While there is much to criticise about Avatar’s plot, its physical worldbuilding remains fascinating even a decade after its initial release. Pandora is unique amongst the other planets on this list, as it is actually a moon of the fictional gas giant Polyphemus, located in the Alpha Centauri system.
The most memorable imagery from Avatar is likely to be its famous floating mountains. While these may seem to be a gross violation of gravity, there is actually a degree of science behind them. The movie explains that Pandora is rich with a mineral called unobtainium (this is an actual term by the way), a superconductor of which we, poor citizens of reality, can only dream of.
Before getting to how mountains can float, one must first understand what superconductors are. In the simplest terms, superconductors are materials that, when cooled below a certain temperature, can conduct electricity without resistance. Electrical current is conducted when a charged particle nudges its neighbours, passing on its charge. This creates a chain reaction of sorts from one end of the conductor to the other. However, the conduction of electricity is often not as efficient as it could be due to resistance- but resistance decreases as temperature decreases. When a superconductor is cooled below its critical temperature, the resistance vanishes, and electricity can flow freely through it.
Now that the definition of a superconductor is clear, we can move on to how it levitates. At normal temperatures, magnetic fields are able to pass through the material. However, superconductors below critical temperature are perfectly diamagnetic; magnetic fields are unable to pass through them and are repelled from its centre. When a superconductor is placed above a magnet, a magnetic field in the opposite direction is induced in the superconductor, cancelling out the magnet’s field that is passing through the superconductor. These induced magnetic fields also act like a magnet with the same pole as the original magnet, repelling it and allowing the superconductor to levitate above the magnet (it is also possible to levitate the magnet above the superconductor). This is known as the Meissner Effect.
While talking about levitation sounds easy, life is cruel and won’t deign to grace us with the ability to make everything float. As previously mentioned, levitation only occurs when the superconductor is below its critical temperature and the highest temperature at which superconductivity is observed is -23 °C.
In other words, Pandora’s floating mountains have just enough theory to make science nerds nod their heads in appreciation… and then promptly wallow in self-pity as the realisation hits that such large-scale demonstrations of the Meissner Effect are nigh impossible.
Pandora gets an A from me because I like superconductors.
What? You still thought this tier list was going to be objective?
Hackett, J. (2015, December 17). How Do They Do That? A Closer Look at Quantum Magnetic Levitation. Retrieved December 24, 2020, from https://www.scientificamerican.com/article/how-do-they-do-that-a-closer-look-at-quantum-magnetic-levitation/
Kirshenbaum, S. (2009, December 30). The Science of Avatar (Part II). Retrieved December 24, 2020, from https://www.discovermagazine.com/the-sciences/the-science-of-avatar-part-ii
Meissner Effect. (2020, May 18). Retrieved 19 January 2021, from https://eng.libretexts.org/Bookshelves/Materials_Science/Supplemental_Modules_(Materials_Science)/Magnetic_Properties/Meissner_Effect
NileRed. (2020, August 01). Making superconductors [Video]. Retrieved from https://www.youtube.com/watch?v=RS7gyZJg5nc
Physics High. (2017, June 11). meissner effect explanation (basic) [Video]. Retrieved from https://www.youtube.com/watch?v=NVeAmKUbXvAWoodford, C. (2020, March 01). Superconductors. Retrieved 19 January 2021, from https://www.explainthatstuff.com/superconductors.html