We don't have spacecraft to take us outside our solar system but astronomers have still been able to develop a good understanding of how our solar system formed and in turn, how others formed. In the last dozen years, the nearly 300 exoplanets have been discovered have added to our knowledge base.
Conventional knowledge said most solar systems were like our own but three Northwestern University researchers questioned that assumption and explored the question in detail. What they learned is that the solar system in which the Earth orbits our sun is actually uncommon.
Edward Thommes, Soko Matsumura and Frederic Rasio were the first to develop large-scale, sophisticated computer simulations to model the formation of planetary systems from beginning to end. Because of computing limitations, earlier models provided only brief glimpses of the process. The findings of their study titled, "Gas Disks to Gas Giants: Simulating the Birth of Planetary Systems," are detailed in the August 8, 2008 issue of Science magazine.