“Despite my best efforts, I have found that the forces that drive our world cannot be abolished. Fortunately there are workarounds and ways to make it look like they’ve been abolished. Such is the magic of science.”
- Thunder Strike
Discovered at the eve of the 21st century, gravity tether technology has since become a crucial part of everyday activity here in Equestria. Foals rarely wonder at the flying marvels that traverse our cities, likely attributing them to the same abilities Pegasi possess. The truth is very different and much more interesting.
But, before we continue, let me be perfectly clear: Gravity cannot be ‘switched off’. I’ve tried, and the results were not pretty. This is why the commonly used vernacular “Gravity Tether” is a useful moniker, and the sometimes-used “Antigravity Belt” is incorrect. Grav-tethers do not switch off gravity, they redirect it. This is done by a curious property known as quantum entanglement.
When two particles are entangled together, they exhibit a number of interesting properties. For example, when the spin of two entangled electrons is measured, they will always yield opposed answers, even if it is not possible for any communication to have occurred between them. The universe seems to regard them as tied regardless of spatial constraints. Of course, the laws of causality are not violated: no information is transmitted by measuring entangled particles, so messages cannot be sent. Another interesting property is the strange interplay between gravitons and entangled particles. Note that there are several more strange and interesting properties, but I have been “encouraged” to stay on-topic.
Gravitons (not to be confused with gravitrons, which are similar, but totally different things) are the particles which transmit mass. You can think of all particles everywhere as tied together by an endless stream of gravitons, each pulling on all the others and on space itself. Large masses of particles have larger streams of gravitons and thus pull more strongly, and this manifests in the phenomena we call gravity. But when an entangled particle is run near a derived stream of anti-gravitons (a graviton’s antiparticle), suddenly all the gravitons pull on the other entangled particle, and none pull near the anti-gravitons!
The result is that the first particle appears to float. This is because it is not being pulled on by gravity at all, and may float out of the atmosphere if left unchecked. I have written a number of papers on the matter and I am thoroughly convinced Lab 8 is still upset about the loss of their particle accelerator. Anyway, the particle’s mass is still intact, and it can be pushed around, but gravity is temporarily not pulling on it.
Gravity tethers work by reversing this effect: A magnetically encased stream of particles is held within the tether, and these particles are entangled with particles somewhere on the ground. A small charge of anti-gravitons is held within the tether, and the result is that all the gravity of the tether pulls on their grounded counterparts and as a result, the object floats.
Naturally there are some difficulties here: entanglement is difficult and I have been instructed to emphasize that constructing materials made of entangled particles is sheer folly lest there is a repeat of the incident at Lab 8. In any event, the final part of the tether comes with the presence of an energy stream run through the anti-gravitons, which amplifies the gravity-siphoning effect and causes liftoff in the other end of the tether. After, heavier objects are attached to the tether to neutralize it while still allowing it to remain airborne, our floating machine is complete!
Now you understand the device that makes much of modern day life possible. Gravity tethers are used in everything from patrolling Sentinal robots to aerial weather maintenance robots. There are even plans to use larger gravity tethers to allow cheap, efficient space travel by reducing the pull on a rocket and vastly reducing its required fuel payload.