(Before It's News)
A bizarre microbe found deep in a gold mine in South Africa could provide a model for how life might survive in seemingly uninhabitable environments through the cosmos. Known asDesulforudis audaxviator, the rod-shaped bacterium thrives 2.8 kilometers underground in a habitat devoid of the things that power the vast majority of life on Earth—light, oxygen, and carbon. Instead, this “gold mine bug” gets energy from radioactive uranium in the depths of the mine. Now, scientists predict that life elsewhere in the universe might also feed off of radiation, especially radiation raining down from space.
“It really grabbed my attention because it’s completely powered by radioactive substances,” says Dimitra Atri, an astrobiologist and computational physicist who works for the Blue Marble Space Institute of Science in Seattle, Washington. “Who’s to say life on other worlds doesn’t do the same thing?”
Essentially all life on Earth’s surface takes in the energy it needs through one of two processes. Plants, some bacteria, and certain other organisms collect energy from sunlight through a process called photosynthesis. In it, they use the energy from light to convert water and carbon dioxide into more complex and energetic molecules called hydrocarbons, thus storing the energy so that it can be recovered later by breaking down the molecules through a process called oxidation. Alternatively, animals and other organisms simply feed off of plants, one another, etc., to steal the energy already stored in living things.
D. audaxviator takes a third path: It draws its energy from the radioactivity of uranium in the rock in the mine. The radiation from decaying uranium nuclei breaks apart sulfur and water molecules in the stone, producing molecular fragments such as sulfate and hydrogen peroxide that are excited with internal energy. The microbe then takes in these molecules, siphons off their energy, and spits them back out. Most of the energy produced from this process powers the bacterium’s reproduction and internal processes, but a portion of it also goes to repairing damage from the radiation.
Atri thinks an extraterrestrial life form could easily make use of a similar system. The radiation might not come from radioactive materials on the planet itself, but rather from galactic cosmic rays (GCRs)—high-energy particles that careen through the universe after being flung out of a supernova. They’re everywhere, even on Earth, but our planet’s magnetic field and atmosphere shields us from most GCRs.
Full article at: