Case Study: Milky Way - Andromeda Collision
Tuan Nhon Dang
1. Description:
One of the more exciting popular astronomical “facts” to emerge in the last decade
is that our own galaxy, the Milky-Way (MW) seems to be on a collision course with our
neighbour spiral galaxy Andromeda (M31)
. A simulation of the MWM31
collision is certainly worth a look both as a specific example of a galaxy collision
in action as well as compelling story that may involve the fate of the Earth and solar
system and any life that might still be hanging around in a few billion years.
2. The purposes of this visualization:
1) Compelling story that may involve the fate of the Earth and solar
system.
2) Exploring one detailed scenario to give a sense of what may happen
and what it might look like to an Earth observer.
3. Spiral Metamorphosis:
In this animation, the collision is depicted from a static
camera placed at a distance of 320 kpc from orthogonal directions aligned with the
galactic plane. These original simulations only used around 30K particles but
the models have been re-run with more particles over the years in various demonstration
calculations with the recent largest version
containing more than 300M particles on a parallel supercomputer in Toronto in 2003
.
The initial conditions for specific galactic models are defined here, including the positions, gravitational
tidal interactions, motions and mass distributions of the two galaxies.
The methods described here only describe renderings of purely stellar galaxies while the dust lanes and star forming regions of
real spiral galaxies are ignored.
Background on universal gravitation and 3D Computer Graphics used in this animation.
Each viewpoint is rendered with 5300 steps covering 2.3 billion years or 440K years per step starting a few hundred million years before the first close passage of the two galaxies. At 30 frames per second, time passes at the rate of 13 million years per second. At this rate, the animation of the collision takes nearly 4 minutes revealing great detail while enhancing the majesty of the event.
5. References:
1) John Dubinski, Department of Astronomy and Astrophysics, University of
Toronto. "Visualizing Astrophysical N-body Systems", May 2008
2) John Dubinski, http://www.galaxydynamics.org/
3) T.J. Cox, Abraham Loeb, Harvard-Smithsonian Center for Astrophysics, "The Collision Between The Milky Way and Andromeda", 9 December 2007
6. More videos:
