THE VIOLENCE OF CREATION

Stargazers in the 17th century named them nebulae, the Latin word for clouds, but modern astronomers have become convinced that many of the faint, fuzzy patches of light that dot the night sky are really huge clumps of interstellar gas that act as cosmic nurseries -- the places where new stars are born. The glow comes from infant suns lighting up the clouds, like fireworks illuminating their surrounding pall of smoke. "Fireworks" is an apt description, since the prevailing theory among astronomers is that star birth must be a cataclysmically violent process. But without detailed pictures of what's going on-something that is impossible to get from ground-based telescopes-the scientists have had no conclusive way to test the accuracy of those theories.

Now, though, from its vantage point above the earth's blurry atmosphere, the Hubble Space Telescope has provided the most detailed and spectacular images ever taken of these stellar nurseries, and they confirm that the theorists had it exactly right. The photos don't show the stars themselves, which are shrouded behind dense clouds of cosmic dust. But they do show enormous jets of gas blasting out of the young suns at speeds of up to 300 miles per sec. and with enough force to propel them trillions of miles into deep space. One of the pictures is a surprisingly clear portrait of a fast-spinning, disk-shaped cloud of cosmic debris that may serve as the raw material for a solar system in eons to come. Says astronomer Chris Burrows at the Space Telescope Science Institute in Baltimore, Maryland: "It sends shivers down my spine when I realize what we're looking at."

What Burrows and his colleagues are looking at is more than a confirmation of astronomical theory. It's also a snapshot of what our own sun must have looked like about 5 billion years ago. And it raises the intriguing possibility that most, if not all, of the stars in the Milky Way may have planets, and that at least some of them may be home to extraterrestrial life.

The key element is the spinning disk. As a cloud of gas and dust collapses under gravity, it spins faster and faster, like a figure skater pulling his arms in against his body as he goes into a rapid whirl. The accelerating rotation, in turn, makes the cloud flatten out into a pancake, with the highest density in the center, where the star starts to form. Unlike a solid disk -- a CD, for example -- this one rotates faster in the center than at the edges. The star, pulling in more matter as it grows more massive, should spin the fastest of all. But it doesn't.

To explain this baffling fact, astronomers in the past decade or so have suggested that jets of matter must be shooting out of these still forming stars. Only by slinging some of the incoming matter away as a counterbalance could the protostars avoid going into a superfast spin. When a new star finally becomes massive enough to ignite the nuclear-fusion reaction that makes it shine, the resulting outward blast of energy would stop any more matter from falling in, the jets would turn off, and the remaining dusty disk would start clumping together to form planets.