Matters of note from around Johns Hopkins
It's getting even harder to get into Johns Hopkins as a
Nigel Sandor / Illustration Works / Getty Images
This year the university attracted and rejected more
qualified applicants than ever before. Some 13,900 students
— 23 percent more than last year's record number
— applied in 2006. Admission was offered only to
3,711 students, or 27 percent of those who applied. By
comparison, Hopkins' admittance rate last year was 35
"It was easily the toughest, most competitive year that Hopkins has seen," says John Birney, associate director of undergraduate admissions.
What was especially surprising to John Latting, director of undergraduate admissions, was the number of students who applied. "The growth in interest in coming to Hopkins was just huge this year," he says, attributing the increase to general trends in higher education and to factors more specific to Hopkins.
First, there's been a gradual increase every year in the number of students graduating from high school — an echo from the baby boom. Second, more people want to apply to private, elite universities. "Universities with name recognition, those that are considered a trusted brand, are attracting more applicants," Latting says. "There's a sense that the world is more competitive and people are more concerned about the reputation of the school they are attending and how it will help in their careers." In addition, urban universities are hot right now. "There's been a renewed interest in going to college in the city," he explains.
The applicants have more impressive credentials, too. Over the last five years the applicant pool at Hopkins has gotten stronger as well as larger. "Students are working harder now than they ever have before," he says. "Everyone is taking AP classes, taking college courses for credit."
Other top undergraduate colleges and universities nationally experienced record low admission rates in 2006. Yale University set an Ivy League record by accepting only 8.6 percent of its 21,099 applicants. Stanford University accepted 11 percent. And the University of Pennsylvania admitted only 17.7 percent of its applicants.
Hopkins' 23 percent increase in applicants was one of the largest spikes among the school's peer institutions. Applications to Swarthmore College rose 19 percent from last year and Cornell University's applications rose 15 percent.
Latting credits Hopkins' dedication to improving the undergraduate experience as part of the reason for the increase in applications for Arts and Sciences and Engineering. But new student housing in Charles Village and changes to the campus food service aren't the only reasons more people want to attend Hopkins than ever before. "I think we're doing a very good job telling people about Hopkins and about the city of Baltimore," Latting says. "There are more compelling stories about this place than we can tell." — Maria Blackburn
Johns Hopkins' schools of Medicine, Nursing, and Public
Health are joining forces to fight HIV/AIDS, malaria,
tuberculosis, hepatitis, flu, and other international
Thomas Quinn, director of the Center for Global Health,
with deans Martha Hill, Michael Klag, and Edward
Photo by Will Kirk
On May 12, university President William R. Brody announced
the launch of the
Center for Global Health, aimed at
encouraging and assisting collaboration among the schools'
experts, many of whom are already working to fight disease
in countries around the world.
"The most effective way to strengthen our efforts is to find smart ways to combine and focus them," Brody said.
Led by Thomas Quinn, a professor of international health, epidemiology, and molecular biology and immunology at the Bloomberg School and professor of medicine at the School of Medicine, the new center will work with nearly two dozen existing programs that operate more than 400 projects globally. It will also secure funding for new programs, recruit faculty with an interest in global health issues, and create opportunities for students to work with mentors in the field.
The center will be governed jointly by Bloomberg School Dean Michael Klag, Medicine Dean Edward D. Miller, and Nursing Dean Martha N. Hill. More than 100 faculty members will work closely with the center, though nearly all international health faculty will be affiliated, and the center initially will be jointly funded by the three schools.
"While the changes are daunting," said Miller, "I have no doubt that this center will play a major role in improving the health and lives of people throughout the world." — Catherine Pierre
The Johns Hopkins community is mourning the loss of senior Austin Rottier, a computer science major from Ellicott City. He was found dead in his off-campus apartment on March 29,a victim of suicide.
Rottier was a participant in the ROTC program at Hopkins and a member of the Hopkins-Loyola chapter of the Pershing Rifles, a national honor society and fraternal organization. He enjoyed kayaking and mountain climbing, and at his memorial service friends and family shared stories about his loyalty, bravery, and adventurousness.
