Finding conclusive proof of life on Mars would be an incredible accomplishment, and something that virtually all astronomers are hoping can happen thanks to the work of the various Mars rovers, including Curiosity. Even if there is no life still living on Mars, it is becoming increasingly likely that it will be possible to prove that there once was life in the distant past.

There are, however, some challenges to overcome for proving the existence of life in the past. Not the least of these challenges is the fact that in order to make such a bold claim as saying that alien life (even if it is just microscopic) has been found requires overwhelming evidence.

According to a new study published in Astrobiology, another step in that direction has been taken.

That study said that the Curiosity rover took samples from mudstone located in Cumberland at a site called Yellowknife Bay. The rover has instruments onboard that can analyze the samples that were taken, and in them they found organic molecules.

These organic molecules are known to be made from life here on Earth, but there are ways that they can develop without life as well. The number of these organic molecules that were found, however, seems to point toward life as being the most likely explanation. The authors of the study said:

“Such a high concentration of large organic molecules in Martian sedimentary rocks cannot be readily explained by the accretion of organics from carbon-rich interplanetary dust particles and meteorites, nor by the deposition of hypothetical haze-derived organics from an ancient Martian atmosphere.”

The molecules are believed to be about 3.7 billion years old, which is further evidence that it is at least possible that they were formed through life since that was a time when the planet was likely covered with water.

Of course, the researchers are careful to say that this does not prove that there was life on Mars at that time. It is just one more piece of evidence that it is entirely possible, or even likely, that Mars once supported life.

It also would say nothing about what type of life would have been there if it indeed did have life. It is unlikely that there would have been anything close to intelligent life like we see on Earth.

Unfortunately, while the instruments on the Curiosity can do a lot, they are not sensitive enough to determine exactly where these compounds developed. To do that, it would be necessary to send a sample back to Earth from Mars.

The budget for Mars research, however, has been cut to the point where return trips are unlikely to occur anytime in the foreseeable future. Because of that, researchers will have to just continue to find what they can to add to the growing body of evidence that strongly supports at least the possibility that there was once life on the Red Planet.

If you found that story interesting, learn more about why people often wake up around 3 AM and keep doing it for life.