European astronomers say an image of a distant galaxy cluster reveals how the birth of stars -- often almost simultaneously -- affects the cluster's landscape. Most stars do not form alone, but with many siblings that are created at about the same time from a single cloud of gas and dust, they said, and images of the cluster NGC 3572, in the southern constellation of Carina, dramatically illustrated the effects of such mass births. Numerous hot young blue-white stars shining brightly and generating powerful stellar winds have dispersed the remaining gas and dust from their surroundings, creating glowing gas clouds, the European Southern Observatory reported from its Garching, Germany, headquarters Wednesday. Stars born inside a cluster may be siblings, the astronomers said, but they are not twins, differing in size, mass, temperature, and color. The course of a star's life is determined largely by its mass, so a given cluster will contain stars in various stages of their lives, providing a perfect laboratory to study how stars evolve, the astronomers said. Groups of young stars stick together for a relatively short time, typically tens or hundreds of millions of years, they said, then are gradually disbanded by gravitational interactions. The image released by the ESO was captured by the Wide Field Imager on the MPG/ESO telescope at the La Silla Observatory in Chile.