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Bedrock at this site added to a puzzle about ancient Mars by indicating that a lake was present, but that little carbon dioxide was in the air to help keep a lake unfrozen. Credit: NASA/JPL-Caltech/MSSS
The study of Mars’ surface and atmosphere has unlocked some ancient secrets. Thanks to the efforts of the Curiosity rover and other missions, scientists are now aware of the fact that water once flowed on Mars and that the planet had a denser atmosphere. They have also been able to deduce what mechanics led to this atmosphere being depleted, which turned it into the cold, desiccated environment we see there today.
At the same time though, it has led to a rather intriguing paradox. Essentially, Mars is believed to have had warm, flowing water on its surface at a time when the Sun was one-third as warm as it is today. This would require that the Martian atmosphere had ample carbon dioxide in order to keep its surface warm enough. But based on the Curiosity rover’s latest findings, this doesn’t appear to be the case.
These findings were part of an analysis of data taken by the Curiosity’s Chemistry and Mineralogy X-ray Diffraction (CheMin) instrument, which has been used to study the mineral content of drill samples in the Gale Crater. The results of this analysis were recently published in Proceedings of the National Academy of Science, where the research team indicated that no traces of carbonates were found in any samples taken from the ancient lake bed.
Simulated view of Gale Crater Lake on Mars, depicting a lake of water partially filling Mars’ Gale Crater. Credit: NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS
To break it down, evidence collected by Curiosity (and a slew of other rovers, landers and orbiters) has led scientists to conclude that roughly 3.5 billion years ago, Mars surface had lakes and flowing rivers. They have also determined, thanks to the many samples taken by Curiosity since it landed in the Gale Crater in 2011, that this geological feature was once a lake bed that gradually became filled with sedimentary deposits.
However, for Mars to have been warm enough for liquid water to exist, its atmosphere would have had to contain a certain amount of carbon dioxide – providing a sufficient Greenhouse Effect to compensate for the Sun’s diminished warmth. Since rock samples in the Gale Crater act as a geological record for what conditions were like billions of years ago, they would surely contain plenty of carbonate minerals if this were the case.
Carbonates are minerals that result from carbon dioxide combining with positively charged ions (like magnesium and iron) in water. Since these ions have been found to be in good supply in samples of Martian rock, and subsequent analysis has shown that conditions never became acidic to the point that the carbonates would have dissolved, there is no apparent reason why they wouldn’t be showing up.
Along with his team, Thomas Bristow – the principal investigator for the CheMin instrument on Curiosity – calculated what the minimum amount of atmospheric carbon dioxide would need to be, and how this would have been indicated by the levels of carbonate found in Martian rocks today. They then sorted through the years worth of the CheMin instrument’s data to see if there were any indications of these minerals.
Comparison of X-ray diffraction patterns of two different samples analyzed by Curiosity’s Chemistry and Mineralogy (CheMin) instrument. Credit: NASA/JPL-Caltech/Ames
But as he explained in a recent NASA press release, the findings simply didn’t measure up:
“We’ve been particularly struck with the absence of carbonate minerals in sedimentary rock the rover has examined. It would be really hard to get liquid water even if there were a hundred times more carbon dioxide in the atmosphere than what the mineral evidence in the rock tells us.”
In the end, Bristow and his team could not find even trace amounts of carbonates in the rock samples they analyzed. Even if just a few tens of millibars of carbon dioxide had been present in the atmosphere when a lake existed in the Gale Crater, it would have produced enough carbonates for Curiosity’s CheMin to detect. This latest find adds to a paradox that has been plaguing Mars researchers for years.
Basically, researchers have noted that there is a serious discrepancy between what surface features indicate about Mars’ past, and what chemical and geological evidence has to say. Not only is there plenty of evidence that the planet had a denser atmosphere in the past, more than four decades of orbital imaging (and years worth of surface data) have yielded ample geomorphological evidence that Mars once had surface water and an active hydrological cycle.
The Gale Crater – the landing location and trek of the Rover Curiosity – as it is today, imaged by the MRO. Credits: NASA/JPL, illustration, T.Reyes
However, scientists are still struggling to produce models that show how the Martian climate could have maintained the types of conditions necessary for this to have been the case. The only successful model so far has been one in which the atmosphere contained a significant amount of CO2 and hydrogen. Unfortunately, an explanation for how this atmosphere could be created and sustained remains elusive.
In addition, the geological and chemical evidence for such a atmosphere existing billions of years ago has also been in short supply. In the past, surveys by orbiters were unable to find evidence of carbonate minerals on the surface of Mars. It was hoped that surface missions, like Curiosity, would be able to resolve this by taking soil and drill samples where water had been known to exist.
But as Bristow explained, his team’s study has effectively closed the door on this:
“It’s been a mystery why there hasn’t been much carbonate seen from orbit. You could get out of the quandary by saying the carbonates may still be there, but we just can’t see them from orbit because they’re covered by dust, or buried, or we’re not looking in the right place. The Curiosity results bring the paradox to a focus. This is the first time we’ve checked for carbonates on the ground in a rock we know formed from sediments deposited under water.”
Annontated version of the bedrock site in the Gale Crater where the Curiosity rover has taken drill samples. Credit: NASA/JPL-Caltech/MSSS
There are several possible explanations for this paradox. On the one hand, some scientists have argued that the Gale Crater Lake may not have been an open body of water and was perhaps covered in ice, which was just thin enough to still allow for sediments to get in. The problem with this explanation is that if this were true, there would be discernible indications left behind – which would include deep cracks in the soft sedimentary lakebed rock.
But since these indications have not been found, scientists are left with two lines of evidence that do not match up. As Ashwin Vasavada, Curiosity’s Project Scientist, put it:
“Curiosity’s traverse through streambeds, deltas, and hundreds of vertical feet of mud deposited in ancient lakes calls out for a vigorous hydrological system supplying the water and sediment to create the rocks we’re finding. Carbon dioxide, mixed with other gases like hydrogen, has been the leading candidate for the warming influence needed for such a system. This surprising result would seem to take it out of the running.”
