12/01/1999 AMERICAN MUSEUM OF NATURAL HISTORY USES AECHELON TECHNOLOGY’S C-GALAXY SIMULATION SOFTWARE TO PERFORM REALISTIC, REAL-TIME RENDERING OF BILLIONS OF STARS FOR FLY-THROUGH OF THE MILKY WAY IN THE HAYDEN PLANETARIUM
Galactic MPIRE: Flying through the Digital Galaxy
Dennis M. Davidson, Carter Emmart,
Myles Gordon, James S. Sweitzer,
Neil de Grasse Tyson, Erik Wesselak,
American Museum of Natural History
|C.R. O’Dell, Zheng Wen,
Jon Genetti, Greg Johnson, David R. Nadeau, Steve Napear, Allan Snavely,
he American Museum of Natural History’s Rose Center for Earth and Space, a $210 million, seven-story exhibition and research facility opening in February 2000, will include the spectacular, all-new Hayden Planetarium. The 87-foot sphere will hold the world’s largest virtual reality simulator–audiences will seem to fly through interstellar space surrounded by the stars and nebulas of the Milky Way galaxy, thanks to a scientifically accurate, high-resolution animation displayed by a seven-projector, supercomputer-controlled image system. Visualizations made possible for the first time by SDSC’s Tera MTA supercomputer and MPIRE volume-rendering software will give these images unprecedented realism.
At the center of the planetarium dome, a state-of-the-art Zeiss Star Projector will display realistic views of star fields and planets as seen from anywhere in the Solar System. But once the audience begins to voyage through the galaxy, the point of view leaves the Solar System and a new visual simulation technology is needed.
“One of the new and most exciting technologies we will have is Trimension’s all-dome digital video,” said James Sweitzer, director of special projects for the Hayden Planetarium. “A normal planetarium star projector typically shows only that part of the universe we see with our unaided eyes from Earth–about 9,000 stars. But the known universe contains billions of galaxies, each containing billions upon billions of stars. With all-dome video, visitors can move all around the universe, as long as we can simulate it.”
The planetarium’s Digital Dome system, custom-built by Trimension virtual reality systems, integrates seven SEOS projectors and a 28-processor SGI Onyx2 computer to display a composite image of 7.34 million pixels. The SGI Onyx2 renders visual simulations in real time and combines them with pre-rendered graphics.
Aechelon Technology’s C-Galaxy simulation software calculates interstellar perspective views of stars in the Milky Way from more than 100,000 nearby stars in the new Hipparcos database and more than two billion stars in a statistical database developed by the museum. “The result,” reports Davidson, “is a breathtakingly realistic real-time rendering of billions of stars in our home galaxy.” But a galaxy is more than just billions of stars.
“The most beautiful, visually complex, and scientifically interesting destinations of the planetarium voyages are nebulas–immense clouds of dust and gas, some of which extend for dozens of light-years through interstellar space,” said Dennis Davidson, project manager and creative director for the planetarium’s Digital Galaxy project.
A reflection nebula shines when the light of nearby stars (which typically have condensed from the substance of the nebula itself) reflects off countless particles of interstellar dust. An emission nebula glows because atoms of gas fluoresce when excited by ultraviolet radiation in starlight, in much the same way that some posters glow under a UV “black light.” The dust in a dark nebula obscures objects behind it. “Many nebulas involve a mix of these effects, all three of which are impossible to simulate realistically in 3-D with traditional polygon-surface computer graphics methods,” he added.