Our solar system.
Celestial mechanics is a branch of astronomy that deals with the motions of celestial bodies. It combines the principles of physics and classical mechanics to stars, planets, and other celestial objects. Modern analytic celestial mechanics started over 300 years ago with Issac Newton. Prior studies addressing the problem of planetary positions are known going back perhaps 3,000 or more years.
Early attempts at celestial mechanics involved many theories that placed the Earth at the center of the universe(geocentric). Different philosophers used a variety of geometrical theories to explain the motions of the bodies that they could see in the sky. It was not until a heliocentric(Sun at the center of the solar system) view was used that celestial mechanics began to emerge as an area of study.
There have been dozens of scientists involved in the evolution of celestial mechanics. The most famous are Johannes Kepler, Issac Newton, Joesph LeGrange, and Albert Einstein. While each worked from earlier theories, they were able to improve and add a great deal of knowledge to astronomy as a whole.
An interesting problem with in celestial mechanics is the perturbation theory. The perturbation comprises mathematical methods that are used to find an approximate solution to a problem which cannot be solved exactly. An early use fro the theory was to deal with unsolvable mathematical problems of celestial mechanics like Newton’s solution for the orbit of the Moon,, which moves noticeably differently from a simple ellipse because of the competing gravitation of the Earth and the Sun. These methods start with a simplified form of the original problem, which is simple enough to be solved exactly, usually a Keplerian ellipse which is correct when there are only two gravitating bodies, or a circular orbit, which is only correct in special cases of two-body motion, but is often close enough for practical use. The solved, but simplified problem is then “perturbed” to make its starting conditions closer to the real problem, such as including the gravitational attraction of a third body. The slight changes that result are used as corrections.
If it were not for the advancements made in celestial mechanics, our understanding of the bodies around us would still be greatly compromised.
We have written many articles about celestial mechanics for Universe Today. Here’s an article about what an orbit is, and here’s an article about planetary motion.
If you’d like more info on the celestial mechanics, check out the Wikipedia page about Celestial Mechanics, and here’s a link to NASA’s Solar System Simulator.
We’ve also recorded a series of episodes of Astronomy Cast about every planet in the Solar System. Start here, Episode 49: Mercury.
Source: Wikipedia
Comments on this entry are closed.