Several aquariums feature large, transparent, underwater domes or tunnels that allow people to walk through and observe fish swimming all around them. The Planetaquarium would simply place a dome-shaped aquarium inside the larger space of a dome-shaped planetarium, using the fish as part of its projection
screen. A projector would sit at the center of the dome, casting the images of stars out to the far wall. When the fish swim in the way, they will momentarily act as the projection screen on which the spot of light appears. With brightly colored and/or shiny fish, this would make a most pleasant effect.
The only engineering difficulty would be creating a dome that can comfortably contain at least fifty people while withstanding the pressure of a few atmospheres' worth of water pressure, all without any support structure or visible seams between its sections. Beyond that, it's all pretty technically feasible.
The Planetaquarium would offer a wide range of lighting options to suit its many uses. Here's what I've come up with so far:
- The outer projection wall wouldn't have to be pitch black all the time. It could be lit with a variety of colors, like the deep blue-green of the ocean or the pinks and purples of twilight as the first few stars become visible. But naturally, near-black would be best for seeing the stars.
- The outer wall could also be fit with small white LEDs in exactly the same positions as the projected stars, so the fish's shadows wouldn't have to affect image of stars. In fact, it might be nice to turn off the projector and only see the black silhouettes of fish against the starry night sky. Granted, the outer dome would not be able to rotate to simulate the motion of the stars, but it would make a nice effect.
- The space could also be lit with blacklights, making the fish glow. Put them in front of a black background and try not to have your mind blown by THAT.
- One could introduce a substance into the water that makes it slightly cloudy, so one could see the beams of light from the projector. Or for that matter, there could be a small amount of fog in the inner dome for the same purpose. It might be especially cool to have one fog system on and not the other, so the beams of light seem to start or stop at the plastic barrier.
- One word: jellyfish.
- Ooh! You could plant a small tracking chip inside every fish, then have an automated spotlight with a fairly narrow beam immediately find and illuminate a specific fish, for instance during a marine biology lecture. With digital projection technology these days, this is not out of the question. Or you could have multiple follow spots following different fish, perhaps to point out all the members of one particular species throughout the tank. Or for that matter, have a follow spot for every fish, and watch as each beam meanders around independently from the others.
Then all you'd need is a sound system playing some soothing ambient music. I would insist that the playlist include the "Aquarium" movement from "The Carnival of Animals" by Camille Saint-Saëns. Also play the Moonlight Sonata, maybe a little Enya, you get the idea.
The Planetaquarium: coming to a science center near you.