I know you like things related to the universe... long read, but I think you'll enjoy it...
ksquared
THE SEEKERS: GENESIS
Part 4 of 5: If the universe is flat, the best way to show how it happened is to take its temperature.m
Wednesday, December 04, 2002 BY AMY ELLIS NUTT Star-Ledger Staff
GREENBELT, Md. -- We are acquainted with the universe through science, but we are intimate with it through ancestry. Mingling in our blood is the breath of creation -- hydrogen molecules born billions of years ago in the nuclear furnace that marked the beginning of time. In some fundamental way, our fascination with the cosmos is nothing more than an attempt to understand our own celestial roots.
For more than two decades, physicist Alan Guth has been fine- tuning his answer to the ultimate cosmic question: How did it all begin?
Late on a winter night in 1979, he believed he'd figured it out when he looked down at the pages of equations he'd just scribbled. Embedded in all those numbers was a theory about the origin and shaping of the universe that would shake the foundations of cosmology.
The theory -- called "inflation" -- explained how in the first fraction of a second of the big bang, space rolled out like a cosmic carpet, flat and infinitely large. And just as the weave of a carpet captures dust, the fabric of space captured bits of matter in its seams until billions of years later there were stars, planets and galaxies.
For the past 15 years, radio astronomer Charles Bennett has been working on experiments that could prove or disprove Guth's theory. Bennett's laboratory tool? The ancient light of the big bang.
Next month, Bennett and his colleagues at NASA's Goddard Space Flight Center here at Greenbelt will announce new findings based on years of studying that light, which is called the cosmic microwave background radiation. The results should help confirm not only the shape of the universe but the origin of all matter.
If Bennett's findings bear out what the preliminary evidence suggests, Guth's concept soon could be elevated to a perch in the pantheon of scientific ideas alongside Einstein's theories of relativity.
The power of Guth's proposal lies in its ability to explain not only our most distant past but our present as well -- how a universe that was infinitely small is now infinitely large.
Bennett and Guth, both New Jersey natives, are peering back nearly to the beginning of time, close to the genesis moment, seeking answers to the why and how of creation. For thousands of years, those were questions only philosophers dared to ask.
THE CARPET UNROLLS
A deep-throated murmur leaks out of a brightly lit computer room at the Goddard Space Flight Center and escapes down a labyrinth of beige corridors. The hum, it turns out, is not coming from the bank of computers inside the room, but from a nest of pulsing, 4-inch-wide silicon coils that are keeping the computers cool. Without the air conditioning, the computers' 170 processors, which are analyzing information about the heat of the universe from a probe nearly a million miles from Earth, would turn to toast.
Charles Bennett checks the thermometer. It reads a steady 73 degrees. The 46-year-old astronomer smiles. The principal investigator of NASA's Microwave Anisotropy Probe, Bennett helped build the spacecraft that today is taking the temperature of the universe as it was when it began.
Most scientists believe the universe came into existence in an event known as the big bang. Contrary to popular belief, big-bang theory is not about an initial explosion of matter. There was no primordial firecracker that exploded in the middle of nothing.
There was, rather, a ferocious spasm of infinitely dense, immeasurably hot subatomic particles. This spasm created the fabric of space, which has been unrolling for 14 billion years, carrying along with it the remnants of light and heat from the beginning of time.
Of the three most fundamental methods of measurement -- time, distance and temperature -- it is temperature, which measures the motion of particles that make up the universe, that has the most to tell about how the universe was created and the shape it took. Temperature helped determine the contents of our solar system, the size of our planet and the conditions for human life.
Before there were stars, even before there was light, the universe had a temperature. Minuscule dips in the temperature of the universe's background radiation are seen as evidence of slightly denser points in space where matter began to coalesce into what would become the planets and stars.
THE SCREAM
The universe's first light -- the background radiation -- has been called the afterglow of creation, and it is streaming all around us, invisibly sifting though our hair, mingling with our breath, even settling in our lungs. Most of the time we are completely unaware of its presence, although 1 percent of the "snow" or static picked up by a TV antenna when no program is being broadcast is big-bang radiation.
"The light comes from a time before there were any stars or galaxies, any carbon or oxygen," says Bennett. "The tiny temperature fluctuations (anisotropies) that we're measuring in the universe hold the key to its shape."
Because light travels at a finite speed (186,282 miles per second), it takes time for it to reach us. The farther away an object, the longer it takes. The light from the sun, for example, takes eight minutes to reach the Earth; the light from the Andromeda Galaxy, 2 million years. Writer Edgar Allan Poe, an amateur astronomer, was the first to suggest some stars were so distant their light had not yet reached us.
