KICP in the News, 2010
Edward Kolb and Michael Turner share the 2010 Dannie Heineman Prize for Astrophysics
The University of Chicago News Office, January 14, 2010
The University of Chicago News Office
Two UChicago scientists garner Heineman Prize for Astrophysics
The University of Chicago's Edward Kolb and Michael Turner share the 2010 Dannie Heineman Prize for Astrophysics, which the American Institute of Physics and the American Astronomical Society jointly award.
Kolb and Turner are cited "for their joint fundamental contributions to cosmology and their development of the field of particle astrophysics, which have resulted in a vibrant community effort to understand the early universe."
Kolb, the Arthur Holly Compton Distinguished Service Professor and Chairman of Astronomy & Astrophysics, focuses his research on understanding the physical processes that occurred in the very earliest moments of the big bang. In these very early moments, the density, energy and pressure of the universe resembled the conditions obtained in the collisions of particles at high–energy accelerators.
Turner, the Bruce V. and Diana M. Rauner Distinguished Service Professor in Astronomy & Astrophysics, applies modern ideas in elementary particle theory to cosmology and astrophysics. His work on inflation showed how quantum fluctuations seeded galaxies and other structures in the Universe and he predicted the existence of the mysterious dark energy that is causing the Universe to accelerate. The National Academy report he led, Connecting Quarks with the Cosmos, laid out the vision for the field of particle astrophysics and cosmology.
Kolb and Turner wrote the handbook for the field, their monograph entitled The Early Universe, and initiated the Fermilab astrophysics group which has grown to a vibrant set of activities that link the University and Fermilab, including the Sloan Digital Sky Survey, the Dark Energy Survey, and the Pierre Auger Observatory. Kolb and Turner, along with the late David Schramm, the Louis Block Professor in Astronomy & Astrophysics, helped to pioneer this field and make Chicago one of the world centers of cosmology.
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KICP Members: Edward W. Kolb; Michael S. Turner
Fermilab physicists honored for uniting physics and cosmology
Fermilab Today, February 17, 2010
Three decades ago, no one had ever heard of particle astrophysics. How could the tiniest pieces of matter and the biggest objects in the universe coexist in a single field of science?
Last month, the American Institute of Physics and the American Astronomical Society honored two scientists who, more than any others, made particle astrophysics, if not a household name, a new scientific discipline.
Theoretical astrophysicists Michael Turner and Rocky Kolb won the annual Dannie Heineman Prize for Astrophysics "for their joint fundamental contributions to cosmology and their development of the field of particle astrophysics, which have resulted in a vibrant community effort to understand the early universe."
Turner and Kolb conducted much of their pioneering work at Fermilab. They were the first members of the NASA/Fermilab Theoretical Astrophysics Group, which blossomed into the realm of experiment and observation and continues today at the Fermilab Center for Particle Astrophysics. In the process, they entertained generations in the Fermilab community with a new genre of cosmic humor, astroparticle shtick.
Former Fermilab Director Leon Lederman and the late David Schramm of the University of Chicago brought the two together in 1983. John Peoples, who followed Lederman as lab director, helped them realize their plan of expanding into particle astrophysics experiments.
Turner said, "While the two of us are getting the prize, really Fermilab and the University of Chicago deserve a lot of credit for all the support they've given us and for taking chances." Not to mention auditioning their act.
For more than 25 years, the two each held joint appointments at Fermilab and the University of Chicago. Now both are professors full-time at the University of Chicago.
Taking the initiative
In the late 1970s, astrophysics had hit a wall. The standard hot Big Bang model seemed to have a problem. Neutrons and protons, the smallest known particles, were too large and interacted too strongly to allow sensible speculations about how the universe began.
Then particle physicists discovered quarks, the weakly interacting, point-like particles that make up neutrons and protons - and saved the model. Scientists could describe the early universe as a hot, primordial soup of quarks instead of a jumble of overlapping neutrons and protons.
It didn't take long for Turner and Kolb to package "Condensed Primordial Soup: A quick meal in just 4.5 billion years" in a familiar red and white can.
Now scientists could start to tackle some big questions about how the universe began and how it was shaped. But neither astrophysicists nor particle physicists could answer those questions alone.
Fermilab made a first attempt to enter the world of astrophysics in 1979, making a bid to NASA to host its Space Telescope Science Institute, which analyzes data from the Hubble Space Telescope. NASA chose the bid from Johns Hopkins University instead. Soon after, Lederman went hiking in the Dolomites with Schramm, an astrophysicist and rising star at the University of Chicago.
"I was complaining about NASA's decision," Lederman said. "Schramm said, 'You don't need to win any contests. You're the director of Fermilab. Why don't you just make yourself an astrophysics group? I'll help you.'"
The laboratory put in a new bid to NASA, this time to host a theoretical astrophysics group. This time, NASA said yes.
In 1983, Lederman hired Turner, a young assistant professor in the Astronomy Department that Schramm chaired at the University of Chicago, along with Kolb, an Oppenheimer Fellow from Los Alamos, to bring Fermilab to the cosmic frontier.
"Leon is a visionary," Peoples said. "He was always looking around for the thing nobody else had thought about."
Kolb and Turner were a perfect fit for the task, which was by no means guaranteed to succeed, Lederman said. They were good communicators; they could make people laugh. "That's a big plus," he said. "It could lighten any disaster."
Kolb and Turner had first met in 1980 at a workshop in Santa Barbara.
"We started out working on similar research, but as competitors," Turner said. "You've got a lot of testosterone when you're a young post-doc trying to make a mark. But we had a lot in common: a passion for this area of science, a similar sense of humor. It was clear to me that we would have a greater impact if we worked together - and it would be more fun."
Turner had already begun to establish himself at the University of Chicago, but he and Kolb were both in their 30s when they first came to Fermilab to head a group of about 10 post-docs and students. "I felt like I'd been given the keys to the candy store," Kolb said. "Who would allow kids like us to run something? I always thought somebody would say, 'Who's really in charge?'"
The young scientists' work paid off, Lederman said, and soon they ran the premier particle astrophysics groups in the nation. They built and studied theories of dark matter, extra dimensions, ultra-high-energy cosmic rays, superstring cosmology, the cosmic microwave background and gravitational lensing.
"We were just a little bit ahead of everybody," Lederman said. "Four of five years after our group had achieved successes, the other universities started to make those connections."
Over the years, between teaching post-docs at Fermilab and students at the University of Chicago, Kolb and Turner trained a large fraction of the people who would become the next generation of leaders in the field they began.
In 1989, Kolb and Turner published what would become the handbook for particle astrophysics: a book called "The Early Universe."
"We were so young, foolish and inexperienced, we thought it would be easy," Kolb said. "It took about three years of pretty hard work."
Around that time, they recognized that they needed to get involved in testing the theories that they had spent years developing. "We realized a purely theoretical activity is not as productive as an operation with connections to experiments and observations," Kolb said. "Even though theorists are smarter and more attractive, we do need experimentalists."
Peoples, then Fermilab's new director, supported their plan. Fermilab joined the Sloan Digital Sky Survey, the most ambitious astronomical survey ever planned; the Cryogenic Dark Matter Search experiment; and the Pierre Auger Observatory, which in 2007 identified supermassive black holes as the most likely source of the highest-energy cosmic rays.
"As a director, you have to have a few things you take a chance on," Peoples said. "If every experiment you do is successful, you're not doing anything new."
About 15 years after Turner and Kolb arrived at Fermilab, experimental results began to come in from the NASA's Cosmic Background Explorer satellite, which found patterns in the way matter and energy had been distributed soon after the universe began. The new data matched predictions based on ideas coming out of early-universe cosmology, including inflation and cold dark matter.
"The world changed on Jan. 1, 1998," Turner said. "These went from ideas to ideas supported by data. It became clear this wasn't just a bunch of airy-fairy theory."
The astrophysics group could not fully enjoy their triumph. Just days before Christmas of 1997, Schramm died in plane crash during a flight from Denver to Aspen in his private plane. He never saw the field that considered him a founder turn the corner toward widespread acceptance.
Kolb, Turner and the particle astrophysicists at Fermilab and the University of Chicago have continued the work he championed. The Fermilab Center for Particle Astrophysics participates in the COUPP dark matter experiment, the Dark Energy Survey and GammeV. The group continues to participate in the Cryogenic Dark Matter Search, the Pierre Auger Observatory and the Sloan Digital Sky Survey. Scientists there hope to join the Joint Dark Energy Mission as well.
Since its inception, the Fermilab Theoretical Astrophysics Group has published more than 1,000 papers. The Experimental Astrophysics Group was an anchor for the SDSS and now leads the Dark Energy Survey, designed to study the acceleration of the expansion of the universe.
Turner said he has high hopes for the current search for dark matter. "We have a full-court press on dark matter. One of these methods is going to pan out."
He does not foresee solving the mystery of dark energy - a term he coined in 1998 to explain the mysterious force pushing the universe to expand at an increasing rate - anytime soon. But "I bet there'll be a surprise ahead," he said. "Each generation wants to get all the answers. After a few it gets a little more generous and says, 'We'd better save some of the big questions for the next generation.'"
Turner and Kolb are recognized as pioneers who not only brought the field new knowledge, but helped frame the questions that drive future research. And left them laughing.
"You're sure dark matter is there?" Turner once asked Kolb in a public debate on dark matter.
"I would bet your life," Kolb replied.
