A team of researchers from Canada's McGill University has just revealed that they've discovered a form of bacteria which can reproduce at -15 degrees Celsius. That's pretty darn cold. The bacteria are native to Canada's Ellesmere Island, which is located far above the arctic circle. When cultured in the laboratory, these hardy creatures doubled in number every 40 days. Lowering the temperature a further ten degrees wasn't even enough to kill them, although it did stop their growth.
If bacteria can live at these temperatures here on Earth, what might their prospects be elsewhere? Although both Mars and Enceladus have mean temperatures that are even colder yet, each also has regions warmer than 15 Celsius. Could these bacteria survive in such an environment? Maybe, but there are a lot of other factors to consider. One important restriction is pressure - Enceladus has virtually no atmosphere, while Mars' atmosphere is only about one percent as thick as Earth's. Also, neither body is really protected from harmful radiation by a magnetic field. Over time, this radiation could wreak havoc on the cellular structure of these creatures, causing the bacterial equivalent of birth defects. Most importantly, though, is probably whether bacteria like this could arise in such an environment. We've (hopefully!) never transplanted any of these guys to Mars or Enceladus, meaning that they would need to evolve there natively. It's one thing to reproduce in an ultra-cold environment, but another thing entirely to evolve there. Chemical reactions tend to progress far more effectively in warm conditions, making a cold start a tough proposition.
Even so, it's exciting to discover yet enough species here on Earth which might be capable of living elsewhere in the solar system. With every breakthrough, it seems just a little more plausible that we might have neighbors on nearby bodies.
Source: The Space Reporter