Early Pandora WikiThe days of the first Na'vi

Floating mountains

From the Early Pandora Wiki Canon Real world Wiki lore

The floating mountains, called Ayram alusìng by the Na'vi and the Hallelujah Mountains by humans, are giant rocks that hover in the air above Pandora. They contain lots of unobtanium, a superconducting mineral pulled by Pandora's strong magnetic currents, so chunks of land are torn loose and drift like icebergs in the sky. Canon

Unobtanium (Na'vi lingtskxe, "floating rock") is the mineral humans came to mine. Waterfalls pour off the floating mountains, and vines hang between them. Canon

How could a mountain float? The real science

Floating mountains sound like magic, but the idea is built on real physics that scientists can show in a lab today. Here is how it works, step by step.

1. Magnets can push, not just pull

You know that magnets stick to a fridge. But hold two magnets with the same ends facing and they push each other apart. That push is real, and with a strong enough magnet it can lift things off the ground. Real world

2. Superconductors push magnets away

A superconductor is a special material that, when it gets cold enough, lets electricity flow with no loss at all. It also does something amazing: it pushes magnetic fields out of itself. Put a superconductor above a magnet and it floats! Scientists call this the Meissner effect. Real world

Real superconductors only work when they are freezing cold, about −135 °C or colder, which is why lab demonstrations steam with liquid nitrogen. In Avatar, unobtanium is a superconductor that works at normal temperatures, which is exactly why it is so valuable. Real world Canon

3. Flux pinning keeps them locked in place

A floating superconductor does not just drift away. Tiny threads of magnetic field get "pinned" inside it, so it stays locked at the same height and angle, even upside down. This is called flux pinning or "quantum locking," and you can watch videos of small discs locked in mid-air above a magnetic track. Real world

This is why the floating mountains hover in one place instead of tumbling around: their unobtanium is pinned by Pandora's magnetic field. Wiki lore

4. Even a frog can float

In 1997, scientists in the Netherlands used a very strong magnet, about 16 tesla, to float a live frog in mid-air. Water and living things push weakly against magnetic fields, and a strong enough field lifts them. The frog was fine, and the experiment later won a prize for science that "makes people laugh, then think." Real world

5. Pandora has a huge magnetic field

Pandora orbits Polyphemus, a gas giant with a powerful magnetic field, and Polyphemus's pull helps create strong magnetic "flux" areas on Pandora's surface. Around the Hallelujah Mountains the field is so strong that the film calls it the flux vortex, where aircraft instruments stop working and pilots have to fly by sight. Canon

Let's do the maths

Scientists use a real formula to work out how hard a magnetic field can push. The push gets stronger very quickly as the field gets stronger: double the field and the push is four times as strong. Real world

Magnetic push = field × field ÷ (2 × a special number called μ₀)

To float, the push must be at least as big as the mountain's weight. Pandora's gravity is about 20% weaker than Earth's, which helps. Canon Using the weight of ordinary rock, a block of rock 500 m thick needs a field of about 5.2 T. That is less than twice as strong as a hospital MRI scanner. Real world

How strong is that magnet? Magnetic field strength in tesla (T). Each step to the right is ten times stronger.
Real magnet on EarthPandora estimate
0.000010.00010.0010.010.1110100Earth's magnetic field0.00005 TFridge magnet0.005 TStrong neodymium magnet1.2 TPandora field to float a 100 m rock2.3 THospital MRI scanner3.0 TPandora field to float a 500 m mountain5.2 TInside the flux vortex (wiki estimate)12 TMagnet that floated a live frog16 TStrongest steady magnet on Earth45 TField strength in tesla (log scale)
Show the numbers as a table
MagnetField strengthSource
Earth's magnetic field0.00005 TReal
Fridge magnet0.005 TReal
Strong neodymium magnet1.2 TReal
Pandora field to float a 100 m rock2.3 TPandora estimate
Hospital MRI scanner3.0 TReal
Pandora field to float a 500 m mountain5.2 TPandora estimate
Inside the flux vortex (wiki estimate)12 TPandora estimate
Magnet that floated a live frog16 TReal
Strongest steady magnet on Earth45 TReal

