In 2003, scientists from NASA’s Goddard Space Center made the first-ever detection of trace amounts of methane in Mars’ atmosphere, a find which was confirmed a year later by the ESA’s Mars Express orbiter. In December of 2014, the Curiosity rover detected a tenfold spike of methane at the base of Mount Sharp, and later uncovered evidence that Mars has a seasonal methane cycle, where levels peak in the late northern summer.
Since it’s discovery, the existence of methane on Mars has been considered one of the strongest lines of evidence for the existence of past or present life. So it was quite the downer last week (on Dec. 12th) when the science team behind one of the ESA’s ExoMars Trace Gas Orbiter (TGO) spectrometers announced that they had found no traces of methane in Mars’ atmosphere.
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.
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.
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 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.
The Indian Space Research Organization (ISRO), India’s space agency, has recently published a beautiful gallery of images featuring a variety of picturesque Martian canyons, volcanoes, craters, moons and more.
We’ve gathered a collection here of MOM’s newest imagery snapped by the probes Mars Color Camera (MCC) for the enjoyment of Martian fans worldwide.
The spectacular 3D view of the Arsia Mons volcano, shown above, was “created by draping the MCC image on topography of the region derived from the Mars Orbiter Laser Altimeter (MOLA), one of five instruments on board NASA’s Mars Global Surveyor (MGS) spacecraft.
The Arsia Mons image was taken from Mars orbit on 1 April 2015 at a spatial resolution of 556 meters from an altitude of 10707 km. Volcanic deposits can be seen located at the flanks of the Mons, according to ISRO.
The view of Pital crater below was released in late May and taken on 23 April 2015. Pital is a 40 km wide impact crater located in the Ophir Planum region of Mars and the image shows a chain of small impact craters. It is located in the eastern part of Valles Marineris region, says an ISRO description. MCC took the image from an altitude of 808 km.
It is an odd shaped crater, neither circular nor elliptical in shape, possibly due to “regional fracture in the W-E trending fracture zone.”
A trio of images, including one in stunning 3D, shows various portions of Valles Marineris, the largest known canyon in the Solar System.
Valles Marineris stretches over 4,000 km (2,500 mi) across the Red Planet , is as much as 600 km wide and measures as much as 7 kilometers (4 mi) deep.
For context here’s a previously taken global image of the red planet from MOM showing Valles Marinaris and Arsia Mons, which belongs to the Tharsis Bulge trio of shield volcanoes. They are both near the Martian equator.
Valles Marineris is often called the “Grand Canyon of Mars.” It spans about as wide as the entire United States.
A gorgeous view of Phobos, the largest of Mars’ two tiny moons, silhouetted against the surface is shown below.
MOM’s goal is to study Mars atmosphere, surface environments, morphology, and mineralogy with a 15 kg (33 lb) suite of five indigenously built science instruments. It is also sniffing for methane, a potential marker for biological activity.
MOM is India’s first deep space voyager to explore beyond the confines of her home planets influence and successfully arrived at the Red Planet after the “history creating” orbital insertion maneuver on Sept. 23/24, 2014 following a ten month journey from Earth. MOM swoops around Mars in a highly elliptical orbit whose nearest point to the planet (periapsis) is at about 421 km and farthest point (apoapsis) at about 76,000 km, according to ISRO.
It takes MOM about 3.2 Earth days or 72 hours to orbit the Red Planet.
MOM was launched on Nov. 5, 2013 from India’s spaceport at the Satish Dhawan Space Centre, Sriharikota, atop the nations indigenous four stage Polar Satellite Launch Vehicle (PSLV) which placed the probe into its initial Earth parking orbit.
The $73 million MOM mission was expected to last at least six months. In March, ISRO extended the mission duration for another six months since its healthy, the five science instruments are operating fine and it has sufficient fuel reserves.
And with a communications blackout between Mars and Earth imminent as a result of natures solar conjunction, it’s the perfect time to catch up on all things Martian.
Solar conjunctions occur periodically between Mars and Earth about every 26 months, when the two planets line up basically in a straight line geometry with the sun in between as the two planets travel in their sun-centered orbits.
Since Mars will be located behind the Sun for most of June, communications with all the Terran spacecraft at the planet is diminished to nonexistent.
“MOM faces a communication outage during June 8-25,” according to The Hindu.
Normal science operations resume thereafter.
“Fuel on the spacecraft is not an issue,” ISRO Satellite Centre Director M. Annadurai told The Hindu.
Including MOM, Earth’s invasion fleet at the Red Planet numbers a total of seven spacecraft comprising five orbiters from NASA, ESA and ISRO as well as the sister pair of mobile surface rovers from NASA – Curiosity and Opportunity.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.