Martian Green Nightglow Seen for the First Time

Artist's impression of the ExoMars Trace Gas orbiter spotting daylight green oxygen at Mars. Credit: ESA

On Earth, there is a phenomenon known as nightglow, where the atmosphere experiences faint light emissions that prevent the night sky from becoming completely dark. This is caused by various processes in the upper atmosphere, like the recombination of atoms, cosmic rays striking the atmosphere, or oxygen and nitrogen interacting with hydroxyl a few hundred kilometers from the surface. Thanks to data obtained by the ESA’s ExoMars Trace Gas Orbiter (TGO), the same phenomenon has been observed in the Martian atmosphere for the first time.

While scientists have long suspected that Mars also experiences this atmospheric phenomenon, this is the first time that effectively proves it. The revelation was made by an international team of scientists based on their analysis of data from the TGO’s Nadir and Occultation for MArs Discovery (NOMAD) spectrometer. When astronauts and rovers explore Mars’ polar regions in the near future, they will see a green glow whenever they look up at the sky and could even use the glow to navigate and find their way in the dark of night.

Continue reading “Martian Green Nightglow Seen for the First Time”

Life Probably Didn't Have a Hand in Creating Organic Deposits on the Surface of Mars

ExoMars Trace Gas Orbiter analyses the martian atmosphere. Credit: ESA/ATG medialab

At this very moment, eleven robotic missions are exploring Mars, a combination of orbiters, landers, rovers, and one aerial vehicle (the Ingenuity helicopter). Like their predecessors, these missions are studying Mars’ atmosphere, surface, and subsurface to learn more about its past and evolution, including how it went from a once warmer and wetter environment to the freezing, dusty, and extremely dry planet we see today. In addition, these missions are looking for evidence of past life on Mars and perhaps learning if and where it might still exist today.

One particularly interesting issue is how the atmosphere of Mars – primarily composed of carbon dioxide (CO2) – is relatively enriched with Carbon-13 (13C), aka. “heavy carbon.” For years, scientists have speculated that the ratio of this isotope to “light carbon” (12C) might be responsible for organics found on the surface (a sign of biological processes!). But after analyzing data from the ESA’s ExoMars Trace Gas Orbiter (TGO) mission, an international team led by The Open University determined that these organics may be “abiotic” in origin (i.e., not biological).

Continue reading “Life Probably Didn't Have a Hand in Creating Organic Deposits on the Surface of Mars”

Dust Storms on Mars Generate Static Electricity. What Does This Do to Its Surface?

Artist's impression of the electricity generated by a Martian dust storm. Credit: NASA

Dust storms are a serious hazard on Mars. While smaller storms and dust devils happen regularly, larger ones happen every year (during summer in the southern hemisphere) and can cover continent-sized areas for weeks. Once every three Martian years (about five and a half Earth years), the storms can become large enough to encompass the entire planet and last up to two months. These storms play a major role in the dynamic processes that shape the surface of Mars and are sometimes visible from Earth (like the 2018 storm that ended the Opportunity rover’s mission).

When Martian storms become particularly strong, the friction between dust grains causes them to become electrified, transferring positive and negative charges through static electricity. According to research led by planetary scientist Alian Wang at Washington University in St. Louis, this electrical force could be the major driving force of the Martian chlorine cycle. Based on their analysis, Wang and her colleagues believe this process could account for the abundant perchlorates and other chemicals that robotic missions have detected in Martian soil.

Continue reading “Dust Storms on Mars Generate Static Electricity. What Does This Do to Its Surface?”

The Bottom of Valles Marineris Seems to Have Water Mixed in With the Regolith

Mosaic of the Valles Marineris hemisphere of Mars, similar to what one would see from orbital distance of 2500 km. Credit: NASA/JPL-Caltech

For generations, humans have dreamed of the day when we might set foot on Mars. For many others, the dream has been one of settling on Mars and creating an outpost of human civilization there. Today, it looks as though both of these dreams are getting closer to becoming a reality, as space agencies and the commercial space industry are deep into planning regular crewed missions to the Red Planet. And when planning for long-duration missions to destinations in deep space, a vital aspect is assessing the local environment.

For example, missions to Mars will need to be as self-sufficient as possible, which means using local resources to meet the needs of the mission and astronauts – a process known as in-situ resource utilization (ISRU). According to new data from the ESA-Roscomos ExoMars Trace Gas Orbiter (TGO), the massive equatorial canyon known as Valles Marineris (Valley of Mars) contains vast deposits of ice that have remained hidden to scientists until now.

