Dark Matters
Faber's research into the 'nothing' of the universe sheds light on the elusive Big Bang
By Jeff Kearns
IN the beginning--that is the very, very, very beginning of absolutely everything, including the event that's since been dubbed the Big Bang--the entire known universe was hot and dense. About 1027 degrees Kelvin, to be exact, and weighing about 1096 grams per cubic centimeter. Written in longhand, that's somewhere in the neighborhood of 1,000,000,000,000,000,000,000,000,000 degrees and
1,000,000,000,000,000,000,000, 000,000,000,000,000,
000,000,000,000,000,000,000,000,000,000,000,000,000,
000,000,000,000,000,000,000 grams per centimeter.
But don't get used to it--that's only the first 10-35 seconds. Between then and 10-32 seconds, everything you know about physics is wrong. During that time, a little less than a millionth of a millionth of a second about 18 billion years ago, what's now called the universe expanded by 1060, rippling out into the vacuum of what could only be called space.
Then, for the next two or three billion years, nothing but darkness. Only then did the first stars start to shine.
Cut to Dr. Sandra Faber, the UC-Santa Cruz astronomer who's got her eyes trained back in time.
Sitting in her office at school, while explaining the process of galaxy formation that's occupied much of her time over the last 30 years, she jumps up and disappears out the door. She returns a minute later with a posterboard photo about 5 feet square.
"Look at this," she says, propping it up against a table. "This is the deepest picture of the universe ever taken."
It's a two-week exposure of one random patch of sky about a 10th the size of the full moon, and a $15 million snapshot that comes to earth courtesy of the Hubble Space Telescope. Each different colored swirl or dot or burst of light is a galaxy.
Faber points to a small cluster of four reddish dots in the bottom left corner. It's some very old light, left over from the earliest days of the universe, those first two or three billion years when the stars first started to shine.
As part of one of the projects Faber is working on, several astronomers are now taking small sections of the galaxies on that poster and figuring out how fast those galaxies are moving.
To do that, they measure the wavelength of light a given galaxy puts out. Much the same way that the Doppler effect changes the pitch of sound depending on whether the source is moving closer or farther away, galaxies moving away from earth give off a reddish light (called redshift) and similarly, galaxies moving closer look bluish (that's blueshift).
The team is only looking at galaxies with a high redshift, or the ones that are the farthest away. The cluster Faber's pointing to is the most distant galaxy anyone's ever seen. So far away, that the light now reaching Earth is some of the first light in the universe. Anything older and farther away, she explains, wouldn't give out any light. "This is like a core drilling back in time," she says. "That little cluster of four is going the speed of light. You'll never see them again."
Sandra Faber looks through one of the lens elements that will be installed into the DEIMOS camera in Hawaii.
Photograph by George Sakkestad
'Science Geek'
Faber, who lives in Monte Sereno, is a self-described "science geek and good student" who grew up in Mt. Lebanon, Pa., a suburb on the south side of Pittsburgh.
At Swarthmore College in Philadelphia, Faber served on the student council budget committee. Not too notable a post for one of the most notable astronomers in the country, but it did introduce her to another committee member, Andy Faber, whom she married in 1967.
After Sandra earned her Ph.D. in physics from Harvard, the Fabers made the move to the Bay Area for Andy, who was on his way to Stanford Law School. He is now a land-use attorney at Berliner Cohen in San Jose, and is city attorney for Gilroy.
Eschewing post-doctoral work, Sandra Faber started as an assistant professor in the astronomy department at UCSC in 1972. Being a science geek and good student over the years earned her the title of University Professor--a step above full professor, and one of only seven professors in the U.C. system with that title.
Faber made news in June of 1990 when she announced to NASA that the Hubble Space Telescope didn't work correctly. The optical error, which Faber diagnosed with one of her students and a staffer from the Space Telescope Institute, meant that none of the telescope's 20 man-years of planning and 200 of testing were salvageable. They broke the bad news to NASA.
She talks about it like fine art: "The Space Telescope mirror is the most beautiful mirror ever made, and the most accurate."
Faber and several other colleagues spent months retracing the steps of the main parts of the telescope, most of which were built and assembled for NASA by subcontractors.
One of the employees of one of those subcontractors, it turned out, drilled into one of the precision-engineered metal pieces to make the corrector fit together for testing.
And that beautiful, precise mirror, of course, is only as good as the corrector which focuses its light into the telescope's electronic eye. The corrector, unfortunately, because of the drilling error, was 1.3 millimeters off.
