Tag Archives: Mars Reconnaissance Orbiter

Mars then and Now. The Red Planet has been stripped of water for billions of years, but the main mechanism of water loss is different now than it was a billion years ago (NASA)

Water stripped from Mars’ upper atmosphere may explain how it became a barren Red Planet

A new study has revealed the detection of water in the upper atmosphere of Mars for the first time. The discovery gives scientists a good idea of the mechanism that is currently stripping the Red Planet of its water. 

The surface of Mars is cold and dry —bereft of liquid water — but this wasn’t always the case. Studies of the Martian surface have discovered the tell-tale tracks of long dry ancient rivers and sedimentary deposits that indicate lake beds into which water once flowed. This poses the question of how the Red Planet lost its liquid water?

A study published in the journal Science suggests a new mechanism that could have driven Mars’ water loss. A team of astronomers has used data collected from Mars’ atmosphere by NASA’s Neutral Gas and Ion Mass Spectrometer on the Mars Atmosphere and Volatile Evolution spacecraft (MAVEN) to discover water in the planet’s upper atmosphere. 

“For the first time, we have seen water in the upper atmosphere of Mars, at around 150 km above the surface. Other scientists have previously observed water in the middle atmosphere,” Shane Wesley Stone, a PhD. Candidate in Planetary Sciences at the Lunar and Planetary Laboratory, University of Arizona, and one of the paper’s authors tells ZME Science. “Water in the upper atmosphere is quickly destroyed and can escape to space, which is why our observations of water in the upper atmosphere are significant.”

Mars then and Now. The Red Planet has been stripped of water for billions of years, but the main mechanism of water loss is different now than it was a billion years ago (NASA)
Mars then and Now. The Red Planet has been stripped of water for billions of years, but the main mechanism of water loss is different now than it was a billion years ago (NASA)

Water transported to the upper atmosphere of Mars is converted to atomic hydrogen, which is then so-light that it is lost to space. This process could have been driving Mars’ water loss for billions of years. Water had previously been detected in the lower atmosphere, where scientists believed it was confined, but this is the first detection of water in the upper atmosphere, which caught the team by surprise. 

“We did not know that water makes it all the way to the upper atmosphere, so we did not know how important this upward transport of water is to the escape of hydrogen to space and thus to water lost from Mars,” Stone says, explaining that water higher in the atmosphere would be broken down much more rapidly than happens closer to the martian surface. “Water which makes it to the upper atmosphere is destroyed in about 4 hours. This destruction of water would be ten times slower in the middle atmosphere, where most of the products of this destruction would be transported downward back toward the surface.”

Rising Damp: How Does Water Make its Way to Mars’ Upper Atmosphere?

Stone explains that the team is not yet certain what processes are lifting water to Mars’ upper atmosphere, but their study has yielded some good clues as to what may be the major players in this phenomenon. 

“We see a seasonal trend in the upper atmospheric water abundance,” says the planetary chemist. “During summer in the southern hemisphere, the water abundance in the upper atmosphere is largest. During summer in the northern hemisphere, the water abundance in the upper atmosphere is smallest but is still significant.”

Stone explains that this seasonal trend is caused by two things. Firstly, during southern summer, Mars is closer to the Sun than it is during the rest of the Martian year. Secondly, this is also the season of dust storms on Mars. He adds: “Relatively close proximity to the Sun and dust storms both lead to heating in the atmosphere, which leads to greater transport of water to the upper atmosphere.”

The researcher points to a massive Martian dust storm that occurred in 2018 as being a major contributing factor to water in the upper atmosphere. The storm was first spotted by NASA’s Mars Reconnaissance Orbiter (MRO) on May 30th 2018 and by June of that year, it had grown to a planet encompassing event. 

Rotating globes from May 28 and July 1 show a global dust storm completely obscuring the surface of Mars. (NASA)

“Dust storms lead to a sudden splash of water into the upper atmosphere: during the global dust storm of 2018, the water abundance in the upper atmosphere increases by 20x relative to the nominal seasonal abundance,” Stone says. “Smaller surges of water are observed during regional dust storms that occur every Mars year of 687 days. Global storms occur about once every 10 Earth years.”

