New discoveries are revealing the potential range of extraterrestrial life forms.

Scientists have found microbes that live nearly two miles underground, completely detached from the surface biosphere.

Previously discovered deep-dwelling organisms had used molecules ultimately derived from surface plants or animals, and thus ultimately from solar-powered photosynthesis.

The newly-identified creatures don’t need sunlight: they live off radiation, combined with sulfur-bearing rocks and water.

This greatly expands places to look for life, beginning with Mars and various of the solar system’s moons.

Curiously, these bacteria live very slowly, dividing only every 45 to 300 years, thousands of times less often than their surface relatives.

This raises the possibility of lifeforms living and perceiving existence at a fundamentally different pace from ours.