Luckily, incongruities in science are what allow for new and better theories to be developed. And as the exploration of the Martian surface continues – which will benefit from the arrival of the ExoMars and the Mars 2020missions in the coming years – we can expect additional evidence to emerge. Hopefully, it will help point the way towards a resolution for this paradox, and not complicate our theories even more!
Olympus Mons on Mars is the largest volano in our Solar System. Analysis of a Martian meteorite that fell to Earth in 2012 confirms that Mars also has the longest-lived volcanoes in our Solar System. Image: NASA/JPL
Mars is renowned for having the largest volcano in our Solar System, Olympus Mons. New research shows that Mars also has the most long-lived volcanoes. The study of a Martian meteorite confirms that volcanoes on Mars were active for 2 billion years or longer.
A lot of what we know about the volcanoes on Mars we’ve learned from Martian meteorites that have made it to Earth. The meteorite in this study was found in Algeria in 2012. Dubbed Northwest Africa 7635 (NWA 7635), this meteorite was actually seen travelling through Earth’s atmosphere in July 2011.
A sample from the meteorite Northwest Africa 7635. Image: Mohammed Hmani
The lead author of this study is Tom Lapen, a Geology Professor at the University of Houston. He says that his findings provide new insights into the evolution of the Red Planet and the history of volcanic activity there. NWA 7635 was compared with 11 other Martian meteorites, of a type called shergottites. Analysis of their chemical composition reveals the length of time they spent in space, how long they’ve been on Earth, their age, and their volcanic source. All 12 of them are from the same volcanic source.
Mars has much weaker gravity than Earth, so when something large enough slams into the Martian surface, pieces of rock are ejected into space. Some of these rocks eventually cross Earth’s path and are captured by gravity. Most burn up, but some make it to the surface of our planet. In the case of NWA 7635 and the other meteorites, they were ejected from Mars about 1 million years ago.
“We see that they came from a similar volcanic source,” Lapen said. “Given that they also have the same ejection time, we can conclude that these come from the same location on Mars.”
Taken together, the meteorites give us a snapshot of one location of the Martian surface. The other meteorites range from 327 million to 600 million years old. But NWA 7635 was formed 2.4 billion years ago. This means that its source was one of the longest lived volcanoes in our entire Solar System.
This false color X-ray of NWA 7635 shows the meteorite’s mineralogy mineral textures. O, olivine; P, plagioclase (maskelynite); C, clinopyroxene (augite). Chemical compositions: Fe (purple), Mg (green), Ca (blue), Ti (magenta), and S (yellow). Purple colors in the mesostasis represent Fe-rich augite. You’re welcome, mineral nerds. Image: Lapen et. al.
Volcanic activity on Mars is an important part of understanding the planet, and whether it ever harbored life. It’s possible that so-called super-volcanoes contributed to extinctions here on Earth. The same thing may have happened on Mars. Given the massive size of Olympus Mons, it could very well have been the Martian equivalent of a super-volcano.
The ESA’s Mars Express Orbiter sent back images of Olympus Mons that showed possible lava flows as recently as 2 million years ago. There are also lava flows on Mars that have a very small number of impact craters on them, indicating that they were formed recently. If that is the case, then it’s possible that Martian volcanoes will be visibly active again.
A colorized image of the surface of Mars taken by the Mars Reconnaissance Orbiter. The line of three volcanoes is the Tharsis Montes, with Olympus Mons to the northwest. Valles Marineris is to the east. Image: NASA/JPL-Caltech/ Arizona State University
Continuing volcanic activity on Mars is highly speculative, with different researchers arguing for and against it. The relatively crater-free, smooth surfaces of some lava features on Mars could be explained by erosion, or even glaciation. In any case, if there is another eruption on Mars, we would have to be extremely lucky for one of our orbiters to see it.
The rim of Tooting Crater on Mars, rendered from HiRISE data using Autodesk Maya and Adobe Photoshop. Credit: NASA/JPL/University of Arizona/USGS/image editing by Kevin Gill.
By day, Kevin Gill is a software engineer at the Jet Propulsion Laboratory. But on nights and weekends he takes data from spacecraft and turns them into scenes that can transport you directly to the surface of Mars.
Gill is one of many so-called “amateur” image editing enthusiasts that take real, high-resolution data from spacecraft and create views that can make you feel like you are standing on the surface of Mars, or out flying around the Solar System.
Gasa Crater on Mars. Rendered using Autodesk Maya and Adobe Photoshop. HiRISE data processed using HiView and gdal. Credit: NASA/JPL/University of Arizona/USGS/image editing by Kevin Gill.
Some of the best data around for these purposes come from the HiRISE camera on board the Mars Reconnaissance Orbiter. Data known as Digital Terrain Model (DTM) files, the HiRISE DTMs are made from two or more images of the same area of a region on Mars, taken from different angles. This data isn’t just for making stunning images or amazing movies. For scientists, DTMs are very powerful research tools, used to take measurements such a elevation information and model geological processes.
So, just how do you go from this DTM image from HiRISE:
DTM image of the Central Peak of Elorza Crater on Mars. Credit: NASA/JPL/University of Arizona/USGS
To this amazing image?
Martian sunrise over the Central Peak of Elorza Crater. Rendered using Autodesk Maya and Adobe Photoshop. HiRISE data processed using HiView and gdal. Credit: NASA/JPL/University of Arizona/USGS/image editing by Kevin Gill
I’m going to let Kevin explain it:
To prep the data, I use Photoshop (to convert the JP2 file to a TIFF), and then standard GIS tools like gdal (Geospatial Data Abstraction Library) to create textures for 3D modeling. Using Autodesk Maya, I input those into a material as a color texture (orthoimagery) or displacement map (the DTM data).
I connect that material to a NURBS plane (sort of like a polygon mesh) that is scaled similarly to the physical properties of the data. I set up a camera at a nice angle (it takes a number of low-resolution test renders to get an angle I like) and let it render.
