Question: I am a big fan of star wars and space do you think there would be anyway to get objects hover with out rotar blades or propellars?

Nathan Langford answered on 26 Jun 2012:

Actually, you can already get objects to float without blades or propellers! You can use something called magnetic levitation and it uses superconductors. Imagine you create a magnetic track in a circle and then place a metal superconductor above it. A superconductor is something that conducts electricity with absolutely no resistance, which means that the electrons carrying the current don’t lose any energy as they move through the metal, meaning that once you switch the current on, it can flow forever.

So how does levitation work? Well, it turns out that if you try and move a metal conductor in a magnetic field, then the magnetic field will push the electrons around inside a metal to create a current flow. But the moving electrons in the current create a magnetic field of their own, and as you know from seeing what happens with normal magnetics, when two objects create magnetic fields, they will either attract each other or repel each other. The cool thing is that the magnetic field created by the electrons will be exactly the one required to try and stop the movement which was creating the current in the first place (this sounds a bit weird, but it’s true). In other words, if you move the conductor towards a magnet, this effect will try to push it away again.

Now, obviously, we all know that lots of metals are attracted to magnets and this is because this effect isn’t big enough for normal metals and other effects are more important. But if you use a superconducting metal instead of a normal metal, the current created by moving the superconductor towards the magnet doesn’t feel any resistance, so the resulting push away is so strong that it can actually balance the force trying to bring it closer.

Specifically, if you place a superconductor over the top of a magnetic track, it can hover there, or even travel around and around or float underneath the track. Check out the following really cool youtube video to see a great demo of this:

http://www.youtube.com/watch?v=llPFFKCpjnU

But it this actually used for anything? You bet! It’s now starting to be used in high-speed trains. I believe they just started building a new high-speed train in Japan last year, with a magnetic track and superconductors on the train, which is going to travel at over 300 miles per hour!

Now, that’s cool physics!