“Formation of Spiral Galaxy” by The Four-Dimensional Digital Universe Project

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SIGGRAPH Video Review:




    Formation of Spiral Galaxy

Company / Institution / Agency:

  • The Four-Dimensional Digital Universe Project


    In this movie, you witness four billion years of spectacular galaxy formation in just two minutes. Please do not blink!

    The movie visualizes the formation process of a spiral galaxy based on an astrophysical simulation. In the standard scenario of galaxy formation, galaxies are formed through merging of small star clusters, gas clouds, and small galaxies. In this simulation, we can see that after the violent merging stage, a spiral galaxy that consists of a “disk” and a “bulge” is formed. This simulation is created with the N-body/smoothed particle hydrodynamic method, which can follow dynamic evolution of both stars and gas. The gravitational interactions between stars and gas are calculated on a special-purpose super computer: GRAPE.

    The simulation data were visualized on 32-bit PCs with an original rendering engine for a many-particle system: ZINDAIJI. To visualize the motion of millions of particles with limited memory, ZINDAIJI stores only necessary informa-tion, such as the position, velocity, and size of particles. With ZINDAIJI, we can interactively render a particle image with a simple GUI interface. The algorithm of visualization is very simple. All particles are z-sorted first, and gas particles and glares of stars are expressed with textured billboards. Since a huge volume of nearly transparent objects is displayed, HDR rendering was adopted to avoid Mach bands. Gas is shown in blue, while stars are expressed as yellow dots.

    This movie is based on Construction of an Image Distribution System for the Four-Dimensional Digital Universe funded by the Special Coordination Fund for Promoting Science and Technology of the Japanese Ministry of Education, Culture, Sports, Science and Technology as part of their Program for the Effective Promotion of Joint Research with Industry, Academia and Government.


    PC, Windows XP


    ZINDAIJI on an astronomical many-abody simulation visualizer, Adobe After Effects 7.0

Additional Contributors:

    Presented By: The Four-Dimensional Digital Universe Project, National Astronomical Observatory of Japan

    Simulation: Takayuki Saitoh

    Visualization: Takaaki Takeda, Sorahiko Nukatani

    Visualization Programming: Takaaki Takeda, Toshiyuki Takahei

    Music: Asako Miyaki

    Voice: Catherine Ishida

    Voice Recording: Hideharu Takayama, Hiroyuki Hatano

    Producers: Eiichiro Kokubo, Shoken Miyama

    Special Thanks: Yumi Iwashita, Tsunehiko Kato, Hidehiko Agata, Junichiro Makino, Toshikazu Ebisuzaki and all other NAOJ 4D2U Project members