Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Supercomputer to Simulate Extreme Stellar Physics

05.05.2008
Robert Fisher and Cal Jordan are among a team of scientists who will expend 22 million computational hours during the next year on one of the world’s most powerful supercomputers, simulating an event that takes less than five seconds.

Fisher and Jordan require such resources in their field of extreme science. Their work at the University of Chicago’s Center for Astrophysical Thermonuclear Flashes explores how the laws of nature unfold in natural phenomena at unimaginably extreme temperatures and pressures. The Blue Gene/P supercomputer at Argonne National Laboratory will serve as one of their primary tools for studying exploding stars.

“The Argonne Blue Gene/P supercomputer is one of the largest and fastest supercomputers in the world,” said Fisher, a Flash Center Research Scientist. “It has massive computational resources that are not available on smaller platforms elsewhere.”

Desktop computers typically contain only one or two processors; Blue Gene/P has more than 160,000 processors. What a desktop computer could accomplish in a thousand years, the Blue Gene/P supercomputer can perform in three days. “It’s a different scale of computation. It’s computation at the cutting edge of science,” Fisher said.

Access to Blue Gene/P, housed at the Argonne Advanced Leadership Computing Facility, was made possible by a time allocation from the U.S. Department of Energy’s Innovative and Novel Computational Impact on Theory and Experiment program. The Flash Center was founded in 1997 with a grant from the National Nuclear Security Administration’s Office of Advanced Simulation and Computing. The NNSA’s Academic Strategic Alliance Program has sustained the Flash Center with funding and computing resources throughout its history.

The support stems from the DOE’s interest in the physics that take place at extremes of concentrated energy, including exploding stars called supernovas. The Flash Center will devote its computer allocation to studying Type Ia supernovas, in which temperatures reach billions of degrees.

A better understanding of Type Ia supernovas is critical to solving the mystery of dark energy, one of the grandest challenges facing today’s cosmologists. Dark energy is somehow causing the universe to expand at an accelerating rate.

Cosmologists discovered dark energy by using Type Ia supernovas as cosmic measuring devices. All Type Ia supernovas display approximately the same brightness, so scientists could assess the distance of the exploding stars’ home galaxies accordingly. Nevertheless, these supernovas display a variation of approximately 15 percent.

“To really understand dark energy, you have to nail this variation to about 1 percent,” said Jordan, a Flash Center Research Associate.

The density of white dwarf stars, from which Type Ia supernovas evolve, is equally extreme. When stars the size of the sun reach the ends of their lives, they have shed most of their mass and leave behind an inert core about the size of the moon. “If one were able to scoop out a cubic centimeter—roughly a teaspoon—of material from that white dwarf, it would weigh a thousand metric tons,” Fisher explained. “These are incredibly dense objects.”

Type Ia supernovas are believed to only occur in binary star systems, those in which two stars orbit one another. When a binary white dwarf has gravitationally pulled enough matter off its companion star, an explosion ensues.

“This takes place over hundreds of millions of years,” Jordan said. “As the white dwarf becomes more and more dense with matter compressing on top of it, an ignition takes place in its core. This ignition burns through the star and eventually leads to a huge explosion.”

The Flash team conducts whole-star simulations on a supercomputer at Lawrence Berkeley National Laboratory in California. At Argonne, the team will perform a related set of simulations. “You can think of them as a nuclear ‘flame in a box’ in a small chunk of the full white dwarf,” Fisher said.

In the simulations at Argonne, the team will analyze how burning occurs in four possible scenarios that lead to Type Ia supernovas. Burning in a white dwarf can occur as a deflagration or as a detonation.

“Imagine a pool of gasoline and throw a match on it. That kind of burning across the pool of gasoline is a deflagration,” Jordan said. “A detonation is simply if you were to light a stick of dynamite and allow it to explode.”

In the Flash Center scenario, deflagration starts off-center of the star’s core. The burning creates a hot bubble of less dense ash that pops out the side due to buoyancy, like a piece of Styrofoam submerged in water. But gravity holds the ash close to the surface of the white dwarf. “This fast-moving ash stays confined to the surface, flows around the white dwarf and collides on the opposite side of breakout,” Jordan said.

The collision triggers a detonation that incinerates the star. There are, however, three other scenarios to consider. “To understand how the simulations relate to the actual supernovae, we have to do more than a thousand different simulations this year to vary the parameters within the models to see how the parameters affect the supernovae,” Jordan said.

Steve N. Koppes | newswise
Further information:
http://news.uchicago.edu/

More articles from Physics and Astronomy:

nachricht A quantum walk of photons
24.05.2017 | Julius-Maximilians-Universität Würzburg

nachricht Scientists propose synestia, a new type of planetary object
23.05.2017 | University of California - Davis

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Devils Hole: Ancient Traces of Climate History

24.05.2017 | Earth Sciences

Discovery of a Key Regulatory Gene in Cardiac Valve Formation

24.05.2017 | Life Sciences

A CLOUD of possibilities: Finding new therapies by combining drugs

24.05.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>