice (93'-94', 95'-96'), posted his career high in assists (20) in November of 95' and scored his career high of 51 in December of 95'. Shortly after spending some time in Sacramento, Rauf would retire from the game of basketball saying that he lost interest in the game.

Rauf is one of many athletes to come out and speak on how things are in America, and he never shied away from criticizing and bringing forth real issues. Were all aware of how he was against the National Anthem and would stand with his head down in Islamic prayer during it. Actions like this led to his house in his home state of Mississippi being burned down in 2001.

Due to his views on the US and the flag, Mahmoud believed he was blackballed from the league, and I have to agree. Weve seen this same episode with former Chicago Bulls guard, Craig Hodges. Hodges used his voice as an athlete to shed light on the poor and disenfranchised. He encouraged his teammates to do the same but was mainly ignored.

When you look at all of the hyper-scoring guards that we have in todays league, you have to look back at players like Rauf who helped set the foundation. His name doesnt get nearly enough recognition for not only his skill set but for his belief in himself and what he believed in.

Excerpt from:

Before Their Time Vol. 3. In the NBAs history, many players have | by Mars Robinson | SportsRaid | Jan, 2024 - Medium

Theres overwhelming evidence that Mars was once wet and warm. Rivers flowed across its surface and carved intricate channel systems revealed by our orbiters. Expansive oceans even larger than Earths may have covered a third of its surface. Then something happened: Mars lost its atmosphere, cooled down, and surface water disappeared.

But as our observations of Mars become more detailed, its looking like Mars didnt lose its water in one cataclysmic episode. Deepening evidence shows that it lost its water gradually. The planet may have had recurring episodes of surface water that persisted intermittently over a longer period of time. If thats true, it has implications for potential life on Mars.

New research published in Earth and Planetary Science Letters is bolstering the idea that Mars may have taken a long time to lose its water. The research letter is titled New Maximum Constraints on the Era of Martian Valley Network Formation. The author is Alexander Morgan, a research scientist at the Planetary Science Institute who studies geomorphology.

Mars today is a global desert, but its surface preserves extensive evidence of past flowing water, including what appear to be river valleys, Morgan says. The timescale over which these valleys formed has big implications for early Mars habitability, as long eras with stable liquid water would be more conducive to life, he said.

The extensive evidence of ancient rivers on Mars is highlighted by the Perseverance Rover and the area it is exploring. Its called Jezero Crater, and its the site of an ancient impact crater. At some time in the past, the crater was flooded with water, creating a massive sedimentary basin. Orbital images of Jezero show ancient river channels flooding into the gigantic crater.

As Perseverances landing site shows, impact craters and rivers mingle with one another across the Martian surface. That fact is the key to Morgans research. By dating craters near river channels, he placed temporal constraints on when the rivers that created the channels were flowing.

In this study, I used craters that predate and postdate valley systems to place maximum bounds of hundreds of millions of years on the era over which these systems formed, Morgan said. Previous work had only determined minimum timescales, so these new results provide an upper bound on the timescale over which Martian valleys were active. Given what we know about erosion rates on early Mars, longer timescales imply that conditions permitting rivers were highly intermittent, with long arid periods interspersed with brief episodes of fluvial activity.

Mars river valleys formed over three billion years ago. Theyre the strongest evidence that the planet had surface water. Research shows that it takes tens of thousands of years for flowing water to carve a valley into the surface, but nobody has figured out how many different flow events there were and how much total time it took for these valleys to form. Until now.

Our understanding of Mars has grown considerably in recent years and will keep growing. Our understanding of its climate history is undergoing a revolution. Previously, there were two opposing versions of Marss ancient past. One says that it was warm and wet and potentially habitable; the other says it was a frigid planet covered in ice sheets.

But things in Nature are seldom so simple, even if wed like them to be. Growing evidence, including this work, shows that theres more complexity to the story than either warm and wet or cold and dry can encapsulate.

Over the past decade or so, weve come to realize that these descriptors are far too general, and it doesnt really make sense to try to condense hundreds of millions of years of climate history into a two-word description, Morgan said.

As weve studied Earth, weve come to realize that the climate oscillated wildly during its long history. During some periods, the Earth was covered with extensive glaciers several kilometres thick. At other times, the glaciers retreated to their mountain redoubts. Why wouldnt other planets have equally as varied histories?

Like Earth, early Mars was complex, and the conditions permitting surface water likely varied considerably. Earth has undergone massive climatic changes throughout its history for example, 20,000 years ago, the area that is now Chicago was beneath half a mile of ice and surface conditions permitting rivers on early Mars likewise probably waxed and waned.

That waxing and waning means it took a long time for the rivers to erode the landscape and form channels and valleys. One possible explanation is that large boulders in the riverbeds inhibited further erosion. Another is that the rivers flowed infrequently, possibly as little as 0.001 % of the time. If thats the case, it could be because of what we call Milankovitch cycles here on Earth.

Milankovitch cycles are changes in the Earths relative position and orientation to the Sun. Things like axial tilt, orbital eccentricity, and precession create changes in our planets climate. Earths axial tilt varies by about 3.5 degrees every 40,000 years or so. Mars has an even more pronounced axial tilt variation that undergoes substantial changes in hundreds of thousands or millions of years.

Over short timescales, river flow is controlled by rainfall or upstream snow melt. Over longer timescales, Earths rivers are affected by climatic changes, Morgan said. For example, 20,000 years ago, there were large lakes and larger rivers across what is now Nevada. Martian rivers would have operated in a similar way, with short-term variability due to storms or snowmelt, and longer-term variability due to changes in the planets spin and orbit around the Sun.

Or powerful volcanic activity couldve periodically warmed the planet, melting ice sheets and spawning rivers that carved telltale channels into the planets surface. The Tharsis Montes region shows that volcanoes played a role in Mars history. Tharsis Montes is home to three massive shield volcanoes that dwarf Earths volcanoes. Another volcano, Olympus Mons, is just northwest of Tharsis Montes and is the largest volcano in the Solar System.

We dont really know what happened on Mars. Is Mars just a standard example of marginally habitable planets that become uninhabitable? Or is it a striking example of a planet that stubbornly held onto its water through multiple climatic episodes? Did simple life get started on Mars before it was snuffed out, and is that just the way things work? Or is surface water on any planet for any period of time extremely rare?

For now, we dont have any clear answers to those big questions. Planets are big, complicated, long-lived, and dynamic objects. Understanding what happened billions of years ago on a planet is a daunting task.

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Early Mars Climate was Complex, with Streams Flowing Intermittently for Millions of Years - Universe Today