"We have looked back 12.8 million light years and seen galaxies quite a bit more mature than we expected. We've used adaptive optics to look into the center of our galaxy, where we seem to have a very nice specimen of a black hole," said Peter Michaud, of the Gemini Northern Telescope, one of the newest and biggest on Mauna Kea.

The Islands can thank tall mountains and a stable atmospheric inversion layer for an industry worth 600 jobs and $150 million a year — Hawai'i's astronomy program.

"The University of Hawai'i astronomy program is one of the absolutely best in the world, easily in the top five. And the reason is that the Institute for Astronomy has access to two of the best sites for astronomy in the world: Mauna Kea and Haleakala," said Rolf-Peter Kudritzki, director of the institute.

The clarity of the observation is possible because of the inversion layer, which is much more stable over a wide tropical ocean than over continents.

If you stand in the cold, rarefied air on either Hawai'i mountaintop, on most days you can look down through the crisp atmosphere and see the inversion layer as kind of a cloudy, dirty blanket layer below which nothing is quite as distinct.

Normally, air temperature cools as you go up, but in an inversion layer temperatures rise with increasing elevation, forming a barrier that prevents upward air movement.

"It traps pollutants and water vapor, and the atmosphere above that is much clearer," said Jim Weyman, head of the National Weather Service forecast office in Honolulu.

Both the Big Island's Mauna Kea and Maui's Haleakala pierce the inversion layer, which normally sits about 6,000 feet above sea level and is 1,000 to 2,000 feet thick. Mauna Kea reaches near 13,800 feet and Haleakala just exceeds 10,000 feet. Mauna Kea is taller, but a little dustier; Haleakala is lower but more dust-free.

"You get to see things with clarity that you don't see anywhere else in the world," said Jeff Kuhn, the Institute for Astronomy's associate director for Haleakala.

Other features also help make the sites so important for astronomy:

• There is comparatively little city light pollution.

• The proportion of cloud-free nights is among the highest in the world.

• Hawai'i's government and economy are stable. Infrastructure — including roads, electrical power and even hotel rooms — is in place. And, recognizing some of these things, the state in the 1960s decided to boost its role in astronomy, so that the world's best astronomers have the support of a world-class astronomy center.

The list of astronomical research directions at the Hawai'i observatories is nearly endless. Astronomers look into our own solar system, into our Milky Way galaxy, at nearby galaxies and far into the deepest space. They study the different things that are viewable at different wavelengths of light, and beyond light at radio and submillimeter wavelengths. They combine light from different telescopes to improve their imagery. They add instrument after instrument to the mirrors to improve their ability to resolve distant glowing specks. They use computers to characterize the disturbances in the atmosphere and correct for them.

"There is an enormous scientific investment in financial terms and all of it is high tech. Astronomy has a technological impact. Astronomy is a technology driver," Kudritzki said.

Astronomy is also a place where international boundaries blur. More than a dozen nations have investments on Mauna Kea alone, and scientists from even more nations participate.

"International collaboration. Many people talk about it, but astronomy practices it. We have well-established international partnerships," Kudritzki said.

If you ask the astronomy community to identify the "sexiest" or most important research projects, several come up repeatedly.

• Mysterious dark energy and dark matter, stuff we can't directly detect but know exists because of its effect on other things, makes up most of the mass and energy in the universe. But physicists and astronomers don't know what it's made of. "It's six-sevenths of everything, and we don't know what it is," said extragalactic observational astronomer John Tonry. "Most people think the dark matter is some kind of super-symmetrical particle we haven't detected yet."

• Our sun's magnetic storms can fry satellite electronics, cause massive power outages on Earth and last year got so strong that two satellites were lost, high-flying aircraft were urged to fly low and other flights were ordered to avoid regions where radio contact would be wiped out. "The magnetism of the sun is a critical issue," said astronomer Kuhn. Observatories on Haleakala are studying the sun to try to better predict and understand the interaction between the sun and the Earth.

• Black holes. Science used to think they were so enormously massive that their gravity sucked in everything, even light, and that anything sucked in was lost forever. Recently, Cambridge physicist Stephen Hawking has argued that something may actually survive black holes, which may lead to a new round of research. Several Mauna Kea telescopes have been peering at the black hole in our own galaxy. It's up there in the night sky, in the constellation Sagittarius, about 24,000 light years away. But if you look, you won't see it.

• For many astronomers, the technology is the thing. Such as improving adaptive optics to get ever-clearer views. And the Gemini telescope's plan to replace the aluminum coating on its mirror with silver "because it reflects better in the infrared and absorbs less heat," Gemini's Michaud said.

To many, the future is even more interesting, like the proposed Pan-STARRS telescope (Panoramic Survey Telescope and Rapid Response System), which would completely inventory the sky visible from Hawai'i for near-Earth asteroids that could collide with our planet. It could go to either Mauna Kea or Haleakala.

"I hope we can convince the public that this is an important project, and it would be good for mankind," Kudritzki said.

Also on the drawing board are the largest solar telescope ever built, which would use adaptive optics to create images of the finest details of the sun's surface, and the largest telescope ever attempted, a 30-meter mirror that would allow direct viewing of planets orbiting distant stars.

The telescope would be a $1 billion project, equivalent to the value of everything now on Mauna Kea, Kudritzki said. His view is to put it on a plateau below the mountain's summit, where it would not be as visible as others from the lowlands, and would not interfere with Hawaiian cultural sites, summit cindercones or native high-elevation insect life.

Those issues are ones the astronomy community has been forced to take seriously in recent years, as it has run into a blockade of Native Hawaiians and environmentalists who challenged the view that astronomy is more important than culture and environment.

Mauna Kea summit's future is now guided by the 2000 Mauna Kea Science Reserve Master Plan, which calls for consultation with the local community. Kudritzki said he believes there is a way to preserve good astronomy while protecting the mountain.

"My vision of the future 30 years from now is that we we will have less telescopes than now, but they will still be the best in the world," he said.