US scientists have thought up a new way to create a second home - by warming up the atmosphere of Mars. Mars - which used to be warm and wet - has an atmosphere rich in carbon dioxide. But because the red planet's atmosphere is so thin, the planet is now freezing cold. But Margarita Marinova, of Nasa Ames research centre in California, and colleagues report in the Journal of Geophysical Research-Planets that artificially created greenhouse gases could set the Martian climate simmering. "Bringing life to Mars and studying its growth would contribute to our understanding of evolution, and the...