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KICP Members: Edward W. Kolb; Michael S. Turner
A CoGeNT result in the hunt for dark matter
NatureNews, February 26, 2010
Deep in the Soudan mine in Minnesota, some 700 metres below ground amid the bones of bats, sits the huge Cryogenic Dark Matter Search (CDMSII) experiment, which at its heart contains a rack of supercooled hockey-puck-sized silicon and germanium detectors nestled within Russian-doll layers of shielding.
Two weeks ago, the CDMSII collaboration published a paper showing that two particles had penetrated its detector's defences - particles that, given the lack of any other particle activity down in the frigid quiet of the detectors, looked very much like dark matter. Dark matter is thought to make up 85% of the mass in the Universe, but has not been detected directly - quite. The attention-grabbing claim of the CDMSII collaboration has many physicists thinking - but not yet convinced - that the team could be on to something.
Just a stone's throw from the CDMSII experiment, across the subterranean cavern, lies a far smaller box that is thickening the dark-matter plot. The box contains a single germanium hockey puck, similar to those in the CDMSII experiment but operated by the Coherent Germanium Neutrino Technology (CoGeNT) collaboration and tuned to detect incoming particles with much lower masses than the CDMSII. It began collecting data in December 2009, and, after just 56 days, the group is reporting hundreds of particle strikes that cannot be explained other than by invoking dark matter.
"If it's real, we're looking at a very beautiful dark-matter signal," says Juan Collar, a physicist at the University of Chicago and CoGeNT spokesperson. Collar presented the work today at a dark-matter conference at the University of California, Los Angeles. The results were posted on the preprint server Arxiv yesterday.
Confirmation of the result - and Collar is careful to say that it is still early days - would radically shift attention to experiments that are sensitive to lower energies. The CoGeNT experiment looks for a type of dark-matter particle called a WIMP, or Weakly Interacting Massive Particle. The new data point to a WIMP with a mass in the range of 7–11 billion electronvolts. Theorists have conjured up hundreds of mathematically consistent models for producing WIMPs of different masses in the early Universe, and the particles detected by CoGeNT fit well in the realm of the theoretically possible.
But the majority of models had favoured WIMP particles that are an order of magnitude heavier, and some experiments - such as the CDMSII, and those using large tanks filled with mineral oil or liquefied noble gases - were aiming for that territory. "The experiments designed to look at the heavier particles aren't going to like the CoGeNT result," says Dan Hooper, a theorist at the Fermi National Accelerator Laboratory in Batavia, Illinois.
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KICP Members: Juan I. Collar; Daniel Hooper
Scientific projects: Coherent Germanium Neutrino Technology (CoGeNT)
Colorado Bound: The Pierre Auger Project
Kavli Foundation Newsletter, March 3, 2010
Kavli Foundation Newsletter
N SOUTHEASTERN COLORADO, a land better known for crops and livestock may soon host the world's largest astrophysical detector.
If an international consortium of scientists gets a green light from funding agencies, it will build an array of tanks of purified water - which make passing cosmic rays visible to sensors - across an area of Colorado nearly as large as the state of New Jersey.
The tanks are only 12 feet in diameter, but the network of 4400 of them placed 1.4 miles apart will cover 8,000 square miles (20,000 square kilometers). The result will be a massive "net" for catching the detritus of some of the highest-energy particles in the universe.
The project is a tremendous undertaking, not only because of its size. The network of tanks will crisscross through farms, ranches, towns and counties, and to succeed, the scientists need more than scientific ingenuity. Also integral is recruiting communities - including farmers and ranchers more interested in agriculture than astrophysics - to become partners in exploring the sky.
Bigger is Better
The Pierre Auger Cosmic Ray Observatory is dedicated to detecting and studying ultra-high energy cosmic rays, the most energetic particles in the universe. The observatory first built a detector array in Argentina, completed in 2008, called Auger South. This array in the southern hemisphere consists of 1,600 water tanks - each holding 3,000 liters of purified water - laid out on a triangular grid 1.5 kilometers on a side.
The array relies on a grid of plastic tanks filled with 12 tons of ultra pure water. When charged particles from a cosmic ray shower zip through the tank, they emit tiny flashes of light which are seen by three very sensitive photomultiplier tubes. These tubes convert light into electrical signals. The source of power is the sun: solar panels are used to charge batteries, which provide all the power the tank needs. Data processing electronics, mounted inside a dome on top of the tank, collects the phototube signals and transmits the processed information via antenna to the main campus. A GPS device provides accurate timing, so that signals from many tanks can be properly compared.
The proposed array in Colorado - Auger North - is more than the northern hemisphere complement to its Argentinean brother; it dwarfs Auger South, covering seven times the area. "As far as size goes, it's really amazing," says Angela Olinto, an astrophysicist who is part of that consortium, as well as a member of the Kavli Institute for Cosmological Physics. "You have to drive for hours to cross from one side to the other. "
Size is important because of the difficulty in detecting these particles. The highest-energy cosmic rays slam into the atmosphere with an energy of 1020 eV, creating a cascade of secondary particles that spread over many square kilometers. Much more energetic than even the highest energy particles that will be collided at the Large Hadron Collider, these mysterious denizens of the cosmos might be able to tell scientists about some of the most energetic events in the universe.
Unfortunately, one of these extremely high-energy cosmic rays only reaches any given square kilometer of the earth once a century. The first ultra-high-energy cosmic ray was detected in Utah in 1991 by a detector array called the Fly's Eye. Its energy was so high it challenged scientists' assumptions about how high the energy of a cosmic ray could be and spawned the international Pierre Auger Collaboration.
There's an intriguing difference between the common low-energy cosmic rays and the rare ultra-high-energy particles: the garden variety ones have been traveling around the universe for perhaps billions of years, bent this way and that by magnetic fields, while the rare gems are relatively local and haven't lost their direction. That means they can point back to where they came from.
"For me that is the exciting part, it is essentially a new window," says Case Western Reserve University astrophysicist Corbin Covault. "It's like a new kind of telescope and a new energy or frequency band. It is just instead of looking at light or electromagnetic particles, you are looking at charged nuclear particles."
So far, they seem to come from the directions of active galactic nuclei, says Auger collaboration co-spokesperson Paul Sommers, a physicist at Penn State University. These are "galaxies that have giant super-massive black holes in their centers that are actively consuming gas and dust and spewing out energetic particles."
Auger South turned up an unexpected mystery. Before this detector was built, astrophysicists would have said that cosmic rays are almost universally protons - that is, hydrogen atoms stripped of their electron so that they are bare, charged protons traveling across the universe. But the cascade of particles - the showers - look quite different than the scientists expected.
"We get something that looks like iron or even gold," says Olinto. "That's weird. Astrophysically, why would iron or something even heavier than that be coming all the way from very far away?"
If the particles really are heavy ions, then that would be exciting and challenging for astrophysicists, says Sommers. If they are protons, then they are interacting in ways that challenge current models of particle physics.
When it came to planning Auger North, Colorado was chosen because it is relatively high, dry and flat, and the array can be expanded to the east if it ever needs to be made bigger. The southeastern part of the state is also sparsely populated, which isn't necessarily an issue for the tanks, but the accompanying air fluorescence telescopes need dark skies to see the development of a cosmic-ray air shower.
The array is slated to be so much larger than Auger South because the highest energy cosmic rays are only detected by Auger South twice a month. For Auger North, tanks will be placed in a square array at the intersections of roads, minimizing the impact on landowners. Completed, the array will cover seven times the area of Auger South with fewer than three times as many tanks.
The project's proposal is currently under review by the National Science Foundation and the Department of Energy. Around a third of the observatory's $125 million budget is expected from the U.S., and the remainder from international collaborators.
While applying for funding, Auger Observatory scientists have also been recruiting community support. The scientists are keenly aware of the importance of the public perception of their project. "We want the people to love our tanks," says Olinto, who helped select the Colorado site. "Our hope is to make them certainly interested in why we are doing this and the whole big picture of why does it matter."
To earn this trust, the scientists are building on the ways Auger South was successfully integrated in Argentina and continues to be a good neighbor. For instance, in Malargue, Argentina, the Auger collaboration hosts an annual science fair and participates in a local parade. Visiting scientists give talks in the community, and children have helped name the tanks.
Because of the economic opportunities the observatory will create in the area, a southeastern Colorado economic development corporation paid the way for some county commissioners and a local newspaper reporter to travel to Argentina. "They got personal experience with how we operate," says John Harton, an Auger Observatory scientist at Colorado State University who serves as a liaison with the local community, "and they were able to come back and tell their neighbors."
Along with organizing and participating in a range of community meetings, scientists also set up tanks at community centers around southeastern Colorado so farmers and ranchers could actually see what the scientists plan to build. This way "they can kick it and they can see that it is smooth and it won't hurt their livestock," said Harton. "The more people know about it and the more they understand, the more they are positive about our project."
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KICP Members: Angela V. Olinto
Scientific projects: Pierre Auger Observatory (AUGER)
Dark Energy: The Biggest Mystery in the Universe
Smithsonian magazine, March 26, 2010
by Richard Panek, Smithsonian magazine
Twice a day, seven days a week, from February to November for the past four years, two researchers have layered themselves with thermal underwear and outerwear, with fleece, flannel, double gloves, double socks, padded overalls and puffy red parkas, mummifying themselves until they look like twin Michelin Men. Then they step outside, trading the warmth and modern conveniences of a science station (foosball, fitness center, 24-hour cafeteria) for a minus-100-degree Fahrenheit featureless landscape, flatter than Kansas and one of the coldest places on the planet. They trudge in darkness nearly a mile, across a plateau of snow and ice, until they discern, against the backdrop of more stars than any hands-in-pocket backyard observer has ever seen, the silhouette of the giant disk of the South Pole Telescope, where they join a global effort to solve possibly the greatest riddle in the universe: what most of it is made of.
