Incredibly, theAqua Terra at the heart of the exhibition withstood a field 16 tesla, or 160,000 gauss. The experiment took place at the Laboratoire National des Champs Magnetiques Intenses (LNCMI) in Grenoble, France, a lab which specializes in research into extremely powerful magnetic fields. Equipment at LNCMI can generate sustained fields of up to 35 tesla, and at the lab’s Toulouse facility, millisecond-duration fields of up to 250 tesla have been generated (although this destroys the field generator coil). For reference, the magnets used to confine the particle beams of the Large Hadron Collider operate at about 8.3 tesla – more than 100,000 times as powerful as the Earth’s magnetic field.
A watch with a silicon balance spring is already significantly more resistant to magnetism than one with a standard balance spring, but Omega achieves this level of antimagnetism through the application of non-ferromagnetic materials throughout the movement, including the pivots – which is why the Aqua Terra not only ran fine after exposure to such a strong field, but during exposure as well.