2-billion-year-old rock could help understand very early life on Earth and the hunt for evidence of life on Mars Phys.orgLiving Microbes Found Within 2-Billion-Year-Old Rock Technology Networks2-Billion-Year-Old Rock Found Harboring Microbes – And They’re Still Alive IFLScienceMicrobiologists Find Living Microbes in 2-Billion-Year-Old Rock Sci.NewsOldest living microbes found in 2-billion-year-old rock Popular Science