Continue reading “The Bottom of Valles Marineris Seems to Have Water Mixed in With the Regolith”

Dust Storms on Mars Continue to Make the Planet Drier

NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft celebrated one Earth year in orbit around Mars on Sept. 21, 2015. MAVEN was launched to Mars on Nov. 18, 2013 from Cape Canaveral Air Force Station in Florida and successfully entered Mars’ orbit on Sept. 21, 2014. Credit: NASA

Despite decades of exploration and study, Mars still has its fair share of mysteries. In particular, scientists are still trying to ascertain what happened to the water that once flowed on Mars’ surface. Unfortunately, billions of years ago, the Martian atmosphere began to be stripped away by the solar wind, which also resulted in the loss of its surface water over time – although it was not entirely clear where it went and what mechanisms were involved.

To address this, a team of scientists recently consulted data obtained by three orbiter missions studying the Martian atmosphere. In the process, they found evidence that the smaller regional dust storms that happen almost annually on Mars are making the planet drier over time. These findings suggest that storms are a major driving force behind the evolution of Mars’ atmosphere and its transition to the freezing and desiccated place we know today.

Continue reading “Dust Storms on Mars Continue to Make the Planet Drier”

ExoMars Sees the Martian Atmosphere Glowing Green

Credit: ESA

In the course of studying Mars, scientists have come to identify some key similarities to Earth’s own. One notable example is the way our atmospheres interact with sunlight to produce dazzling displays of energy. On Earth, these include not just the aurorae near the polar regions (Aurora Borealis and Australis), but the constant green glow that is the result of oxygen molecules interacting with sunlight (aka. “airglow”).

On Earth, airglow can be seen “edge-on” from space, as exemplified by the many spectacular images that are taken by astronauts aboard the International Space Station (ISS). This phenomenon was recently observed around Mars for the first time by the ESA’s Trace Gas Orbiter (TGO), which arrived at Mars in 2016 a part of the ExoMars program. Like aurorae, this observation is yet another example of how Mars is “Earth’s Twin.”

Continue reading “ExoMars Sees the Martian Atmosphere Glowing Green”

This Crater on Mars Traps the Cold, and Remains Filled With Ice, All Year Round

This image from ESA’s Mars Express shows Korolev crater, an 82-kilometre-across feature found in the northern lowlands of Mars. Credit: ESA/DLR/FU Berlin

On June 2nd, 2003, the European Space Agency’s Mars Express mission left Earth to begin its journey to Mars. Six months later (on December 25th) the spacecraft fired its main engine and entered orbit around Mars. This Christmas will therefore mark the fifteenth anniversary of the orbiter’s arrival and all the observations it has made of the Red Planet since then.

Appropriately, the Mars Express mission was able to commemorate this occasion by capturing some beautiful photos of a Martian crater that remains filled with ice all year round. This feature is known as the Korolev crater, which measures 82 km (51 mi) in diameter and is located in the northern lowlands, just south of the northern polar ice cap.

Continue reading “This Crater on Mars Traps the Cold, and Remains Filled With Ice, All Year Round”

ExoMars Has Sent Back its First Images From Mars

ExoMars images Korolev Crater. Copyright: ESA/Roscosmos/CaSSIS

On October 19th, 2016, the European Space Agency’s Exobiology on Mars (ExoMars) mission established orbit around Mars. Consisting of the ExoMars Trace Gas Orbiter (TGO) and the Schiaparelli lander, the purpose of this mission is to investigate Mars for past signs of life. And whereas the Schiaparelli unfortunately crashed during deployment, the TGO has managed to begin its mission ahead of schedule.

A few weeks ago, the satellite achieved a near circular orbit around Mars after performing a series of braking maneuvers. Since that time, the orbiter’s Color and Stereo Surface Imaging System (CaSSIS) took a stunning image of the surface. This picture was not only the TGO’s first image of Mars, it was also a test to see if the orbiter is ready to being its main mission on April 28th.

The image captured a 40 km- (25 mi) long segment of the Korolev Crater, which is located high in Mars’ northern hemisphere. The image was a composite of three images in different colors that were taken simultaneously on April 15th, 2018, which were then assembled to produce this color image. The bright material that appears at the edge of the crater is water ice.

