Cosmic Cathedral is 21st Century fox.

Mayor Rudolph Giuliani expanded his role last week, becoming "Mayor of the Universe" as he ceremonially snipped a star-studded ribbon that officially opened the Rose Center for Earth and Space at the American Museum of Natural History in Manhattan.

Designed by James Stewart Polshek and Todd H. Schliemann of Polshek Partnership Architects, and constructed by Morse Diesel International, the airy and dramatic seven-level Rose Space Center becomes the first 21st Century building for New York City. To the delight of futurists, it has landed seemingly without moorings within the 20-acre complex of the 131-year old American Museum of Natural History on the grimy Upper West Side.

"It is first and foremost about science and education, and speaks to what it is about being a museum in the 21st Century," said museum president Ellen V. Futter. "It is architecture in the service of science and makes the beauty of the universe transparent and alluring to all."

That the new Hayden Planetarium exists at all is a testament to the Giuliani administration, which declined to landmark its 65-year old, scientifically outdated predecessor despite numerous entreaties from its Upper West Side neighbors.

Although the museum board had expected to merely update the Planetarium and complete its circle, its confining building and antique equipment were as moored in the past as its science, which revolved around the stars as seen from the Earth. Once Futter asked what the architects could do with a clean slate, its geometry was instantly lifted from Earth to space.

City Landmarks Commissioner Jennifer Raab joined politicians such as Council Member Stanley Michels, Public Advocate Mark Green, former Borough President Ruth Messinger and NYC Planning Commissioner Joseph Rose, a nephew of the museum's benefactors, for the ceremonies and a preview of the planetarium show, which officially opened to the public on February 19th.

Giuliani was joined at the ribbon-cutting by Council Speaker Peter Vallone, museum benefactors Sandra Priest Rose, for whom the Space Center is named along with her late-husband, Frederick Phineas Rose, their son, Jonathan F.P. Rose, Richard Gilder, Dorothy Cullman, and David S. Gottesman, Futter, and museum chairman Anne Sidamon-Eristoff.

Fred Rose passed away last September after six years of work planning, fund-raising and actively developing the Space Center as one of the museum's trustees.

Mayor Giuliani said he thought of Moses, wandering in the desert with his people and not being there when they crossed over to the Promised Land. "But he knew they would be there. [Rose][ldots] knew we would be here," the Mayor said.

Speaker Vallone agreed, "It wasn't just Fred Rose's vision, but he was a generous and kind man who gave in abundance[ldots] this will be the most lasting act of kindness."

The original Hayden Planetarium was a confining half sphere, and its new full sphere appears suspended within its 120-foot glass cube, and weighs in at four million pounds. "And we used to worry whether the whale would fall," recalled Futter, looking up at the 87-foot high aluminum ball, as did the crowd gathered directly underneath in the Dorothy and Lewis B. Cullman Hall of the Universe.

Here, the 13-foot Astro Bulletin that provided a backdrop for the speakers and Andrea McArdle singing "America the Beautiful" will soon feature high-definition space images and programs. Other three-dimensional and kinetic exhibits in this 7,000 square-foot area illustrate the processes that led to the creation of stars, planets, galaxies and the universe.

The top half of the seemingly suspended sphere contains the Space Theater planetarium, where after paying for a separate ticket, visitors will learn about their place in the universe. A pre-show in an outer holding area takes its cues from Disney, with a multi-video screen presentation designed to gather up the crowd before allowing them into the actual theater.

Narrated by Tom Hanks, who took his own space voyage in the movie "Apollo XIII," the first 20-minute program, "Passport to the Universe," was co-authored by Ann Druyan, a writer of popular science programs including the "COSMOS" series and the upcoming 3D IMAX movie Comet, and widow and collaborator of the late Carl Sagan; and Steve Soter, a staff scientist in the museum's Department of Astrophysics.

Once inside the 429-seat circular theater, visitors will virtually, yet comfortably, tour the scientifically accurate known observable universe as it is displayed on the Digital Dome by the Zeiss Mark IX projector and other, computers. Data from scientists around the world contributed to the computerized images of the Milky Way and Orion Nebula, which are among the areas explored before entering the imaginary realm of a black hole and embarking on an artistic, 2001-like, liquified, color-filled return to Earth. The theater can shake its seats when a space ship launches or zoom in on tiny molecules yet to be discovered.

An escalator then whisks space travelers to the lower half of the sphere, which is bisected by a well-like theater housing a Big Bang program narrated by Jodie Foster. That dark space leads back out to the glass atrium and the cantilevered, Heilbrunn Cosmic Pathway.

This is a 360-foot rampway encircling the sphere, where each inch represents 3.6 million years. Exhibits illustrate the development of the universe through historical timelines, photographs and displays marking 13 billion years. The Age of Dinosaurs, which ended 65 million years ago, comes two feet from the bottom, where finally, recorded human time is marked by the thickness of a single human hair.

The exhibitions were designed by Ralph Appelbaum Associates with the museum staff and integrate items such as a 39-inch ecosphere, video screens, projections, mosaics, the 15-ton Willamette Meteorite with high technology prisms and the instantly iconic planets.

The 17-foot rings of Saturn, the 8-foot 11.125-inch Jupiter and 9.5-inch Earth are suspended next to the 87-foot sphere and are visible from the street, providing onlookers weighs in at 450 pounds. These are anchored by steel "spider" fittings and sealed with silicon to provide clarity, yet they will also "give" as the winds and Earth moves them.

Architect Polshek designed the structure as a "cosmic cathedral," taking design cues from the I.M. Pei glass pyramid entrance to the Louvre, the 1939 World's Fair Peresphere and other historical and spatial references. He is respectful of the surrounding building's materials and uses them to anchor and incorporate the edges of the Space Center and enhance the sphere's seeming suspension.

To the east, the adjacent 8,830-foot David S. and Ruth L. Gottesman Hall of Planet Earth opened last June and provides enormous and touchable examples of the earth's rocks and its geologic history. Here, school children gleefully jumped to see if they could make a bigger earthquake than their friend, as recorded by a seismograph's pen.

By spring, the Arthur Ross Terrace, a garden based on a lunar eclipse and designed by Kathryn Gusafson and Anderson & Ray in collaboration with the architects, will be completed over the new parking garage. It will open to the Space Center's west and provide another entrance to the Museum near the IMAX theater. A hallway will lead to the new Kids Planetarium Shop and Rose Gallery.

This coming June, in further celebration of the magic of light, diffraction gratings will be installed to radiate rainbows of color throughout the glass cube, while an updated armillary sphere of concentric circles will be unveiled at the Columbus Avenue entrance and depict New York City's location on January 1, 2000.

As Futter advised, the museum's 81st Street and Central Park West address has been extended to New York City, New York, USA, Planet Earth, Solar System, Milky Way, Virgo Supercluster, the Universe. It can also be found at www.amnh.org.