"Austin was one of the funniest and most politically aware people you could meet," Robert Velasco, a senior and former lab partner of Rottier's, recalled at the memorial service. "I wish the best for all those who care for Austin and that they'll get through this difficult time. My guess is he's wishing the same thing, too." — MB
Though women sometimes complain about their sexual lot in
life, in many ways, it's good to be a girl. Girls in the
United States have a 20 percent lower mortality rate than
boys, do better in school, and are more likely to go to
college. And it turns out that women — because of
their two X chromosomes — are less susceptible than
men to some diseases. After decades of research on X
chromosome-linked diseases, and with a new book on the
subject coming out this fall,
Johns Hopkins School of Medicine researcher Barbara
Migeon is getting the word out
to doctors that X chromosomes are the key to many sex
differences in health. "The response from my physician
colleagues has been tremendous," Migeon says. "They're both
surprised and interested."
Most doctors, Migeon says, attribute "women's diseases" to
female reproductive organs and hormones. But many common
diseases that have little to do with reproductive organs
— like meningitis or heart disease — are
expressed differently in men and women. When studying the
sex differences in many diseases, Migeon says, "many
doctors really haven't made the leap to a genetic
Every one of the trillions of cells in the body holds the genetic instructions for life: chromosomes. During the development of an embryo, two kinds of chromosomes — called X and Y — determine sex. Women inherit one X chromosome from each parent; men get a Y from their father and an X from their mother. A few decades ago, it was believed the sex chromosomes did little besides, well, determine the sex — as they harbor the genes responsible for sex organs, and thus the production of hormones. Migeon says the mere 75 genes located only on the Y chromosome contribute to male testicular differentiation and function and little else. But the X chromosome, home to more than 1,000 genes, is much more important. "The X chromosome is really very eclectic," Migeon explains, coding for the proteins involved in everything from immunity and infection to blood clotting, muscular development, and color vision. Though females have two copies of each X chromosome-linked gene, only one copy can be expressed in each cell. So once developed, a woman's body is made up of a mixture of cells, some expressing the X-linked genes from her father, and some expressing the X-linked genes from her mother — she is what geneticists call a "mosaic."
This mosaicism, Migeon explains, often gives women
protection from genetic disease. When a gene on the lone X
chromosome is mutated in men, it doesn't get expressed
normally, and this often leads to disease. In contrast, if
a woman has a mutation of the same gene, she is likely to
have a normal copy on the other X chromosome. "Because the
two populations of cells — some from the mother's X
and some from the father's — interact with one
another," Migeon explains, women get the benefits of the
two. "I think it's just great," she says, "because our
[women's] cells can collaborate. One cell population can
help the other one along."
|Many common diseases that have little to do with reproductive organs are expressed differently in men and women. But, Migeon says, "many doctors really haven't made the leap to a genetic component."||
The benefits, though, are not always so obvious. Rett
syndrome — a progressive neurological disorder that
causes seizures, mental retardation, and loss of muscle
tone — affects mostly girls, and thus has been
thought to be a female-only disease. "But we're finding out
that it does in fact occur in males," Migeon says. "It's
just that males with the same mutation have a more severe
disease, or die during infancy, or have different
manifestations." That is, a girl's mosaic nature actually
"protects" her from dying of the Rett mutation, so that the
only ones to live to show symptoms of the classic disease
are girls. Autoimmune disorders — which result when
the body attacks its own tissues — also may be linked
to a woman's mosaic nature; if the ratio of a woman's cells
from her mother's X and her father's X is drastically
skewed, then her immune system might not recognize the
smaller proportion of cells as its own.
