A spacecraft dedicated to atmospheric research in orbit has identified the strong-smelling gas hydrogen chloride above surface cracks on a vast ancient volcano on Mars, indicating that the planet may still exhibit volcanic activity.
In a finding that holds significance for the potential existence of microbial life beneath Mars’ surface, scientists reported that the ExoMars Trace Gas Orbiter has observed the gas, which is commonly found in volcanic emissions on Earth, in the lower atmosphere around Alba Mons.
Alba Mons, the largest volcano on Mars by surface area, is a wide, gently sloping formation known as a shield volcano due to its resemblance to a warrior’s shield. This volcano is situated in the northern hemisphere of the planet.
“We determined that the most probable source of the hydrogen chloride is volcanic seepage,” stated planetary scientist Daniel Mège from the Space Research Centre of the Polish Academy of Sciences and co-lead author of the study, which is detailed in the journal Science Advances.
The seepage of hydrogen chloride may result from volcanic outgassing through the numerous surface fractures in the Alba Mons area, potentially linked to an underground magma chamber.
This image shows a crater and linear fractures on the eastern flank of Alba Mons. (NASA/JPL-Caltech/ASU)
“The gas is released from chlorine-containing compounds that dissolve in magma as it ascends and pressure drops. Thus, its presence may align with magmatic degassing,” explained Alexander Trokhimovskiy, a planetary scientist and co-lead author from the Space Research Institute of the Russian Academy of Sciences.
This discovery implies that Mars is not geologically inactive but is rather in a state of relative dormancy.
“It indicates that the interior of the planet may still hold enough heat to maintain magmatic activities, and that atmospheric trace gases can serve as a means to detect and study geological processes that are otherwise challenging to observe directly,” Trokhimovskiy noted.
An elite club
Confirmed volcanically active celestial bodies are part of an exclusive group within our solar system, which includes Earth, Venus, and Jupiter’s moon Io.
The Martian landscape has been significantly altered by ancient volcanic activity. Indeed, Mars is home to Olympus Mons, the tallest volcano in the solar system. However, the question of whether Mars is currently experiencing volcanic activity has remained uncertain.
Olympus Mon, photographed by Viking 1 in 1978. It’s the largest volcano and highest mountain in our solar system. (NASA/Jet Propulsion Laboratory)
“While evidence of volcanism from millions of years ago on Mars has been documented, no signs of active magmatic processes have been reported until now,” Mège remarked.
Marsquakes detected by NASA’s InSight seismometer have also indicated the possibility of volcanic activity.
On Earth, sulfur dioxide is generally more prevalent than hydrogen chloride in volcanic emissions. However, hydrogen chloride may be more abundant on Mars due to differences in the composition of the two planets.
“It has a strong odor, and I would advise against inhaling it as it is corrosive and can irritate or harm the nasal passages,” Mège warned.
NASA scientists believe there could be an ocean of water deep below the surface of Mars. It’s a discovery that advances the search for life beyond our planet and suggests Mars might have conditions that could sustain microbial life, either in the past or present. Matthew Cimone, head interpreter at the H.R. MacMillan Space Centre in Vancouver, tells us more about this finding.
The orbiter, which is a joint venture between the European Space Agency and the Russian space agency Roscosmos, was the first to identify hydrogen chloride in the Martian atmosphere and has recorded seasonal increases of this gas along the northern slope of Alba Mons during early summer.
The researchers believe that the surface fractures may be obstructed by ice at different times of the year, but the warming temperatures in early summer could lead to the melting of this ice, allowing volcanic gases trapped below to escape into the atmosphere.
-
New evidence finds Mars may have had conditions that could have supported life
-
NASA’s Curiosity rover takes striking image of dawn on Mars
The presence of underground magma reservoirs raises intriguing questions regarding the potential for life on Mars. Active volcanic activity would suggest that areas of heat may still exist in the planet’s crust, its outer layer.
Mars is already known to possess water trapped beneath its surface, and it is believed that life on Earth first appeared billions of years ago in hydrothermal systems.
“As magma ascends through the crust, it can interact with, melt, and heat subterranean water, creating environments that are insulated from the harsh conditions found on the surface,” Trokhimovskiy stated.
“Such active hydrothermal systems could offer the necessary energy sources and favorable conditions to support microbial life, making warm subsurface environments some of the most promising locations in the search for life on Mars.”