For thousands of years our species has studied the night sky and wondered if anything else is out there. Last year we celebrated the 400th anniversary of Galileo's answer: Yes. Galileo trained a new instrument, the telescope, on the heavens and saw objects that no other person had ever seen: hundreds of stars, mountains on the Moon, satellites of Jupiter. Since then we have found more than 400 planets around other stars, 100 billion stars in our galaxy, hundreds of billions of galaxies beyond our own, even the faint radiation that is the echo of the Big Bang.
Now scientists think that even this extravagant census of the universe might be as out-of-date as the five-planet cosmos that Galileo inherited from the ancients. Astronomers have compiled evidence that what we've always thought of as the actual universe - me, you, this magazine, planets, stars, galaxies, all the matter in space - represents a mere 4 percent of what's actually out there. The rest they call, for want of a better word, dark: 23 percent is something they call dark matter, and 73 percent is something even more mysterious, which they call dark energy.
"We have a complete inventory of the universe," Sean Carroll, a California Institute of Technology cosmologist, has said, "and it makes no sense."
Scientists have some ideas about what dark matter might be - exotic and still hypothetical particles - but they have hardly a clue about dark energy. In 2003, the National Research Council listed "What Is the Nature of Dark Energy?" as one of the most pressing scientific problems of the coming decades. The head of the committee that wrote the report, University of Chicago cosmologist Michael S. Turner, goes further and ranks dark energy as "the most profound mystery in all of science."
The effort to solve it has mobilized a generation of astronomers in a rethinking of physics and cosmology to rival and perhaps surpass the revolution Galileo inaugurated on an autumn evening in Padua. They are coming to terms with a deep irony: it is sight itself that has blinded us to nearly the entire universe. And the recognition of this blindness, in turn, has inspired us to ask, as if for the first time: What is this cosmos we call home?
Scientists reached a consensus in the 1970s that there was more to the universe than meets the eye. In computer simulations of our galaxy, the Milky Way, theorists found that the center would not hold-based on what we can see of it, our galaxy doesn't have enough mass to keep everything in place. As it rotates, it should disintegrate, shedding stars and gas in every direction. Either a spiral galaxy such as the Milky Way violates the laws of gravity, or the light emanating from it - from the vast glowing clouds of gas and the myriad stars - is an inaccurate indication of the galaxy's mass.
But what if some portion of a galaxy's mass didn't radiate light? If spiral galaxies contained enough of such mystery mass, then they might well be obeying the laws of gravity. Astronomers dubbed the invisible mass "dark matter."
"Nobody ever told us that all matter radiated," Vera Rubin, an astronomer whose observations of galaxy rotations provided evidence for dark matter, has said. "We just assumed that it did."
The effort to understand dark matter defined much of astronomy for the next two decades. Astronomers may not know what dark matter is, but inferring its presence allowed them to pursue in a new way an eternal question: What is the fate of the universe?
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KICP Members: Michael S. Turner
Scientific projects: South Pole Telescope (SPT)
Josh Frieman of the KICP named Director of the Dark Energy Survey
Fermilab Today, March 30, 2010
New leaders named for dark energy experiment
An experiment that scientists hope will help them understand what is causing the acceleration of the universe is under new management. On March 15, Josh Frieman succeeded Fermilab Director Emeritus John Peoples as project director of the Dark Energy Survey. Rich Kron will serve as deputy director.
"It was long enough," said Peoples of his seven years leading the experiment. Peoples, a founding member of the DES collaboration, now has retired from three director roles at Fermilab. "I want to do more hands-on science again and I want a slightly simpler life," he said.
Plus, Peoples said, this is a natural time to step down. The experiment is currently under construction and collaborators plan to complete installation and commissioning by late 2011.
"Josh has been organizing, planning and getting the collaboration ready," Peoples said. "At this stage, we're looking for a scientist to lead, not a politician. There are 130 prepared minds out there working under Josh and getting ready for science."
The data from the experiment will provide scientists with four methods that they can use to determine the nature of the dark energy thought responsible for the acceleration of the universe. The survey experiment, which will use a very large digital camera mounted to a telescope in Chile, is the first of a new generation of projects that can help to address that question. The Dark Energy Camera and its infrastructure are currently under construction at Fermilab. Other experiment components are being built elsewhere .
To help usher the collaboration into the next era, Frieman asked Kron, fellow DES collaborator and former Sloan Digital Sky Survey project director and spokesperson, to serve as his deputy director.
"Rich directed SDSS very successfully. He knows what it takes to get a project like this done," Frieman said.
Both Frieman and Kron hold joint appointments at the University of Chicago. Frieman is a founding member of the DES experiment, a former SDSS collaborator, and co-leader of SDSS's supernova search team.
Frieman cited the broad, distributed nature of this experiment as his and Kron's biggest challenge.
"We have to bring together all the different elements - the hardware, software, upgrades to the telescope, and the scientists, all of which have operated somewhat independently until now," he said.
To do that, Frieman said, they'll stay in close contact with the collaboration members. While they know that getting the experiment ready to take data won't be easy, they are excited about the prospect of taking real measurements to answer some of the most fundamental questions of the universe.
"In 2003, when the project began, the start of data-taking seemed a long way off," Frieman said. "But we're now at the point where we can almost taste it."
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KICP Members: Joshua A. Frieman
Scientific projects: Dark Energy Survey (DES)
Michael Turner named new Director of the KICP
The University of Chicago News Office, April 2, 2010
The University of Chicago has named Michael S. Turner as director of its Kavli Institute for Cosmological Physics, effective March 29, in an ongoing commitment to probing some of the most puzzling scientific questions about the origin and evolution of the universe.
Turner, the Bruce and Diana Rauner Distinguished Service Professor in Astronomy & Astrophysics at UChicago, succeeds John Carlstrom as director. Carlstrom, the S. Chandrasekhar Distinguished Service Professor in Astronomy & Astrophysics, leaves the directorship to devote more time to his research with the South Pole Telescope and other projects.
"Over the six years of its young history, the Kavli Institute has seen great accomplishments, has been a powerful incubator for new ideas, and has served as a world center for cosmology," said Robert Fefferman, dean of the Physical Sciences Division, in announcing Turner's appointment. He further lauded Turner as "one of the world's leading theoretical cosmologists," and the Kavli Institute as "one of the division's crown jewels."
UChicago's Kavli Institute is one of 15 research institutes worldwide that have the distinction of carrying the Kavli name, noted University President Robert Zimmer.
"Michael Turner is an eminent cosmologist, known for pioneering the deep connections between particle physics and cosmology and his seminal work on dark energy. He has had a distinguished career at the University and at the National Science Foundation. He is also an inaugural member of the Kavli Institute," Zimmer said. "Michael will ably lead the next phase of cosmological discovery at the University, and advance Fred Kavli's passionate convictions that basic scientific research is essential and beneficial for humanity."
Turner is a member of the National Academy of Sciences. He has received numerous honors, including this year's Dannie Heineman Prize for pioneering cosmological physics research from the American Astronomical Society and the American Institute of Physics. Turner has formerly served as the National Science Foundation's assistant director for mathematical and physical sciences (2003 - 2006), and as chief scientist of Argonne National Laboratory (2006 - 2008).
The University established the Center for Cosmological Physics in 2001 with National Science Foundation support. The center was renamed the Kavli Institute for Cosmological Physics in 2004 in honor of Fred Kavli, who through the Kavli Foundation provided $7.5 million to endow the institute and support its programs.
UChicago's Kavli Institute works closely with the other Kavli Institutes in astrophysics at Stanford University, Peking University, Massachusetts Institute of Technology, University of California, Berkeley; and the University of Cambridge.
KICP Members: Michael S. Turner
Scholars, scientists gather to discuss value of 'the art of science'
The University of Chicago News Office, April 13, 2010
by Greg Borzo, The University of Chicago News Office
A provocative panel of speakers explored the striking similarities - and the discordant differences - between art and science at the first program in the University of Chicago, Argonne National Laboratory, and Fermi National Accelerator Laboratory Joint Speaker Series held last month at the Oriental Institute.
About 100 faculty members, scientists, engineers and researchers came together to launch a series of informal events intended to spark new connections between members of the University and those of the national laboratories.
"We often gather over science, but rarely informally," said Donald Levy, the Albert A. Michelson Distinguished Service Professor in the James Franck Institute, Chemistry, and the College, and the Vice President for Research and for National Laboratories. Levy, along with Eric Isaacs, Director of Argonne, and Pier Oddone, Director of Fermilab, hosted the event. "This series will further our research goals by narrowing the distance between our three institutions - literally and figuratively," said Levy.
With a mix of scientists, researchers, artists and art historians comprising a panel, the program, titled "The Art of Science," kicked off with the panelists addressing some of the distinctions between the practice of making art and doing scientific research.
"Science would never sacrifice content for beauty, which is something artists do all the time," said panelist Elena Shevchenko.
