- In 2015, physicists created a tiny magnetic wormhole to connect 2 different space regions.
- This is something different from a gravitational blackhole, in which magnetic field can travel through an invisible tunnel.
- The results of the constructed wormhole have been experimentally verified on for DC fields.
A wormhole basically creates a shortcut between two far distinct points by distorting space-time. They might be dangerous as they bring with them high radiation, chances of sudden collapse and risky contact with exotic matter.
First theorized in 1916 in Einstein’s theory of General Relativity, a wormhole could connect any distance, from a few meters to a billion light years or different universes. It’s very hypothetical at this point, and no one thinks we are going to find a wormhole anytime soon.
Creating an artificial gravitational wormhole connecting two distant regions in the universe is an extremely challenging task. It would require massive amounts of negative gravitational energy, which is impossible to generate with existing technologies.
However, the physicists in Spain created a tiny magnetic wormhole (something different from gravitational wormhole) in 2015, and they used it to connect two different space regions so that a magnetic field can travel invisibly between them.
This wormhole won’t let you travel rapidly across space like in sci-fi movies. But the scientists managed to build a tunnel that makes magnetic field disappear at one point and then reappear at another, which is still a pretty big deal.
How They Created a Magnetic Wormhole?
At present, physicists are good at creating and manipulating electromagnetic energy, so the team at Autonoums University of Barcelona planned to build a magnetic wormhole, and it actually worked.
Greenleaf AL, et al. described a theoretical method for building a wormhole using electromagnetic waves. Such an object could enable electromagnetic wave to propagate between two distinct points in space via an invisible tunnel.
This would require several metamaterials with complex permittivity and permeability parameters. These metamaterials allow to precisely control electromagnetic waves, including a few realizations mimicking celestial bodies.
The design provided by Greenleaf is capable of altering the space topology because it would make electromagnetic waves to propagate in three dimensional space with an invisible tunnel joining two distinct regions.
Inspired by this theoretical concept, physicists constructed an actual 3D wormhole for magnetostatic field that allows the magnetic field to pass between two different regions while region of propagation or channel remains magnetically invisible.
Instead of building a wormhole based on transformation optics, physicists took advantage of metamaterials to manipulate or shape static magnetic fields. These metamaterials are built from several combinations of natural magnetic materials ranging from zero magnetic permeability to superconductor or ferromagnets.
The Shape of Wormhole
As we have mentioned, the magnetostatic wormhole requires a magnetic field tunnel behaving as if was outside the regular 3D space. The first thing is to magnetically decouple a specific volume from the surrounding 3D space. Here, we are taking taking volume enclosed by a spherical superconducting shell.
Another thing that needs to be satisfied is the entire wormhole can’t be magnetically detectable from its exterior. Therefore, physicists used a cylindrical magnetic cloak with superconducting layer surrounded by magnetic layer.
Reference: Nature | doi:10.1038/srep12488
Ultimately, what they came up with is a spherical bilayer composed of a superconducting layer surrounded by a ferromagnetic layer, and a ferromagnetic sheet rolled into a cylinder internally to allow the magnetic fields to propagate through its interior.
Specifically, the core of the device is the magnetic hose made of high-permeability mu-metal foil, folded into a spiral. It’s surrounded by a spherical superconducting layer, made of high-temperature superconducting strips stuck to a spherical former. On the top of this superconducting is a thin ferromagnetic layer (which is an outer layer). An array of mu-metal plates is arranged in a manner so that they can provide the desired magnetic response.
Although the wormhole is spherical in shape, similar outcomes could be obtained for elongated ellipsoid that could be extended to longer distances in a single direction.
Validity and Accuracy
Both ends of the magnetic wormhole are not accurate – they are considered in an approximate way. Since the spherical shell has finite openings, these regions would not exhibit perfect cloaking properties. However, one can reduce the field distortion at the ends by optimizing the design.
The results of the constructed wormhole have been experimentally verified on for DC (Direct Current) fields. Both superconductors and ferromagnets work perfectly in low frequency electromagnetic waves, so the magnetic wormhole could also be effective at low AC (Alternating Current) frequencies.
The study will have practical applications, especially in the sector that use magnetic fields, for instance, it could help building an MRI machine that does not need patients to lie inside the claustrophobic machine, or you can say more targeted MRI scans.
Furthermore, it teaches us more about the techniques of tunneling our way through space – an endeavor that holds infinite possibilities.