August 12, 2003
COLUMN ONE
A Whole Other Cosmos
With better tools and collaboration, scientists are discovering a more violent and vibrant universe than could be observed just years ago.
By K.C. Cole, Times Staff Writer
There's nothing like quietly contemplating the sky on a clear, moonless night to make us feel we can touch the cosmos in its entirety â the bright canopy of stars, the ever-shifting play of planets, the vast, cold silence of infinite space.
How little we know.
All this glory is but the barest glimpse of what's actually out there. Tales of extreme violence and profound mystery stream at us from every corner of the cosmos, and yet we're constrained to peering through the tiniest keyhole, seeing only the thin band that beams in visible light. Until very recently, even astronomers, who see nearly the entire electromagnetic spectrum, from radio to gamma rays, have been able to tune in to only the barest trickle from the flood of news.
In the last few years, however, new instruments have begun painting a far more vibrant image of the universe. The celestial story now unfolding has as much in common with the picture of decades past as a Technicolor, Dolby Digital surround-sound production has with a grainy silent film.
Consider: In the last year alone, a satellite tuned to faint microwaves still glowing from the Big Bang took a picture of the quantum mechanical quivers in the newborn universe that pulled matter into what eventually became galaxies, stars, and ultimately, us. The picture pinned down the age of the universe precisely â 13.7 billion years â and confirmed its exact mix of ingredients. The same astonishing image suggested that the fires of the first stars electrified the skies 200 million years after the Big Bang â much earlier than most astronomers predicted.
Meanwhile, X-ray telescopes have been finding black holes â objects of such concentrated energy and warped space that they trap even light â virtually everywhere they've looked. One satellite alone found 1,500 supersized holes feeding on surrounding gas and stars in just a small patch of sky. Other telescopes found a whole new species of midsized models previously unknown to exist.
"Far more black holes are lurking out there than anyone thought," said Sonoma State University astrophysicist Lynn Cominsky. "If you look at the universe in visible light, it's pretty calm. But in X-rays and gamma rays, it's very violent."
From the infrared end of the spectrum comes UCLA astronomer Andrea Ghez's discovery that the supermassive black hole in the middle of the Milky Way is flinging a star around at 3% of the speed of light as if it were a pebble from a slingshot.
And the adventure has barely begun. On Aug. 23, NASA is set to launch the last of its four "great observatories," grand telescopes in the sky, each tuned to a particular swath of the electromagnetic spectrum. While Hubble, Chandra and the now defunct Compton telescopes looked at visible light, X-rays and gamma-rays, respectively, the new infrared telescope will allow astronomers to peer through the fog that shrouds the births of stars and planets.
Following not far behind them are two more "Great Einstein" observatories. Both involve arrays of telescopes flying in formation like well-practiced flocks of birds, in one case effectively creating an observatory millions of kilometers across.
Almost every month, new ground-based telescopes open their eyes, and new special-purpose explorers take off for the clearer skies of space. Some, like the Sloan Digital Sky Survey, are mapping much of the sky in great detail, pinning down the location of galaxies, stars and distant quasars to create a three-dimensional image of its large-scale structure. Others, like Hubble, often go deep and narrow, taking what amounts to a core sample of the universe.
"It's amazing to think about how much this has developed since I was in graduate school," said Michael Jura, a 55-year-old astronomer at UCLA. The laws of physics haven't changed, "but the consequences are enormously greater than people imagined," he added.
The vast expansion of the spectrum of the possible puts scientists on the brink of being able to answer some of the thorniest questions ever posed: How do solar systems form? How did matter come into being? Does space really crinkle, and time really stop, at the horizon of a black hole?
As Einstein once put it, the most incomprehensible thing about the universe may well be that it's comprehensible at all. Certainly, the recent unveilings â and those to come â have been made possible not only by leaps in technology but also by a willingness to follow the often outlandish lead of theoretical predictions.
In fact, one of the niftiest new tools astronomers use to see deep into space comes straight out of an outrageous suggestion by Einstein. His theory of general relativity implied that large concentrations of mass should bend light just as glass does, forming "gravity lenses."
The first such lens was discovered in 1979, and more than 100 have been found since. Today, they are regularly put to use as natural "telescopes," enabling astronomers to find everything from previously unseen distant galaxies to concentrated globs of dark matter.
At present, most of the eye-opening discoveries stem from improved techniques for tuning into the electromagnetic spectrum, which ranges from gamma rays smaller than atoms to radio waves bigger than mountains. (The rainbow of visible light our eyes detect is a narrow ribbon midway through the spectrum.)
The universe broadcasts in all these bands, yet very little gets through. X-rays, for example, can easily see through Lois Lane's clothes but can no more penetrate our atmosphere than they could a sheet of lead. And violent objects like collapsing stars and black holes broadcast their presence almost exclusively in X-rays.
Some infrared light does get through to Earth, but only in patches, with a lot of interference from sources like infrared telescopes themselves. Everything above absolute zero temperature radiates in infrared â including air and icebergs.
Thus, even astronomers like Ghez who already observe in infrared from the ground are excited about NASA's Space Infrared Telescope Facility, or SIRTF, which will be chilled to close to absolute zero. That, plus state-of-the-art detectors, means that SIRTF will be a million times more sensitive than previous infrared missions.
(In all respects, SIRTF is a very Southern California enterprise. The SIRTF Science Center, which evaluates proposals for observing time and processes data, is based at Caltech. Two of the original science team members â Jura and Ned Wright â are professors at UCLA.)
Infrared astronomy is particularly effective at looking back at the earliest moments of time. In an expanding universe, light that began its multibillion-year journey as X-rays would have by now become almost entirely stretched into longer wavelength infrared. Infrared also slips through the thick, dark dust that clouds the birth of stars. Astronomers don't even know whether stars are typically born in splendid isolation, like our sun, or as twins, which seem to be far more common.
And it's the only way to study the cool dust itself, critical to understanding how planetary systems form. (Planets are little more than clumps of dust left over from coalescing stars.)
It would be misleading to credit space-based astronomy with all the big advances. At the Keck telescopes in Hawaii, Ghez, for example, keeps track of stars speed-racing around the Milky Way's center. Their vision was dramatically improved when they were fitted with "adaptive optics" that can clear up atmospheric blurring using mirrors that flex thousands of times per second, effectively taking the twinkle out of starlight.
Another breakthrough is the increasing use of interferometry â the combining of waves from many different telescopes, often widely spaced, to produce a single, vastly magnified image. Long a staple of radio astronomy, it's exceedingly difficult with short-wavelength light. Still, most major observatories are working on it, and recently the twin Keck telescopes successfully combined infrared light to bring into focus a swirling disk of dust around a very young star.
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