Blue gloom over Hubble flaws fades with "terrific" discoveries

NASA's Hubble Space Telescope is marking its second anniversary with new discoveries about star and galaxy formation and new questions about "dark matter" that could reveal the ultimate fate of the universe, astronomers said Monday.

The enthusiasm that initially surrounded the launch of the $2.5 billion orbiting telescope two years ago Friday soon dimmed when ground controllers found an optical flaw that prevented it from bringing the faintest, most distant objects into sharp focus. Spacewalking astronauts are scheduled to repair the defects during a shuttle mission now slated for November 1993.

In the meantime, though, astronomers associated with the much-scrutinized space telescope say experts have been able to overcome many of the technical obstacles.

"Those days of blue gloom have turned into some weeks and months and now two years of what I might call true grit," astronomer Steve Maran of NASA's Goddard Space Flight Center told reporters at a news conference. "As a result, we have had a lot of terrific findings."

Some of the discoveries may challenge conventional theories of star and galaxy formation, yet even the surprises seem to add weight to the pioneering theoretical work in cosmology of Albert Einstein. In one case, a single Hubble photograph of the wreckage left by two colliding galaxies, one containing a bright quasar, appears to challenge the long-held idea that galaxies formed about the same time following a huge explosion that dispersed the matter in the universe.

Left in the aftermath of the collision were a large number of star colonies called globular clusters.

"What that tells me is that we may have been very wrong about our theories of galaxy formation," said astronomer Daniel Weedman. "It may be that galaxies didn't primarily form at one instant 15 billion years ago, but that in fact their formation is something that is ongoing."

An equally surprising discovery that has unfolded less dramatically over the past 18 months involves a star "nursery" in the Large Magellanic Cloud, a galaxy 169,000 light years distant.

According to astronomer Sally Heap, the nursery is a compact region of space with about 50 young stars, with most 100 times more massive than the sun.

Similar observations in our own Milky Way galaxy had led astronomers to conclude that typically new stars are small. What makes the observations more puzzling is that the Large Magellanic Cloud is considered a more primitive galaxy than our own and devoid of the heavier elements found in the Milky Way.

"What we are seeing now is that stars in another galaxy are forming a different way than they are in our galaxy," said Heap.

Using predictions formulated by Einstein, Hubble scientists have searched for evidence of the large quantities of so-far-unobserved "dark matter" that would reveal whether the universe will expand forever, reach a limit or collapse.

By observing bright light from distant quasars, astronomer John Bachall has searched for instances where the light is bent by the gravity of intervening celestial objects or galaxies. The bending of the light would make the quasars appear in multiple images. By observing the amount of bending, the mass of the galaxy or objects can be calculated.

After 350 observations, Bachall's team has found just one case where the light was bent sufficiently to produce the multiple images. The results would indicate that dark matter is not compressed in the cores of galaxies, he said.