Life on Mars finally discovered? NASA detects largest organic compounds on Martian land

Curiosity’s Mars Hand Lens Imager camera captured this view of the hole in Cumberland on the same sol it was drilled. The hole measures approximately 0.6 inches (1.5 cm) in diameter and 2.6 inches in depth. (Image: NASA)

The largest organic molecules ever found on Mars have now been identified by scientists. The compounds, discovered in ancient rocks, could be evidence of past life. They show that there were favorable conditions once, but they do not indicate life existed.

Indications of Previous Habitability

This discovery was made at Gale Crater by NASA's Curiosity rover. 'Cumberland' is the rock the rover drilled into in 2013. This rock is in Yellowknife Bay, which was previously a lake. Scientists say there has been water here for millions of years.

Alkanes are the organic compounds discovered. These consist of chains of hydrogen and carbon that bear some resemblance to materials in fatty acids. They may have developed from life formed long ago, say some researchers. Some believe chemical reactions in nature have formed them.

The connection came to light as French astrochemist Caroline Freissinet presented results. "This shows that Mars samples could retain chemical evidence for extinct life,"

NASA's Search for Organic Molecules

The team made the discovery using Curiosity's Sample Analysis on Mars (SAM) instrument. The rover drilled a sample and then heated it to very high temperatures. Gases were released as a byproduct, and they were analyzed to identify key constituents. Rather than discovering amino acids, the team found large alkanes.

Among them were undecane, decane, and dodecane, each with very long chains of carbon atoms. The largest molecule on Mars is dodecane, containing 12 carbon atoms. On Earth, similar molecules have over 150 carbon atoms.

These chemicals may have formed 3.7 billion years ago, say scientists. At that time, life on Earth emerged. This raises the question of whether there was ever life on Mars.

Future Missions May Solve the Secrets

Dodecane is the largest molecule that curiosity can detect. Scientists need to analyze Mars rocks here on Earth in order to learn more. The next step was highlighted by Daniel Glavin, NASA's lead scientist for sample return. "To settle this controversy, we need to bring samples from Mars home."

NASA plans to bring back the Perseverance rover rock samples. The mission has been delayed, though, because of design issues and financing problems. Private companies can now bring them back. Proceedings of the National Academy of Sciences posted the finding on March 24. Scientists look forward to more answers from future expeditions.