Researchers from McGill University in Montreal have discovered a bacterium living in the frozen permafrost of the high Arctic. The permafrost bacterium, Planococcus halocryophilus strain Or1, grows and divides at -15°C and can even remain metabolically active at -25°C.

This bacteria is yielding clues about how extraterrestrial organisms might endure extreme conditions - as one of the things that makes it extremely hard for life to flourish in foreboding places like Mars and the moons of Saturn is the punishing cold. ...

The strangest moon in the Solar System is bright yellow. Taken by the Galileo spacecraft, this image shows Jupiter's moon, Io, and its incredibly bright colours derived from sulphur and molten silicate rock. Io is covered in volcanoes that are so active, they effectively turn the whole moon inside out. And some of Io's volcanic lava is so hot, it glows in the dark.

Mercury's surface looks similar to our Moon's. Each is heavily cratered and made of rock. Mercury's diameter is about 4800 km, while the Moon's is slightly less at about 3500 km (compared with about 12,700 km for the Earth). But Mercury is unique in many ways. Mercury is the closest planet to the Sun, orbiting at about 1/3 the radius of the Earth's orbit. As Mercury slowly rotates, its surface temperature varies from an unbearably cold -180 degrees Celsius to an unbearably hot 400 degrees Celsius. The place nearest the Sun in Mercury's orbit changes slightly each orbit - a fact used by Albert Einstein to help verify the correctness of his then newly discovered theory of gravity: General Relativity. The above picture was taken by the only sp ...