Gravity Laboratory
The structure of our Universe is determined by gravity. From the motions of the planets in our solar system, to the dynamics of galaxies, gravity is the key force that orchestrates all that we see. Yet gravity is the weakest force we know, much weaker than magnetism for example, or the electric force that holds an electron inside an atom. But gravity becomes a dominant force where large amounts of matter are present and on the vast scales of the universe an abundance of matter is available. Under these circumstances gravity is king. So it is, for example, that when a enough mass has been gathered, gravity becomes strong enough to contain the nuclear furnace inside a star, turn massive planets into orbits about even more massive stars, or deflect stars into orbits about the centre of a galaxy. Gravity rules all. Indeed, whatever is the destiny of our solar system, our galaxy, or even our universe, gravity will undoubtedly have a leading role to play. That is why all astronomers must have a grasp of what gravity can do.
This web page is dedicated to the effects of gravity, which are demonstrated through the medium of computer simulation. To this end it hosts a number of computer programs that calculate the effects of gravity on various models of astronomical interest. I call them "Gravity Toys" or "Gravitoys" if you are looking for a buzzword. Some of these programs are intended to be exact solutions (within the accuracy obtainable by methods applied) of realistic dynamical models for the given system. Some offer solutions to fairly crude models, which serve to give some idea of how gravity exerts its influence - models that are hopefully instructive if not quantitative. Some are, frankly, just for fun, because nobody said astronomy wasn't meant to be fun. But in all cases I hope the programs give you some insight into why gravity is important and how it casts its spell over everything out there in the universe. To a scientist (and astronomers are, above all, scientists!) insight is the key to everything and far more important than mere numbers.
1/. Kepler's Planetary Orbits
2/. How Stable is the Solar System?
3/. How do Comets Move?
4/. Saturn's Rings
5/. Galaxy Maker
6/. Apollo Challenge
7/. Ring Maker
8/. Tide Maker
9/. The Trojans
10/. Globular Clusters
11/. Star Maker