Life on star-free planets?

It is possible for planets to get gravitationally ejected from a developing solar system and thenceforth wander alone through the galaxy. Current estimates are that there are a lot of these. Of course we normally think that a planet would need the energy from a sun, a star, to power any possibility of life. But a new study has raised the intriguing possibility that a supermassive black hole or Active Galactic Nuclei (AGN) gives off sufficient ultra-violet light to produce a Goldilocks zone from maybe 100 to 140 light-years from a Sag A* size AGN in where the radiation is not so severe that it would strip any atmosphere from the planet but sufficient UV would be available to power photosynthetic life. Moreover copious UV could break apart molecules to make the building blocks of life more available. The paper estimates that there could be a billion free-floating planets in the Goldilocks zone of our own galaxy. article