Science refers to either the entire collection of knowledge gained by mankind or to the scientific method used for gaining that knowledge. The knowledge of science includes what can be observed by the senses and, therefore, only deals with the physical world and universe. Models are often made to explain an event or phenomena. The scientific method is a process by which models and ideas are carefully tested and includes the steps of observation, research, hypothesis, prediction, experiment, and review. The main categories of science included on this website include the physical or natural sciences that study non-living matter, the earth sciences that focus exclusively on the planet Earth, and the biological sciences that focus on organisms including plants, animals, and mankind.
Astronomy is the scientific study of the physical universe beyond the Earth. Astronomy is one of the oldest of the sciences, which has been used in making calendars and the understanding the daily, monthly, and annual cycles of heat, light, and gravity. There is an emphasis on the relationship of the Earth with the Moon and this solar system. Measurements of planetary density, rotation, angular momentum, and magnetic fields all indicate a young solar system only a few thousand years old. The rapid spiral movement of galaxies, lack of supernova remnants, and existence of short and long term comets show the youthfulness of the entire universe.