The team believe that water is moving upward past what planetary scientists call the hygropause — a cold layer in the atmosphere at which water condenses from vapour to liquid, forming clouds. “This because, as we and other scientists have found, the Martian hygropause is not as efficient at trapping water close to the surface as the hygropause on Earth,” Stone says. “The hygropause on Mars is not as efficient because it is too warm: when Mars is closest to the Sun and when dust storms occur, heating caused by these processes warms the hygropause, allowing water to move upward.”

The mechanism their finding reveals is currently the main way that Mars loses water, but Stone points out that this likely wasn’t always the case.

The Changing Picture of Water Loss on Mars

Water transported to Mars’ upper atmosphere by seasonal effects and dust storms where it is broken down to hydrogen and then lost to space is currently the predominant mechanism of water loss on Mars, but the team says this is only because of the Red Planet’s current environment. The water loss mechanisms that have proceeded for billions of years were likely different in the past in terms of both dominance and the speed at which they proceed.

“This process we describe is an important factor in Martian water loss today. However, this water could only be transported to the upper atmosphere relatively recently, over the last billion years or so,” Stone says. “Much of Mars’ atmosphere was lost to space before this time, leading to the weak hygropause which allows water into the upper atmosphere. All escape processes we observe today were likely faster in the past.”

NASA scientists have determined that a primitive ocean on Mars held more water than Earth's Arctic Ocean and that the Red Planet has lost 87 percent of that water to space. Credits: NASA/GSFC
NASA scientists have determined that a primitive ocean on Mars held more water than Earth’s Arctic Ocean and that the Red Planet has lost 87 per cent of that water to space. Credits: NASA/GSFC

The team reached this conclusion due to the fact that when all the water loss rates of the present-day escape processes are summed, their current escape rate is too slow to explain all the water loss that scientists know must have occurred over the last few billion years. 

“We know that over 4 billion years, Mars lost about 66% of its atmosphere to space,” Stone explains. “If we talk about water specifically, Mars has lost 10s to 100s of meters of a ‘global equivalent layer’ of water — equivalent to spreading all of the water lost by Mars over its surface to form an even layer and then reporting how deep this layer would be.”

The process the team describe is responsible for the loss of 44 cm of H2O over the last billion years, and global dust storms are responsible for the loss of an additional 17 cm on top of this over the last billion years.

“In the present epoch, during most of the Martian year, this process we describe is just as important as the ‘classical process’ — the basic process scientists thought responsible for the transport of hydrogen to the upper atmosphere since the first work on this topic in the early 1970s,” Stone says. “During global storms, this water which makes it to the upper atmosphere produces 10x more escaping hydrogen than does the classical process.”

Big Surprises and Future Investigations

Stone describes that the next steps for this research involve figuring out exactly how important this new water loss mechanism has been throughout the history of Mars. 

“Extrapolating back over billions of years is extremely difficult and doing it correctly takes time. We still need to understand better the specific transport processes responsible for delivering this water to the upper atmosphere,” he says, adding that the team’s findings came as something as a shock even to them. “The entire project was a huge surprise to us: we were surprised to see water this high in the atmosphere, we were surprised to see the seasonal trend in the water abundance, and we were surprised by just how big an effect the global dust storm has on the upper atmospheric water abundance.” 

Comparing the atmospheres of earth and Mars could help scientists determine the chances of liquid water existing on exxoplanets. (ESA)

Researching water loss from Mars is likely to be an important step in understanding how abundant water is throughout the Universe, as Dimitra Atri, a researcher from the Space Science at NYU Abu Dhabi (NYUAD), recently told ZME Science: “Since it is extremely difficult to observe the escape process in exoplanets, we are planning to study this phenomenon in great detail on Mars with the UAE’s Hope mission.”

Thus, this type of study could tell us how unique Earth is in terms of the possession of liquid water in the Universe. Something that could, in turn, tell us about the chances of life on exoplanets. 

“Mars used to look like Earth: warmer and wetter with a thick atmosphere and abundant liquid water on its surface,” Stone concludes. “But over the history of the solar system, Mars’ water was lost to space, leaving behind the cold, dry, red planet we see today. Regardless, Mars will be the next planet on which humans step foot.”

