This composite image shows the hot gas around the elliptical galaxy M84 in an X-ray image (blue) and a radio image (red). The bubbles (some visible in the hot gas) were generated by jets coming out of M84's central black hole. The top bubble (blue) is bursting and the hot relativistic gas, shown in red, is spilling out. Credit: X-ray (NASA/CXC/MPE/A.Finoguenov et al.); Radio (NSF/NRAO/VLA/ESO/R.A.Laing et al); Optical (SDSS)