If you want to be humbled by life's tenacity, look no further than extremophiles — organisms that thrive in conditions that would instantly destroy most living things. Boiling acid, crushing pressure, lethal radiation, total desiccation. Life finds a way.
Half a millimetre long. Can survive: the vacuum of space, temperatures from -272°C to +150°C, radiation 1000x lethal to humans, pressure 6x deeper than the ocean floor, complete desiccation for 30 years. The most resilient animal ever discovered.
This archaeon was the heat record holder for years. It can't even grow below 90°C — temperatures that would sterilise a hospital. Found at black smoker vents in the Atlantic Ocean. Literally thrives in water hot enough to cook pasta.
Found metabolising slowly in Antarctic ice cores estimated to be 10,000 years old. Uses antifreeze proteins to prevent ice crystal formation inside cells. May give clues to life on icy moons like Europa or Enceladus.
Lives in acid drainage from iron mines where the pH approaches zero — as acidic as battery acid. Has no cell wall, yet survives. Its proteins are specially adapted to fold correctly even when bathed in acid that would dissolve most materials.
At the bottom of the Mariana Trench, pressure is so intense it compresses water itself. Yet bacteria thrive there with specially adapted membranes and proteins that resist compression. Life colonised even the deepest point on Earth.
Nicknamed "Conan the Bacterium." When radiation shatters its DNA into hundreds of fragments, it stitches them back together perfectly within hours. Has multiple redundant copies of its genome and extraordinary DNA repair enzymes. Almost literally unkillable.
Dies in normal seawater — too fresh. Needs salt concentrations that would mummify most organisms. The pink and red hues of salt lakes worldwide are caused by trillions of these archaea. Found preserved and possibly viable in 250-million-year-old salt crystals.
Astrobiology: Every environment extremophiles colonise expands where we might find alien life — icy moons, acid clouds of Venus, deep Mars aquifers
Biotechnology: Heat-resistant enzymes from hot spring bacteria make PCR possible — the basis of COVID tests and DNA fingerprinting
Origin of Life: Hydrothermal vents, where extremophiles thrive, may be where life first emerged on Earth 4 billion years ago
Industrial Applications: Enzymes that work at extreme temperatures, pH levels, and salt concentrations have enormous pharmaceutical and industrial uses
Climate Resilience: Understanding how organisms adapt to extremes may help us understand life's response to climate change
Extremophiles redefine what we mean by "habitable." Every time we discover a new extreme environment on Earth, we find life already there. Whatever the conditions — scorching, frozen, acidic, radioactive, pressurised, desiccated — life has almost certainly evolved a solution.
It makes the universe feel considerably less empty.