This bubbling mud vat contains the combination needed to form a mudpot: heat, gases, rock, minerals, acid, water, and living microorganisms. Heat-loving thermophiles consume some gases and help convert them into sulfuric acid, which breaks down rock into clay that mixes with water in the mud. Scientists study such extreme environments to understand the limits of life, and what they learn from Earth helps guide the search for life and evidence of past life elsewhere in the solar system. Known as Mammoth Paint Pots until 1927, this huge mudpot changes with the seasons, spitting thin, sloppy mud in spring and, in drier conditions, oozing thick bubbles of mud and gas through cracks that burst and collapse into cone-shaped mounds.

Photo: Bernard Fisher

Photo: Bernard Fisher

Mammoth, Wyoming · USA