Assistant Professor and visual artist Jason Salavon noted that, "Scientists want to see what's there while artists want to express themselves. He added, "Most artists work alone while most scientists work collaboratively."
Although the discussants highlighted where art and science diverge, they also agreed that both fields provide fertile ground for creativity and curiosity.
"Art and science are both based on the ability to imagine, and if we were limited to things we could see, there would be no joy," said art historian Barbara Stafford.
The discussion also focused on how art can be vital to understanding science.
"Computer-generated art allows us to look at things that we couldn't see otherwise, like the universe from outside the universe," said astrophysicist Nick Gnedin.
Mike Papka from Argonne noted that art aids scientists in moving their research to new levels of exploration. "An experiment that simulates the explosion of a star can create more than one billion data points. Artistic representation is a powerful tool that helps scientists make sense of mountains of data and furthers their experiments."
"Now there will be closer collaboration between art and science at these three institutions," said Chairman of Astronomy & Astrophysics Edward "Rocky" Kolb, who moderated the panel. "The take-home message was that science can inform art, and art can be a great way of representing research results to scientists and the public," said Kolb, the Arthur Holly Compton Distinguished Service Professor and a member of the Enrico Fermi Institute.
Larry Norman, Deputy Provost for the Arts at the University, appreciated the dialogue. "A beautiful moment for me was when someone in the audience said that science and art both slow things down because they both demand intense focus and concentration," he said. "This slowing down is true not only for the artist and scientist but also for those seeking to appreciate the art or understand the science."
At the event, Norman pointed out that the University is committed to ensuring that arts activities across campus contribute to the intellectual life of the entire University as well as the Labs, and that the new Reva and David Logan Center for Creative and Performing Arts will be central to this effort.
Elton Kaufmann, Associate Director of the Strategic Planning Group at Argonne, said of the discussion, "This kind of thing is great because it gets the right side of my brain working. Something I've been trying to do for years," he quipped.
The panel members were Nick Gnedin, Theoretical Astrophysicist at Fermilab and Associate Professor of Astronomy and Astrophysics at the University; Mike Papka, Deputy Associate Laboratory Director of Computing, Environment and Life Sciences at Argonne; Jason Salavon, Assistant Professor in Visual Arts at the University and Research Fellow at the Computation Institute; Elena Shevchenko, Nanoscientist at Argonne; and Barbara Stafford, the William B. Ogden Distinguished Service Professor Emerita in Art History.
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KICP Members: Nickolay Y. Gnedin
Simon Swordy, astrophysicist and expert on cosmic radiation, 1954-2010
The University of Chicago News Office, July 21, 2010
Simon Swordy, a leading expert on the origins of high-energy particles and gamma rays that bombard the earth from deep space, died of lymphoma on Monday at the University of Chicago Medical Center. He was 56.
Swordy, the James Franck Professor of Physics, Astronomy and Astrophysics, and the College, worked with his students to invent and build numerous detector systems for the observation of cosmic rays and gamma rays. He played a leading role in many international collaborations, including VERITAS (Very Energetic Radiation Imaging Telescope Array System). VERITAS, a collection of four large telescopes in southern Arizona that have been in operation since 2007, observes high-energy gamma rays from the sky, the most energetic "light" ever seen in astronomy.
Swordy was a founding member and leader of VERITAS. "He was a leading light in the design of VERITAS, translating a concept into a real project and gently prodding us to back off from personal agendas to practical solutions," said Trevor Weekes of the Harvard Smithsonian Observatory, a senior colleague at VERITAS. "He was largely responsible for holding the collaboration together during difficult times. In our darkest hours, when it appeared that the intransigence of the funding agencies might lead to VERITAS not going forward, it was Simon who rallied the troops and with his 'once more into the breach' philosophy got us fired up again."
Pioneering work in gamma-ray astrophysics
Along with similar installations overseas, VERITAS helped establish gamma-ray astrophysics as a new and flourishing branch of astronomy. Such gamma-ray emissions may come from the remnants of exploding stars and may help explain the mysterious source of high-energy cosmic rays - subatomic particles of matter that bombard our planet from all directions. These emissions also give insight into the processes driving the violent jets at the cores of distant galaxies, and may even provide hints on the nature of dark matter.
Swordy also led a number of observations using instrumentation on balloon or space-based platforms. When he first came to Chicago as a research associate in 1979, he was charged with the task of helping to implement a novel and very large cosmic-ray detector that had been proposed by his senior colleagues - the late Peter Meyer, Professor in Physics, and Dietrich Muller, Professor Emeritus in Physics - for flight on the space shuttle. This was an enormously large and complex project.
Affectionately called the "Chicago Egg," it remains one of the largest pieces of scientific hardware ever flown on the shuttle, and it provided the first direct observations of cosmic rays in the unexplored high-energy region, Muller recalled.
"This was a time of very hard work, full of surprises, but also full of good camaraderie resulting from Simon's wit and dry humor," Muller said. "The shuttle was still in development, and NASA imposed new requirements almost daily; the type of detector we were trying to build was entirely new and not proven before. If it had not been for Simon, with his never exhaustible supply of new ideas and unconventional solutions, 'the Egg' might not have become as successful as it was."
A number of students participated in this work, including John Grunsfeld, SM'84, PhD'88, who later became famous as a NASA astronaut and expert on the Hubble Space Telescope. However, after the space shuttle Challenger disaster in 1986, NASA turned away from projects like the Egg. High-altitude balloons once again had to be used to carry innovative instruments above the atmosphere. Swordy was a key participant in a number of such investigations, including a large instrument called RICH, which employed a new Cherenkov detector that Swordy designed. Another major collaboration investigated cosmic anti-particles, positrons and antiprotons, in a search for dark-matter candidates.
Meanwhile, the art of ballooning had advanced to the point where very long observation times, several weeks or so, became possible in circumpolar flights in Antarctica. Swordy took advantage of this development as a member of two teams building cosmic-ray detectors, CREAM and TRACER. He had developed major plans for future observations, but his death will leave these as a challenge to his successors.
Over the course of his career, Swordy authored or co-authored more than 200 scientific papers. He was admired for his ability to distill complicated ideas into simple figures or images. "He had this one figure that is so iconic that you see it now in virtually every presentation given on cosmic ray physics," said friend and colleague Scott Wakely, Assistant Professor in Physics. "He never stopped being amused seeing it translated into some other, new language."
Expertise aided undergraduate teaching
Born in Birmingham in the United Kingdom, Swordy was a student of the eminent cosmic-ray researcher Peter Fowler and received his Ph.D. at the University of Bristol in 1978. The following year he became a research associate at the Enrico Fermi Institute at UChicago. He joined the faculty of the Physics Department in 1986 and attained the rank of professor in 1997. From 2000 to 2003 he served as Master of the Physical Sciences Collegiate Division and associate dean of the Physical Sciences. In 2007, he became director of the Enrico Fermi Institute.
As Master of the Physical Sciences Collegiate Division, Swordy helped undergraduates become more interested in science. "The presence of a group of enthusiastic, young people who are primed to learn gives the University a different character than research labs at NASA or the Department of Energy," he said in 2000.
He was particularly interested in helping students outside the physical sciences appreciate the value of science. "Compared with the necessary dialogue about a book in a humanities classroom, where everyone is going to have their own interpretation, the correct answer in a scientific experiment is not only always the same, it's not up to the people who seek it. That's outside human control," he explained.
Swordy was a Fellow of the American Physical Society, was the George E. Uhlenbeck Visiting Professor at the University of Michigan in 1991 and served on numerous professional committees, including the Commission on Cosmic Rays (C4) of the International Union of Pure and Applied Physics, which he chaired from 2005-08.
In addition to his scientific career, Swordy was an accomplished craftsman and talented musician. He trained in flamenco guitar under the famous master Juan Martin and played on a semi-professional basis around Chicagoland for many years.
He was a resident of Oak Park. Survivors include his wife Josephine Ryan; children Christopher, John and Julia; brothers Stephen, Andrew and Peter, sister Marie Slater, and mother Zena Swordy.
Services will be private, but a public memorial will be held at the University in the autumn.
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KICP Members: Simon P. Swordy
Dark-matter search plunges physicists to new depths
The University of Chicago News Office, August 11, 2010
This month physicist Juan Collar and his associates are taking their attempt to unmask the secret identity of dark matter into a Canadian mine more than a mile underground.
The team is deploying a 4-kilogram bubble chamber at SNOLab, which is part of the Sudbury Neutrino Observatory in Ontario, Canada. A second 60-kilogram chamber will follow later this year. Scientists anticipate that dark matter particles will leave bubbles in their tracks when passing through the liquid in one of these chambers.
Dark matter accounts for nearly 90 percent of all matter in the universe. Although invisible to telescopes, scientists can observe the gravitational influence that dark matter exerts over galaxies. "There is a lot more mass than literally meets the eye," said Collar, Associate Professor in Physics at the University of Chicago. "When you look at the matter budget of the universe, we have a big void there that we can't explain."
Likely suspects for what constitutes dark matter include Weakly Interacting Massive Particles (WIMPS) and axions. Theorists originally proposed the existence of both these groups of subatomic particles to address issues unrelated to dark matter. "These seem to be perfect to explain all of these observations that give us this evidence for dark matter, and that makes them very appealing," Collar said.
SNOLab will be the most ambitious in a series of underground locations where Collar and his colleagues have searched for dark matter. In 2004, they established the Chicagoland Observatory for Underground Particle Physics (COUPP) at Fermi National Accelerator Laboratory.
