astrophysics

astrophysics application of the theories and methods of physics to the study of stellar structure , stellar evolution , the origin of the solar system , and related problems of cosmology . The distinction between astrophysics and modern astronomy is disappearing in scientific usage.

astrophysics The study of the physical nature of the Universe and the objects in it, notably stars, galaxies, and the composition of the space between them. Astrophysics originated in the application of spectroscopy to the study of starlight in the 19th century. It complements the traditional branches of astronomy, astrometry and celestial mechanics, which are concerned with the positions and motions of objects. Observational astrophysics interprets the electromagnetic and gravitational radiation emitted by celestial objects. Theoretical astrophysics attempts to explain the processes involved, which can lead to new understanding of the behaviour of matter under conditions not encountered on Earth. For example, nuclear physics had to develop before energy generation inside stars could be understood, and study of objects such as white dwarfs and neutron stars has helped confirm predictions about the behaviour of matter under extreme compression and intense gravitational fields. Astrophysics can also probe the extremely tenuous gas between the stars, where complex molecules are formed and high-energy particles called cosmic rays move close to the speed of light. It also addresses ultimate questions about the origin of the Universe, the conditions shortly after its creation, and the origin of the chemical elements, are dealt with by astrophysics. Closer to home, astrophysics deals with matters such as the environment of the planets and the effects of the solar wind, which could explain short-term changes in our weather and long-term changes in climate. Many areas of physics are involved in such studies, including spectroscopy, plasma physics, atomic physics, and relativity. In recent years, astrophysical advances have resulted from observations by satellites in space, which allow astronomers to study the Universe at all wavelengths from radio waves to gamma rays.