Grains of sand from ancient supernova found in meteorites

Scientists working at Washington University in St. Louis have discovered two tiny grains of silica (SiO2; the most common constituent of sand) in meteorites that fell to earth in Antarctica. Because of their isotopic composition these two grains are thought to be pure samples from a massive star that exploded before the birth of the solar system, perhaps the supernova whose explosion is thought to have triggered the collapse of a giant molecular cloud, giving birth to the Sun.