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Heavenly Bodies Simulation. By Chris Worman and Andrey Mirtchovski. Why Galaxies?. Interest in scientific computation and simulation Visually appealing results To learn how to model gravity based systems. Galaxy Collision.
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Heavenly Bodies Simulation By Chris Worman and Andrey Mirtchovski
Why Galaxies? • Interest in scientific computation and simulation • Visually appealing results • To learn how to model gravity based systems
Galaxy Collision • A galaxy is modeled as a grouping of stars around a massive body • Only stars with a velocity that is less than the escape velocity will remain in the galaxy:
Velocity • If the velocity of a star is too low then it will be sucked into the center of the galaxy • The direction of the velocity should also be tangential to the desired orbit
Gravity • If a body A of mass m is at a distance of r from a body B of mass M then Where G is the gravitational constant
Gravity • This implies that the acceleration in the i-th component ci is given by
2D Results • Initially the simulation was implemented in two dimensions • The following slides depict a collision between two galaxies • The galaxy on the top of the screen is the more massive of the two • There are 10,000 stars per galaxy
Challenges in 3D Implementation • Computationally expensive • O(n^2) or O(n*log(n)) minimum • Scientific simulations run on 256+ processor machines • Memory requirements • Based on design and number of galaxies memory requirements can grow up to gigabytes • Visualization – creating a visually appealing galaxy
Galaxy Collision Realism • Very close to real-life galaxy collisions • Compare a two-galaxy collision with images taken from Hubble Space Telescope
3D Results • Due to the extreme computation requirements for the 3D version, real-time galaxy collision is limited to about 500 stars per galaxy • The following slides depict a 3D galaxy collision with 1000 stars per galaxy
Expandability • Both 2D and 3D models could be extended to more than 2 galaxies. • Number of stars per galaxy can vary • Galaxy masses vary • Simulation of different celestial objects (quasars, black holes, etc)
Conclusion • Java3D is a viable tool for creating scientific simulations and visualizations • Performance losses from using Java3D are relatively big compared with pure OpenGL • Development time is significantly less, due to higher level abstraction of Java3D’s API • NASA officials have already contacted us… (which leads us to ‘Future Plans’)
Future Plans • Over the next 5 years we plan to run a 3D simulation of 2 galaxies with 100 000 stars each. We plan to complete a 500-frame movie by the end of the run. • Simulate evolution of stars, galaxies and solar systems • http://research.amnh.org/~summers/mihos/mihos.html