... Credit B. Woodgate ( GSFC ), J. Hutchings (DAO), STIS Team , NASA Explanation: Glowing gas clouds are streaming from the core of galaxy NGC4151 at hundreds of thousands of miles per hour. ... Emission at two wavelengths characteristic of Oxygen atoms in the gas clouds is visible along this line. ... As evidence mounts, the widely accepted explanation for energetic nuclear activity in galaxies is based on material spiraling into a central black hole with over a million times the mass of our sun . ...