Gravity and pressure are the weapons. Two hot spots, at the end of energetic bursts, are seen in yellow, left and right. We are witnessing a battle between the gravity of the Cygnus A galaxy, which is trying to pull the hot gas inwards, and the pressure of material created by the jets, which is trying to push the hot gas outwards. Cygnus A is about 700 million light-years away and has long been known as the brightest source in the sky for radio emissions. Researchers suspect that a black hole at the center of the galaxy is the root of all the activity.
Black holes are incredibly massive objects that suck nearly all nearby matter inward.
As gas swirls toward the center in what's called an accretion disk, it becomes magnetized. Some of this material is thought to be spit out in opposite directions, in two powerful jets of energy. And, for now at least, pressure is the victor over gravity. The two jets crash into the bubble of gas about 300,000 light-years from the galaxy's center, creating a pair of hot spots and forcing the bubble to expand continuously, even as the black hole tries to suck it inward. Researchers had seen these hot spots previously in radio wavelengths, but could not explain them.