The first colour image of Mars transmitted by the Viking 1 lander.
| Photo Credit: NASA/JPL
A: Since the previous century, scientists have been reporting signs of life on Mars. In 1976, a Viking mission experiment reported signs of metabolism but another detector found no organic molecules. In 1996, the meteorite ALH 84001 was presented with microfossil-like shapes but lab studies later reproduced similar features through nonbiological processes. In the 2000s, several teams reported methane in Mars’s atmosphere but later measurements failed to confirm those levels. In the 1960s, the Mariner programme briefly suggested methane presence near the poles. Reports in 2005 described life sheltered in Martian caves and sustained by liquid water. However, NASA issued a correction later saying there was no observational evidence.
On September 10, scientists reported data from the Perseverance rover indicated the presence of mudstones in Mars’s Jezero Crater containing carbon, ferrous phosphate, and sulphide minerals. On earth, the reactions that create these minerals can happen without life or when some microbes metabolise iron or sulphur. The study said organic materials and these minerals often occur together, raising questions about their origin. The authors concluded only detailed lab studies of samples brought from Mars to earth could settle the questions.
Published – September 11, 2025 10:54 am IST