The deeper we look into space, therefore, the deeper we are looking into our past. What astronomers such as Bennett are hoping to find there is a snapshot of the infant universe and evidence of its first features -- the tiny bits of subatomic matter that one day would become the stars, planets and galaxies.
When the universe was 100 million years old, the first stars appeared. At 1 billion years old, the first galaxies. Galaxies gathered into clusters. Clusters congregated into superclusters. The universe cooled to minus 475 degrees, and the primal scream of creation became a sigh.
For decades scientists sifted through the background radiation like cosmic archeologists trying to dig up an artifact -- some piece of evidence that their theories about the big bang and the beginning of time weren't just numbers and equations, but had substance and reality.
If a detailed picture of the universe's background radiation revealed subtle variations in temperature, that would be evidence that the landscape of the early universe had tiny hills and valleys where matter would gather, just as Guth's theory predicted.
Those were the issues facing Bennett when he worked on the Cosmic Background Explorer from 1984 to 1996. COBE was the most ambitious effort to measure the background radiation since its discovery in 1965.
Bennett loves sweating the small stuff. In fact, he was born for it. The son of a scientist, he spent the first two years of his life in New Brunswick, where his father was in graduate school at Rutgers studying solid-state physics. The family moved to Bethesda, Md., when his father landed a job as a research scientist with the National Bureau of Standards (now the National Institute of Standards and Technology).
Bennett grew up a tinkerer, happiest when he was building things -- especially new and better antennae for his ham radio. His world was circumscribed by circuits, transistors and capacitors until he was 14, when his grandmother gave him a telescope.
"Every night I'd take it into the back yard and look at whatever I could see. I loved looking at the moon, the planets and especially the rings of Saturn. Then I learned that there was something called radio astronomy. You get to build circuits to look at stuff in the sky.
"That really just combined the two hobbies I had, and I decided right then that that's what I was going to do. ... It used to drive my friends crazy that I knew exactly what it was I wanted to do. I didn't want to do just physics or astronomy. I wanted to do radio astronomy."
His freshman year at the University of Maryland, Bennett was one of about 120 physics majors. By the time he graduated four years later, there were half a dozen.
"I wasn't the brightest guy in there," he says with a laugh, "and so I had to make up for it with harder work ... but I loved it. I loved being able to solve problems."
Bennett graduated with high honors in physics and astronomy and headed off to the Massachusetts Institute of Technology for his Ph.D.
In the mid-1980s, just as he was finishing his doctorate in radio astronomy, COBE came calling. The COBE team, headquartered at Goddard, was starting to build the instruments that would be used to measure the cosmic microwave background radiation, and the team needed a radio astronomer.
By the time COBE launched on Nov. 18, 1989, Bennett was the deputy principal investigator for the Differential Microwave Radiometer, the instrument that would measure the brightness of the radiation and produce a map of the average anisotropies in cosmic temperature. The measurements of these variations, it was hoped, would bring into clearer focus the origin, shape and size of the universe.
THE RIPPLES
At the beginning of the 20th century, the universe was thought to be finite, bounded by the edges of the Milky Way. By the end of the century, the Milky Way was just one of a hundred billion galaxies, and the sun one of trillions of stars. The limits of space had been pushed into infinity.
The Hubble Space Telescope, launched in 1990, was an attempt to see into that vastness. And its views confirmed what scientists had believed for some time -- that the universe was uniform in all directions, but also that it was a bit lumpy. Instead of matter being spread out evenly through space like butter on bread, it looked like a bowl of cold, clumpy oatmeal someone forgot to stir. Oceans of stars were pooled into galaxies, galaxies were bunched into superclusters, and in between was a latticework of gas and dust and seemingly empty space.
Throughout the summer and fall of 1991, Bennett sat in front of his computer at the Goddard Space Flight Center. Day after day, hour after hour, he studied thermal maps of the sky. When he was not on his computer at Goddard, he was on his laptop at home, often spread out on the floor of the family room after he and his wife, Renée, had put their two young boys to bed.
Finally, that December, Bennett felt satisfied with what he was seeing. When the team announced its findings in the spring of 1992, the reaction by the scientific community was nothing short of astonishment.
COBE had produced a map that showed the background radiation differing in temperature ever so slightly in different directions, sometimes just 30 millionths of a degree hotter or colder than average. "These variations are so small," says Bennett, "they're like height variations of only 4 inches on a mile- high plateau," or the difference in the weight of a cup of sand when one grain is removed. Still, these ripples in the background radiation were just irregular enough to correspond to the slight clumpiness from which all structure in the universe evolved.