S.W. Stone; R.V. Yelle; D.Y. Lo, et al, [2020], ‘Hydrogen escape from Mars is driven by seasonal and dust storm transport of water,Science.

Mysterious martian gouges carved by hovering dry ice

It’s like Christmas before Christmas – the Mars Reconnaissance Orbiter has started sending back images it took of the red planet, and there’s just so many fantastic stuff it feels like Christmas has come earlier this year. Now, the MRO sent back images peculiar features along the slopes of dunes: long, sharply defined grooves (pictured) that seem to appear and disappear seasonally.

Image: NASA

The fact that they appear and disappear indicates that they are something seasonal; astronomers initially thought they were trails left by tumbling boulders, but there are no boulders at the end of the line, so this couldn’t be the case. The next theory was that they are signs of flowing water, but that seemed to be a bit too optimistic. Now, a new model shows that those lines are likely the result of sand-surfing dry ice.

During the planet’s winter, it gets extremely cold and carbon dioxide freezes, creating what is called “dry ice”. During the spring thaw however, the carbon dioxide sublimates back into gas, but some of it may actually break off and slide down, much like a boulder would. This explains why astronomers didn’t see the boulders at the end of the gullies – it was dry ice which then sublimated.

But it gets even more interesting – the pieces of dry ice aren’t simply rolling down; according to the model, the bases of the chunks are continually sublimating, resulting in a hovercraftlike motion that gouges the dune while propelling the ice down slopes. The model has been recreated by scientists in Utah, and it worked just as expected. While researchers are working on refining the model even more, they also hope to observe the actual process as it’s happening.

The Marte Vallis channel system (white area, center). (c) NASA

Buried Mars river tells of recent megaflood

Our understanding and appreciation of Mars has greatly shifted in the past decade alone. If previously scientists used to thought the planet had been dead and bared geologically-wise for billions of years, recent evidence shows that Mars has been marked by a series of geological events. Using radar technology, scientists have now found water-carved channels buried beneath the Red Planet’s surface that are believed to have been generated by a megaflood.

Today Mars is as dead – a cold and dry planet that’s only a shallow image of its once glorious self. Billions of years ago, the planet was crossed by channels and rivers of flowing water and had a much thicker atmosphere than today. The largest river system is 600 mile-long Marte Vallis system, which lies in Elysium Planitia, an expanse of plains along the Martian equator.

Coincidence or not this area is the youngest volcanic region on Mars, riddled with evidence of once massive amounts of flowing lava, hiding a lot of the feature’s planets, including important portions of the Marte Vallis, like its origin, which most likely was a lot longer than its current pathetic remnants.

The Marte Vallis channel system (white area, center). (c) NASA

The Marte Vallis channel system (white area, center). (c) NASA

Using the Mars Reconnaissance Orbiter, scientists at NASA’s Goddard Space Flight Center and the Jet Propulsion Laboratory have used the orbiting spacecraft’s shallow Radar (SHARAD) instrument to peer through the Elysium Planitia surface. This allowed a 3-D reconstruction of the Marte Vallis, revealing a number of features previously obscured by ancient lava deposits.

“This is the first time we’ve been able to see buried flood channels on a planet other than the Earth,” lead study author Gareth Morgan, a geologist at the Smithsonian’s National Air and Space Museum.

What they found was staggering – both the headwaters and floodplain of the river  had been covered by lava from a volcanic eruption no more than 500 million years ago. Two different phases of channel formation were observed: one phase etched a series of smaller branching channels that are now on a raised ‘bench’ next to the main channel, the other phase carved the deep, wide channels.

“In this region, the radar picked up multiple ‘reflectors,’ which are surfaces or boundaries that reflect radio waves, so it was possible to see multiple layers, ” says Lynn Carter of NASA’s Goddard Space Flight Center. “We have rarely seen that in SHARAD data outside of the polar ice regions of Mars.”

(c) NASA

(c) NASA

Moreover, the researchers found the channels of Marte Vallis were at least 230 feet (70 meters) deep, making them at least twice as deep as previously thought.

“That shows previous ideas of erosion, of how much water have gone through Marte Vallis, have been underestimated,” Morgan said. “There was more significant flooding than before thought, and it’s interesting to think of where this water might have come from during this relatively dry period.”