Then I just pull that render into Photoshop where I have a series of monochromatic color tints which gives the image it’s Martian feel. For the sky, I use either a sky from a MSL MastCam image or one that I took outside with my cell phone. If I’m using a sky I took with my cell phone, I’ll adjust the colors to make it look more like it would on Mars. If the colors in the image are still boring at this point, I may run a HDR adjustment on it in Photoshop.
Fissure in the Cerberus region. This false color view of a volcanic fissure in the Cerberus region of Mars was created using a digital terrain model (DTM) from the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter. The horizon was taken from Curiosity Mastcam imagery. Credit: NASA/JPL-Caltech/University of Arizona/ image editing by Kevin Gill.
What all this means is that you can create all these amazing view, plus incredible flyover videos, like this one Kevin put together of Endeavour Crater:
Or you can have some fun and visualize where the Curiosity rover is sitting:
Doin’ Science with Curiosity. Created using HiRIST DTM and Ortho data and NASA model of Curiosity. Rendered using Autodesk Maya and Adobe Photoshop. Curiosity Model: Brian Kumanchik, NASA/JPL-Caltech. Image editing by Kevin Gill.
We’ve written about this type of image editing previously, with the work of the people at UnmannedSpaceflight.com and others. Of course, the image editing software keeps improving, along with all the techniques.
Kevin also wanted to point out the work of other image editing enthusiast, Sean Doran.
“Sean’s work is resulting in views similar to mine,” Kevin said via email. “I know he’s using a process very different from mine, but we are thinking along the same lines in what we want out of the end product. His are quite impressive.”
For example, here is a flyover video of the Opportunity rover sitting along the rim of Endeavour Crater:
13 Years on Mars! On Christmas Day 2016, NASA’s Opportunity rover scans around vast Endeavour crater as she ascends steep rocky slopes on the way to reach a water carved gully along the eroded craters western rim. This navcam camera photo mosaic was assembled from raw images taken on Sol 4593 (25 Dec. 2016) and colorized. Credit: NASA/JPL/Cornell/Ken Kremer/kenkremer.com/Marco Di Lorenzo
13 Years on Mars!
On Christmas Day 2016, NASA’s Opportunity rover scans around vast Endeavour crater as she ascends steep rocky slopes on the way to reach a water carved gully along the eroded craters western rim. This navcam camera photo mosaic was assembled from raw images taken on Sol 4593 (25 Dec. 2016) and colorized. Credit: NASA/JPL/Cornell/Ken Kremer/kenkremer.com/Marco Di Lorenzo
NASA’s truly outstanding Opportunity rover continues “making new discoveries about ancient Mars” as she commemorates 13 Years since bouncing to a touchdown on Mars, in a feat that is “truly amazing” – the deputy chief scientist Ray Arvidson told Universe Today exclusively.
“Reaching the 13th year anniversary with a functioning rover making new discoveries about ancient Mars on a continuing basis is truly amazing,” Ray Arvidson, Opportunity Deputy Principal Investigator of Washington University in St. Louis, told Universe Today.
Put another way Opportunity is 13 YEARS into her 3 MONTH mission! And still going strong!
During the past year the world famous rover discovered “more extensive aqueous alteration within fractures and more mild alteration within the bedrock outcrops” at Endeavour crater, Arvidson elaborated.
And now she is headed to her next target – an ancient water carved gully!
The gully is situated about 0. 6 mile (1.6 km) south of the robots current location.
But to get there she first has to heroically ascend steep rocky slopes inclined over 20 degrees along the eroded craters western rim – and it’s no easy task! Slipping and sliding along the way and all alone on difficult alien terrain.
Furthermore she is 51 times beyond her “warrantied” life expectancy of merely 90 Sols promised at the time of landing so long ago – roving the surface of the 4th rock from the Sun during her latest extended mission; EM #10.
How was this incredible accomplishment achieved?
“Simply a well-made and thoroughly tested American vehicle,” Arvidson responded.
NASA’s Opportunity rover scans around and across to vast Endeavour crater on Dec. 19, 2016, as she climbs steep slopes on the way to reach a water carved gully along the eroded craters western rim. Note rover wheel tracks at center. This navcam camera photo mosaic was assembled from raw images taken on Sol 4587 (19 Dec. 2016) and colorized. Credit: NASA/JPL/Cornell/Ken Kremer/kenkremer.com/Marco Di Lorenzo
The six wheeled rover landed on Mars on January 24, 2004 PST on the alien Martian plains at Meridiani Planum -as the second half of a stupendous sister act.
Her twin sister Spirit, had successfully touched down 3 weeks earlier on January 3, 2004 inside 100-mile-wide Gusev crater and survived more than six years.
NASA’s Opportunity explores Spirit Mound after descending down Marathon Valley and looks out across the floor of vast Endeavour crater. This navcam camera photo mosaic was assembled from raw images taken on Sol 4505 (25 Sept 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
Opportunity concluded 2016 and starts 2017 marching relentlessly towards an ancient water carved gully along the eroded rim of vast Endeavour crater – the next science target on her heroic journey traversing across never before seen Red Planet terrains.
Huge Endeavour crater spans some 22 kilometers (14 miles) in diameter.
Throughout 2016 Opportunity was investigating the ancient, weathered slopes around the Marathon Valley location in Endeavour crater. The area became a top priority science destination after the slopes were found to hold a motherlode of ‘smectite’ clay minerals based on data from the CRISM spectrometer circling overhead aboard a NASA Mars orbiter.
The smectites were discovered via extensive, specially targeted Mars orbital measurements gathered by the CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) spectrometer on NASA’s Mars Reconnaissance Orbiter (MRO) – accomplished earlier at the direction of Arvidson.
Opportunity was descending down Marathon Valley the past year to investigate the clay minerals formed in water. They are key to helping determine the habitability of the Red Planet when it was warmer and wetter billions of years ago.
What did Opportunity accomplish scientifically at Marathon Valley during 2016?
“Key here is the more extensive aqueous alteration within fractures and more mild alteration within the bedrock outcrops,” Arvidson explained to me.
