Free Newsletter
Register for our Free Newsletters
Newsletter
Zones
Advanced Composites
LeftNav
Aerospace
LeftNav
Amorphous Metal Structures
LeftNav
Analysis and Simulation
LeftNav
Asbestos and Substitutes
LeftNav
Associations, Research Organisations and Universities
LeftNav
Automation Equipment
LeftNav
Automotive
LeftNav
Biomaterials
LeftNav
Building Materials
LeftNav
Bulk Handling and Storage
LeftNav
CFCs and Substitutes
LeftNav
Company
LeftNav
Components
LeftNav
Consultancy
LeftNav
View All
Other Carouselweb publications
Carousel Web
Defense File
New Materials
Pro Health Zone
Pro Manufacturing Zone
Pro Security Zone
Web Lec
Pro Engineering Zone
 
 
 
News

New model explains sound before sight

National Science Foundation : 05 June, 2006  (Company News)
In most explosions, there's the flash and then the 'bang.' But in the exploding stars known as supernovae, it may be just the opposite. In fact, according to new computer simulations carried out by University of Arizona astronomer Adam Burrows and his colleagues, the bang actually makes the flash.
Or to put it another way, says Burrows, 'it's the sound waves that actually cause the star to explode.'

This conclusion sounds paradoxical, says Burrows. But if borne out, it would solve a long-standing puzzle.

Astronomers know that a supernova explosion can occur only in a very massive star--say, 10 to 25 times the mass of our own Sun. And they know the initial release of energy is confined to the very deepest core of the star. The puzzle is how the energy gets out. Previous simulations suggested the layers of gas surrounding the core were just too dense for the energy to escape. The simulated blast wave would stall and die before it reached the star's surface, as if it were muffled by a blanket, and observers on the outside would see nothing at all.

But, those earlier simulations had always used highly simplified models of supernovae outbursts, because that was the only way to cope with the complex calculations. Many, for example, assumed the explosions were completely spherical and symmetric.

Now, however, Burrows and his colleagues have developed computer models that allow them to simulate a more natural flow of material and radiation, especially in the central regions of the star. They found that the initial energy release at the core pulsates the surrounding layers of gas, with a typical frequency around middle C. Within a fraction of a second, moreover, the pulsations grow so violent they tear the star apart, blowing its outer layers into space.

Burrows has posted images and videos of the simulations online. He and his colleagues were funded by the National Science Foundation, the Department of Energy, and the Joint Institute for Nuclear Astrophysics. They will be publishing their research in the Astrophysical Journal.
Bookmark and Share
 
Home I Editor's Blog I News by Zone I News by Date I News by Category I Special Reports I Directory I Events I Advertise I Submit Your News I About Us I Guides
 
   © 2012 NewMaterials.com
Netgains Logo