Last year, NASA’s Curiosity rover made a fascinating discovery after boring into a suspected ancient lake bed on Mars: long-chain organic molecules, called alkanes, that could serve as a potential chemical relic of ancient life on the Red Planet. The molecules, researchers suggested at the time, could have derived from fatty acids, which are common building blocks of cell membranes on Earth, once again strengthening the case that Mars could’ve been teeming with life billions of years ago. It was just another tantalizing clue in our search for extraterrestrial life, not the smoking gun we’ve all been waiting for. Nonetheless, scientists continue to be fascinated by the finding. In a paper published in the journal Astrobiology last week, a team led by NASA Goddard Space Flight Center’s Alexander Pavlov argues that the presence of these molecules — despite the millions of years of destructive radiation that pummeled the Martian surface after it lost much of its atmosphere — “cannot be readily explained” by non-biological processes alone. One theory is that carbon-rich dust particles and meteorites …