Introduction and Motivation

The idea is to write an application that integrates the geodesic equations in a reasonably general space-time with a friendly front end, or graphic user interface (GUI) and then visualize the geodesics. This represents a powerful way to understand the physics of strongly curved space-times and its departure from Newtonian mechanics.

Nowadays we believe that black holes, neutron stars and other super-massive compact objects exist in nature. The dynamics of matter in the surroundings will be determined at least by the Schwarzschild metric (more precise models will employ the Kerr metric, for example). This appeals to the study of orbits in these space-times. Evidence indicates that the bright and peculiar galaxy $M82$ had collided with its neighboring galaxy $M81$. Inspection of images from the Hubble Space Telescope now indicate massive young globular star clusters were formed during the encounter. Stars in these clusters that are 600 million years old are just now exhausting their central hydrogen fuel, indicating that $M82$ brightening occurred just that long ago. $M82$ is located about 12 million light years away and visible with binoculars towards the constellation of Ursa Major. The typical star-field spans about 10,000 light years.

Recent observation in 2004 suggests that these star clusters may harbor blackholes of intermediate-mass in the 100 - 1000 solar-mass range. This kind of medium blackhole with mass in between the supermassive blackhole at the center of galaxy and the stellar blackhole with a few solar mass is expected but has never been detected until observations from NASA's Chandra space observatory captured the X-ray image. Analysis shows that one cluster, $MGG 11$, coincides spatially with the brightest ULX (ultraluminous X-ray source) discovered so far, the luminosity of which corresponds to an intermediate-mass blackhole of 300 - 900 solar masses. Numerical simulations indicate that collisions between stars could have created a "runaway" star that ultimately became an intermediate-mass blackhole. On the other hand, another star cluster $MGG 9$ fails to develop a blackhole because the larger cluster radius leads to a timescale of five times longer than for $MGG 11$.