Once again, the "rainbow" of Revelation 4-3-2 provides a clue. Pinnerman first persuaded me that the Philadelphia Experiment, aka "Project Rainbow," is a major influence on the show. And I've long loved clayseason's speculation that the Island is located inside a tesseract accessible via portals accross the planet.
(Adapted with permission from CS's Wrinkle in Time thread.)
Mysterious jazzman unified these ideas with his provocative suggestion that the Island was inside a hypersphere (i.e., the 4D equivalent of the 3D sphere). Another key insight was yung's that the Island's origins yielded its own magnetic field out of synch with the earth's. The final puzzle piece was magnetic resonance imaging, which lacenaire highlighted with this intriguing screencap on Freud Meets the Matrix.
Nuclear magnetic resonance results when an oscillating (e.g., rotating or alternating) magnetic field is applied at a right angle to a static (e.g., permanent) magnetic field. Such magnetic resonance has many useful real-world applications, most notably the aforementioned MRI technology in medical diagnosis. That much is science.
Any serious scientist will also tell you that gravity and electromagnetism are two separate and unrelated forces. Einstein struggled in vain to find a unified field theory, a goal that remains the holy grail of physics. Nevertheless, pseudo-scientific types insist the distinction is illusory, that the right electromangetic force will affect space-time just like gravity.
The "how" goes back to Nikola Tesla, whose scientific discoveries formed the basis of MRI technology. Tesla claimed to have discovered a new type of longitudinal (as opposed to transverse) scalar electromagnetic wave. Some say his experiments using such longitudinal scalar waves to transmit power wirelessly were the true cause of the Tunguska devastation.
Late in life, Tesla further claimed to have used these concepts to unify the fields in a dynamic theory of gravity. He never published his claims but they nonetheless spawned an entire pseudo-science of scalar electromagnetics. Proponents believe that gravity is really the force of longitudinal electromagnetic waves affecting space-time in the fourth dimension.
Tesla's technology supposedly formed the basis for Project Rainbow, the military experiment that culminated in the disastrous disappearance of the USS Eldridge. The premise is that three electromagnetic field coils are arranged so their magnetic fields cancel each other out in three dimensions but generate powerful longitudinal scalar em waves in the fourth dimension.
The resulting fourth-dimensional "hyperflux," as one author terms it, can be used to affect the fabric of space-time. The key is to pulse the coils at the proper frequency:
We are held to three dimensional space by an elastic force that can only be overcome by either expending a lot of power to charge an x-y-z coil, or to pulse the coil at the resonant frequency of fourth dimensional space. Think of space as a flat rubber sheet. To deviate a point on the sheet up or down, you can either push and hold it down with much effort, or you can vibrate the sheet so that the points on it swing up and down. If you get the mix of frequencies just right, you create a standing wave on the sheet, equating to minimal energy being used to get maximum warp in this sheet.
Wrinkle the sheet of space-time at its resonant frequency and the eventual result is jazzman's hypersphere:
If the standing wave in the rubber sheet is of sufficient amplitude, this wave rips itself out of the rubber sheet and becomes a rubber balloon. If you map the magnetic field of an x-y-z coil, it looks like an unfolded hypersphere. If the resonant frequency is reached, this field collapses into a magnetic hypersphere, carrying all objects in its proximity out into hyperspace. The teleporting object is encased in a bubble of space floating somewhere in the fourth dimension, disconnected from three-dimensional reality.
This is Desmond's snow globe. The Island's static magnetic field combines with that of the earth, which both interact with the oscillating field in Swan Hatch. The resulting magnetic resonance wrinkles space-time sufficiently to envelope the Island almost completely in the fourth dimension. That's how Hanso planned to shield the Island from apocalypse.
Tesla's Egg and Oscillation Resonance
So what's behind the concrete in Swan Hatch? My guess is a glorified version of Tesla's Egg of Columbus, which used rotating magnetic fields to stand a copper egg on end, and supposedly inspired Project Rainbow's coil arrangement.
The 108-minute countdown may relate to the periodic electromagnetic pulse of the coil at the resonant frequency of space-time. Many threads have noted the link between 108 and the basic structure of the universe. A related possibility is that entry of the code interrupts forced-oscillation resonance that would otherwise rip the Island's wrinkle in space-time apart.
You're likely familiar with this effect, though you may not realize it. A famous example is the opera singer whose sustained high note shatters crystal glass. Another is the Tacoma Narrows bridge, which purportedly collapsed when the wind caused the bridge to gyrate at its precise structural frequency. You may have seen pictures or film of the collapse.
Forced-oscillation effect is what created, and may even maintain, the Island's wrinkle by vibrating space-time in the fourth dimension. But too much vibration eventually causes the snowglobe to shatter like the opera singer's glass. We were witnessing the start of that effect in at the end of Season 2.
The electromagnet was spinning faster and growing stronger, atttracting metallic objects to the concrete. The magnetic resonant effect even seemed to be warping space-time, as suggested by the shaking, which was felt across the Island. When Des turned the key, the result was noise and a bright white light, yet another sign of scalar electromagnetism.
The implication seems to be that activation of the fail-safe does the same thing as entering the code during system failure (but presumably only once). My guess is that both preserve the integrity of the space-time wrinkle by reversing the polarity of the electromagnetic field, interrupting the fourth dimensional hyperflux. This polarity reversal is what sent the quarantine door flying to the beach like a rail gun.
Pfft! and Penny's Sign
Ordinarily, that venting process creates no major effects. In the case of system failure, however, an excess of scalar energy builds up in the fourth dimension from the oscillation-resonance overload. When the hyperflux ends, that energy gets vented into our dimension, briefly enveloping the Island in a bubble of scalar energy known as a Tesla shield:
The air molecules and atoms in the shell are totally ionized and thus highly excited, giving off intense, glowing light. Anything physical which hits the shell receives an enormous discharge of electrical energy and is instantly vaporized -- it goes pfft! like a bug hitting one of the electrical bug killers now so much in vogue. (Full text here.)Obviously, Flight 815 didn't go pfft! and the foregoing is anything but a rigorous description. Still, scalar waves have been blamed by conspiracy buffs for the Challenger and TWA 800 crashes, among other aeronautical disasters. Such a scalar electromagnetic effect could also explain the anomaly that Penny's monitors detected at the south(?) pole.
I like the latter possibility because it dove-tails neatly with renewed speculation following the Foot that the Island was once home to an ancient Atlantis-like civilization. Some believe that Atlantis was plugged into an ancient planetary power grid that operated by the same wireless transmission principles espoused by none other than our own Mr. Tesla.
Perhaps our Portugese friends detected the electromagnetic anomaly via the remains of that ancient planetary grid.