Once they figured out what was wrong, Faber and others condensed years of work into months. They put together a clone of the space telescope's main optics using duplicate parts left on Earth.
Faber talks about the intricacies of those errors and the rush to correct them without the anger one might expect, but some resentment creeps into her voice as she talks, recounting the months of frustration while the telescope orbited the earth unable to perform its main functions--and was the butt of jokes for late show hosts.
She cheerfully describes the complex optical correction in layman's terms: "The answer was to put glasses on it."
Photograph by George Sakkestad
Sandra Faber and chief optician David Hilyard inspect a lens which will be installed in the DEIMOS.
Cosmos Girl
Faber keeps busy juggling several different projects at any given time, but as a researcher, she's spent most of her career as a cosmologist studying galaxy formation. That's what's taken her back to those first tiny fractions of a second: the Big Bang.
Just after she became a full professor at UCSC, Faber co-authored a journal article on dark matter with John Gallagher in 1979: "The Masses and Mass to Light Ratios of Galaxies."
It wasn't exactly beach reading, but it did make waves in the astronomy community.
Dark matter, which researchers had been speculating about for about 40 years, was emerging as a controversial topic in the field.
Camps had appeared. Some argued for the existence of the mysterious dark matter, and others tried to poke holes in the theory.
Dark matter is a sort of mystery meat of the universe: nobody's quite sure exactly what it is, but it's definitely there. Astronomers were first tipped off to its presence by galaxies that seemed to be orbiting, well, nothing.
Faber and Gallagher's paper weighed the most current research and concluded that the universe was about 90 percent dark matter, invisible matter swirling around galaxies. Today, this is something that's taken for granted in the astronomy world, even though no one's quite sure just what dark matter really is.
In 1984, Faber and two other astronomers teamed up to write another paper that roughly sketched out where galaxies came from. It must have been the ripples, they concluded.
Looking at the first 1032 seconds of the universe, Faber and her colleagues (physicist Joel Primack and astronomer George Blumenthal) theorized that in that explosion, expanding gasses didn't quite expand exactly in unison, and that they started to cling together.
"There must have been some mechanism close to the Big Bang that generated small density ripples," Faber says. "And if the density isn't exactly uniform, then the ripples grow. It's like economic instability, how the rich get richer and the poor get poorer."
The rich areas, as it were, grow in mass, and in turn collect matter, growing and growing until they turn into galaxies of stars.
Since then, Faber has been trying to work out the details of that theory. Other researchers, too, have started using computer models to make detailed predictions on how the first galaxies formed.
Those computer models, which take advantage of the many technological leapfrogs computing has made in the last 15 years, try to approximate how the universe looked when it began by creating a model and running it backwards.
That's the same thing Faber is doing with her research on galaxy formation, but from a different vantage point--Earth.
"I'm an observer, basically, not a theoretician," says Faber, who prefers to look back in time herself, only through a telescope. "They're time machines. By looking into a telescope, you're basically looking back in time."
Photograph by George Sakkestad
Sandra Faber exits the interior of the partially completed DEIMOS at the Lick instrument laboratory at UCSC.
Looking Backward
Faber spends several weeks each year looking back through the historical records from billions of years ago that are just reaching Earth now, in the form of visible light.
She spends three or four weeks each year at the top of Mauna Loa on the Big Island in Hawaii, observing for a week at a time at the Keck Telescope. And about one week a year, she's at the Lick Observatory atop Mt. Hamilton, which is jointly owned by the University of California and the California Institute of Technology.
Those weeks she spends observing tend to run about 110 hours. After the long hours, however, Faber gets to relax when she returns to her usual 70-80 hour work week.
To measure just how fast those most distant galaxies are actually receding, Faber and her partners use the Keck Telescope, one of the most powerful in the word, in conjunction with the deep space images from Hubble.
She's also helping to build a spectrograph, one of the optical instruments that will be used at the Keck.
Starting in the fall of 2000, the spectrograph--called DEIMOS (Deep-Imaging Multiobject Spectrograph)--will go on Keck 2, a second powerful telescope that's being built on top of the same mountain as the original Keck. But even though the two telescopes will only be separated by a few meters, the two operating in unison will enhance the resolution by 10 times what's now possible, giving astronomers an even better view of the very edge of the universe, and into the distant past.
"I feel it's a great achievement for one lifetime--but all we've done is push back the boundaries," Sandra Faber says. "And as far as we can see into the future, it will be the same, but I do know I'll die knowing much more about the universe than Einstein."
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