“Fractures have red pebbles enhanced in Al and Si (likely by leaching out more soluble elements), hematite, and in the case of our scuffed fracture, enhanced sulfate content with likely Mg sulfates and other phases. Also the bedrock is enriched in Mg and S relative to other Shoemaker rocks and these rocks are the smectite carrier as observed from CRISM ATO data.”
Marathon Valley measures about 300 yards or meters long. It cuts downhill through the west rim of Endeavour crater from west to east – the same direction in which Opportunity drove downhill from a mountain summit area atop the crater rim.
Opportunity has been exploring Endeavour since arriving at the humongous crater in 2011. Endeavour crater was formed when it was carved out of the Red Planet by a huge meteor impact billions of years ago.
“Endeavour crater dates from the earliest Martian geologic history, a time when water was abundant and erosion was relatively rapid and somewhat Earth-like,” explains Larry Crumpler, a science team member from the New Mexico Museum of Natural History & Science.
Opportunity has been climbing up very steep and challenging slopes to reach the top of the crater rim. Then she will drive south to Cape Byron and the gully system.
“We have had some mobility issues climbing steep, rocky slopes. Lots of slipping and skidding, but evaluating the performance of the rover on steep, rocky and soil-covered slopes was one of the approved extended mission objectives,” Arvidson explained.
“We are heading out of Cape Tribulation, driving uphill to the southwest to reach the Meridiani plains and then to drive to the western side of Cape Byron to the head of a gully system.”
What’s ahead for 2017? What’s the importance of exploring the gully?
“Finish up work on Cape Tribulation, traverse to the head of the gully system and head downhill into one or more of the gullies to characterize the morphology and search for evidence of deposits,” Arvidson elaborated.
“Hopefully test among dry mass movements, debris flow, and fluvial processes for gully formation. The importance is that this will be the first time we will acquire ground truth on a gully system that just might be formed by fluvial processes. Will search for cross bedding, gravel beds, fining or coarsening upward sequences, etc., to test among hypotheses.”
How long will it take to reach the gully?
“Months to the gully,” replied Arvidson. After arriving at the top of the crater rim, the rover will actually drive part of the way on the Martian plains again during the southward trek to the gully.
“And we will be driving on the plains to drive relatively long distances with an intent of getting to the gully well before the winter season.”
As of today, Jan 31, 2017, long lived Opportunity has survived 4630 Sols (or Martian days) roving the harsh environment of the Red Planet.
Opportunity has taken over 216,700 images and traversed over 27.26 miles (43.87 kilometers) – more than a marathon.
NASA’s Opportunity rover discovers a beautiful Martian dust devil moving across the floor of Endeavour crater as wheel tracks show robots path today exploring the steepest ever slopes of the 13 year long mission, in search of water altered minerals at Knudsen Ridge inside Marathon Valley on 1 April 2016. This navcam camera photo mosaic was assembled from raw images taken on Sol 4332 (1 April 2016) and colorized. Credit: NASA/JPL/Cornell/ Ken Kremer/kenkremer.com/Marco Di Lorenzo
See our updated route map below. It shows the context of the rovers over 13 year long traverse spanning more than the 26 mile distance of a Marathon runners race.
The rover surpassed the 27 mile mark milestone on November 6, 2016 (Sol 4546).
The power output from solar array energy production is currently 416 watt-hours, before heading into another southern hemisphere Martian winter in 2017. It will count as Opportunities 8th winter on Mars.
Meanwhile Opportunity’s younger sister rover Curiosity traverses and drills into the lower sedimentary layers at the base of Mount Sharp.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
13 Year Traverse Map for NASA’s Opportunity rover from 2004 to 2017. This map shows the entire 43 kilometer (27 mi) path the rover has driven on the Red Planet during more than 13 years and more than a marathon runners distance for over 4614 Sols, or Martian days, since landing inside Eagle Crater on Jan 24, 2004 – to current location at the western rim of Endeavour Crater. After descending down Marathon Valley and after studying Spirit Mound, the rover is now ascending back uphill on the way to a Martian water carved gully. Rover surpassed Marathon distance on Sol 3968 after reaching 11th Martian anniversary on Sol 3911. Opportunity discovered clay minerals at Esperance – indicative of a habitable zone – and searched for more at Marathon Valley. Credit: NASA/JPL/Cornell/ASU/Marco Di Lorenzo/Ken Kremer/kenkremer.com
Credit and copyright: ESA/DLR/FU Berlin (G. Neukum)
Ah, the good old days. ESA’s Mars Express imaged Reull Vallis, a river-like structure believed to have formed when running water flowed in the distant Martian past, cuts a steep-sided channel on its way towards the floor of the Hellas basin. A thicker atmosphere that included methane and hydrogen in addition to carbon dioxide may have allowed liquid water to flow on Mars at different times in the past according to a new study. Credit and copyright: ESA/DLR/FU Berlin (G. Neukum)
Water. It’s always about the water when it comes to sizing up a planet’s potential to support life. Mars may possess some liquid water in the form of occasional salty flows down crater walls, but most appears to be locked up in polar ice or hidden deep underground. Set a cup of the stuff out on a sunny Martian day today and depending on conditions, it could quickly freeze or simply bubble away to vapor in the planet’s ultra-thin atmosphere.
These rounded pebbles got their shapes after polished in a long-ago river in Gale Crater. They were discovered by Curiosity rover at the Hottah site. Credit: NASA/JPL-Caltech
Evidence of abundant liquid water in former flooded plains and sinuous river beds can be found nearly everywhere on Mars. NASA’s Curiosity rover has found mineral deposits that only form in liquid water and pebbles rounded by an ancient stream that once burbled across the floor of Gale Crater. And therein lies the paradox. Water appears to have gushed willy-nilly across the Red Planet 3 to 4 billion years ago, so what’s up today?
Blame Mars’ wimpy atmosphere. Thicker, juicier air and the increase in atmospheric pressure that comes with it would keep the water in that cup stable. A thicker atmosphere would also seal in the heat, helping to keep the planet warm enough for liquid water to pool and flow.