"We started with a detector the size of a test tube and now have increased the mass by a factor of more than a thousand," said Fermilab physicist Andrew Sonnenschein. "It's exciting to see the first bubble chamber being sent off to SNOLab, because the low level of interference we can expect from the cosmic rays there will make our search for dark matter enormously more sensitive."
The COUPP collaboration consists of scientists from UChicago, Fermilab and Indiana University at South Bend. In 2008 the collaboration released its first results that established an old technology of particle physics - the bubble chamber - as a potential dark-matter detector.
COUPP extends to the city of Chicago's flood-control infrastructure, called the Tunnel and Reservoir Project. The city has granted COUPP scientists access to the tunnels, 330 feet underground, to test prototypes of their instruments. The collaboration also tested instruments in a chamber 350 feet below Fermilab, and in a sub-basement of the Laboratory for Astrophysics and Space Research on the UChicago campus.
Collar continually seeks underground venues for his research in order to screen out false signals from various natural radiation sources, including cosmic rays from deep space. "It's an interesting lifestyle," Collar said.
The troublesome underground radiation sources consist of charged particles that lose energy as they traverse through a mile or more of rock. But rock has no impact on particles that interact weakly with matter, such as WIMPS, thus the move to Sudbury.
"SNOLab is a very special, spectacular place, because the infrastructure that the Canadians have developed down there is nothing short of amazing," Collar said. Even though SNOLab sits atop a working nickel mine, conditions there are pristinely antiseptic.
"As you walk in, you have to shower to remove any trace of dust," he said. "It's a clean-room atmosphere, meaning that there's essentially no specks of dust anywhere. We have to worry about such things, sources of radiation associated with dust."
Collar also is a member of the Coherent Germanium Neutrino Technology (CoGeNT) collaboration, which operates a detector that sits nearly half a mile deep at the Soudan Underground Mine State Park in northern Minnesota. The 60-kilogram detector that Collar and colleagues will install at SNOLab later this year, meanwhile, undergoes testing in a tunnel 350 feet beneath Fermilab.
Linking the two sites is an invisible beam of neutrinos that stretches 450 miles from Fermi to Soudan. The beam is part of the Main Injector Neutrino Oscillation Search (MINOS), a particle-physics experiment that is unrelated to the search for dark matter.
The two detectors rely on entirely different techniques. CoGeNT uses a new type of germanium detector that targets the detection of light WIMPS.
"Most of us have been concentrating on intermediate-mass WIMPS for decades," Collar said. "In the last few years the theoreticians have been telling us more and more, look, under these other sets of assumptions, it could be a lighter WIMP. This device is actually the first of its kind in the sense that it's targeted specifically for light WIMPS. We're seeing interesting things with it that we don't fully understand yet."
Collar estimates that it'll take a decade or more for physicists to become completely convinced that they've seen dark-matter particles.
"It's going to take a lot of information from very many different points of view and entirely independent techniques," he said. "One day we'll figure it out."
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KICP Members: Juan I. Collar
Scientific projects: COUPP/PICO
Celestial wish list: Astronomers prioritize projects for the coming decade
ScienceNews, August 17, 2010
by Ron Cowen, ScienceNews
Astronomers tasked with compiling a priority list of U.S. astronomy projects for the next decade are seeing red, and not just because of NASA's meager science budget. A National Research Council report released August 13 ranks several telescopes observing the universe at infrared and at even longer, redder wavelengths among the highest-priority instruments to be developed between 2012 and 2021.
These include the proposed Wide-Field Infrared Survey Explorer, an estimated $1.6-billion orbiting observatory that would examine the nature of dark energy, provide broad snapshots of the infrared sky and search for habitable, Earthlike planets. The telescope, which could be launched around 2020, would complement the ultrasharp but narrow vision of the James Webb Space Telescope, the infrared successor to the Hubble Space Telescope that is set to launch around 2015.
Infrared- and longer-wavelength telescopes enable astronomers to see farther away and thus further back in time, to the first stars, black holes and galaxies, fulfilling one of the overall goals set by the National Research Council panel. Chaired by astrophysicist Roger Blandford of Stanford University, the panel marks the sixth time that astronomers have come together to map the coming decade of U.S. astrophysics research projects.
But for the first time, this decadal survey includes independent appraisals of the technical readiness of missions, their cost and a development schedule. The committee also suggested that an independent panel be appointed to reappraise priorities in astrophysics more frequently, perhaps annually, as new technologies emerge and the risks associated with specific projects become clearer over the decade.
Given the burst of new technologies for ground-based and space missions, "I think we all wished we were back in the year 2000 trying to figure out how to spend a surplus," rather than in the economically depressed era of 2010, says panel member Michael Turner of the University of Chicago. "I think we stopped whining after the first six months" and tried to emphasize international and private partnerships for funding missions, he adds.
The panel recommended that the United States continue with plans to develop the Laser Interferometer Space Antenna, an array of low-frequency detectors that would aim to detect gravitational waves - ripples in spacetime generated by distant black hole mergers and the motions of closely orbiting, dense stars within the Milky Way. The estimated $2.4 billion mission might be ready in 2025, but should go forward only if a test mission meets with success, the panel concluded.
Most of the proposed projects - both in space and on the ground - selected by the panel would not be ready until the 2020s, Turner says.
In addition, the committee highly ranked two other newly proposed space missions - the International X-ray Observatory, which would examine the hot gas around stars and galaxies, and a probe to further study the early epoch of expansion known as inflation and the cosmic microwave background, the whisper of radiation left over from the Big Bang. The mission would be a follow-up to the European Space Agency's Planck mission, launched in 2009.
One mission that failed to make the cut was the SIM Lite Astrometric Observatory, designed to survey some 40 nearby stars for Earthlike, habitable planets. Although the proposed mission has mastered all technological obstacles and could be launched relatively quickly, the panel decided that the money would be better spent on the development of missions that could survey a much larger number of stars and lay the groundwork for imaging Earthlike planets, Turner says.
Among large-scale, ground-based projects, the panel ranked highest the $465 million Large Synoptic Survey Telescope, a wide-field visible-light telescope that would observe more than half the sky every four nights, search for supernovas and probe the nature of dark energy by examining how the shapes of galaxies are distorted over cosmic time.
Blandford and his colleagues also recommended a federal contribution of 25 percent to the roughly $1.4 billion International Giant Segmented Mirror Telescope, an endeavor geared to building one of the largest visible-light and infrared telescopes ever constructed.
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KICP Members: Michael S. Turner
ASTRO 2010: Charting the Next Decade in Astronomy
Kavli Foundation, September 2, 2010
MORE THAN MOST SCIENTIFIC ENDEAVORS, exploring the Universe requires plenty of time, planning and money. Big space and ground telescopes can be decades-long projects requiring billions of dollars in funding from complex public-private and international partnerships. Competing for limited funds are smaller projects with the potential to deliver earthshaking discoveries at relatively low cost.
Leading scientists seek to guide this process every 10 years with a comprehensive survey, sponsored by the National Research Council, that sets priorities and recommends federal budget outlays for the projects deemed most promising.
The latest such document, Astro2010, draws on insights from throughout the U.S. astronomical and astrophysics community and offers a list of large, medium-sized and small projects recommended for federal funding over the next 10 years. Leading the effort was Roger Blandford, a professor of astrophysics at Stanford University and head of the Kavli Institute for Particle Astrophysics and Cosmology.
The Kavli Foundation Newsletter recently talked with Blandford and fellow survey committee member Michael Turner, director of the Kavli Institute for Cosmological Physics at the University of Chicago, about the new decadal survey, the thinking behind it and its role in the future of astronomy and astrophysics.
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KICP Members: Michael S. Turner
Changing One of Nature's Constants: If correct, new finding could upend physicists' view of universe
Science News, September 8, 2010
by Ron Cowen, Science News
The constants, they may be a-changin' - and so may some of the fundamental laws of nature, a controversial new study suggests.
Studying the pattern in which gas clouds absorb the light from distant quasars, astronomers say they have found evidence that one of nature's physical constants changes in a lopsided manner.
Along one direction the fine-structure constant, which governs the strength of the electromagnetic force, grows slightly weaker with time, while in the other direction it grows slightly stronger. The research, by John Webb of the University of New South Wales in Sydney, Australia, and his colleagues, was posted online at arXiv.org on August 25. The work is the latest in a series of controversial studies on the fine-structure constant, also known as alpha, that the researchers have conducted since 1999.
If the study is correct, it would force physicists to reconsider many of their most cherished ideas about the universe, including the notion, touted by Einstein, that the laws of physics are the same everywhere in the cosmos.
"This would be sensational if it were real, but I'm still not completely convinced that it's not simply systematic errors" in the data, comments cosmologist Max Tegmark of MIT. Craig Hogan of the University of Chicago and the Fermi National Accelerator Laboratory in Batavia, Ill., acknowledges that "it's a competent team and a thorough analysis." But because the work has such profound implications for physics and requires such a high level of precision measurements, "it needs more proof before we'll believe it."
Webb's team plans to post a more detailed paper on the analysis, "but in the meantime, the physicists' intuition is to worry about systematic errors, which by definition have not yet been understood or modeled," Hogan says. Systematic errors are errors inherent in the measuring device.