When Migeon spoke of her X chromosome research last November, at the Hopkins Medical School's Gala Celebration of 100+ women professors, she mentioned that most physicians studying the cause of sex differences in health don't think about sex chromosomes. One double-X in the audience, editor of the Journal of the American Medical Association Cathy DeAngelis, later asked Migeon to write a commentary for the journal. (DeAngelis was formerly vice dean for academic affairs and faculty at the School of Medicine.) Migeon's piece, published in the March 22/29 issue, has already opened many doctors' eyes. "When they get discrepancies between the sexes," Migeon says, "now they'll think about it. They'll ask, Do the genes on the X-chromosome have some role in this?"
Migeon, who came to Hopkins in 1956, became the founding director of the PhD training program in human genetics and molecular biology in 1979. She is a professor in the Pediatrics and Biology departments and a member of the McKusick-Nathans Institute of Genetic Medicine. Her new book, Females Are Mosaics: X-Inactivation and Sex Differences in Disease, will be published by Oxford University Press this fall. — Virginia Hughes, A&S ¹06 (MA)
For author Ann Finkbeiner, it was all about questions that
no one would answer. The questions concerned an enigmatic
group of elite physicists called Jason. Once a year,
beginning in 1960, they gathered in the summer to study
problems of interest to the U.S. Department of Defense and
other government agencies. The Jasons, as they referred to
themselves, were not exactly a secret society, but they
were discreet, and they usually worked on secret projects
that required security clearances. When she tracked a few
of them down, they were not keen on answering her
questions. "You don't get a question answered, you keep
asking, right?" Finkbeiner says. She eventually got enough
answers to write The Jasons: The Secret History of
Science's Postwar Elite (Viking 2006).
Photo by Will Kirk
Finkbeiner, who directs the Johns Hopkins
graduate science writing program, first heard of Jason in
1990, when her husband, Hopkins
retired) James C. Walker, took her to a department dinner
to hear Freeman Dyson, a physicist from the Institute for
Advanced Study. Dyson told several stories, including one
about a night he spent on the Mexican border working on a
system for detecting drug smugglers. "Why would a physicist
be looking for drugs?" she asked Dyson. Doing a Jason
study, he replied.
A Jason study?
As a science writer, Finkbeiner began casting about for more details about the group. A few Jasons, like Dyson and John Archibald Wheeler, the physicist who coined the term "black hole" (and received his PhD from Hopkins in 1933), reluctantly agreed to interviews, and eventually she gathered enough details to write an article in the early 1990s for the periodical Science. In 2000, she proposed a book on the subject.
The Jason management told her they did not see any benefit from cooperating with her research. But, she notes, Jason operates like a faculty, not a corporation. Each Jason could decide individually whether or not to be interviewed. In the end she convinced 36 of the about 75 current and former Jasons to talk to her. What emerged is the fascinating story of some of the best scientists in the United States — 43 are members of the National Academy of Sciences and 11 have won Nobels — most but not all physicists, who for 45 years have studied defense-related problems. They have worked on means of detecting nuclear tests, electronic sensors for monitoring troop and supply movements in war zones, and atmospheric turbulence. The latter study led to the adaptive optics that now enable terrestrial telescopes to produce ultra-sharp images of distant celestial objects. Lately, Jason has turned its attention to security threats like bioterrorism.
Jason's future, Finkbeiner writes, is uncertain. The government still needs this sort of independent scientific think tank, she says, and seems to recognize that. But when Jason started in the 1960s, scientists could take six weeks out of their summers, move their wives and children to wherever the Jasons convened (usually La Jolla, California), and devote themselves to the group's work. Jason depended on that concentrated period of collaboration and face-to-face give-and-take to be effective. Now, both scientists and spouses — there are a few female Jasons now — frequently find it impossible to put the rest of their lives on hold for half the summer. The Jasons have tried to figure out a new way to preserve their internal cohesion and collegial method, without much success. Their chronicler hopes they find it. Says Finkbeiner, "I'm glad they're out there. I hope they stay together. They're the government's only independent, fact-based, really smart group of scientists who do their own work. Plus, they're just an interesting thing to have in the world." — Dale Keiger
The history of nursing education at Johns Hopkins isn't always a happy one. Depending on the decade you revisit, you'll find stories of thwarted ambitions, broken promises, and painful uncertainty. That's just fine with Mame Warren, whose new book, Our Shared Legacy: Nursing Education at Johns Hopkins, 1889-2006, is just out from Johns Hopkins University Press (www.press.jhu.edu).
