Upload
jocelyn-blackler
View
214
Download
1
Tags:
Embed Size (px)
Citation preview
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