The method used to measure the fine-structure constant by Webb's team, as well as by other groups, relies on quasars, powerful beacons whose light passes through and is absorbed by the atoms in gas clouds that lie between the quasars and Earth. If the fine-structure constant changes during the light's journey, atoms in gas clouds at different distances would absorb slightly different wavelengths of light.
By comparing the light absorbed by the atoms in the gas clouds with the light absorbed by the same species of atoms on Earth, researchers can attempt to calculate the value of the fine-structure constant at different distances and times in the universe.
Previous studies by Webb and his collaborators, which used data recorded by just one telescope, at the Keck Observatory atop Hawaii's Mauna Kea, had found that the fine-structure constant remained the same as far back as about 6 billion years ago but then began to slightly weaken at earlier times.
Other teams, including Kim Griest of the University of California, San Diego, and his colleagues, have argued that the Keck spectrometer called HIRES, used by Webb's team, isn't stable enough to measure the fine-structure constant to the precision needed. The level of uncertainty "may make it difficult to use Keck HIRES data to constrain the change in the fine-structure constant," the team noted in the Jan. 1 issue of Astrophysical Journal (http://arxiv.org/abs/0904.4725).
The new work by Webb and his colleagues includes more than double their previous amount of data and combines observations from Keck in the north with the Very Large Telescope atop Cerro Paranal in Chile in the south. The locations of the two telescopes allowed the team to compare measurements taken in two different general directions. The observations include gas clouds that date further than 12 billion years back in time. Webb notes that for those six quasars observed with both Keck and the Very Large Telescope, the data are in agreement. In both directions the researchers observed from Earth, the study indicates that the fine-structure constant varied noticeably only very far back, during the first several billion years of cosmic history.
Nonetheless, the study "is as speculative as the previous claims," asserts Patrick Petitjean of the Institute of Astrophysics in Paris, whose team has looked for variations in the fine-structure constant with the Very Large Telescope as far back as about 11.5 billion years ago and found none (SN: 4/8/04, p. 301).
But cosmologist Paul Davies of Arizona State University in Tempe says the new evidence for a difference in the strength of the fine-structure constant along different directions "adds a new and potentially more significant twist, enabling us to get to grips with the effect more easily." The newfound spatial variation makes the work more convincing because it's easier to test and is on firmer footing because it's based on data from two telescopes, he adds.
If the fine-structure constant really does vary in both space and time, says Davies, it's an obvious extension that other presumed constants of nature - such as the gravitational constant that determines the strength of the gravitational force - might vary in a similar lopsided manner. "If we can accept a varying fine-structure constant, then all bets are off."
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KICP Members: Craig J. Hogan
Michael S. Turner to become American Physical Society's first astrophysicist president
The University of Chicago News Office, September 20, 2010
The University of Chicago News Office
The American Physical Society has elected the University of Chicago's Michael S. Turner vice president as of Jan. 1, 2011. The election puts Turner in line to serve later as president-elect, president, and then past-president in successive years.
Turner, the Bruce V. and Diana M. Rauner Distinguished Service Professor in Astronomy & Astrophysics and Director of the Kavli Institute for Cosmological Physics at UChicago, will become the first astrophysicist to serve as APS president.
In his candidate's statement, Turner wrote that his priority as president will be to ensure that the APS "be a strong and respected voice for the importance of basic research to the long-term health of the country and the world."
Founded in 1899, the APS is the world's leading physics organization, representing 48,000 physicists in academia, national laboratories and industry.
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KICP Members: Michael S. Turner
Revealing the Galaxy's Dark Side
U.S. News & World Report, November 4, 2010
by Ron Cowen, U.S. News & World Report
Excess of gamma rays at Milky Way's center may indicate universe's missing mass
For years, most claims that scientists had found evidence of dark matter, the ghostly material believed to account for more than 80 percent of the universe's mass, have seemed to dissolve into thin air. But a new claim of dark matter detection may have more than a dollop of cosmic credibility, scientists say
Physicists Dan Hooper of the Fermi National Accelerator Laboratory in Batavia, Ill., and the University of Chicago and Lisa Goodenough of New York University base their findings, posted October 15 at arXiv.org, on an unexplained excess of energetic gamma rays emitted from the core of the galaxy. The gamma rays were recorded over the past two years with an instrument aboard NASA's Fermi Gamma-ray Space Telescope, launched in 2008.
Dark matter, like ordinary atomic matter, is expected to concentrate at the galaxy's center. That makes the Milky Way's crowded core one of the most promising places to look for signs of the dark stuff, theorists agree. It's also one of the most complex places to search, because the core is riddled with a variety of ordinary but poorly understood sources of gamma ray emission, notes Fermi scientist Steve Ritz of the University of California, Santa Cruz.
Hooper and Goodenough analyzed gamma rays recorded by Fermi from the innermost 175 light-years of the galaxy and found a sharply rising gamma-ray signal that peaked at energies between 2 billion and 4 billion electron volts, about a billion times the energy of visible light. Hooper asserts that the location and energy of the gamma rays can't easily be explained by run-of the-mill sources, such as ultradense, rapidly spinning stars called pulsars.
"In our paper, we discussed a number of astrophysical possibilities for the origin of the signal, including a population of pulsars, cosmic ray interactions and emission from our galaxy's supermassive black hole," notes Hooper. "And in the end, no combination of any astrophysical sources could give us the signal we're seeing," he adds. "Eventually we just got fed up and concluded there doesn't seem to be a way to explain the signal except for one thing - we tried dark matter and it fit beautifully without any special bells or whistles."
Astronomers require some kind of dark or missing matter to explain why galaxies and galaxy clusters don't fly apart, and how the universe evolved from the Big Bang to its present state. The gravitational glue provided by ordinary matter isn't nearly enough to keep the universe intact, or explain how the complex structure of the cosmos came to be. The density of dark matter inferred by Hooper and Goodenough is in the right ballpark to account for the missing material, the team says.
In a paper Hooper and Goodenough posted online last year at arXiv.org, based on only a year of Fermi data, the team was more circumspect. But with the second year of data, says Hooper, "this is the most confident I have ever been that something we were seeing in an experiment was a signal of dark matter."
In addition, the mass of the proposed dark matter particles that Hooper and Goodenough infer from the analysis is consistent with findings from two direct dark matter detection experiments - COGENT, located in the Soudan mine in northern Minnesota, and DAMA, in the underground Gran Sasso National Laboratory near Rome (SN: 8/28/10, p. 22).
Hooper says he's particularly excited by the apparent match with the COGENT and DAMA experiments, results he had been independently considering for several months. "You should have seen the look on my face when those numbers came out of my computer code. I thought, 'No one is going to believe this.' ...Either this is something or this is a remarkable coincidence. And I think this is something."
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KICP Members: Daniel Hooper
Scientific projects: Fermi Gamma-ray Space Telescope (Fermi)
Michael Turner expects scientists to detect dark matter this decade
MSNBC, November 11, 2010
by Alan Boyle, MSNBC
Cosmology: Dark matter demystified
Only about 4 percent of the universe consists of the kind of matter we all know and love. Another 24 percent is made up of mysterious stuff called dark matter, and the remaining 72 percent comes in the form of even more mysterious dark energy.
The nature of dark energy is the "most profound question" in cosmology, says University of Chicago physicist Michael Turner -- and it could take many years to figure that one out. But dark matter?
"2010 is the decade of dark matter," Turner told the audience. "We're going to finish this problem off."
The breakthrough is likely to come from the Large Hadron Collider, the European particle - smasher that's just now hitting its stride. There's a chance that Fermilab's Tevatron, sited in a Chicago suburb, could make some dark-matter discoveries as well. The prospects for success are so promising that Turner calls the two particle accelerators "dark matter factories."
Smashing protons at higher and higher energies is expected to lead eventually to the creation of exotic particles under controlled circumstances -- particles that are around all the time, but are too rare and elusive to be studied in nature.
Physicists are even narrowing down the list of usual (and unusual) suspects for dark matter: Could they be axions .... Or perhaps they're neutralinos, a breed of supersymmetric particle, or "sparticle," that could be produced at the Large Hadron Collider if they exist. The common neutrino could account for some of the missing mass, but nowhere near all of it. "They're not the dark matter," Turner said. "They're just a spice put in there to make things interesting."
Just how many of such particles have to exist to explain dark matter? I can imagine drinking one down right now: Current models suggest that a one dark-matter particle is zipping through a cup of coffee at any given time.
Then there's the problem of dark energy. One possibility is that even in the absence of matter, the empty stuff of space-time is sizzling with energy at an undetectable quantum level. That sizzle may be what space probes such as the Wilkinson Microwave Anisotropy Probe have captured in measurements of the big bang's microwave afterglow.
"That is an amazing idea," Turner said. "If that's true, that means when we look at the microwave background, we're actually looking at subatomic noise, and that got blown up" by cosmic inflation to sky-filling size.
If that's what happened just after the big bang, what happened just before? "This question is now within the realm of science," Turner said. (In his latest book, "The Grand Design," British physicist Stephen Hawking agrees.)
The favored view among cosmologists is that our inflationary universe was triggered by one of those sizzling spasms in space-time. And if that's the case, theory dictates that it could happen again and again, spawning an infinite number of universes bubbling out from a higher-dimensional multiverse.
"This is an incredibly bold idea. It may even be the most important idea since Copernicus," Turner said. "But these pieces are disconnected, so how do you test it? And if you can't test it, is it science? I call this the multiverse headache. You've got this unbelievably important idea, but is it science?"