This megaflood is likened by the researchers with the Missoula outpourings of some 15,000 years ago in the Pacific Northwest, which flooded the large areas of what is now Washington and Oregon, after an ice dam at the glacial Lake Missoula broke. The huge 200-mile-long lake would have likely drained within 48 hours.

A similar event on Mars, on a much larger scale, would have most likely led to climate change, and by studying them researchers only deepen their understanding of both ancient and contemporary Martian climate. Still, it’s rather remarkable how much we’ve learned in the past few years about Mars watery history and how much still remains to be uncovered. For instance, just a few weeks ago ZME Science reported on ESA’s remarkable discovery of Mars’ longest river found thus far, the 1,000 miles long Reull Vallis.

The findings were detailed in a paper published in the journal Science.

Mars Global Surveyor photo of mars 1999

Mars covered in oceans of water: how the red planet might have looked billions of years ago [FANTASTIC PHOTOS]

There seems to be consisting evidence supplied both by past and recent rover missions – like the ever sturdy Opportunity, the eager newcomer Curiosity – and the Mars Reconnaissance Orbiter – a spacecraft currently hovering over Mars – that our neighboring red planet was once most likely covered by oceans and lakes and was layered by a thick atmosphere, very much similar to Earth. Kevin Gill, a New Hampshire software engineer, digitally painted how Mars might have looked like some two billion years ago using scientific data and human imagination – the end result is strikingly provocative and stunning at the same time.

An artist’s impression of what ancient Mars may have looked like, based on geological data. Image by Ittiz.

Gill used an open-source geospatial program to design the terrain for the “paradisaical” Mars, while atmosphere and vegetation features were added based on NASA’s Blue Marble: Next Generation imagery. The painting’s geological features were plotted based on genuine elevation data from topographical NASA mappings. Countless surveys have revealed Mars’ surface was layered with river deltas, gullies, and oceanic coastlines. Also, previous findings suggest that Mars was once covered in a thick atmosphere, which gradually became ever thinner from the lack of a magnetic field. Concerning the vegetation, clouds and other features painted in these quite exquisite views, these were all based on Gill’s artistic impression of how Mars might have looked like in its heyday.

“There is no scientific reasoning behind how I painted it; I tried to envision how the land would appear given certain features or the effects of likely atmospheric climate. For example, I didn’t see much green taking hold within the area of Olympus Mons and the surrounding volcanoes, both due to the volcanic activity and the proximity to the equator,” Gill says.

“This wasn’t intended as an exhaustive scientific scenario as I’m sure (and expect) some of my assumptions will prove incorrect,” Gill continued. “I’m hoping at least to trigger the imagination, so please enjoy!”

As presented above, Mars would definitely be capable of harboring life, although no one is currently capable of positively asserting that life was or is presented on the red planet – so far. This is what Curiosity is tasked with and this is why we’re so keen on following the rover’s every step. Maybe an even more interesting idea inevitably pops when looking at these dazzling photos – can we, humans, turn these stunning views of Mars into reality through terraforming?

The image below is an actual rendition of Mars as seen from space captured by the Mars Global Surveyor in 1999.

Mars Global Surveyor photo of mars 1999

(c) NASA/JPL/University of Arizona

New craters sighted on Mars [PICS]

(c) NASA/JPL/University of Arizona

Last year, the Mars Reconnaissance Orbiter’s low-res, grayscale Context camera cought a patch of new dark spots on the martian surface which weren’t there just two years before. Further, detailed investigations soon followed as MRO’s more sharp-eyed HiRISE camera went in for a closer look – its capable of spotting even beach ball sized objects on Mars’ surface.

What scientist found were four distinct craters, each ringed with a dark blanket where soil was blasted out in the impact. Scientists believe the craters were actually caused by a single meteorite which broke as multiple pieces as it entered the martian atmosphere.

The MRO helps researchers determine how often Mars gets hit by interplanetary debris by watching the Martian terrain change beneath it. Based on the number of craters, planetary scientists gauge the age of a planet’s surface features.

(c) NASA/JPL/University of Arizona

(c) NASA/JPL/University of Arizona