How Mars’ atmosphere went missing: New study offers clues

Sub: Sci

Sec: Space sector

Water on Mars:

Mars today is a cold and barren desert. However, water flowed on the Martian surface once upon a time.
Existing theories suggest that a thick atmosphere would have enveloped the planet, to keep the water flowing on the Martian surface from freezing.
Then, some 5 billion years ago, the water dried up as the carbon dioxide-rich atmosphere dramatically thinned.
Understanding why this atmospheric change occurred has been a key focus area of scientists.
A study published in Science Advances by MIT geologists Joshua Murray and Oliver Jagoutz explores how water and rock interactions may have impacted Mars’ atmosphere.

What the study suggests:

Water trickled through certain rock types on the Martian surface. and set off a slow chain of reactions that progressively drew carbon dioxide out of the planet’s atmosphere and converted it into methane.
Methane is a form of carbon that can theoretically be stored for long periods on the Mars’ clay surface.

Smectite clay:

The two geologists formulated this theory based on their research on Earth, on a type of clay material known as smectite, which is known to be a highly effective carbon trap. They also found the same smectite clay on Mars.
Each grain of smectite comprises of large number of folds, within which carbon can sit for billions of years.
They found that if left exposed to the atmosphere on Earth, smectite can draw and store atmospheric carbon dioxide over millions of years, enough to cool down the planet. This, they suggest could be how the Martian atmosphere disappeared.

How was smectite formed on Mars:

On Earth, smectite is a product of tectonic activity, but Mars does not see such activity.
Upon further research, it was concluded that smectite was formed on the Mars due to reaction betweenwater and olivine, a ferrous rock that is abundant on the planet’s surface.
- Oxygen in water binds with iron in olivine, freeing hydrogen.
- Hydrogen combines with carbon dioxide to form methane.
- Over time, olivine converts into smectite, which traps the generated methane.

Potential Resource:

The trapped methane could be a crucial energy source for future human missions to Mars.