I can imagine physicists finding out, sometime in the next decade, that everything they know is wrong. And so can Turner. He'd love to find out someday whether dark energy is actually something other than the sizzle of empty space-time. If so, he said, "that means there's something weirder than the energy of nothing."
He compared the effort to understand the foundations of the universe to the efforts of proverbial blind men to understand an elephant by feeling its parts. (Is it a rope? a fan? a tree?)
"We're the blind cosmologists, feeling the universe," Turner said, "and with each piece of data we describe something. We're trying to put it all together. We might actually, in the next 10 or 15 years, put it all together. And that's absolutely amazing."
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KICP Members: Michael S. Turner
Dark matter hunt deepens at Ontario mine
CBCNews, November 15, 2010
The hunt for an unknown particle that could explain one of the great mysteries of the universe has ramped up at the deepest underground physics lab in the world.
Researchers from Canada, the U.S. and Europe have recently set up new experiments at SNOLAB, located two kilometres underground near Sudbury, Ont., in hopes of figuring out the composition of dark matter - invisible mass that makes up about a quarter of the universe.
"You know it's there from the way it affects things, by their gravitation attraction to dark matter, but you can't visibly see it," said Nigel Smith, the director of the facility, located in a spotlessly clean offshoot of the Vale Inco Creighton Mine.
University of Chicago researcher Juan Collar and his collaborators at the Chicagoland Observatory for Underground Particle Physics (COUPP) think they may have a way to make dark matter show itself.
"We expect to have possibly even the best sensitivity to dark matter particles in the world," Collar said.
The team installed and turned on the four-kilogram dark matter particle detector at SNOLAB this summer. The researchers have been remotely keeping an eye on the device, known as a bubble chamber, ever since, tweaking the system over time. They expect to reach their maximum sensitivity to dark matter particles within the next three months.
Juan Collar and his research team have been remotely keeping an eye on their dark matter detector since installing it at SNOLAB this past summer. Many physicists hypothesize dark matter is made up of a theoretical type of subatomic particle called a weakly interacting massive particle (WIMP). Unlike the matter we are familiar with, which is made up of charged particles such as protons and electrons, WIMPs don't have any electrical charge and only interact with other particles by gravity. That makes them very difficult to detect, Smith said.
"They would pass right through the Earth without noticing, generally," he said.
On the other hand, physicists believe there are so many of these particles that, occasionally, they should crash into the nucleus of an atom and create a detectable signal. The problem is, the tiny, faint signal would be drowned out by the roaring din of signals generated by cosmic radiation at the surface of the Earth.
But deep underground in SNOLAB, the level of cosmic rays is reduced 10 millionfold, Smith said. In addition, the lab space, purposely excavated starting 2004, has been painstakingly cleaned of all dust particles and is climate controlled. Researchers have to shower before entering to make sure they don't bring any new dust with them.
That makes Collar optimistic about being able to detect WIMPs passing through the underground lab and into his team's bubble chamber. The old, simple technology has been used to detect subatomic particles for decades.
The steel bubble chamber vessel at SNOLAB is filled with iodotrifluoromethane, or CF3I, which is often used as a fire extinguishing liquid. The liquid is kept at 30 to 40 degrees Celsius - superheated above its boiling point. That means anything that disturbs it could cause boiling and therefore bubble formation.
The system is designed to be disturbed by a collision involving a dark matter particle.
The researchers expect that WIMPs, the subatomic particles that make up dark matter, would leave a single bubble in the chamber, right, while other kinds of particles would leave multiple bubbles, left. "I like to compare it with the opening of a game of pool," Collar said. "Your cue ball is your WIMP, and when it strikes a material, it produces this tremendous mass of material flying in all directions."
The particle struck by the WIMP hits other particles, generating disorder and heat. That creates a bubble that grows until it is one millimetre in diameter. At that point, the bubble becomes visible to a camera that automatically detects motion and triggers a series of actions. For example, the camera will save a video of the event.
Collar believes the system has a good chance of detecting dark matter because theories suggests WIMPs should interact through one of two methods - one of which is detectable with fluorine and the other with iodine. Both iodine and fluorine are present in the bubble chamber liquid. The researchers expect that a WIMP would leave a single bubble while other kinds of particles would leave multiple bubbles.
The team plans to return in the new year with a detector that at 60 kg is 15 times bigger than the original one and is working on a 500 kg one that will be deployed in 2013.
In the meantime, SNOLAB, which is an expansion of existing facilities constructed for the Sudbury Neutrino Observatory (SNO) solar neutrino experiment, has been busy getting its facilities ready.
Excavation of the new lab space was only completed in 2007.
"We've just really finished making it clean and installing the new infrastructure there," Smith said. "This is an extremely busy and extremely exciting time for the facility."
The last section of lab space is expected to open in the spring of 2011.
More dark matter detectors
Besides COUPP, two other dark matter experiments are running at SNOLAB:
* The Picasso project, involving researchers from Canada, the U.S. and the Czech Republic, uses a similar superheated liquid but in the form of droplets dispersed through a polymer gel. Their 32 detectors were installed in November 2008.
* The DEAP/CLEAN project is a collaboration of Canadian and U.S. researchers who are watching for light scintillation caused by the interaction of WIMPs with liquid argon and neon at very low temperatures. A seven-kilogram prototype has been running since 2007, but the installation of infrastructure for full-scale 360 kg and 3,600 kg experiments are underway.
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KICP Members: Juan I. Collar
Scientific projects: COUPP/PICO
Making stars: Studies show how cosmic dust and gas shape galaxy evolution
The University of Chicago News Office, November 22, 2010
Astronomers find cosmic dust annoying when it blocks their view of the heavens, but without it the universe would be devoid of stars. Cosmic dust is the indispensable ingredient for making stars and for understanding how primordial diffuse gas clouds assemble themselves into full-blown galaxies.
"Formation of galaxies is one of the biggest remaining questions in astrophysics," said Andrey Kravtsov, associate professor in astronomy & astrophysics at the University of Chicago.
Astrophysicists are moving closer to answering that question, thanks to a combination of new observations and supercomputer simulations, including those conducted by Kravtsov and Nick Gnedin, a physicist at Fermi National Accelerator Laboratory.
Gnedin and Kravtsov published new results based on their simulations in the May 1, 2010 issue of The Astrophysical Journal, explaining why stars formed more slowly in the early history of the universe than they did much later. The paper quickly came to the attention of Robert C. Kennicutt Jr., director of the University of Cambridge's Institute of Astronomy and co-discoverer of one of the key observational findings about star formation in galaxies, known as the Kennicutt-Schmidt relation.
In the June 3, 2010 issue of Nature, Kennicutt noted that the recent spate of observations and theoretical simulations bodes well for the future of astrophysics. In their Astrophysical Journal paper, Kennicutt wrote, "Gnedin and Kravtsov take a significant step in unifying these observations and simulations, and provide a prime illustration of the recent progress in the subject as a whole."
Kennicutt's star-formation law relates the amount of gas in galaxies in a given area to the rate at which it turns into stars over the same area. The relation has been quite useful when applied to galaxies observed late in the history of the universe, but recent observations by Arthur Wolfe of the University of California, San Diego, and Hsiao-Wen Chen, assistant professor in astronomy and astrophysics at UChicago, indicate that the relation fails for galaxies observed during the first two billion years following the big bang.
Gnedin and Kravtsov's work successfully explains why. "What it shows is that at early stages of evolution, galaxies were much less efficient in converting their gas into stars," Kravtsov said.
Stellar evolution leads to increasing abundance of dust, as stars produce elements heavier than helium, including carbon, oxygen, and iron, which are key elements in dust particles.
"Early on, galaxies didn't have enough time to produce a lot of dust, and without dust it's very difficult to form these stellar nurseries," Kravtsov said. "They don't convert the gas as efficiently as galaxies today, which are already quite dusty."
The star-formation process begins when interstellar gas clouds become increasingly dense. At some point the hydrogen and helium atoms start combining to form molecules in certain cold regions of these clouds. A hydrogen molecule forms when two hydrogen atoms join. They do so inefficiently in empty space, but find each other more readily on the surface of a cosmic dust particle.
"The biggest particles of cosmic dust are like the smallest particles of sand on good beaches in Hawaii," Gnedin said.
These hydrogen molecules are fragile and easily destroyed by the intense ultraviolet light emitted from massive young stars. But in some galactic regions dark clouds, so-called because of the dust they contain, form a protective layer that protects the hydrogen molecules from the destructive light of other stars.
"I like to think about stars as being very bad parents, because they provide a bad environment for the next generation," Gnedin joked. The dust therefore provides a protective environment for stellar nurseries, Kravtsov noted.
"There is a simple connection between the presence of dust in this diffuse gas and its ability to form stars, and that's something that we modeled for the first time in these galaxy-formation simulations," Kravtsov said. "It's very plausible, but we don't know for sure that that's exactly what's happening."
The Gnedin-Kravtsov model also provides a natural explanation for why spiral galaxies predominately fill the sky today, and why small galaxies form stars slowly and inefficiently.
"We usually see very thin disks, and those types of systems are very difficult to form in galaxy-formation simulations," Kravtsov said.
That's because astrophysicists have assumed that galaxies formed gradually through a series of collisions. The problem: simulations show that when galaxies merge, they form spheroidal structures that look more elliptical than spiral.
