A volcano erupted, sending puffy clouds of gray smoke across the Air & Space Museum's giant Imax screen last night. A huge glacier crashed to the ice, triggering a violent avalanche. Giraffes ran for cover as thunder crashed on the plains of the Serengeti.

Then the camera moved in on the Persian Gulf -- the water still clean and sparkling.

The audience, full of ecologically minded types, shifted uneasily. They were there for the gala for "Blue Planet," the glorious 45-minute look at the Earth that has been showing at the museum, but reality intruded.

"I felt a chill when the now very familiar landscape of the Middle East went up on the screen," said Kathryn Fuller, president of the World Wildlife Fund. "Not only because of the short-term impact the {oil} spill will have on the environment, but also the long-term effects on human survival in that area. Human suffering will go on long after the war has ended."

The environmental senator, Tennessee Democrat Al Gore, standing with his 8-year-old son Albert, had an even gloomier appraisal of the spill in the gulf. "If the oil had not been spilled," Gore said, "it would have been joined with other oil, used for fuel and converted into carbon dioxide. And that would contribute to climate change."

And we all know what that means.

Members of Congress, the defense industry and environmental organizations and their families made up the crowd of nearly 1,000 guests who milled around under the Spirit of St. Louis and an X-15 jet. In between screenings, they nibbled on such delicacies as peanut-butter-and-jelly finger sandwiches, popcorn and hot fudge sundaes. A handful of NASA's stable of astronauts -- including space shuttle crew member James Buchli, Skylab member Robert Crippin and Gemini mission alum and former Air & Space Museum director Mike Collins -- were on hand to provide a little commentary from a perspective most Americans will never get: above what Buchli describes in the film as "the thin blue line" that makes up the Earth's atmosphere.

"Over the last few years there has been an increasing sense that the planet needs protection -- especially now after what's happened this year," said the film's writer, editor and narrator, Toni Myers. "We wanted a film that looks at the whole Earth, to look at the changes going on and the serious impact on our lives."

Apparently, she and the film's producer, Graeme Ferguson, succeeded.

"I walked out thinking, 'What am I supposed to do now?' " said Tom Freudenheim, the Smithsonian's assistant secretary for museums.

"I was really moved," said Tipper Gore as her daughter Sarah, 12, polished off a plate of goodies. "I mean, Al has come home and told me about the destruction in the rain forests, but to see this -- the burning! It really drives home the point of how fragile the ecosystem is."