"It's engaging, the story of Hopkins nursing," says Warren.
"I knew just enough to be really interested [before taking
the book on]. And I wasn't disappointed."
Student nurses at the Harriet Lane Home for
Photo courtesy The Alan Mason Chesney Medical Archives of The Johns Hopkins Medical Institutions
From the founding of the Johns Hopkins Hospital Training School for Nurses in 1889, leaders envisioned a training program aligned with the university. But the dream of being a university-based school took decades to be realized — for reasons that Warren frankly explores in her 320-page history, which draws heavily on research by Fran Keen, Nurs '70, and Linda Sabin, Nurs '67. The book was produced in association with the Johns Hopkins Nurses' Alumni Association.
The hospital-based school was closed in 1973, and a short-lived School of Health Services was launched and shut down (1975-78) during a turbulent decade that ultimately laid the groundwork for the existing Johns Hopkins University School of Nursing, launched in 1984.
In the book's final two chapters, Warren teases out a variety of perspectives through interviews she conducted with more than 40 nursing alumni, faculty, administrators, and university leaders. "These were the people who lived through the creation of the present university school. I let them tell the story in their own words," she says. "It gives us a happy ending, which, goodness knows, we wouldn't have had otherwise." — Sue DePasquale
Modern body armor has saved the lives of many soldiers
wounded by explosions. But that armor does not shield
extremities. Hundreds of U.S. troops have returned from
Iraq missing limbs that were blown off or so grievously
damaged they had to be amputated. Responding to the need
for vastly improved prosthetic arms, the Johns Hopkins
Laboratory has taken on a four-year project
to develop an arm that will look, feel, and perform much
more like a natural limb.
|An artist's rendering of the next generation of prosthetic arm||
The effort, named Revolutionizing Prosthetics 2009, is
funded by the Defense Advanced Research Projects Agency
(DARPA), which last February granted APL $30.4 million for
the first phase of the project. APL has assembled an
interdisciplinary team involving scientists, engineers, and
physicians from its own labs, the
School of Medicine, the
Whiting School of Engineering, and the
Bloomberg School of
Public Health. Private contractors in the United States
and Europe, more than 10 other universities, and various
government agencies also are part of the project. Stuart D.
Harshbarger of APL directs the effort.
The human arm is an extraordinarily sophisticated piece of natural engineering. To replicate its range of motion, sensory feedback, and ability to perform delicate tasks, says Harshbarger, will require much more than advanced engineering.
"The biggest challenge is to get access to the neural signals we use to control a natural arm, to then control the mechanical limb," he says. "The mechanical limb is a challenge in itself, but it's more of an engineering challenge, something you can apply good engineering talent to with a high likelihood of a successful outcome." Project participants are at work on the neural control problems, plus developing new power, actuation, and control technologies.
They are also working on advanced sensors for better feedback — the sense of touch, for example. "You realize how difficult it is to do the sort of tactile manipulation of objects that we take for granted if you don't have that feedback," Harshbarger says. "Getting that back for the patient is one of the big challenges."
The researchers want to vastly improve the variety and subtlety of motion achievable by a prosthetic arm. Current technology allows about three degrees of movement; raising the arm to be parallel to the ground, for example. Harshbarger's team wants to achieve more like 22 degrees of motion.
"I had a pretty strong appreciation for the human arm going in," Harshbarger says. "It's one of the most delicate systems that I've ever studied in depth." He cites the hand, for example: It has remarkable dexterity, is so sensitive that people can read Braille, but also has an extraordinary strength of grip. "Trying to replicate that overall performance in a mechanical device is really quite a challenge."
