What will Webb see? Supercomputer models yield sneak previews

Nov 03, 2010 by Francis Reddy

As scientists and engineers work to make NASA's James Webb Space Telescope a reality, they find themselves wondering what new sights the largest space-based observatory ever constructed will reveal. With Webb, astronomers aim to catch planets in the making and identify the universe's first stars and galaxies, yet these are things no telescope -- not even Hubble -- has ever shown them before.

"It's an interesting problem," said Jonathan Gardner, the project's deputy senior project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "How do we communicate the great scientific promise of the when we've never seen what it can show us?"

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Two spiral galaxies undergo a protracted crash lasting two billion years, eventually merging into a single elliptical galaxy. Credit: NCSA/NASA/B. Robertson (Caltech) and L. Hernquist (Harvard Univ.)

So the project turned to Donna Cox, who directs the Advanced Visualization Laboratory (AVL) at the National Center for Supercomputing Applications (NCSA). Located at the University of Illinois in Urbana-Champaign, NCSA provides enormous computing resources to researchers trying to simulate natural processes at the largest and smallest scales, from the evolution of the entire universe to the movement of protein molecules through cell walls.

Cox and her AVL team developed custom tools that can transform a model's vast collection of ones and zeroes into an incredible journey of exploration. "We take the actual data scientists have computed for their research and translate them into state-of-the-art cinematic experiences," she said.

Armed with an ultra-high-resolution 3D display and custom software, the AVL team choreographs complex real-time flights through hundreds of gigabytes of data. The results of this work have been featured in planetariums, IMAX theaters and TV documentaries. "Theorists are the only scientists who have ventured where Webb plans to go, and they did it through complex computer models that use the best understanding of the underlying physics we have today," Cox said. "Our challenge is to make these data visually understandable -- and reveal their inherent beauty."

The new visualizations reflect the broad science themes astronomers will address with Webb. Among them: How did the earliest galaxies interact and evolve to create the present-day universe? How do stars and planets form?

"When we look at the largest scales, we see galaxies packed into clusters and clusters of galaxies packed into superclusters, but we know the universe didn't start out this way," Gardner said. Studies of the cosmic microwave background -- the remnants of light emitted when the universe was just 380,000 years old -- show that the clumpy cosmic structure we see developed much later on. Yet the farthest galaxies studied are already more than 500 million years old.

"Webb will show us what happened in between," Gardner added.

Cox and her AVL team visualized this epoch of cosmic construction from a simulation developed by Renyue Cen and Jeremiah Ostriker at Princeton University in New Jersey. It opens when the universe was 20 million years old and continues to the present-day, when the universe is 13.7 billion years old.

AVL team members Robert Patterson, Stuart Levy, Matthew Hall, Alex Betts and A. J. Christensen visualized how stars, gas, dark matter and colliding galaxies created clusters and superclusters of galaxies. Driven by the gravitational effect of dark matter, these structures connect into enormous crisscrossing filaments that extend over vast distances, forming what astronomers call the "cosmic web."

"We worked with nine scientists at five universities to visualize terabytes of computed data in order to take the viewer on a visual tour from the cosmic web, to smaller scales of colliding galaxies, to deep inside a turbulent nebula where stars and disks form solar systems like our own," Cox said. "These visuals represent current theories that scientists will soon re-examine through the eyes of Webb."

Closer to home, Webb will peer more deeply than ever before into the dense, cold, dusty clouds where stars and planets are born. Using data from models created by Aaron Boley at the University of Florida in Gainesville and Alexei Kritsuk and Michael Norman at the University of California, San Diego, the AVL team visualized the evolution of protoplanetary disks over tens of thousands of years.

Dense clumps develop far out in a disk's fringes, and if these clumps survive they may become gas giant planets or substellar objects called brown dwarfs. The precise outcome depends on the detailed makeup of the disk. "Dr. Boley was interested in what happened in the disk and did not include the central star," Cox said, "so to produce a realistic view we worked with him to add a young star."

This is astrophysics with a pinch of Hollywood sensibility, work at the crossroads of science and art. "The theoretical digital studies that form the basis of our work are so advanced that cinematic visualization is the most effective way to share them with the public," Cox said. "It's the art of visualizing science."

"What AVL has done for the Webb project is truly amazing and inspiring," Gardner noted. "It really whets our appetites for the science we'll be doing when the telescope begins work a few years from now."

Explore further: Image: NGC 6872 in the constellation of Pavo

More information: www.jwst.nasa.gov/

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Burnerjack
not rated yet Nov 03, 2010
If you are able to observe primordial stars/galaxies in a particular region, does that point to the "center of the universe"? I've always been taught that there is no center and that the universe looks the same no matter the viewpoint. Seems illogical to have both realities coexist. No?
Slotin
1 / 5 (3) Nov 03, 2010
It seems, the bared galaxies could be often a products of some galactic collision (note the left object at the animation). The collision leads to strong longitudinal waves and mutual gravitational interaction of individual stars within the galaxy. The very old, quiet galaxies are usually of elliptical shape because of smoothing effect of tidal forces.
..Seems illogical to have both realities coexist. No?..
The fact, universe is infinite doesn't contradict the fact, universe is inhomogeneous by its very nature - so that one substantial part of it may appear more compact/older, then the others. At the case of conditions quite distant from human perspective the reality often becomes dualistic by its very nature.
Slotin
1 / 5 (3) Nov 03, 2010
Try to imagine Universe like giant clouds and/or sample of Perlin noise - such unparticle geometry appears both homogeneous, both inhomogeneous at the same moment. If it would be observed from perspective of one part of it, it visibility scope will appear quite uniform, but with subtle hyperbolic geometry superposed onto it - compare the Doppler shift of CMB.

http://upload.wik...rlin.png
yyz
5 / 5 (1) Nov 03, 2010
"What will Webb see?"

I'm partial to a data-derived computer sim of a James Webb 'deep field' included in a technical report on JWST a few years back: http://www.nasa.g...high.jpg
rwinners
not rated yet Nov 04, 2010
No one knows where the 'center' of the universe lies. Everything we can see is incredibly far from us, in all directions.
Remember, the 'age' and 'size' of the universe are very theoretical concepts. But, it seems, some scientists just hate the unexplainable.
jsa09
not rated yet Nov 04, 2010
so crowded! If we can zoom in and magnify each pixel to the size of that nasa photo wow then we can see something again.
Thraxzer
not rated yet Nov 04, 2010
Allow me to paraphrase, so we can reach a mutual understanding of what you said: "The bar galaxies are products of galactic collisions (See left object in image). A collision like this produces longitudinal waves and the stars within interact gravitationally. Older galaxies have been smoothed by tidal forces."
Does that sound right?
Ok then, so is a longitudinal wave supposed to be like a shock wave? Or sound wave? There is no medium for this propagate, right?