The ExoMars Colour and Stereo Surface Imaging System, CaSSIS, captured this view of the rim of Korolev crater (73.3ºN/165.9ºE). Copyright ESA/Roscosmos/CaSSIS

As Antoine Pommerol, a member of the CaSSIS science team working on the calibration of the data, explained in a recent ESA press release:

“We were really pleased to see how good this picture was given the lighting conditions. It shows that CaSSIS can make a major contribution to studies of the carbon dioxide and water cycles on Mars.”

Prior to the test phase, the camera team transmitted new software to the TGO, and after a few minor issues, they determined that the instrument was ready to work. The camera is one of four instruments on the TGO, which also carries two spectrometer suites and a neutron detector. The spectrometers began their science mission on April 21st by taking the first sample of the atmosphere to see how its molecules absorb sunlight.

By doing this, the TGO hopes to determine the chemical composition of Mars atmosphere and find evidence of methane and other trace atmospheric gases that could be signatures of active biological or geological processes. Eventually, the camera will help characterize features on the surface that could be related to trace gas sources. Hence the importance of this recent test.

ExoMars’ Trace Gas Orbiter (TGO) and Schiaparelli lander seperating in orbit of Mars. Credit: ESA/ATG medialab

“We aim to fully automate the image production process,” said Nicolas Thomas, the camera’s principal investigator from the University of Bern. “Once we achieve this, we can distribute the data quickly to the science community for analysis.”

A lot of challenges lie ahead, which includes a long period of data collection to bring out the details of rare (or yet to be discovered) trace gases in Mars’ atmosphere. This is necessary since trace gases (as the name would suggest) are present in only very small amounts – i.e. less than 1% of the volume of the planet’s atmosphere. But as Håkan Svedhem – the ESA’s TGO project scientist – indicated, the test image was a good start.

“We are excited to finally be starting collecting data at Mars with this phenomenal spacecraft,” he said. “The test images we have seen so far certainly set the bar high.”

By 2020, the second part of the ExoMars mission is scheduled to launch. This will consist of a Russian surface platform and a European rover landing on the surface in support of a science mission that is expected to last into 2022 or longer. Alongside NASA’s proposed Mars 2020 rover, the Red Planet is due to have several more visitors in the coming years!

Further Reading: ESA

Is There Life on Mars?

Is There Life on Mars?
Is There Life on Mars?


Perhaps the most important question we can possible ask is, “are we alone in the Universe?”.

And so far, the answer has been, “I don’t know”. I mean, it’s a huge Universe, with hundreds of billions of stars in the Milky Way, and now we learn there are trillions of galaxies in the Universe.

Is there life closer to home? What about in the Solar System? There are a few existing places we could look for life close to home. Really any place in the Solar System where there’s liquid water. Wherever we find water on Earth, we find life, so it make sense to search for places with liquid water in the Solar System.

I know, I know, life could take all kinds of wonderful forms. Enlightened beings of pure energy, living among us right now. Or maybe space whales on Titan that swim through lakes of ammonia. Beep boop silicon robot lifeforms that calculate the wasted potential of our lives.

Sure, we could search for those things, and we will. Later. We haven’t even got this basic problem done yet. Earth water life? Check! Other water life? No idea.

It turns out, water’s everywhere in the Solar System. In comets and asteroids, on the icy moons of Jupiter and Saturn, especially Europa or Enceladus. Or you could look for life on Mars.

Sloping buttes and layered outcrops within the "Murray formation" layer of lower Mount Sharp. Credit: NASA
Sloping buttes and layered outcrops within the “Murray formation” layer of lower Mount Sharp. Credit: NASA

Mars is similar to Earth in many ways, however, it’s smaller, has less gravity, a thinner atmosphere. And unfortunately, it’s bone dry. There are vast polar caps of water ice, but they’re frozen solid. There appears to be briny liquid water underneath the surface, and it occasionally spurts out onto the surface. Because it’s close and relatively easy to explore, it’s been the place scientists have gone looking for past or current life.

Researchers tried to answer the question with NASA’s twin Viking Landers, which touched down in 1976. The landers were both equipped with three biology experiments. The researchers weren’t kidding around, they were going to nail this question: is there life on Mars?

In the first experiment, they took soil samples from Mars, mixed in a liquid solution with organic and inorganic compounds, and then measured what chemicals were released. In a second experiment, they put Earth organic compounds into Martian soil, and saw carbon dioxide released. In the third experiment, they heated Martian soil and saw organic material come out of the soil.

