Galaxies: Masters of Recycling.

An enormous galaxy within the MAMMOTH-1 nebula is drawing in material from its surroundings to spawn new stars. The material contains elements formed by past supernovae that were flung into the nebula by the galaxy's central black hole. The galaxy is now forming stars from material that had previously been hurled out into intergalactic space by a galaxy, either itself or another nearby. The research team created kinematic models of both the galaxy and nebula to see exactly how the gaseous streams were moving. Two of the streams of gas headed toward the galaxy pulling them in originated from the same quasar.