Since there is no way to go back in time and see how our own solar system formed, astronomers have to find clues to its origin by other means. Detailed observations of stellar nurseries reveal the characteristics of young suns and their surroundings, including disks of gas and dust that presumably turn into planetary systems. Sophisticated computer simulations, based on our understanding of physical laws, can follow the collapse, under the influence of gravity, of a gas cloud into a star. Experiments with dust balls show how tiny grains stick together to make bigger clumps in disks girdling young stars. Other evidence comes from the solar system it-self—the ordering of planetary ...
No credit card required