DARPA requires the team to deliver by November 2007 a system integration plan that demonstrates a technical understanding of how to create a new arm that can enter clinical trials by November 2009. Harshbarger says that by the end of 2006 he wants to complete a first prototype to test on patients. A year later the team wants to deliver a second prototype that will mechanically comply with DARPA's requirements.
"We're optimistic that we can do what we signed up to do," says Harshbarger. — DK
During Germany's Weimar Republic, avant-garde cultural arts flourished at the hands of left-leaning experimental artists. Historians usually date the Weimar period as 1919 to 1933, but according to historian Peter Jelavich, the death of Weimar culture actually occurred in 1931 — two years before Adolf Hitler came to power.
That may sound like a small difference, but it's an
important distinction. "Hitler's appointment as chancellor
in 1933 was by no means certain in 1931," says Jelavich, a
Krieger School professor of
author of the
recently published book Berlin Alexanderplatz: Radio,
Film, and the Death of Weimar Culture (University of
Press). According to Jelavich, the Nazis didn't end Weimar
culture — fear of the Nazis did. "The anticipation of
a possible radical right-wing regime led to the sacrifice
of specific works, and soon an entire culture, that
embodied the values of the republic," he says. "Simply out
of fear of a right-wing takeover, a whole culture shut
Alexanderplatz, circa 1900 — the setting, two
decades later, of what Hopkins historian Peter Jelavich
calls "arguably the most important German novel of the 20th
Photo courtesy of
University of California Press
To make his case, Jelavich focuses in on Alfred Do¨blin's Berlin Alexanderplatz, an innovative modernist novel published in 1929 that was turned into a radio play in 1930 and a film in 1931. "This is arguably the most important German novel of the 20th century," says Jelavich, who compares the book to James Joyce's Ulysses and John Dos Passos' Manhattan Transfer.
Do¨blin was a Jewish physician who, after serving in World War I, opened a practice caring for low income patients in the neighborhood east of Alexanderplatz. A prolific writer who was actively involved in Berlin's literary avant-garde, Do¨blin abhorred the German bourgeoisie and aimed to use his writing to close the divide between what he considered pretentious literature and the common man.
Berlin Alexanderplatz tells the story of Franz Biberkopf, a man who emerges into Alexanderplatz after four years in prison for killing his girlfriend and who struggles to control his life. Do¨blin uses an innovative fractured narrative, snippets from various media, and the Berlin dialect to evoke the chaos and confusion of his main character. But the novel isn't just about Biberkopf; it's about 1920s Berlin. Lines from folk songs and Bible verses, statistics, tales of scandal, scenes of slaughterhouses, accidents, advertisements, and pamphlets handed out in the street jumble together and paint Biberkopf as a man caught between respectability and criminality, leftism and Nazi jargon, heterosexuality and bisexuality.
As a novel it is challenging, somewhat controversial material, both in style and in substance. But Berlin Alexanderplatz changed greatly when it was adapted for radio and film.
During the winter of 1930 and the spring of 1931, verbal and physical attacks by Nazis led managers of publicly owned radio stations and producers at major, privately owned film studios to depoliticize their programs and films. Because of this "fear psychosis," the political oversight committee at the Berlin radio station balked at airing a work by Do¨blin, a well-known leftist Jewish author. The radio play of Berlin Alexanderplatz, scheduled for broadcast on September 30, 1930, was canceled because of fears of Nazi protests.
By the time the novel was made into a sound film the following year, Do¨blin and the studio, responding to fears over the film's reception, changed it so much that it bore little resemblance to the original piece of literature, says Jelavich, who examined radio and film scripts as well as archival materials for the book. Gone from the film version was any talk of sexuality, politics, or religion. The fractured narrative also gets tossed out in favor of a traditional narrative.
The end result? "It's a simple crime story," he says.
