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Teaching Award-Dr. Roxanne Springer 
 
Dr. N. Russell Roberson retires 
 
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Dr. Daniel Gauthier receives tenure   

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Dr. Carlos Frenk, Exchange Program Between Duke University and the University of Durham, England

Professor Carlos Frenk of the University of Durham was the first official guest lecturer under the auspices of this new exchange program.  Professor Frenk is a well-known astrophysicist who investigates the formation of large-scale structure in the cosmos.  The following article appeared in the Duke Dialogue on the occasion of his visit in October 1998. 

  Soon after the universe began with a "Big Bang," scientists think "lumps" developed in the originally "smooth" texture of the evolving cosmos. They also believe those imperfections eventually turned into all of today's billions on billions of star-strewn galaxies. The question is, how?  These changes already were evident just 100,000 years after the Big Bang in the "ripples" that physicists have found in the "Cosmic Background Radiation," the earliest evidence of those long-ago times that now are detectable.

"We know the ripples are the fossil records of today's galaxies," said cosmologist Carlos Frenk.  "Our job is to simulate how those ripples turned into the galaxies that we see  today."  A physicist at the University of Durham in England, Frenk was at Duke last week to describe how his international collaboration, the VIRGO Project, is using some of the world's most powerful supercomputers  to demonstrate what could have happened in the 10 billion-plus years that followed.  "We start off with the universe 100,000 years old, which is nothing," Frenk said in an interview before his Oct. 8 colloquium address in the Physics Building. "If that was the equivalent of a human lifetime, when we start our simulation would correspond to the first three hours." 

The VIRGO website displays four1996 front-page pictures in The New York Times, each representing a separate calculation of how galaxies might have coalesced into patterns resembling today's universe. Work like this requires awesome amounts of supercomputing power. VIRGO currently has access to a Cray T3E supercomputer at the Max Planck Institute for Astrophysics in Munich, Germany, that can perform simultaneous calculations on 672 processors. It also is using a 256-processor Cray T3E in Edinburgh, Scotland. 
"It's very nice to make galaxies in the computer, but after all that's just a figment of the human mind," Frenk noted. "The simulated universe is just an aid to understanding the real one."  Using the combination of VIRGO simulations and real observations with the Hubble Space Telescope and other land-based observatories, "I think we now have, for the first time, a fairly clear picture of the main processes responsible for the generation of galaxies," he said. 

According to this emerging picture, the seeds for galaxies were sown by subatomic changes called "quantum fluctuations" only an infinitesimally small part of a fraction of a second after the Big Bang itself, when the universe was tiny. Those fluctuations are what led to the ripples in the Cosmic Background Radiation 100,000 years later, when the rapidly expanding universe was much larger. 

Following the template of the ripples, the modern universe may have arranged itself under the collective gravitational influences of all the matter that astronomers can detect in the radiation from stars and gaseous nebulae, plus the gravitational tugs of a suspected much larger amount of unseen "dark matter." 
 
While the nature and amount of dark matter in the universe is the subject of much controversy, scientists can actually strongly infer its presence by observing examples of "gravitational lensing," when a strong, unseen source of gravity bends the light from visible stars and galaxies, he said. 

Frenk visited Duke as part of an exchange program with Durham, England, the medieval city where he has lived and worked since 1986. "It is dominated completely by this fantastic 11th century cathedral which even the French guidebooks say is the most imposing Norman cathedral in the world," he said. 

With traffic patterns laid down in the Middle Ages, "it is pointless to drive" in most of his city, "so it's all pedestrian," Frenk added. "I only use a car on Saturdays to go to the supermarket, and on Sundays to go to places for hiking. Also, we don't have the concept of the university campus that you have here. The University of Durham is spread all over the whole city. 

"The only thing that we share is the rain," Frenk said, who arrived in the Triangle during a welcome wet spell following a dry summer. 

The VIRGO website is at http://www.mpa-garching.mpg.de/~jgc/sim_virgo.html  

Article in Duke Dialogue by Monte Basgall