Different ideas have been proposed to explain the putative thinning of the air including the loss of the planet’s magnetic field, which serves as a defense against the solar wind.
This figure shows a cross-section of the planet Mars revealing an inner, high density core buried deep within the interior. Magnetic field lines are drawn in blue, showing the global scale magnetic field associated with a dynamic core. Mars must have had such a field long ago, but today it’s not evident. Perhaps the energy source that powered the early dynamo shut down. Credit: NASA/JPL/GSFC
Convection currents within its molten nickel-iron core likely generated Mars’ original magnetic defenses. But sometime early in the planet’s history the currents stopped either because the core cooled or was disrupted by asteroid impacts. Without a churning core, the magnetic field withered, allowing the solar wind to strip away the atmosphere, molecule by molecule.
Solar wind eats away the Martian atmosphere
Measurements from NASA’s current MAVEN mission indicate that the solar wind strips away gas at a rate of about 100 grams (equivalent to roughly 1/4 pound) every second. “Like the theft of a few coins from a cash register every day, the loss becomes significant over time,” said Bruce Jakosky, MAVEN principal investigator.
This graph shows the percent amount of the five most abundant gases in the atmosphere of Mars, as measured by the Sample Analysis at Mars (SAM) instrument suite on the Curiosity rover in October 2012. The season was early spring in Mars’ southern hemisphere. Credit: NASA/JPL-Caltech, SAM/GSFC
Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) suggest a different, less cut-and-dried scenario. Based on their studies, early Mars may have been warmed now and again by a powerful greenhouse effect. In a paper published in Geophysical Research Letters, researchers found that interactions between methane, carbon dioxide and hydrogen in the early Martian atmosphere may have created warm periods when the planet could support liquid water on its surface.
The team first considered the effects of CO2, an obvious choice since it comprises 95% of Mars’ present day atmosphere and famously traps heat. But when you take into account that the Sun shone 30% fainter 4 billion years ago compared to today, CO2 alone couldn’t cut it.
“You can do climate calculations where you add CO2 and build up to hundreds of times the present day atmospheric pressure on Mars, and you still never get to temperatures that are even close to the melting point,” said Robin Wordsworth, assistant professor of environmental science and engineering at SEAS, and first author of the paper.
NASA’s Cassini spacecraft looks toward the night side of Saturn’s largest moon and sees sunlight scattering through the periphery of Titan’s atmosphere and forming a ring of color. The breakdown of methane at Titan into hydrogen and oxygen may also have occurred on Mars. The addition of hydrogen in the company of methane and carbon dioxide would have created a powerful greenhouse gas mixture, significantly warming the planet. Credit: NASA/JPL-Caltech/Space Science Institute
Carbon dioxide isn’t the only gas capable of preventing heat from escaping into space. Methane or CH4 will do the job, too. Billions of years ago, when the planet was more geologically active, volcanoes could have tapped into deep sources of methane and released bursts of the gas into the Martian atmosphere. Similar to what happens on Saturn’s moon Titan, solar ultraviolet light would snap the molecule in two, liberating hydrogen gas in the process.
When Wordsworth and his team looked at what happens when methane, hydrogen and carbon dioxide collide and then interact with sunlight, they discovered that the combination strongly absorbed heat.
Carl Sagan,American astronomer and astronomy popularizer, first speculated that hydrogen warming could have been important on early Mars back in 1977, but this is the first time scientists have been able to calculate its greenhouse effect accurately. It is also the first time that methane has been shown to be an effective greenhouse gas on early Mars.
This awesome image of the Tharsis region of Mars taken by Mars Express shows several prominent shield volcanoes including the massive Olympus Mons (at left). Volcanoes, when they were active, could have released significant amounts of methane into Mars’ atmosphere. Click for a larger version. Credit: ESA
When you take methane into consideration, Mars may have had episodes of warmth based on geological activity associated with earthquakes and volcanoes. There have been at least three volcanic epochs during the planet’s history — 3.5 billion years ago (evidenced by lunar mare-like plains), 3 billion years ago (smaller shield volcanoes) and 1 to 2 billion years ago, when giant shield volcanoes such as Olympus Monswere active. So we have three potential methane bursts that could rejigger the atmosphere to allow for a mellower Mars.
The sheer size of Olympus Mons practically shouts massive eruptions over a long period of time. During the in-between times, hydrogen, a lightweight gas, would have continued to escape into space until replenished by the next geological upheaval.
“This research shows that the warming effects of both methane and hydrogen have been underestimated by a significant amount,” said Wordsworth. “We discovered that methane and hydrogen, and their interaction with carbon dioxide, were much better at warming early Mars than had previously been believed.”
I’m tickled that Carl Sagan walked this road 40 years ago. He always held out hope for life on Mars. Several months before he died in 1996, he recorded this:
” … maybe we’re on Mars because of the magnificent science that can be done there — the gates of the wonder world are opening in our time. Maybe we’re on Mars because we have to be, because there’s a deep nomadic impulse built into us by the evolutionary process, we come after all, from hunter gatherers, and for 99.9% of our tenure on Earth we’ve been wanderers. And, the next place to wander to, is Mars. But whatever the reason you’re on Mars is, I’m glad you’re there. And I wish I was with you.”
An artist’s impression of what Mars might have looked like with water. Credit: ESO/M. Kornmesser
For some time, scientists have suspected that life may have existed on Mars in the deep past. Owing to the presence of a thicker atmosphere and liquid water on its surface, it is entirely possible that the simplest of organisms might have begun to evolve there. And for those looking to make Mars a home for humanity someday, it is hoped that these conditions (i.e favorable to life) could be recreated again someday.
But as it turns out, there are some terrestrial organisms that could survive on Mars as it is today. According to a recent study by a team of researchers from the Arkansas Center for Space and Planetary Sciences (ACSPS) at the University of Arkansas, four species of methanogenic microorganisms have shown that they could withstand one of the most severe conditions on Mars, which is its low-pressure atmosphere.
