An anonymous reader writes: Life as we know it requires small, rocky planets. The gas giants of our solar system aren't habitable (to our knowledge), but a research team has discovered that smaller, Neptune-like planets can be transformed into gas-free, potentially habitable worlds with a little help from red dwarf stars. Such planets are usually formed far out in a planetary system, but tidal forces can cause them to migrate inward. When they reach the habitable zone of their host star, they absorb far larger amounts of x-ray and ultraviolet radiation. This can eventually boil off most of the the gas atmosphere, leaving behind the core: a small, rocky world capable of supporting life.