The current theory is that its entire contents expanded explosively from a hot, dense, chaotic mass. Stars condensed by gravity out of clouds of molecules of the lightest elements until nuclear fusion of the light elements into heavier ones began to occur. Fusion released great amounts of energy over millions of years. Eventually, some stars exploded, producing clouds of heavy elements from which other stars and planets could later condense. The process of star formation and destruction continues.
Stars produce energy from nuclear reactions, primarily the fusion of hydrogen to form helium.
These and other processes in stars have led to the formation of all the other elements. The student will use a variety of resources to identify techniques used to investigate Earth and the Universe. The student will explain the role of natural forces in the formation of galaxies. Information Searches Module Overview Click on the hot links below to download PowerPoint slides or to follow links to other sites. Exploration Discussion of student answers and presentation of various images of nebulae and regions of star formation.