Astronomy

Astronomy is the scientific study of the universe as a whole and of objects that exist naturally in space, such as the Moon, planets, stars, and galaxies. The Sun is a rather typical star moving around the center of the Milky Way at a distance of 20,000 light years. This Milky Way, our galaxy, is made of hundreds of millions of stars with vast empty regions and diffuse gas in between all held together by gravity. There are at least another hundred billion galaxies in the observable universe.

Every day and night astronomers collect data on these objects in all bands of the electromagnetic spectrum of light. From radio waves through X-rays, small and large telescopes on the ground and in space record immense amounts of data. Analyzing these data is one of the major challenges of modern astronomy. Sophisticated time-dependent, three-dimensional models of astronomical objects and the universe as a whole are now routinely constructed to help astronomers interpret their observations.

In 1823 the president of the Royal Astronomical Society presented the society's gold medal to British mathematician Charles Babbage (1791–1871) for the invention of the first digital calculating machine. The president remarked: "In no department of science or of the arts does this discovery promise to be so eminently useful as in that of astronomy… The practical astronomer is interrupted in his pursuit, is diverted from his task of observation, by the irksome labour of computation;…" Before the first electronic computers became available to astronomers, many observatories employed humans referred to as computers for this "irksome labour of computation."

In the 1950s theoretical astronomers began tapping the potential of programmable computing systems. Their first programs derived the solution of the restricted three-body problem (the gravitational interaction of three massive bodies) and also the solution to the equations of stellar structure. Model stellar atmospheres were also constructed from atomic data to be compared with observations of stellar spectra. The first practical applications were computations of precise apparent star positions and analysis routines transforming photoelectric observational data into meaningful scientific quantities.

By the 1960s computers had become an integral part of research in astronomy. In particular, progress in the theoretical understanding of stellar structure and evolution was driven largely by results of numerical investigations.

Astronomical research stimulates new advances in computing. A prime example is SETI@home, a project that uses the computing power of idle home and office computers. SETI, which stands for Search for ExtraTerrestial Intelligence, involves the analysis of the many gigabytes of data collected daily at radio telescopes. A freely distributed screensaver connects to a central data server and collects a small part of these data. When the home computer is otherwise idle, its processing power is used to look for extraterrestial signals. Upon completion of the analysis, the results of the computation are relayed back to the central server. Although no alien life has been found to date, millions of SETI@home users are contributing to this scientific endeavor.

The rapid growth in computing technologies also enables new areas of astronomical research. The data obtained at telescopes are now all stored in large databases that can be accessed by astronomers around the globe. These archived data repositories act as virtual observatories. Scientist can retrieve (observe) data on the same astronomical objects in many different wave-bands in a very short time without even having access to a telescope. Any relevant scientific studies are cross-referenced with the observed objects and are readily accessible on the Internet worldwide.

Supercomputers play an important role in astronomy today. Perhaps one of the most important uses of supercomputers is the physical modeling of the origin and evolution of astrophysical objects. Computational astrophyics has become a mature science in the past decades, driven not only by the ever-increasing power of computers but especially by new algorithmic breakthroughs. Novel techniques allow scientists to capture the vast space and time scales that astronomical objects span. It has become possible to study in detail such difficult problems as the collision of black holes; the formation of planets, stars, and galaxies; and the large-scale structure of the universe.

In detailed three-dimensional models, computational astrophysicists follow the time evolution of magnetic fields, radiation, gas dynamics, chemistry, gravitational interactions, cosmic ray interactions, and many more physical processes. Physicists can experiment in laboratories to test their theories. Only numerical experiments allow the astronomers and astrophysicists to test their theories in the quest to understand the nature of astronomical objects.

Rapidly evolving computing technologies and their uses in astronomical research will continue to lead to profound new insights into the nature, origin, and evolution of the cosmos and the complex structures within.