Compression and turbulence in this shockwave triggers the formation of stars, much as the shockwave of a supersonic aircraft creates a vapor trail by precipitating water droplets out of the air. To test this theory, De Young modeled jets in Abell 1795 and Abell 2597, two giant elliptical galaxies with blue lobe regions. This work appeared in the June 1995 Astrophysical Journal. From Shockwave to Stars A blue lobe jet encountering the interstellar medium, 10.3 million years into the simulation. The graph represents a slice through the jet along the direction of motion.
Red arrows represent velocity vectors of the gas.
Note the curved shockwave boundary at the front of the jet. Blue dots represent current positions of stars formed in the moving shockwave, taking into account the stars' motions through space since their birth. If they're short-lived, it may be that production of jets is an intermittent process, perhaps interrupted by the occasional disruption of a disk of matter around a black hole in the center of the galaxy. The atmosphere sustains life on Earth, but astronomers nevertheless have cursed it for centuries. Changes in optical refraction cause stars to twinkle, and even tiny air currents and eddies can distort images in high-powered telescopes.