Tag Archive | "Department of Physics"

Physicist Develops Formula for Predicting Insurgent Attacks

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Physicist Develops Formula for Predicting Insurgent Attacks

Neil Johnson, a professor of physics in UM's College of Arts and Sciences, has developed a formula for predicting terrorist and insurgent attacks.

University of Miami physicist Neil Johnson and his collaborators have developed a simple mathematical model that can estimate the progression of fatal terrorist and insurgency attacks around the world. The research findings are published in the current issue of the journal Science.


The report unveils a new mathematical model that utilizes the time interval between the first couple of attacks in order to forecast the evolution of the conflict. The study, titled “Pattern in Escalations in Insurgent and Terrorist Activity,” establishes how the frequency of fatal attacks escalates following initial incidents arising in particular parts of the world. This simple tool can be useful in creating a plan of action.

The researchers describe a sequence in the timing and frequency of the attacks by using a simple power-law progress curve. The relationship between actions of the insurgency and the counterforce is the result of the two sides continually adapting to each other’s strategies.

Read the full story

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Physics department honors Alexandrakis


Physics department honors Alexandrakis

During his 25 years as chair of the College of Arts and Sciences’ Department of Physics, George C. Alexandrakis raised the reputation of his department to new heights, recruiting world-class faculty members and spearheading the construction of the James L. Knight Physics Building. On January 21, the department honored Alexandrakis for his many years of service by dedicating the chair’s office in his honor. A professor of physics educated at Princeton, Alexandrakis is a two-time chair of UM’s Department of Physics, serving in that capacity from 1976 to 1980 and again from 1986 to 2007.

At the dedication ceremony, College of Arts and Sciences Dean Leonidas G. Bachas heralded Alexandrakis for his commitment to the University, the department, and to his students. The dedication is the culmination of several generous gifts from faculty, former students, alumni, and friends—funds that will be used to establish the Alexandrakis Undergraduate Travel Fund.

Pictured from left to right are Alexandrakis and his wife, Aphrodite; Ken Voss, professor and current chair of the Department of Physics; and Dean Leonidas G. Bachas.

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A cosmic look back at the dawn of time

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A cosmic look back at the dawn of time

Analyzing remnants of light left over from the Big Bang with data beamed to Earth from an observatory nearly one million miles in space, a University of Miami physicist will help answer important questions about the origins of the universe and how it will continue to evolve.

UM astrophysicist Kevin Huffenberger is part of a multinational team of scientists who are analyzing data from the European Space Agency's Planck satellite, which is taking the most highly detailed and accurate measurements ever recorded of the cosmic microwave background, or the ancient light left over from the Big Bang.

As a middle school student growing up in Columbus, Ohio, Kevin Huffenberger developed a keen interest in cosmology, reading books by the British theoretical physicist Stephen Hawking and learning all he could about black holes, distant galaxies, and the nature of time.

But it was one topic, in particular, that captured his curiosity: how the universe developed after the Big Bang.

Today, as a University of Miami physicist, Huffenberger is still enthralled with how the universe came to be, only now he is part of a multinational endeavor that could very well provide definitive answers about its origin, development, and continued evolution.

He is one of the many scientists analyzing data from Planck, a European Space Agency (ESA) observatory nearly one million miles from Earth that will survey and map the entire sky until early 2012, taking precise measurements of fluctuations in the cosmic microwave background (CMB)—or ancient light from the fireball out of which the universe sprang into existence some 13.7 billion years ago.

“It’s always been part of our natural human curiosity to wonder where the universe around us came from,” says Huffenberger, an assistant professor of physics in UM’s College of Arts and Sciences. “This project will give us insight into that.”

Planck will specifically measure fluctuations in the CMB, which is encoded with a treasure trove of information from the hot, primordial soup of particles that eventually became our universe. With those measurements, scientists will get the clearest picture yet of the early universe, when it was a mere 380,000 years old.

The data will help them determine the large-scale properties of the universe; investigate the amount of dark matter, a mysterious, invisible substance scientists assume exists because of gravitational effects on visible matter; probe the properties of dark energy, which accounts for as much as 73 percent of the total matter-energy budget of the universe; find out what triggered the rapid expansion of the universe; study the origin of structures (galaxies, clusters of galaxies, and large voids); map, for the first time, the magnetic field spread throughout our own Milky Way; and observe distant galaxies and determine how they form stars.

“It will provide a data set that’s unprecedented in quality and scope,” explains Huffenberger, whose primary research is in developing reliable analysis techniques used in current and future experiments that measure the CMB. He started working on the Planck project when he was a postdoctoral researcher at NASA’s Jet Propulsion Laboratory, a partner in the mission, and he credits his undergraduate research in neutron stars and black holes as the most influential experience that led him to pursue an academic career in physics.

The Planck satellite is named for Max Planck, the German Nobel laureate who was one of the early pioneers in quantum mechanics. Equipped with a powerful telescope, it blasted off from ESA’s spaceport in Kourou, French Guiana, in May 2009, carrying the hopes of Huffenberger and the hundreds of other scientists, engineers, physicists, and astronomers who are collaborating on the project.

Huffenberger describes his role in the mission as small but important. He developed a portion of the data processing pipeline that calibrates the Planck telescope’s response to fluctuations in the cosmic microwave background.

The first all-sky image from the Planck mission, taken at millimeter wavelengths too long to be seen with the human eye. In the foreground, wispy shades of blue and white show faintly glowing gas and dust in our own Milky Way galaxy, which is associated with the production of new stars and solar systems. In cosmic terms, most of this dust is nearby, within a few 10,000 light-years. The faintly mottled orange and red background shows a far more distant feature, variations in the intensity of the cosmic microwave background, the faint afterglow of the Big Bang. This light has traveled about 13.7 billion light-years to reach us. Photo credit: European Space Agency.

He will also study and analyze data from far-away galaxies, which emit radiation like the Milky Way’s “but are so small and distant that their contribution could be mistaken for additional small-scale fluctuations, if not properly accounted for,” he explains.

And with UM postdoctoral associate Jan Kratochvil, he will study slight distortions in the microwave background measured by Planck. “As the light from the Big Bang travels to us, it is deflected by the gravitational attraction from matter it passes near,” says Huffenberger. “By looking for certain patterns in these deflections, we can learn about the distribution of matter as the universe developed from the Big Bang to the present day.”

Planck recently transmitted its first all-sky image, showing in one expansive view our own Milky Way galaxy and the universe as it existed 380,000 years after the Big Bang.

Scientists are using some of the fastest and most powerful supercomputers in the world to analyze the image and other data sent by Planck. But the first set of major results won’t be released until January or February of next year, according to Huffenberger.

But already the image, along with others released before it, have given astronomers and cosmologists new insight into the way stars and galaxies form.

“They make for some pretty compelling images, regardless of their scientific value,” says Huffenberger, whose research is being funded by NASA and UM’s Office of the Provost. “I was pretty amazed by the delicate structures that you can see in the distribution of wisps of dust. You’re left thinking, ‘That’s the universe we live in, and it has all of this structure to it that, before an instrument like Planck was built, you had no idea was there.’ It’s the first little taste of things to come.”

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