Key Takeaways:
- The search for life on Mars shouldn’t be limited to its distant past, as some researchers believe that Mars may still harbor life today.
- Despite drastic changes in Mars’ environment over the past billions of years, including the loss of its global magnetic field, some experts argue that life could persist in hidden or underground environments.
- Scientists are intrigued by the presence of methane on Mars, as it could be a potential indicator of modern Martian life. However, the origin of the methane remains uncertain, and abiotic processes could also produce it.
- Future Mars rovers, including NASA’s 2020 Mars rover and the European-Russian ExoMars rover, will search for signs of both ancient and current Martian life.
- The Search for Extra-Terrestrial Genomes (SETG) project aims to develop an instrument capable of detecting DNA- or RNA-based life on Mars, supporting the idea of panspermia, where life spreads throughout the solar system.
The ongoing quest for life on Mars is taking an intriguing turn, with researchers urging a shift in focus from the distant past to the possibility of present-day Martian life. Approximately four billion years ago, Mars boasted a habitable surface with rivers, lakes, and an expansive ocean. Some astrobiologists argue that ancient Mars may have been a superior cradle for life compared to Earth, suggesting that life on our planet might have originated from Mars rocks ejected into space by a powerful impact.
The transformation of Mars into the cold, dry world we see today occurred around 3.7 billion years ago when it lost its global magnetic field, allowing solar wind to strip away its once-thick atmosphere. However, this environmental shift doesn’t necessarily mean that Mars is currently a lifeless planet. Michael Finney, co-founder of The Genome Partnership, suggests that if Mars harbored life four billion years ago, it likely still does, having possibly adapted, moved, or gone into hiding.
One promising location for potential Martian life is the underground, where buried aquifers might contain liquid water. While the surface currently lacks liquid water, Europe’s Mars Express orbiter hints at the existence of a substantial underground lake beneath the planet’s south pole.
Unlike Earth, where signs of life are evident in the atmosphere, Mars presents subtler hints. NASA’s Curiosity rover detected methane plumes inside Gale Crater, and seasonal cycles in baseline methane concentrations raise the possibility of modern Martian life. However, the source of methane remains uncertain, with abiotic processes being a potential explanation.
The upcoming NASA 2020 Mars rover and the European-Russian ExoMars rover aim to search for signs of ancient Martian life. Molecular biologist Gary Ruvkun advocates expanding the search to include extant Martian life. Ruvkun, part of the Search for Extra-Terrestrial Genomes (SETG) project, proposes deploying an instrument on future Mars rovers to detect DNA- or RNA-based life.
Ruvkun supports the idea of panspermia, the widespread distribution of life throughout the solar system and beyond. If life reached Earth from elsewhere, Mars could have been a source or been similarly “seeded” like Earth. Panspermia implies a potential relationship between Earth life and any life forms found on Mars.
While Mars is a prime target, other celestial bodies in our solar system offer intriguing possibilities for current alien life. Europa and Enceladus, moons of Jupiter and Saturn, respectively, possess subsurface oceans, while Titan, Saturn’s moon, boasts lakes and seas of liquid hydrocarbons. Even Venus, despite its harsh surface conditions, may have habitable regions about 30 miles above its surface.
The search for life in our solar system continues to evolve, expanding from the exploration of ancient Martian environments to the quest for potential current extraterrestrial life, not only on Mars but on various celestial bodies holding the promise of life beyond Earth.
