Posted by: goatberg | February 28, 2008

Gravitas: Galaxy Dynamics

Yesterday Boing posted a link to these incredible supercomputer animations that were recently made available for streaming or download.  From the website:

GRAVITAS is a visual and musical celebration of the beauty in a dynamic universe driven by gravity. Animations from supercomputer simulations of forming galaxies, star clusters, galaxy clusters, and galaxy interactions are presented as moving portraits of cosmic evolution. Billions of years of complex gravitational choreography are presented in 9 animations – each one interpreted with an original musical composition inspired by the exquisite movements of gravity. The result is an emotive and spiritually uplifting synthesis of science and art.

Astrophysicist John Dubinski combines a knowledge of cosmology, galaxy dynamics and computer graphics to create breathtaking portraits of a universe in motion. Composer-pianist John Kameel Farah merges the soundworlds of renaissance and baroque counterpoint, free improvisation, Middle-Eastern music, minimalism, techno and electronica to create a musical feast that crosses time and dimension.

 They’re really quite beautiful, and all nine are worth checking out.  Here’s my favorite: 

Klemperer’s Dream


Nature provides us with random acts of gravitational violence in the form of galaxy collisions. Graceful spiral forms, tails and bridges are sculpted by these interactions. But we know how gravity works and galaxies are structured, so we can take the sculptors tool from Natures hand and play with it in a supercomputer removing the random element.

Klemperer found that special symmetric arrangements of particles could follow predictable orbits. These exact N-body solutions seem to have no natural counterpart and even Klemperer stated that he really just studied them for fun! In the same spirit, I have put galaxies in similar unnatural symmetric configurations to explore their evolution. One amazing consequence of Newtons laws of motion is that any system with some symmetry built in should preserve that symmetry even if complex dynamical behaviour is occuring. For the sequence of simulations here, it seems that symmetry is preserved even when spiral patterns emerge after the galaxies interact strongly. But by the end of each sequence, the symmetry is lost. So is Newton wrong afterall? No! These nonlinear dynamical systems are unstable and become chaotic. Tiny deviations introduced by computer imprecision are eventually amplified and lead the system away from symmetry. So these simulations are not just for fun after all. They are an interesting illustration of the emergence of chaos in nonlinear dynamical systems.

The quicktime or avi files available for download are obviously of higher quality than the youtube videos. There is one track apparently rendered in 3D. I’m tempted to spend the $15 for the DVD – it comes with the necessary glasses.


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