Astronomers know full well that the sun is very slowly getting brighter, and in a billion or so years time it will make Earth too hot to live on. One scientist is now proposing a radical solution that will let humans live on this planet for longer – physically moving it away from the sun. Albert Zijlstra, a professor of astrophysics at the University of Manchester, suggests shifting Earth further back from the sun by about three million miles. At the moment, Earth is orbiting the sun at a distance of 93 million miles (150 million km) but this needs...