Pandora's fields are strong, but not impossible. Scientists on Earth have already built magnets almost four times stronger than the field this wiki estimates for the flux vortex. Real world Wiki lore

Thicker mountains need stronger fields. Field needed to hold up a block of solid rock on Pandora, by how thick it is.
02468101205001,0001,5002,000Hospital MRI scanner, 3 TField needed (tesla)Thickness of the rock (metres)
Show the numbers as a table
Rock thicknessField needed
100 m2.3 T
250 m3.6 T
500 m5.2 T
1,000 m7.3 T
2,000 m10 T

The curve rises quickly at first and then levels out. Because the push grows so fast with field strength, you only need a little more field to hold up a much thicker mountain. Real world

Why the mountains float at one height

A magnetic field gets weaker the farther you go from its source. Near the valley floor, the field is strong and the push is huge. Higher up, the field fades and the push gets smaller. A mountain rises until the push exactly matches its weight, and stops there. If it drifts higher, the push gets weaker and it sinks back. If it drops lower, the push gets stronger and it rises again. Real world

Why a mountain floats at one height. For a 500 m thick mountain: the upward magnetic push (fading with height) and the downward weight, in tonnes on every square metre.
Magnetic push upWeight pulling down
01,5003,0004,5006,0007,50001,0002,0003,0004,000Floats here, about 1,700 m upToo low: pushed upToo high: sinks back downTonnes per square metreHeight above the valley floor (metres)
Show the numbers as a table
Height above valleyMagnetic push (t per m²)Weight (t per m²)
0 m7,3011,350
500 m4,4281,350
1,000 m2,6861,350
1,500 m1,6291,350
1,700 m1,3341,350
2,000 m9881,350
3,000 m3631,350
4,000 m1341,350

For this chart, the wiki assumes a field of 12 T at the valley floor that halves about every 1,400 m going up. Those numbers are wiki estimates, but the balance idea is real physics. Wiki lore Real world

Good questions

Why don't the mountains crash into each other?
Flux pinning holds each one in its own pocket of the field, like eggs in an egg box. Real world Wiki lore
Why does water fall off them?
Only the unobtanium in the rock is held by the field. Rain and river water are not, so they pour off the edges as waterfalls. Canon Wiki lore
Do compasses work there?
No. A compass needle lines up with magnetic fields, and in the flux vortex the field is so strong and twisted that needles spin or point the wrong way. Real world Wiki lore
Could this happen on Earth?
Not with mountains. Earth's magnetic field is about 0.00005 T, about a hundred thousand times too weak, and we have no room-temperature superconductors in the ground. Small things float in labs every day, though. Real world

Inspired by Earth

The mountains were inspired by the tall stone pillars of Zhangjiajie and the Huangshan mountains in China, often wrapped in mist. Real world

In early Pandora

Wiki lore says the early swamp clans believed the floating mountains were the "stepping stones of Eywa," and that the tak migrated by flying from one to another in a great blue V each season. Na'vi elders said a mountain floats "because Eywa holds it in her open hand," which is not so far from a field holding it up. Wiki lore

Try it yourself

With an adult, search for videos of "quantum levitation" and "Meissner effect" to see real superconductors floating. Science stores also sell safe kits where a thin sheet of pyrolytic graphite (a kind of pencil "lead") floats above strong magnets, with no cold needed. Always keep strong magnets away from phones, cards and small children, and never swallow them. Real world

See also

References

  1. Why do the islands float in Avatar? – The Digital Fix
  2. Pandora (Avatar) – Wikipedia
  3. Polyphemus – Avatar Wiki
  4. Superconductivity – Wikipedia
  5. Meissner effect – Wikipedia
  6. Magnetic levitation of a frog (Andre Geim) – Wikipedia
  7. National High Magnetic Field Laboratory – Wikipedia
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