"Seeing these fluctuations is like the first peek into a window of the physics of the early universe," says Princeton cosmologist and MAP team member David Spergel. "All these things we couldn't measure before are emerging and keep fitting with the standard model" of the big bang.
Another COBE team member said that seeing that first thermal map of the background radiation was like "seeing the face of God."
COBE's detection of tiny temperature fluctuations was the strongest evidence yet in support of theories that suggest the universe is flat, with just enough matter to keep it glued together while it continues to expand -- instead of too little matter, which would make it fly apart, or too much, which would make it collapse back on itself.
Bennett and his team of astronomers had done something cosmologists usually only dream about: They had verified that all the late-night musings and academic papers of theoreticians, all the mathematical hypotheses and conjectures, were grounded in reality. Big-bang and inflation theories were the best things on the table not because they were the best guesses, but because they fit the evidence.
COBE's limitation, however, was that it could measure the differences in average temperature only for huge swaths of the sky. It couldn't pinpoint the fluctuations. Enter the Microwave Anisotropy Probe, or MAP, launched in June 2001. Next month Bennett and the MAP team will release its first findings, which are expected to answer the question: What did the universe look like shortly after its birth?
"What we have is a bunch of theoretical possibilities of what the temperature patterns mean for what the universe is like," says Bennett. "And each of those specific theories predicts a kind of pattern. MAP is going to measure the pattern that's really on the sky, and then it's like a detective story: matching the fingerprint with the mug book."
THE WAIT TO BE RIGHT
Alan Guth believes he made that match more than 20 years ago. In 1979, the young physicist invented inflation theory, which described why the big bang happened and then what happened in the next trillionth of a trillionth of a trillionth of a second.
By the time COBE was launched, Guth had been waiting more than a decade, without much hope, for the empirical evidence that would tell him he was on the right track.
That pessimism was born from historical frustration. Cosmology is unlike most sciences, where theories spring from evidence. Ideas about the universe, such as Guth's, are born in the absence of evidence . For the better part of the 20th century, facts about the origin and shape of the universe had been impossible to come by.
Guth seems an unlikely candidate for a scientific revolutionary. The 54-year-old physicist is boyish in appearance, his slightly graying hair swept over his forehead like a'60s surfer. He sits, hunched over, on the edge of a threadbare armchair in his office at M.I.T. in Cambridge, Mass., and speaks quietly, almost conspiratorially, as if he is letting his visitor in on some secret of the universe.
He is.
"The classical big-bang theory was never really a theory of a bang," says Guth. "It was a really a theory about the aftermath of the bang. Inflation answers the question of what happened before that -- what made the universe bang in the first place."
Where Charles Bennett is a cosmic gumshoe, tracking down leads and gathering evidence to prove his case, Guth is a cosmic magician, a lover of numbers and equations who still marvels that something he thought up in the solitude of night might be the key to creation.
Both men believe the cosmic microwave background radiation holds the clues to solving the mysteries of the universe's creation, evolution, shape and fate. For Guth, who created his inflation theory 20 years ago in an empirical wasteland, the thermal maps of the microwave background could either confirm or destroy his idea of creation.
In 1979, Guth was at the Stanford Linear Accelerator Center in Menlo Park, Calif. It was his fourth stop on the postdoctoral "beauty pageant" circuit, during which freshly minted Ph.D.s audition for university professorships. Eight years and stints at Princeton, Columbia and Cornell well behind him, Guth saw his career wilting on the vine.
The son of a grocer, Guth grew up in Highland Park and went to the local public schools, then on to M.I.T. for his undergraduate and graduate degrees. Now, with his tenure at SLAC in its final months, he was facing unemployment and, worse, failure as a scientist.
Everything changed in the space of four hours late on the night of Thursday, Dec. 6, 1979.
Guth was holed up in his small study in a rented one-bedroom house not far from the Stanford campus. While his wife, Susan, and 2-year-old son, Larry, slept in the next room, Guth began writing. He and a colleague were trying to rush a paper into print on a topic in particle physics dealing with the transitional phases of the early universe as it expanded and cooled. Guth's job that night was to check whether one of these phases would affect the expansion rate.
By 1 a.m. Guth had the answer, and it was a surprising, emphatic "yes." What came next can be described only as a "eureka" moment, because Guth realized that this idea of an early transition phase could have profound implications for solving the mystery of why the big bang happened at all.
"In order to make the big- bang theory work," he says, "you have to very carefully fine-tune your assumptions about the initial conditions of the universe, to put the universe just on the borderline of the right mass density to allow eternal expansion. Too much mass density would cause the universe to collapse back on itself. Too little would cause it to fly apart. The mass density at the time of big bang had to be just right. ... So the big question was, what caused that to happen?"
