As far as anyone knows, there’s no life currently sticking it out on Mars. The Red Planet may have conditions suitable for life, especially deep underground, but scientists haven’t been able to actually confirm it. For now, looking for signs of past life on the surface is as close as we’re going to get to Martian life, and NASA’s Curiosity rover may have actually found it.

Many months ago, NASA announced that its trusty rover had found what has been described as organic molecules. These compounds could have been created by some biological process — which would mean life existed at some point on Mars — or by other, non-biological means. Now, a new research paper published in Astrobiology examines the possible biological routes by which the compounds could have been created.

The organic compounds are called thiophenes, and we know that they can be created by biological processes because we’ve seen it in action here on Earth. We’ve found such compounds in fossil fuels like coal as well as living organisms like certain species of mushrooms. But why does Mars have such molecules? That’s what scientists are working to find out.

“We identified several biological pathways for thiophenes that seem more likely than chemical ones, but we still need proof,” Dirk Schulze-Makuch, co-author of the study, said in a statement. “If you find thiophenes on Earth, then you would think they are biological, but on Mars, of course, the bar to prove that has to be quite a bit higher.”

If the compounds were indeed formed by life on Mars, it may have been formed by bacteria. That bacteria may be long dead, existing on the planet several billions of years ago. Unfortunately, we may need to wait for new hardware to arrive on Mars before we know for sure. If that is indeed the case, however, it would be a groundbreaking historical event — the first proof that life exists, or at least has existed, beyond our planet.

The researchers note that future missions to Mars, including the ExoMars Rosalind Franklin rover, could provide additional information and either help to confirm the theory that life existed on the Red Planet, or potentially squash it. One tool, in particular, the Mars Organic Molecule Analyzer, is expected to play a large role in this investigation, and it will be carried by the rover when it launches in July 2020.

Mike Wehner has reported on technology and video games for the past decade, covering breaking news and trends in VR, wearables, smartphones, and future tech. Most recently, Mike served as Tech Editor at The Daily Dot, and has been featured in USA Today, Time.com, and countless other web and print outlets. His love of reporting is second only to his gaming addiction.