Haloarcula bacteria from Triassic rock salt.
© Science Museum / Science & Society Picture Library
This petri dish is covered wih populations of Haloarcula bacteria which were isolated by Bill Grant of Leicester University from a 230 million-year-old sample of Triassic rock salt. It is possible that these micro-organisms have lain 'dormant' since the salt was deposited, but more likely that they are the descendants of those alive in Triassic times. Their viability demonstrates the resilience of living organisms and the reason why such micro-organisms may one day be found in similar extra-terrestrial environments.