Jelavich refers to what happened to Berlin Alexanderplatz as a "cautionary tale." "What surprises me most is the speed with which the people who should have defended the republic just gave up the fight," he says. "I don't think there was anything inevitable about Hitler." — MB
Victims of Alzheimer's disease suffer loss of neurons and
the formation of amyloid plaques in their brains. The onset
of the disease, however, is an insidious loss of memory
function that can begin years before any structural damage
to the neural system. The agency of this loss is not
understood. But new research by a team that included
professor Michela Gallagher and postdoc Ming Teng Koh, both
from the Krieger School's
Brain Sciences, has found a protein that causes memory
in laboratory rodents prior to the formation of plaques or
the loss of neurons. If this protein causes the same loss
in humans, it could be a target for more effective
diagnosis and treatment of Alzheimer's.
Photo by Will Kirk
As part of a group led by Karen Ashe of the University of
Minnesota Medical School, Gallagher (who also chairs the
Hopkins department) and Koh performed experiments on mice
specially bred to develop cognitive deficits similar to
those experienced by human Alzheimer's patients. The mice,
designated type Tg2576, begin to lose memory, but not
neurons, when they are about 6 months old. The researchers
had evidence that a protein designated amyloid-beta was
responsible, but no one ever had been able to pinpoint a
specific form of the protein, whose appearance in the brain
coincided with onset of memory loss. So Ashe and her
co-authors began a hunt for the right amyloid-beta.
What they found in Tg2576 mice was the presence of an assembly, an amyloid-beta protein molecule composed of units linked in a chain and known as an oligomer. The scientists developed a method for extracting this protein assembly from the impaired mice, then they purified it and injected it into normal laboratory rats. Next, Gallagher and Koh conducted behavioral tests, placing the normal rats in a water maze that required them to remember the location of a platform hidden just beneath the water's surface. Unaffected rats will recall the platform's location, and in repeated tests at a later time they will swim directly to it and climb out of the water. When rats were tested in this maze after receiving the amyloid-beta oligomer, they swam aimlessly, unable to remember the location of the platform. This loss of spatial memory is significant, Gallagher says, because of how it corresponds to humans: "Spatial memory in rodents uses the same brain circuitry that is generally used for episodic memory in humans, like being able to recall where you had dinner last night or some event that happened last month."
In a letter announcing the results, published recently in the journal Nature, the authors propose that the protein assembly impairs memory independent of any plaque formation or loss of neurons, though no one yet knows how it affects this impairment. If the proposal proves correct, the amyloid-beta assembly could be used as a biomarker to detect the disease, and pharmaceutical researchers could target it with new drugs that might abort Alzheimer's disease before it irreversibly damages the brain. — DK
J. Michael Collaco has long been fascinated by the belching steam locomotives and dusty, packed commuter trains he used to see and hear while visiting his grandparents in India as a child. Six years ago, he even started collecting books on the subject, amassing more than 30 about pre-1945 trains in Bombay, with titles like Railways of the Raj and The Great Railway Bazaar.
Still, Collaco, now a student in the
School of Professional
Studies in Business and Education's medical management
MBA program, never really considered himself a
At right, J. Michael Collaco's collection focuses on
pre- 1945 trains in Bombay; below, Kevin Clark's is an
inspiration to his work in musical
Both photos by Will Kirk
"They were always just more of a personal interest," he
That changed when he took home one of the top prizes in this year's Friends of the Library Student Book Collecting Contest. A total of 49 undergraduate and graduate students from seven out of Johns Hopkins University's eight divisions participated in the contest by submitting an essay and a bibliography. They competed for cash prizes ranging from $250 to $1,000. Collaco, one of six winners, won first place in the graduate division.
The book collecting contest dates back to 1993 and was held biannually until 2000. When Winston Tabb came to Hopkins as dean of the Sheridan Libraries in 2002, he was eager to start up the contest again, but had doubts that many students would enter. At an awards ceremony recognizing contest winners, he said that he was thrilled by how numerous and diverse the entries were.
"We are so excited that we have the opportunity to recognize young people who have seen the power of books," says Tabb, who judged the contest along with Richard A. Macksey, A&S '54, '57 (PhD), co-founder of Hopkins' Humanities Center and professor of history of science, medicine, and technology, and two members of the Friends of the Libraries.