The landing site of Viking 1 on Mars in 1977, with trenches dug in the soil for the biology experiments. Credit: NASA/JPL
The landing site of Viking 1 on Mars in 1977, with trenches dug in the soil for the biology experiments. Credit: NASA/JPL

Three experiments, and stuff happened in all three. Stuff! Pretty exciting, right? Unfortunately, there were equally plausible non-biological explanations for each of the results. The astrobiology community wasn’t convinced, and they still fight in brutal cage matches to this day. It was ambitious, but inconclusive. The worst kind of conclusive.

Researchers found more inconclusive evidence in 1994. Ugh, there’s that word again. They were studying a meteorite that fell in Antarctica, but came from Mars, based on gas samples taken from inside the rock.

They thought they found evidence of fossilized bacterial life inside the meteorite. But again, there were too many explanations for how the life could have gotten in there from here on Earth. Life found a way… to burrow into a rock from Mars.

NASA learned a powerful lesson from this experience. If they were going to prove life on Mars, they had to go about it carefully and conclusively, building up evidence that had no controversy.

Greetings from Mars! I’m Spirit and I was the first of two twin robots to land on Mars. Unlike my twin, Opportunity, I’m known as the hill-climbing robot. Artist Concept, Mars Exploration Rovers. NASA/JPL-Caltech
Artist Concept, Mars Exploration Rovers. NASA/JPL-Caltech

The Spirit and Opportunity Rovers were an example of building up this case cautiously. They were sent to Mars in 2004 to find evidence of water. Not water today, but water in the ancient past. Old water Over the course of several years of exploration, both rovers turned up multiple lines of evidence there was water on the surface of Mars in the ancient past.

They found concretions, tiny pebbles containing iron-rich hematite that forms on Earth in water. They found the mineral gypsum; again, something that’s deposited by water on Earth.

Opportunity's Approach to 'Homestake'. This view from the front hazard-avoidance camera on NASA's Mars Exploration Rover Opportunity shows the rover's arm's shadow falling near a bright mineral vein informally named Homestake. The vein is about the width of a thumb and about 18 inches (45 centimeters) long. Opportunity examined it in November 2011 and found it to be rich in calcium and sulfur, possibly the calcium-sulfate mineral gypsum. Opportunity took this image on Sol 2763 on Mars (Nov. 7, 2011). Credit: NASA/JPL-Caltech
A bright mineral vein informally named Homestake. The vein is about the width of a thumb and about 18 inches (45 centimeters) long. Opportunity examined it in November 2011 (Sol 2763) and found it to be rich in calcium and sulfur, possibly the calcium-sulfate mineral gypsum. Credit: NASA/JPL-Caltech

NASA’s Curiosity Rover took this analysis to the next level, arriving in 2012 and searching for evidence that water was on Mars for vast periods of time; long enough for Martian life to evolve.

Once again, Curiosity found multiple lines of evidence that water acted on the surface of Mars. It found an ancient streambed near its landing site, and drilled into rock that showed the region was habitable for long periods of time.

In 2014, NASA turned the focus of its rovers from looking for evidence of water to searching for past evidence of life.

Curiosity found one of the most interesting targets: a strange strange rock formations while it was passing through an ancient riverbed on Mars. While it was examining the Gillespie Lake outcrop in Yellowknife Bay, it photographed sedimentary rock that looks very similar to deposits we see here on Earth. They’re caused by the fossilized mats of bacteria colonies that lived billions of years ago.

A bright and interestingly shaped tiny pebble shows up among the soil on a rock, called "Gillespie Lake," which was imaged by Curiosity's Mars Hand Lens Imager on Dec. 19, 2012, the 132nd sol, or Martian day of Curiosity's mission on Mars. Credit: NASA / JPL-Caltech / MSSS.
A bright and interestingly shaped tiny pebble shows up among the soil on a rock, called “Gillespie Lake,” which was imaged by Curiosity’s Mars Hand Lens Imager on Dec. 19, 2012, the 132nd sol, or Martian day of Curiosity’s mission on Mars. Credit: NASA / JPL-Caltech / MSSS.

Not life today, but life when Mars was warmer and wetter. Still, fossilized life on Mars is better than no life at all. But there might still be life on Mars, right now, today. The best evidence is not on its surface, but in its atmosphere. Several spacecraft have detected trace amounts of methane in the Martian atmosphere.

