'Cosmic Collisions': Prepare for Deep Impact

The vastness is easy to forget, isn't it?

Walking around down here, shopping for holiday gifts, worrying about project deadlines, bickering about movies or restaurants -- banal, absorbing existence, persisting day after day after day.

Almost never jarring us into contemplation of the space beyond.

Space.

"Out here in space, the stars look peaceful, don't they?" Robert Redford's voice intones as the lights at Einstein Planetarium go from green to black and the universe opens up overhead.

And they do look peaceful, gauzy and glittering as van Gogh would have us see them.

But one comes to a planetarium show, and this one in particular, to be reminded that space is far from stagnant, that the celestial canopy lighting up every night is dynamic, unknowable, a little scary.

"People used to believe that comets, like this one, were bad omens," Redford continues during the first minutes of the "Cosmic Collisions" show at the National Air and Space Museum on the Mall. "Knowing what a comet is doesn't mean it won't cause trouble -- that comet is heading towards Earth. Will it hit?

"Not this time."

But the point is, sometimes they do hit, to tremendous result. Redford is our guide on this 23-minute constitutional around the universe, reciting the scientific community's conclusions on the dramatic role collisions play in shaping solar systems.

Forming the moon, for instance, and causing the eventual extinction of the dinosaurs when a seven-mile-wide asteroid hit the Earth, and "everything that could caught fire. Smoke and soot filled the atmosphere. For six months, it would be too dark for plants to grow."

Frightening, until Redford calmly adds: "Without this collision, we might not be here."

He goes on to say that scientists think they've found a way to stop other asteroids from hitting our planet, which is hopeful, if certainly not proven, solace. (The plan? Fly a spacecraft alongside the asteroid, using the force of gravity to knock it off course enough to avoid impact.)

The show, which opened in November, will run indefinitely at Air and Space's Einstein Planetarium, was created by the American Museum of Natural History in New York and debuted there in March. In previous years, the Smithsonian produced its own planetarium shows, but resources have been shifted away from the costly endeavor.

"Now we're looking for the best that's out there," said David DeVorkin, the museum's senior space history curator. DeVorkin and a Smithsonian committee reviewed a dozen planetarium shows before deciding on this one. "The reason we chose 'Cosmic Collisions' is that it's accessible. And it says something about the way the universe works that we haven't known for very long. . . . The mechanism of meteor impact has not been appreciated to be such an important feature of planetary formation."

DeVorkin said his team was impressed as much by the show's approach as by its scientific accuracy, which projects out billions of years to give audiences a glimpse of what the solar system might look like long after we're gone.

"We humans occupy a tiny part of a vast and evolving cosmic landscape," Redford reminds us. And every once in a while, it's good to remember.

COSMIC COLLISIONS Einstein Planetarium, National Air and Space Museum, Independence Avenue at Sixth Street SW. 202-633-7827. http://www.si.edu/planetarium. Show runs every half-hour between 10:30 and 5. $8.50, $7 ages 2 to 12, $7.50 seniors.