Speeder Bikes
The speeder bike is one of the coolest pieces of Star Wars technology. You ride it like a motorcycle except that it flies through the air without ever touching the ground. In " Return of the Jedi,"soldiers use them to ride through the forest at 50 MPH. They fly between the trees with the grace of a bird.

You see this floating technology in lots of Star Wars vehicles. Luke's landspeeder uses it in the very first Star Wars film. Lots of droids use it so they can float through the air. Jabba the Hutt rides around in a floating land barge. Many space ships (like Luke's X-Wing fighter and the Millennium Falcon) also use it for taking off and landing.

The technology that makes this all possible in the Star Wars universe is called a repulsorlift. It is a device that repels gravity and allows something to float. You can imagine how a repulsorlift might work by thinking about what happens when two magnets repel each other. If you could get the same kind of repulsion to happen with gravity, you would have a repulsorlift. The question is, "Will you be able to get repulsorlift technology on your bicycle any time soon?"

Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved. All Digital work by ILM.

There are two problems. The first problem is that nobody really understands gravity right now. That may sound funny, given that gravity is all around us and we live with it every day. But scientists really do not understand it very well.

What we know about gravity is that any two atoms have a very, very tiny gravitational attraction for each other.

Scientists are not sure how the atoms attract each other, so they have no idea how to create the "anti-gravity" force that would let a repulsorlift do its thing.

Let's say someone were to figure out gravity next week and also invent a way to do anti-gravity. Then, in theory, we could have repulsorlifts available in just a few years. But then there would be another problem.

That other problem is "changing direction" -- accelerating, turning and stopping. When you ride in a car, you have four tires that stick to the ground. When you turn the steering wheel, those sticky tires apply the force that moves the car in a new direction. If you are floating in the air, there is no way to apply the force. Luke's landspeeder has jet engines to make it go forward. But you would also need equally big engines pointed the other way to act as the brakes, and you would also need side thrusters to turn.

When you add it all up, tires may not be so bad after all!