Methanogenic organisms that were found in samples of deep volcanic rocks along the Columbia River and in Idaho Falls. Credit: NASA
To put it simply, Methanogens are ancient group of organisms that are classified as archaea, a species of microorganism that do not require oxygen and can therefore survive in what we consider to be “extreme environments”. On Earth, methanogens are common in wetlands, ocean environments, and even in the digestive tracts of animals, where they consume hydrogen and carbon dioxide to produce methane as a metabolic byproduct.
And as several NASA missions have shown, methane has also been found in the atmosphere of Mars. While the source of this methane has not yet been determined, it has been argued that it could be produced by methanogens living beneath the surface. As Rebecca Mickol, an astrobiologist at the ACSPS and the lead author of the study, explained:
“One of the exciting moments for me was the detection of methane in the Martian atmosphere. On Earth, most methane is produced biologically by past or present organisms. The same could possibly be true for Mars. Of course, there are a lot of possible alternatives to the methane on Mars and it is still considered controversial. But that just adds to the excitement.”
As part of the ongoing effort to understand the Martian environment, scientists have spent the past 20 years studying if four specific strains of methanogen – Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, Methanococcus maripaludis – can survive on Mars. While it is clear that they could endure the low-oxygen and radiation (if underground), there is still the matter of the extremely low air-pressure.
Graduate students Rebecca Mickol and Navita Sinha prepare to load methanogens into the Pegasus Chamber housed in W.M. Keck Laboratory. Credit: University of Arkansas
With help from the NASA Exobiology & Evolutionary Biology Program (part of NASA’s Astrobiology Program), which issued them a three-year grant back in 2012, Mickol and her team took a new approach to testing these methanogens. This included placing them in a series of test tubes and adding dirt and fluids to simulate underground aquifers. They then fed the samples hydrogen as a fuel source and deprived them of oxygen.
The next step was subjecting the microorganisms to pressure conditions analogues to Mars to see how they might hold up. For this, they relied on the Pegasus Chamber, an instrument operated by the ACSPS in their W.M. Keck Laboratory for Planetary Simulations. What they found was that the methanogens all survived exposure to pressures of 6 to 143 millibars for periods of between 3 and 21 days.
This study shows that certain species of microorganisms are not dependent on a the presence of a dense atmosphere for their survival. It also shows that these particular species of methanogens could withstand periodic contact with the Martian atmosphere. This all bodes well for the theories that Martian methane is being produced organically – possibly in subsurface, wet environments.
This is especially good news in light of evidence provided by NASA’s HiRISE instrument concerning Mars’ recurring slope lineae, which pointed towards a possible connection between liquid water columns on the surface and deeper levels in the subsurface. If this should prove to be the case, then organisms being transported in the water column would be able to withstand the changing pressures during transport.
The possible ways methane might get into Mars’ atmosphere, ranging from subsurface microbes and weathering of rock and stored methane ice called a clathrate. Ultraviolet light can work on surface materials to produce methane as well as break it apart into other molecules (. Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan
The next step, according to Mickol is to see how these organisms can stand up to temperature. “Mars is very, very cold,” she said, “often getting down to -100ºC (-212ºF) at night, and sometimes, on the warmest day of the year, at noon, the temperature can rise above freezing. We’d run our experiments just above freezing, but the cold temperature would limit evaporation of the liquid media and it would create a more Mars-like environment.”
Scientists have suspected for some time that life may still be found on Mars, hiding in recesses and holes that we have yet to peek into. Research that confirms that it can indeed exist under Mars’ present (and severe) conditions is most helpful, in that it allows us to narrow down that search considerably.
In the coming years, and with the deployment of additional Mars missions – like NASA’s Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander, which is scheduled for launch in May of next year – we will be able to probe deeper into the Red Planet. And with sample return missions on the horizon – like the Mars 2020 rover – we may at last find some direct evidence of life on Mars!
This peculiar rock, photographed on Jan. 12 (Sol 1577) by NASA's Curiosity rover, appears to be a metal meteorite. When confirmed, this will be the rover's third meteorite find on the Red Planet. Click for the high resolution original. Credit: NASA/JPL-Caltech/MSSS
This peculiar rock, photographed on Jan. 12 (Sol 1577) by NASA’s Curiosity rover, appears to be a metal meteorite. When confirmed, this would be the rover’s third meteorite find on the Red Planet. Click for the high resolution original. Credit: NASA/JPL-Caltech/MSSS
Rolling up the slopes of Mt. Sharp recently, NASA’s Curiosity rover appears to have stumbled across yet another meteorite, its third since touching down nearly four and a half years ago. While not yet confirmed, the turkey-shaped object has a gray, metallic luster and a lightly-dimpled texture that hints of regmaglypts. Regmaglypts, indentations that resemble thumbprints in Play-Doh, are commonly seen in meteorites and caused by softer materials stripped from the rock’s surface during the brief but intense heat and pressure of its plunge through the atmosphere.
Oddly, only one photo of the assumed meteorite shows up on the Mars raw image site. Curiosity snapped the image on Jan. 12 at 11:21 UT with its color mast camera. If you look closely at the photo a short distance above and to the right of the bright reflection a third of the way up from the bottom of the rock, you’ll spy three shiny spots in a row. Hmmm. Looks like it got zapped by Curiosity’s ChemCam laser. The rover fires a laser which vaporizes part of the meteorite’s surface while a spectrometer analyzes the resulting cloud of plasma to determine its composition. The mirror-like shimmer of the spots is further evidence that the gray lump is an iron-nickel meteorite.
Meet Egg Rock, another iron-nickel meteorite and Curiosity’s second meteorite find. The white spots/holes are where the object was zapped by the rover’s laser to determine its composition. The rover spotted Egg Rock (about the size of a golfball) on Oct. 27, 2016. Credit: NASA/JPL-Caltech
Curiosity has driven more than 9.3 miles (15 km) since landing inside Mars’ Gale Crater in August 2012. It spent last summer and part of fall in a New Mexican-like landscape of scenic mesas and buttes called “Murray Buttes.” It’s since departed and continues to climb to sequentially higher and younger layers of the lower part of Mt. Sharp to investigate additional rocks. Scientists hope to create a timeline of how the region’s climate changed from an ancient freshwater lake environment with conditions favorable for microbial life (if such ever evolved) to today’s windswept, frigid desert.