Entries ranged from collections of antique grammar and children's fantasy books to books that examine the effects of war on warriors. "One of the things that struck me was that these were all books that were read," says Macksey, the owner of an extraordinary collection himself. "It's possible to collect books without reading them, but that wasn't the case here."
Kevin Clark, a fourth-year double-degree student at Peabody and the Krieger School, took home the first prize for undergraduates with his "Composer's Library: Volumes of Inspiration." Clark collects books that contain text he wants to set to music, including everything from The Poems of Catullus and The Portable Dante to poems by e. e. cummings and Marianne Moore. "I have a particularly strange view of book collecting — I get to cross genres more than other people," says Clark, who plans to use his award to finance a trip to a composition festival this summer.
SPSBE's Collaco is donating his $1,000 to the Johns Hopkins Children's Center and the Mount Washington Pediatric Hospital, where he is a post-doctoral student in pediatric pulmonology. He would like the money to be used to purchase children's books for the two hospitals. "There were always books all over the place when I was growing up," he says. "I want to encourage reading and book collecting in kids." — MB
When cosmologists think about the universe's early days,
they are not talking about the first Monday or Tuesday, but
the first, most minute fraction of a second. Astonishing
events took place in the initial trillionth of a second,
and new research led by Johns Hopkins' Charles L. Bennett
has produced evidence in support of a 25-year-old theory
that would explain what powered those events.
WMAP looks back to about 400 million years after the big
bang, when the first stars in the universe turn
NASA / WMAP Science Team
Because the prevailing theory of the origins of the
universe is called the Big Bang theory, many people assume
that the universe began with an explosion. Bennett, a
Krieger School professor of
pains to point out that this is not true. "The theory only
says that the universe began much more hot and dense than
it is now, and that it has been expanding and cooling," he
says. "The theory never says anything about a big bang,
only that as you look back in time, the universe gets more
and more dense and hotter and hotter and hotter. The
obvious question is, What happened at the beginning? How
did the expansion and cooling get going?"
The Big Bang theory accounts for some observable phenomena, but not all. For example, it doesn't explain why the universe is so extraordinarily uniform on the largest scales, or what led to the formation of smaller-scale structures like galaxies. To better describe the expansion and composition of the cosmos, cosmologists in the early 1980s proposed the inflation theory, which posits an immense energy that, 13.7 billion years ago, drove the near-instantaneous expansion of the universe from submicroscopic to universal dimensions.
One remnant of the universe's expansion is what scientists call cosmic microwave background: radiation left over as a sort of afterglow. Inflation theory predicts a pattern of fluctuations in the temperature of various spots in this afterglow. To measure these fluctuations, NASA launched the Wilkinson Microwave Anisotropy Probe (WMAP) in 2001, with Bennett as principal investigator. From a stable orbit 1 million miles from the Earth, WMAP can measure fluctuations that amount to less than a millionth of a degree Fahrenheit.
In 2003, WMAP produced what was then the most detailed image of background temperature fluctuations ever achieved, answering fundamental questions about the age, composition, and development of the universe. The new work by Bennett's team measured signals less than a hundredth of the strength of the 2003 observations; they are the weakest cosmological signals ever detected, and they support predictions made by the inflation theory.
"We're starting to pile up evidence upon evidence," Bennett says. "It's starting to become a much stronger case." While WMAP's findings add considerable support for inflation theory, they have not confirmed it. The results from the latest observations are also consistent with a rival theory known as the cyclic universe theory, which proposes a series of big bangs, each followed by an eventual collapse of the universe, which some scientists call the Big Crunch. Says Bennett, "One key difference between those two theories is that inflation predicts gravitational waves, which the cyclic theory does not." Bennett's team plans to continue to look for these waves with WMAP, but the spacecraft may not be able to detect them. "I think we're going to need a new satellite," he says. "We're working on designing it." — DK
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