The problem now is that as scientists try to find harsher and harsher environments to put a limit on where life can survive, we just keep finding hardier strains of bacteria. We haven't found the limit yet. These bacteria thrive in temperatures about 200 Fahrenheit, and in corrosive acid levels that rival the inside of a car battery. At the other end of our biosphere, bacteria have been found many miles high in our atmosphere, at the very limit of space. They survive in negligible air pressure, and never interact with life-forms from the surface of our planet.
Some microbes love radiation.
Bacteria are now known to inhabit the interior chambers of nuclear reactors, as well as nuclear waste dump sites. The passage of time is no way to kill extremeophiles either. The insect had been sealed in a blob of amber. But I have to say that there is one, last kind of extremeophile that really takes my breath away. When the first generations of spacecraft were launched, scientists didn't worry about how to sterilize them.