Runaway World

During the final decades of the twenty first century, a rogue brown dwarf star passed through the solar system and its gravity threw the Earth out of orbit around the sun.
Two hundred years later, when the atmosphere has finished freezing onto the surface, explorers from the last refuge of humanity venture out to see what's become of their world. Things looks bleak. Mankind faces a future of huddling in whatever warm refuges it can make for itself until the Earth's core goes cold, but then a discovery is made. An opportunity exists for mankind to leave the planet and find its destiny among the stars, but to do so requires an all or nothing gamble and losing would mean the end of the human race. Some want to take the gamble. Others don't, and so conflict and violence breaks out as the survey teams explore a planet transformed out of all recognition...