Methane is a chemical that breaks down quickly in sunlight. If you farted on Mars, the methane from your farts would dissipate in a few hundred years. If spacecraft have detected this methane in the atmosphere, that means there’s some source replenishing those sneaky squeakers. It could be volcanic activity, but it might also be life. There could be microbes hanging on, in the last few places with liquid water, producing methane as a byproduct.

The European ExoMars orbiter just arrived at Mars, and its main job is sniff the Martian atmosphere and get to the bottom of this question.

Are there trace elements mixed in with the methane that means its volcanic in origin? Or did life create it? And if there’s life, where is it located? ExoMars should help us target a location for future study.

The European/Russian ExoMars Trace Gas Orbiter (TGO) will launch in 2016 and sniff the Martian atmosphere for signs of methane which could originate for either biological or geological mechanisms. Credit: ESA
The European/Russian ExoMars Trace Gas Orbiter (TGO) will sniff the Martian atmosphere for signs of methane which could originate for either biological or geological mechanisms. Credit: ESA

NASA is following up Curiosity with a twin rover designed to search for life. The Mars 2020 Rover will be a mobile astrobiology laboratory, capable of scooping up material from the surface of Mars and digesting it, scientifically speaking. It’ll search for the chemicals and structures produced by past life on Mars. It’ll also collect samples for a future sample return mission.

Even if we do discover if there’s life on Mars, it’s entirely possible that we and Martian life are actually related by a common ancestor, that split off billions of years ago. In fact, some astrobiologists think that Mars is a better place for life to have gotten started.

Not the dry husk of a Red Planet that we know today, but a much wetter, warmer version that we now know existed billions of years ago. When the surface of Mars was warm enough for liquid water to form oceans, lakes and rivers. And we now know it was like this for millions of years.

A conception of an ancient and/or future Mars, flush with oceans, clouds and life. Credit: Kevin Gill.
A conception of an ancient Mars, flush with oceans, clouds and life. Credit: Kevin Gill.

While Earth was still reeling from an early impact by the massive planet that crashed into it, forming the Moon, life on Mars could have gotten started early.

But how could we actually be related? The idea of Panspermia says that life could travel naturally from world to world in the Solar System, purely through the asteroid strikes that were regularly pounding everything in the early days.

Imagine an asteroid smashing into a world like Mars. In the lower gravity of Mars, debris from the impact could be launched into an escape trajectory, free to travel through the Solar System.

We know that bacteria can survive almost indefinitely, freeze dried, and protected from radiation within chunks of space rock. So it’s possible they could make the journey from Mars to Earth, crossing the orbit of our planet.

Even more amazingly, the meteorites that enter the Earth’s atmosphere would protect some of the bacterial inhabitants inside. As the Earth’s atmosphere is thick enough to slow down the descent of the space rocks, the tiny bacterialnauts could survive the entire journey from Mars, through space, to Earth.

In February 2013, asteroid DA 2014 safely passed by the Earth. There are several proposals abounding about bringing asteroids closer to our planet to better examine their structure. Credit: NASA/JPL-Caltech
Credit: NASA/JPL-Caltech

If we do find life on Mars, how will we know it’s actually related to us? If Martian life has the similar DNA structure to Earth life, it’s probably related. In fact, we could probably trace the life back to determine the common ancestor, and even figure out when the tiny lifeforms make the journey.

If we do find life on Mars, which is related to us, that just means that life got around the Solar System. It doesn’t help us answer the bigger question about whether there’s life in the larger Universe. In fact, until we actually get a probe out to nearby stars, or receive signals from them, we might never know.

An even more amazing possibility is that it’s not related. That life on Mars arose completely independently. One clue that scientists will be looking for is the way the Martian life’s instructions are encoded. Here on Earth, all life follows “left-handed chirality” for the amino acid building blocks that make up DNA and RNA. But if right-handed amino acids are being used by Martian life, that would mean a completely independent origin of life.

Of course, if the life doesn’t use amino acids or DNA at all, then all bets are off. It’ll be truly alien, using a chemistry that we don’t understand at all.

There are many who believe that Mars isn’t the best place in the Solar System to search for life, that there are other places, like Europa or Enceladus, where there’s a vast amount of liquid water to be explored.

But Mars is close, it’s got a surface you can land on. We know there’s liquid water beneath the surface, and there was water there for a long time in the past. We’ve got the rovers, orbiters and landers on the planet and in the works to get to the bottom of this question. It’s an exciting time to be part of this search.