Scientists have theorised that if we are going to find life on Mars, it will be microbes and they will be living in caves below the surface. The Perseverance rover, NASA’s exploration robot on the Red Planet, is currently searching for signs of ancient life in the Jezero Crater. Scientists already know that there are so-called lava tubes on Mars, which some think could be large enough to shelter the first human astronauts from the cosmic radiation which is bombarding the planet. When these were formed, they thought conditions on Mars were more similar to those on Earth, with flowing water, an atmosphere and a warmer climate. One theory is that as conditions changed on the surface and Mars lost its magnetic field and atmosphere, life could have shifted underground. Daniel Viúdez-Moreiras from Spain’s National Institute for Aerospace Technology calculated that UV radiation levels would be about 2 percent of the radiation levels found at the surface. Fortunately, we have lava tubes here on Earth too, which could tell us what life could look like in similar conditions elsewhere in the Solar System. Hawai’i’s Mauna Loa volcano lava tubes were recently explored by NASA. Within them, life is sheltered from conditions on the surface. On Earth, that is a bad thing: we have sunlight and oxygen. But on Mars, where conditions are much harsher, that is a big advantage. “The microbes we found in Hawaii could be similar to microbes that once lived on Mars,” researcher Chloe Fishman explained to NASA following a trip to collect samples in April, “or even microbes that live there today.” The team brought back samples from the cave so as to sequence the genomes of the microbes they found there. And there are already plans to explore lava tubes on the Moon, too. So maybe, just maybe, they will hold the secret to life on Mars. Sign up to our free Indy100 weekly newsletter Have your say in our news democracy. Click the upvote icon at the top of the page to help raise this article through the indy100 rankings.