Origins of our solar system probed

Our solar system may have been kick-started by a shock wave from an exploding star that rippled through a giant rotating cloud of gas, U.S. astronomers say. The solar system is thought to have coalesced from a cloud of gas and dust known as the solar nebula about 4.6 billion years ago, and scientists have long theorized a shock wave from a supernova explosion caused regions of the nebula to collapse and come together. The theory also holds that material from the shock wave would have been injected into the solar nebula, and scientists have found evidence of this material in meteorites. Astronomers have developed computer models of supernova shock waves and solar system formation to see if they match the pattern of this material seen in primitive meteorites from the solar system's early forming. "The evidence leads us to believe that a supernova was indeed the culprit," study lead author Alan Boss, an astrophysicist at the Carnegie Institution in Washington, D.C., told SPACE.com The 3D computer model showed the shock wave striking the solar nebula, compressing it and creating fingerlike indentations in the cloud's surface. These "fingers" injected short-lived radioactive isotopes from the supernova into the nebula -- the material detected in meteorites -- and less than 100,000 years later the cloud collapsed, triggering the birth of our solar system, the model suggests.