A few pages of equations later, Guth had the answer: inflation.
THE MOMENT OF TRANSITION
Guth's insight was to see that before there was a universe, there was an infinitely small energy field of subatomic particles, and what caused the universe to "bang" into existence was a fluctuation in that energy field. Like shaking a can of Coke and then popping its top, in the first trillionth of a trillionth of a trillionth of a second of the universe's existence, an enormous amount of energy was trapped, creating a negative pressure, which in turn caused a sudden and violent stretching of space. In one brief massive burst, the budding universe -- smaller than the width of a proton -- doubled in size 100 times over.
This transitional phase left small pockets of subatomic particles scattered through space, like the bubbles left in a boiling pot of water after the heat is suddenly turned down. It was those particles that created the seams in the early universe where matter would gather, eventually growing into galaxies and galaxy clusters.
Everything that exists today -- from the stars and planets to every rock, tree and human being -- can trace its ancestry to less than an ounce of original matter, according to Guth's theory.
Early on the morning of Dec. 7, 1979, on little sleep, Guth bicycled to the center -- somehow having the presence of mind to time his ride, a habit he had picked up in graduate school. The soon-to-be- world-renowned cosmologist would proudly note in his journal that night that he had broken his personal speed record with a time of 9 minutes and 32 seconds.
When he sat down at his desk at the center, his first notation wasn't about his bike ride, but his new theory. With equations stirring restlessly around in his brain, Guth wrote at the top of a page in his notebook, "SPECTACULAR REALIZATION."
Within weeks of announcing his theory, the physicist was inundated with offers from universities. But Guth wanted to return to his alma mater, and took his cue from a fortune cookie he opened at dinner one night: "An exciting opportunity lies just ahead if you are not too timid."
Guth called the physics department at M.I.T. to see whether there was an opening. Twenty-four hours later he was offered an associate professorship.
More than a decade later, Charles Bennett's team on NASA's Cosmic Background Explorer project provided the first empirical evidence validating the equations Guth had puzzled out with pen and paper.
Today, inflation is considered by many scientists to be one of the greatest achievements in cosmology in the 20th century. Last year Guth received the Benjamin Franklin Medal in Physics, which in past years had been given to Albert Einstein, Edwin Hubble and Stephen Hawking. Several months ago he was awarded, along with two other cosmologists, the 2002 Paul Dirac Medal by the Institute for Physics, which honored Hawking in 1987.
'GORGEOUS TO LOOK AT'
Using his IBM Thinkpad, which sits on his desk in his M.I.T. office wedged between discarded computer keyboards and 3-foot stacks of paper, Guth calls up four graphs on the screen, one on top of the other. He does this a few times a week, he says, just because he likes looking at them. The graphs are four different measurements of the cosmic microwave background, and the lines appear nearly identical.
"Back when I came up with inflation, I never believed anybody would ever measure the predictions," says Guth, smiling at the results on the computer screen in front of him. "I just thought it would be fun to calculate it. Now that they have, it's amazing. Looking at the results of COBE, and how the measurements agreed perfectly with the predictions of the inflationary model, was absolutely wonderful. It's really gorgeous to look at."
From its debut as little more than a theoretical blip on the screen, inflation theory has become the golden child of cosmology, the best explanation yet of what happened at the genesis moment.
"When inflation was introduced, there were a lot of disbelievers," says Michael Turner, chairman of the astronomy and astrophysics department at the University of Chicago. "So far it has passed the test. It predicted the universe was flat, and that's what we're seeing. It predicted these 'acoustic' peaks in the cosmic microwave background, and that's what we're seeing and what we're zeroing in on. The real question now in terms of inflation is how much of the truth it has and, of course, what caused it."
If inflation is the dynamite of the universe, says Turner, "then cosmologists are still looking for the match."
Inflation theory has been refined and updated and altered. There are now several variations on the theme, including chaotic inflation, extended inflation, hyperextended inflation, open inflation and two-round inflation. All can trace their ancestry to Guth, the struggling Ph.D.
Other recent findings about the cosmic microwave background radiation offer more direct evidence that what is now the standard model of cosmology -- big bang plus inflation -- is correct. There also is every indication that when the MAP team announces its results next month, the evidence finally may be overwhelming.
"I believe it will be a major success for inflation," says cosmologist Andreas Albrecht of the University of California at Davis. "Whenever I talk with someone from the MAP collaboration, they can barely contain their joy at the success of their experiment. The results should be fantastic."
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