Assuming the examination of the rock proves a metallic composition, this new rock would be the eighth discovered by our roving machines. All of them have been irons despite the fact that at least on Earth, iron meteorites are rather rare. About 95% of all found or seen-to-fall meteorites are the stony variety (mostly chondrites), 4.4% are irons and 1% stony-irons.
Curiosity found this iron meteorite called “Lebanon” back in 2014. It’s about two yards or two meters wide (left to right). The smaller piece in the foreground is named “Lebanon B. This photo combines a series of high-resolution circular images across the middle taken by the Remote Micro-Imager (RMI) with a MastCam image. Credit: NASA/JPL-Caltech/LANL/CNES/IRAP/LPGNantes/CNRS/IAS/MSSS
NASA’s Opportunity rover found five metal meteorites, and Curiosity’s rumbled by its first find, a honking hunk of metallic gorgeousness named Lebanon, in May 2014. If this were Earth, the new meteorite’s smooth, shiny texture would indicate a relatively recent fall, but who’s to say how long it’s been sitting on Mars. The planet’s not without erosion from wind and temperature changes, but it lacks the oxygen and water that would really eat into an iron-nickel specimen like this one. Still, the new find looks polished to my eye, possibly smoothed by wind-whipped sand grains during the countless Martian dust storms that have raged over the eons.
Curiosity really knows how to put you on Mars. This view of exposed bedrock and dark sands was taken by the rover’s navigation camera on Friday, Jan. 13. Credit: NASA/JPL-Caltech/MSSS
Why no large stony meteorites have yet to be been found on Mars is puzzling. They should be far more common; like irons, stonies would also display beautiful thumprinting and dark fusion crust to boot. Maybe they simply blend in too well with all the other rocks littering the Martian landscape. Or perhaps they erode more quickly on Mars than the metal variety.
Every time a meteorite turns up on Mars in images taken by the rovers, I get a kick out of how our planet and the Red One not only share water, ice and wind but also getting whacked by space rocks.
As soon as people learn how inhospitable Mars, Venus, and really the entire Solar System are, they want to know how we can fix it. There’s a word for fixing a planet to make it more like Earth: terraforming.
If you want to fix Mars, all you have to do is thicken and warm up its atmosphere to the point that Earth life could survive. You’d need to do the opposite with Venus, cooling it down and reducing the atmospheric pressure.
But it’s hard to wrap your brain around the scale it would take to do such a thing. We’re talking about an incomprehensible amount of atmosphere to try and modify. The atmospheric pressure on the surface of Venus is 90 times the pressure of Earth. It’s carbon dioxide, so you need some chemical, like magnesium or calcium to lock it away. If you can mine, for example, 4 times the mass of asteroid Vesta, it should be possible.
Credit: NASA/Pat Rawlings
No, from our perspective, that’s practically impossible. In fact, it’s kind of ironic, when you consider the fact that we’re making our own planet less habitable to human civilization every day.
There’s another path to making another world habitable, however, and that’s changing life itself to be more adaptable to surviving on another world.
Instead of terraforming a planet, what if we terraformed ourselves?
Actually, that’s a really bad term. We’d really be changing ourselves to be better adapted to living on Mars. So we’d be Marsiforming ourselves? Venisfying ourselves? Okay, I’ll need to work on the terminology. But you get the gist.
Life, of course, has been evolving and adapting on Earth for at least 4.1 billion years. Pretty much as soon as life could arise on Earth, it did. And those early lifeforms went on to modify and change, adapting to every environment on our planet, from the deepest oceans, to the mountains. From the deserts to the icy tundra.
But in the last few thousand years, we’ve taken a driving role in the evolution of life for the domesticated plants and animals we eat and care for. Your pet dog looks vastly different from the wolf ancestor it evolved from. We’ve increased the yield of corn and wheat, adapted fruit and vegetables, and turned chickens into flightless mobile breast meat.
And in the last few decades, we’ve gained the most powerful new tools for adapting life to our needs: genetic modification. Instead of waiting for evolution and selective breeding to get the results we need, we can rewrite the genetic code of lifeforms, borrowing beneficial traits from life over here, and jamming it into the code of life over there. What doesn’t get cooler when it glows in the dark? Nothing, that’s what.
Can we adapt Earth life to live on Mars? It turns out, our toughest life isn’t that far off. During the American Society for Microbiology meeting in 2015, researchers presented how well tough bacteria would be able to handle the conditions on Mars. They found that 4 species of methanogens might actually be able to survive below the surface, consuming hydrogen and carbon dioxide and releasing methane.
It would still look like a desolate wasteland, but there would be life on Mars even if we have to put it there ourselves. Credit: NASA/JPL
In other words, under the right conditions, there are forms of Earth life that can survive on Mars right now. In fact, as we continue to explore Mars, and learn that it’s wetter than we ever thought, we risk infecting the planet with our own microbial life accidentally.
But when we imagine life on Mars, we’re not thinking about a few hardy methanogens, struggling for life beneath the briny regolith. No, we imagine plants, trees, and little animals scurrying about.
Do we have anything close there that we could adapt?
It turns out there are strains of lichen, the symbiosis of fungi and algae that could stand a chance. You’ve probably seen lichen on rocks and other places that suck for any other lifeform. But according to Jean-Pierre de Vera, with the German Aerospace Center’s Institute of Planetary Research in Berlin, Germany, there are Earth-based lichen which are tough enough.
They put lichen into a test environment that simulated the surface of Mars: low atmospheric pressure, carbon dioxide atmosphere, freezing cold temperatures and high radiation. The only things they couldn’t simulate were galactic radiation and low gravity.
What’s not to lichen about this plan? Credit: Roantrum (CC BY 2.0)
In the harshest conditions, the lichen was barely able to hang on and survive, but in milder Mars conditions, protected within rock cracks, the lichen continued to carry out its regular photosynthesis.
