Science•
on January 5th, 2010•
In astronomy and cosmology, dark matter is theoretical matter that is undetectable by its emitted radiation, but whose presence can be inferred from gravitational effects on visible matter. As important as dark matter is believed to be in the universe, direct evidence of its existence and a concrete understanding of its nature have remained elusive.
Unsolved problems in physics: What is dark matter? How is it generated? Is it related to supersymmetry?
Can we use Dark Matter as an Energy Source for Rocket Technology?
Current rocket technology can not send the spaceship very far, because the amount of the chemical fuel it can take is limited. Dark matter (DM) may be used as fuel to solve this problem. A DM engine uses dark matter annihilation products as propulsion. The acceleration is proportional to the velocity, which makes the velocity increase exponentially with time in non-relativistic region. The important points for the acceleration are how dense is the DM density and how large is the saturation region. The parameters of the spaceship may also have great influence on the results. We show that the (sub)halos can accelerate the spaceship to velocity $ 10^{- 5} c \sim 10^{- 3} c$.
3D Model of dark matter, reconstructed from measurements of weak gravitational lensing with the Hubble Space Telescope.
Written by Todd Borghesani
Engineering, People, Science•
on December 20th, 2009•
Guess what’s on the U.S. Air Force’s wish list this holiday season. Sony’s popular PlayStation 3 gaming console. Thousands of them. The Air Force Research Laboratory in Rome, N.Y., recently issued a request for proposal indicating its intention to purchase 2,200 PlayStation 3 (PS3) consoles.
But the military researchers don’t plan to play “Call of Duty: Modern Warfare 2″ or any of the season’s other blockbuster games. They plan to string the consoles together into a massive supercomputer and study how well they can enhance the military’s high-performance computing systems.
Once the researchers configured the hardware, they installed the Linux operating system on them, turning the gaming consoles into a military-grade supercomputer. Linderman said their first PS3 cluster was used in applications such as high-definition video processing and “neuromorphic” computing, which mimics the way the human brain perceives and processes images and information. When the new cluster of 2,200 PS3 consoles arrive in the next month or so, he said they will likely be used for similar projects.
Researchers Across the Country Harness Power of PlayStation 3. David Bader, a professor and executive director of high performance computing at the Georgia Institute of Technology, has been involved in a number of projects involving PlayStation clusters.
When the PlayStation launched in 2006, he said, its processor far surpassed those of its generation. “Sony wanted a processor that they could use inside a game box that would be able to render the games but also incorporate real-world physics, emotion and really new aspects to game playing,” Bader said.
The same chip that enabled high-octane game play also powered Toshiba’s high-end HD TVs and technology created by IBM for oil and gas exploration.
At Georgia Tech, Bader has researched the possibility of using PS3 clusters in aircraft monitoring and financial risk assessment.
One project proposed using PlayStation 3 consoles on board commercial airplanes, he said. Consoles would not only provide in-flight entertainment for each passenger, but also serve as sensors around the aircraft that would alert the pilot to potential problems and failures.
Astrophysicists at the University of Massachusetts at Dartmouth are using a cluster of PS3 consoles to research gravitational waves and black holes. And even the U.S. Immigration and Customs Enforcement agency’s Cyber Crimes Center has used linked PS3s to solve Internet crimes.