Scientists at NASA, analyzing rock samples collected by the Curiosity rover, have discovered the largest organic molecules found on Mars to date. The carbon chains are composed of up to 12 atoms, which could be key evidence of life existing on the Red Planet.

Curiosity has previously discovered small organic molecules on Mars, but these recently found compounds are larger and would have require chemistry to reach a more advanced state to be produced. The finding is also good news for potential life hunters, as it shows that the indicators of life could still be around even after billions of years.

While the presence of these molecules is not proof of ancient life on Mars, scientists say it shows we could detect chemical signatures of past life, if it ever existed.