It seems that lichen too is ready to go to Mars.
Methanogens and hardy lichen don’t make for the most thrilling forest canopy. In a second, I’m going to talk about what we can do to tweak life to survive and thrive on Mars. But first, I’d like to thank Zach Kanzler, Jeremy Payne, James Craver, Mike Janzen, and the rest of our 709 patrons for their generous support. If you love what we’re doing and want to help out, head over to patreon.com/universetoday.
If our current life isn’t going to get the job done, well then we’re just going to need to adapt it ourselves. Just like we’ve done in the past, with breeding and more recently with rewriting the DNA itself.
Without dramatically changing the environment of Mars to thicken its atmosphere and boost its temperatures, it’s inconceivable to think that we’ll ever adapt anything more complex than bacteria or lichen to survive outside on Mars. But if those give us a toehold, and other techniques can improve the environment, it’s possible to take incremental steps in that direction.
Engineering concept of a plant growth module. Credit: NASA/Langley
Even within the protected environments of Martian colonies, our current plants and animals probably aren’t up to the task.
The regolith on Mars, for example, contains toxic perchlorates that would kill any Earth-based plants that would try to grow in it. There are Earth-based lifeforms that love perchlorates and it should be possible to create organisms that will strip this toxin out of the regolith and turn it into something useful, like rocket fuel.
Earth-based plants and animals evolved in a 24-hour daily cycle, but a day on Mars is 40 minutes longer than an Earth day. We could grow plants with artificial light, but if we want to use natural Martian light, some adaptation might be required.
Perhaps the biggest risk we face to living on Mars, the one that our technology really can’t help us with is the lower gravity. We don’t know if living in 38% gravity for generations is going to be good for us. We know we can run around on the surface for a few years, but can pregnancy carry to term in this lower gravity?
We just don’t know. In order to find out safely, we’ll need to create rotating space station colonies, where we vary the artificial gravity and see what happens with animals over multiple generations with lower gravity.
A NASA artist’s concept of a vehicle which could provide an artificial-gravity environment of Mars exploration crews. The piloted vehicle rotates around the axis that contains the solar panels. Levels of artificial gravity vary according to the tether length and the rate at which the vehicle spins. Credit: NASA
If there are health problems, we can take the results of these experiments, and modify genetic code to have better adaptation to this environment. And since humans are animals too, the lessons we learn will help us adapt ourselves to be better prepared to survive on Mars, forever.
Here’s a link to an awesome video from Kurzgesagt about the state of genetic engineering, and the amazing technology that’s just around the corner.
If we are able to change humans to live on Mars, we can probably do the same with other worlds. Image a far future, where human colonies on different worlds are adapted to survive there, using a mixture of technology and genetic manipulation. This will be good and bad. On the good side, human colonies will be able to survive over many generations. On the bad side, they might never be able to live anywhere else in the Solar System without going through the whole adaptation process again.
Would you be willing to change your body permanently to be better adapted to live on another world? Let me know your thoughts in the comments.
A view of Earth and its Moon, as seen from Mars. It combines two images acquired on Nov. 20, 2016, by the HiRISE camera on NASA's Mars Reconnaissance Orbiter, with brightness adjusted separately for Earth and the moon to show details on both bodies. Credit: NASA/JPL-Caltech/Univ. of Arizona.
The incredible HiRISE camera on board the Mars Reconnaissance Orbiter turned its eyes away from its usual target – Mars’ surface – and for calibration purposes only, took some amazing images of Earth and our Moon. Combined to create one image, this is a marvelous view of our home from about 127 million miles (205 million kilometers) away.
Alfred McEwen, principal investigator for HiRISE said the image is constructed from the best photo of Earth and the best photo of the Moon from four sets of images. Interestingly, this combined view retains the correct positions and sizes of the two bodies relative to each other. However, Earth and the Moon appear closer than they actually are in this image because the observation was planned for a time at which the Moon was almost directly behind Earth, from Mars’ point of view, to see the Earth-facing side of the Moon.
A view of Earth and its Moon, as seen from Mars. It combines two images acquired on Nov. 20, 2016, by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter, with brightness adjusted separately for Earth and the moon to show details on both bodies. Credit: NASA/JPL-Caltech/Univ. of Arizona.
“Each is separately processed prior to combining (in correct relative positions and sizes), so that the Moon is bright enough to see,” McEwen wrote on the HiRISE website. “The Moon is much darker than Earth and would barely show up at all if shown at the same brightness scale as Earth. Because of this brightness difference, the Earth images are saturated in the best Moon images, and the Moon is very faint in the best (unsaturated) Earth image.”
Earth looks reddish because the HiRISE imaging team used color filters similar to the Landsat images where vegetation appears red.
“The image color bandpasses are infrared, red, and blue-green, displayed as red, green, and blue, respectively,” McEwen explained. “The reddish blob in the middle of the Earth image is Australia, with southeast Asia forming the reddish area (vegetation) near the top; Antarctica is the bright blob at bottom-left. Other bright areas are clouds. We see the western near-side of the Moon.”
HiRISE took these pictures on Nov. 20, 2016, and this is not the first time HiRISE has turned its eyes towards Earth.
Back in 2007, HiRISE took this image, below, from Mars’ orbit when it was just 88 million miles (142 million km) from Earth. This one is more like how future astronauts might see Earth and the Moon through a telescope from Mars’ orbit.
An image of Earth and the Moon, acquired on October 3, 2007, by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/University of Arizona.
If you look closely, you can make out a few features on our planet. The west coast outline of South America is at lower right on Earth, although the clouds are the dominant features. In fact, the clouds were so bright, compared with the Moon, that they almost completely saturated the filters on the HiRISE camera. The people working on HiRISE say this image required a fair amount of processing to make such a nice-looking picture.
You can see an image from a previous Mars’ orbiter, the Mars Global Surveyor, that took a picture of Earth, the Moon and Jupiter — all in one shot — back in 2003 here.
