Extremophiles are rewriting the rules of life on Earth

What does it really mean to be alive? From microscopic tardigrades that can survive the vacuum of space to cave-dwelling microbes that photosynthesise using near-infrared light, scientists are uncovering organisms that defy our assumptions about life’s limits. Their extraordinary abilities are not only rewriting biology textbooks but also reshaping the search for life beyond Earth — and raising provocative questions about whether we would even recognise alien life if we found it.