Chris Hadfield, Canadian Astronaut, currently living in space aboard International Space Station as Commander of Expedition 35.

Space life: Commander Chris Hadfield aboard International Space Station Expedition 35. Photo: Chris Hadfield, @Cmdr_Hadfield

Space, the final frontier, 140 characters at a time. Canadian astronaut Chris Hadfield has a birds-eye view of Earth during a five-month stint on the International Space Station, and he is using it to share what he sees.

The Great Barrier Reef, Sydney and rivers in Brazil are just a few of the images he has tweeted.

Since arriving on the space station in December last year, the astronaut has highlighted unique land formations, weather events and the glittering lights that mark out human development.

View of a Brazilian River aboard the International Space Station.

Spaced out: A river in Brazil. Photo: Chris Hadfield, @Cmdr_Hadfield

Commander Hadfield answers tweets from followers but rarely does interviews. In a video posted to the Canadian Space Agency's blog he said Twitter allows him to share experiences as they happen.

''The favourite pastime of astronauts is looking at the world out of the window. It is so fundamentally beautiful and mesmerising and I've been doing my best with words to try and describe it ever since I first saw it … now I can directly, as I see beautiful things, send those pictures to the ground,'' he said.

In February, he snapped a massive cyclone off the Western Australian coast, and a bright green lake in south-western Queensland. The lake, he said, ''somehow reminds me of a haggis''.

Sydney, Australia, glowing green and lovely in the night.

View from the top: Sydney at night. Photo: Chris Hadfield, @Cmdr_Hadfield

Commander Hadfield has more than 650,000 followers. Last week he won a Shorty award - awards that recognise the best of social media - for science.