'Hey Bill Nye, Can We Use Giant Magnets to Build a Space Elevator?'

Television Host and Science Educator

Bill Nye answers a question submitted by Nick: is it possible to take two giant magnets and use the repulsion force between them to lift objects into space? Or can we set up stages along the way and use the attraction and repulsion force to build a space elevator to the moon, or anywhere else we may want to go?

Nick is definitely onto something. Building a reliable space elevator has been the dream of many physicists, beginning with the Russian scientist Konstantin Tsiolkovsky. Inspired by the Eiffel Tower in Paris, Tsiolkovsky boldly envisioned a tower extending from the surface of the Earth into its atmosphere in geostationary orbit.

Perhaps the most popular source of the idea came with Arthur C. Clarke's novel, The Fountains of Paradise, featuring engineers who construct a space elevator from the top of a mountain. A career engineer and science educator himself, Bill Nye tackles the practicality of a space elevator — at least one relying on magnets — that has captured the imagination of generations of scientists.

As it turns out, the repulsion force in magnets is strong but at very short distances. And any spacecraft one would hope to lift from the surface of the planet would be — well, it would be large. This doesn't automatically disqualify magnets; it simply means that gigantic magnets are called for. And gigantic magnets must be powered by a gigantic power source.

Just to power protons around CERN, a particle accelerator straddling the Swiss/French border, the amount of energy needed could power a small city. And to further complicate matters, balancing a large object that is being pushed up requires stabilizing it, i.e. a place for it to be pushed up from.

Still, getting to space at less expense has driven the success of companies like Elon Musk's SpaceX and Jeff Bezos's Blue Origin, so there is certainly a market for whoever can get there with less overhead. It might be you, Nick! Good luck!

Bill Nye's most recent book is Unstoppable: Harnessing Science to Change the World.

  • Transcript

TRANSCRIPT

Nick: Nick here. I was wondering if it’s possible to take two giant magnets and use the repulsion force between the two to lift objects into space or can we set up stages along the way up and how that attraction and repulsion force send a type of space elevator up to the moon or anywhere we want to go. Let me know what you think.

Bill Nye: Nick, Nick, Nick. This is an interesting question. Let me say though starting out we all when you play with magnets and you feel the repulsive force it seems strong. But notice that it acts over a very short distance. Just nominally it goes – it’s not perfect but you can estimate it by saying it goes off as the cube of the distance. So if you have magnets this far apart and you make them twice that far apart they only haven an eighth as much umph. So using a magnet to push things up as high as the atmosphere would take an enormously strong magnet and where would that energy come from? And to give you an idea of the kind of energy we’re talking about the particle collider in Switzerland which we call CERN, the Center for Nuclear Research but in French the adjective is at the end. That takes the electricity of a small city to keep protons going in a circle, just protons. So just imagine how much magnetism you would need to push something of reasonable mass up into the sky. It would take a huge amount of energy. So shooting from the hip I’d say it’s really not possible.

With that said I like the way you think. Then you also referred to using stages to get the magnet, this magnetic car or craft pushed up. Keep in mind that whatever you push it up from has to be pushed from a place which is somehow anchored to the Earth or magnetically repulsed from the Earth. So it becomes really difficult practically to have a stack of magnets that’s stable that has all that energy required to create that much magnetism. You probably couldn’t do it. But that’s very creative. That was cool. Carry on Nick.