But early in the history of the universe, cosmic gas clouds were inefficient at making stars, so they collided before star formation occurred. "Those types of mergers can create a thin disk," Kravtsov said.
As for small galaxies, their lack of dust production could account for their inefficient star formation. "All of these separate pieces of evidence that existed somehow all fell into one place," Gnedin observed. "That's what I like as a physicist because physics, in general, is an attempt to understand unifying principles behind different phenomena."
More work remains to be done, however, with input from newly arrived postdoctoral fellows at UChicago and more simulations to be performed on even more powerful supercomputers. "That's the next step," Gnedin said.
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KICP Members: Nickolay Y. Gnedin; Andrey V. Kravtsov
Lives of Music and Physics, Lovingly Bound
NYTimes.com, November 26, 2010
In the Printers Row apartment shared by Sergio Assad and Angela Olinto, two Latin Grammy awards occupy an inconspicuous spot in the office. In the kitchen, Stephen Hawking's latest opus, "The Grand Design," rests next to a MacBook containing Ms. Olinto's review of the book written for the journal Physics Today.
These objects do not usually coexist in the same part of the time-space continuum, but they say a great deal about an extraordinary household, and a family that connects three generations of arts and science.
Ms. Olinto, 49, is an internationally known astrophysicist in the department of astronomy and astrophysics at the University of Chicago. She has expertise in several fields, including high-energy cosmic rays, but she also teaches a course called "Cosmology for Poets." She spends much of her time in Chicago, except when visiting Europe or Asia for a conference, or Argentina for her semiannual visit to the massive Pierre Auger Observatory, which she helped design.
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KICP Members: Angela V. Olinto
Eckhardt Center to foster precision science
The University of Chicago News Office, December 14, 2010
The University of Chicago next September will begin construction of the William Eckhardt Research Center, an architecturally innovative building that will host a broad spectrum of 21st-century science, from investigation of the deepest cosmic mysteries to manipulations of matter on the scale of atoms and molecules. The building is named for Chicago futures trader and alumnus William Eckhardt, SM'70, in recognition of his $20 million gift in support of advanced science at the University.
Precision will characterize the science that goes on within the Eckhardt Center, which will house significant portions of the Physical Sciences Division and the University's new Institute for Molecular Engineering.
'Mr. Eckhardt's tremendous generosity will greatly promote excellent scientific discovery here for a substantial fraction of the next century."
- Robert Fefferman, dean, Physical Sciences Division
"The University has an active tradition of preeminence in the physical sciences, generating discoveries and theories that continue to change our understanding of the world," says University President Robert J. Zimmer. "The work at the Eckhardt Center will enrich that tradition and extend it to new areas of study and emerging technology."
In addition to providing new facilities for the University's globally recognized programs in astrophysics, astronomy, chemistry, and physics, the building will foster trailblazing work in molecular engineering, says University Provost Thomas Rosenbaum, the John T. Wilson Distinguished Service Professor in Physics.
"The combination of a state-of-the-art laboratory building and the University's intellectual climate of rigorous inquiry and collaboration should be a tremendous draw for scientific talent from around the world," Rosenbaum says. "This building will foster interdisciplinary studies among our current faculty and students as well as researchers who will help define the nascent field of molecular engineering."
The Institute for Molecular Engineering will explore innovative technology made possible by modern advances in nanoscale manipulation. UChicago's partner in the Institute will be Argonne National Laboratory, which brings deep expertise in nanoscale research with relevance to energy, public health, biology, homeland security, and other fields. Institute researchers likely will pursue a range of innovative technology involving the manipulation of atoms and molecules, potentially including the development of biologically inspired materials or new computing approaches.
"With this new Institute, we will expand our leadership in learning how to manipulate molecules to create practical new technologies that address critical national problems," says Argonne Director Eric Isaacs.
An international search is under way for the founding Pritzker Director of the Institute. A $10 million gift from the Pritzker Foundation supports the directorship.
Math Alum Promotes Scientific Discovery
The Eckhardt Center will occupy the site of the current Research Institutes building on the west side of Ellis Avenue between 56th and 57th Streets, across the street from the Joe and Rika Mansueto Library. Offices will begin moving out of the Research Institutes Building in early 2011 to prepare for that building's demolition and construction of the new facility. Scheduled for completion in February 2015, the $215 million project will provide 265,000 square feet of space on seven floors, including two below ground.
Eckhardt, the chairman and CEO of Eckhardt Trading Company, holds two mathematics degrees, a master's from Chicago (1970), and a bachelor's from DePaul University (1969). As a graduate student at UChicago, Eckhardt worked closely with the late Saunders Mac Lane, the Max Mason Distinguished Service Professor Emeritus in Mathematics. He drew on his background in the history of scientific methods and mathematical statistics to develop his trading program. He established Eckhardt Trading Company in 1991.
"Mr. Eckhardt's deep technical understanding of a wide range of mathematical and scientific topics has both amazed and delighted me in recent years," says Robert Fefferman, dean of the Physical Sciences Division.
"It therefore gives me great personal satisfaction to know that our newest science building will carry his name. His tremendous generosity will greatly promote excellent scientific discovery here for a substantial fraction of the next century."
The Eckhardt Center is the most recent in a series of infrastructure enhancements for the physical sciences, following the renovation of Searle Chemistry Laboratory last year and the 2006 opening of the Gordon Center for Integrative Science.
Scientific Program Shapes Architecture
The Eckhardt Center design team is working to craft the facades, materials, joinery, and structure of the building to be as finely detailed as the scientific research that will unfold within its walls, says Steve Wiesenthal, associate vice president for Facilities Services and University architect. "There's nothing extraneous. It all fits together in an understandable, logical, and beautiful way."
The project is a collaboration between HOK, an architecture firm with a prolific track record of designing science and technology buildings, and Jamie Carpenter, an artist, sculptor, and architect known for his innovative work with light and glass.
The Eckhardt Center ultimately will accommodate 24 faculty members of the Institute for Molecular Engineering along with their affiliated research programs, including graduate students, College students, and research and support staff. The Center also will provide space for more than 220 faculty members, staff, and graduate students in the Department of Astronomy & Astrophysics, the Kavli Institute for Cosmological Physics, the theoretical physics group of the Enrico Fermi Institute, and part of the James Franck Institute.
"The new building will help to build stronger institutes and departments because of the enhanced inter-connectivity and new facilities," says Stephan Meyer, Professor in Astronomy & Astrophysics. "Not only will we have modern laboratory space with good connection to faculty and research offices, the new building will provide well thought-out space for meetings, seminars, and informal collaboration. We have a lot to look forward to when the building is complete."
Light-filled Design Connected to Nature
The two basement levels will contain specially designed, vibration-dampening space for clean rooms and molecular imaging. The clean rooms will filter out the vast majority of airborne contaminants such as dust, microbes, aerosols, and vapors that would interfere with experiments.
"One of the challenges is how to make the space feel light and connected to nature, given that so much of it is below grade," Wiesenthal says.
The building's design will do so in several ways, while also paying quiet homage to the University's legacy of research on the electromagnetic spectrum that stretches back to Nobel Prize-winning physicists Albert A. Michelson, Robert Millikan, and Arthur Holly Compton and reaches into the future with the Giant Magellan Telescope and other instruments. The design will influence how light plays on the building's facades and also will draw light deep inside to illuminate laboratories and hallways.
Perforated metal fins connected to serrated glass facades on the east and west will capture and reflect light horizontally into the building throughout the day. Further, a louvered glass ceiling over the north lobby will serve as a light well, capturing and driving light vertically into the building.
An atrium will span the upper three floors of the building, forming an axis that will allow light to cross from east to west. The atrium also spatially interconnects the top three floors and various units of the Physical Sciences Division that will reside there.
"Another way that the building speaks to the interests and program of the research within is about our place in the world and an emphasis on environmental sustainability," Wiesenthal says. "This building will consume less energy than a typical laboratory building of this size."
In fact, the University will apply for LEED (Leadership in Energy and Design) Gold certification from the U.S. Green Building Council for the Eckhardt Center.
Both chilled beams and heat recovery systems will save an estimated $240,000 annually in energy costs, says project manager John Ekholm. A chilled beam is essentially a chilled coil that cools spaces without moving air. "It's like a radiator except you're using chilled water rather than hot water. It allows you to reduce fan sizes and energy consumption to cool the building," Ekholm says.
Bringing Faculty Under One Roof
A cafe will occupy part of the ground floor. Dispersed throughout the floor plan are areas for formal and informal interactions, a feature especially important for fostering collaboration among the experimentalists and theoreticians in the physical sciences. "Their productivity is much greater when they interact. Things get done that wouldn't get done otherwise," Fefferman says.
The Astronomy & Astrophysics faculty currently work out of four campus buildings. The Eckhardt Center will bring the faculty under one roof.
The history of the department began in the 1890s, when George Ellery Hale founded the department and launched a continual quest to build the world's largest telescopes. The department renewed this quest last summer when it became a founding member of the effort to build the Giant Magellan Telescope.
The Kavli Institute was founded in 2001 to study astrophysical phenomena still unexplained by the known laws of physics. Kavli scientists use the South Pole Telescope and other tools to probe the mysteries of the universe.
The Fermi and Franck institutes were founded in 1945 in recognition of the wealth of intellectual talent that had assembled at Chicago to work on the Manhattan Project. The institutes continued the dialogue between pure science and technology that the Manhattan Project had initiated, and helped ease the barriers between traditional scientific disciplines.
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