The search for life on Mars is now stronger than it's ever been

Many people might think the search for life on Mars ended when NASA’s first rovers revealed its barren, inhospitable surface.

However, scientists at the University of Minnesota continue to explore the possibility of life on Mars by expanding their understanding of the extreme conditions that can support life on Earth.

They are rethinking what extraterrestrial life might look like, keeping the search for Martian life very much alive.

Perchlorate salts, brines, and life on Mars

Perchlorate salts are compounds that contain the perchlorate anion (ClO4-), which is a stable oxyanion of chlorine in its highest oxidation state (+7).

Due to their oxidizing properties and high oxygen content, they are often used as oxidizers in rocket propellants, fireworks, and explosives.

In recent years, NASA missions have discovered abundant perchlorate salts on Mars’ surface. These salts can absorb atmospheric water, forming concentrated solutions known as brines.

Perchlorate brines are highly concentrated aqueous solutions that contain dissolved perchlorate salts. These brines often form naturally in arid and semi-arid regions, such as the Atacama Desert in Chile and parts of the southwestern United States.

The perchlorate salts in these brines primarily originate from the atmospheric deposition of perchlorate, which is thought to be produced by photochemical reactions involving chlorine species in the upper atmosphere.

Since liquid water is essential for life, NASA’s strategy to search for life on Mars is to “follow the water.” As a result, perchlorate brines have become a significant focus of research.

Understanding the formation and behavior of perchlorate brines on Earth can provide valuable insights into the potential habitability of Mars and other planetary environments.

Mars’ geochemical environment

New research published in Nature Communications by investigators at the University of Minnesota College of Biological Sciences examines how Mars’ unique geochemical environment could have shaped life, past or present.

Led by Assistant Professor Aaron Engelhart, the team studied two types of ribonucleic acids (RNAs) and protein enzymes from Earth to determine their functionality in perchlorate brines.

RNA and protein enzymes

The research revealed several key findings:

• All the RNAs worked surprisingly well in perchlorate brines.
• Protein enzymes did not function as effectively as RNAs in these brines. Only proteins evolved in Earth’s extreme environments, such as those living at high temperatures or in high salt, could function.
• In perchlorate brines, RNA enzymes performed unique actions, like generating new molecules that incorporate chlorine atoms, a reaction previously unobserved by scientists.

“Taken together, these results show that RNA is uniquely well-suited to the very salty environments found on Mars, and could be found on other bodies in space,” said Engelhart. “This extreme salt tolerance could influence how life may have formed on Mars in the past or how it is forming in the conditions on Mars today.”

The team is continuing to explore the chlorination chemistry they discovered and other reactions that RNA can perform in high-salt conditions.

Their ongoing research aims to further understand the potential for life in extreme environments, both on Mars and other planetary bodies.

Life on Mars and the future of astrobiology

The study’s implications extend beyond finding possibilities of life on Mars. The findings contribute to the broader field of astrobiology by demonstrating how life might adapt to extreme conditions on other planetary bodies.

This knowledge is crucial as scientists prepare for missions to other moons and planets in our solar system, such as Europa, Enceladus, and Titan.

By exploring the limits of life on Earth and beyond, researchers are laying the groundwork for future discoveries that could answer one of humanity’s most profound questions: Are we alone in the universe?

In summary, the ongoing research into Martian brines and their potential to support life represents a significant step forward in our quest to understand the possibilities of life beyond Earth.

As scientists continue to uncover the secrets of Mars’ geochemical environment, the dream of discovering extraterrestrial life comes closer to reality.

The full study was published in the journal Nature Communications.

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