By Chris Worman and Andrey Mirtchovski

trexpeeverΛογισμικό & κατασκευή λογ/κού

13 Δεκ 2013 (πριν από 4 χρόνια και 6 μήνες)

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By Chris Worman and
Andrey Mirtchovski

Why Galaxies?

Interest in scientific computation and

Visually appealing results

To learn how to model gravity based

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


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


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


This implies that the acceleration in the i

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

Memory requirements

Based on design and number of galaxies
memory requirements can grow up to gigabytes


creating a visually appealing

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
galaxy collision is limited to about 500 stars
per galaxy

The following slides depict a 3D galaxy
collision with 1000 stars per galaxy


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)


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
movie by the end of the run.

Simulate evolution of stars, galaxies and
solar systems