I AM standing in the middle of a room that looks like a TV cartoon. Except the mass in front of me is not a character but a big, blue-green-red molecule. It's floating. I turn my head to the left, find a smaller blue-green-red molecule, and reach out my hand. The small molecule turns white when I "grab" it (using a computer mouse).
This is my first experience with "virtual reality." I want to make the most of it.
The scene shifts. I am flying toward a merry-go-round and, once there, I have a hard time mounting the horse. He whinnies when I succeed. The merry-go-round starts up and I look out at other horses going up and down as the horizon begins to rotate.
Virtual reality is a computer-generated world.
Want to explore Mars? NASA's Virtual Environment Research Lab here has simulated a flyover based on information from Viking orbiters. Want to know how two molecules attract and repel? Researchers at the University of North Carolina (UNC) at Chapel Hill have a mechanical arm that reproduces the feel of the electrostatic and bump forces.
The point of virtual reality is that you no longer just see other worlds. You enter them.
To enter the one generated by the UNC computer, I have donned a special headset with two miniature TV screens as goggles. An overhead sensor tracks my movements and the computer instantaneously recalculates my position and transmits a new view to the goggles. I use the mouse to reach out because the computer senses that too.
In another part of the lab, I'm traveling through a house lighted at night. No goggles this time. Just a large TV screen and a black box with two joysticks - like a computer game. The picture is no longer cartoonish but almost realistic, with textures of wood and the effect of light bouncing off surfaces. I walk through doors and walls.
This architectural application is one of the coming benefits of the technology. Already a small North Carolina company called Virtus Corporation is selling "WalkThrough" for $895. It allows architects to design buildings on a MacIntosh computer.
The movement isn't real-time yet. Depending on the sophistication of the image and the power of the computer, WalkThrough recalculates the position at a speed of two to eight frames a second. By contrast, movies run at 24 frames a second; television, at 30 frames a second.
That performance will improve as desktop computers get more powerful. Eventually, an architect and his customer could put on some goggles, "travel" to the building site, and design a virtual house or building on location.
What's happening here is that scientists are expanding the ways in which people and computers interact. The learning potential is enormous.
Imagine finding out about 19th-century England by dropping in for a visit. Wander the streets of London, take part in a debate in Parliament, or chat with Charles Dickens about one of his new books. Improve your tennis by playing against a virtual Steffi Graf. Already a Sausalito, Calif., company called Autodesk has linked up two riders on Exercycles and simulated a bicycle race with virtual reality.
There's a danger in overselling this technology. It's a little like visualizing the compact disc while Edison is still playing with a wax cylinder.
Much of this stuff is decades away. We don't have to worry that people will lose themselves in a virtual world or fall in love with a virtual person (a la Star Trek). If anything, scientists who travel in virtual worlds consistently say they learn to appreciate the richness of the real one.
But there's a twist. If virtual reality lets us sense things in different ways and from different vantage points, we may well trust our senses less. Bob Jacobson, associate director of Washington State's Human Interface Technology Lab in Seattle, sees people becoming more skeptical about what they see as real.
"They will understand that all things can be fabricated and most things are," he says. "That's positive in my book."