Explanations for events in our spectacular universe, based on our understandings of the electromagnetic spectrum, allow for insights into the relationships between supernovae, star formation and evolution, and extreme events, such as high gravity environments of a neutron star or black hole. Our understanding of celestial objects depends upon observations made from Earth or space near the Earth. Spectroscopy is a vital tool for astronomers and provides a wealth of information. Photometric measurements can be used for determining distance and comparing objects. The study of binary and variable stars reveals vital information about stars.
Stars evolve and eventually die .
In the early part of the twentieth century, many experimental and theoretical problems remained unresolved. Attempts to explain the behaviour of matter on the atomic level with the laws of classical physics were not successful. Phenomena, such as black-body radiation, the photoelectric effect, the emission of sharp spectral lines by atoms in a gas discharge tube, could not be understood within the framework of classical physics. Between 1900 and 1930, a revolution took place and a new more generalised formulation called quantum mechanics was developed. This new approach was highly successful in explaining the behaviour of atoms, molecules and nuclei.