Could Life Still Be On Mars? | Aliens: The Big Think | BBC Earth Science

Biology's early emergence on Earth offers hope that life might have formed elsewhere in our solar system and possibly not too far away because our next door neighbour had a remarkably similar early life. Mars was made at the same time as the Earth was made, so roughly 4.5 billion years ago, made from the same materials by the same processes. It did have active volcanoes, it had rain, it had water, water flowing over its surface. So for the first billion years of its life, it was like the Earth. And in the first billion years of Earth, life got going. But if life did get going on Mars, it would have soon found it tough going. Mars cooled down fast. Its small size meant it couldn't retain its internal heat. And with no magnetic field, much of its atmosphere was lost to space. Could life still be there now? Until recently, most people would have said no. But the more we learn about simple bacterial life of the kind that might have formed on Mars, the more we realise that it's more robust than we ever thought possible. If you think of the range of environments in which people can survive, you know, some of us get really sunburned if we go, you know, out into the garden and the temperature's above about 25 degrees C. But bacteria is everywhere. I mean, you know, absolutely everywhere. Deep inside nuclear reactors, deep below the surface of the Earth, in boiling hot water, frozen in Antarctica. It's all over the place.