Organisms containing anti-freeze salts are particularly good at adapting to these conditions and some could be active at temperatures as low as -40 degrees Celsius.

Sunlit areas of P/67 Churyumov-Gerasimenko have approached this temperature last September, when at 500 million km from the Sun and weak gas emissions were evident.

As it travels to its closest point to the Sun – perihelion at 195 million km – the temperature is rising, gassing increasing and the micro-organisms should become increasingly active.