Many fans have speculated what or where the island was located: it could have been at the edge of a wormhole, or at an inter-dimensional portal between universes, or a gateway between spiritual realms.
Science fiction writers such as Jules Verne or Mark Twain used time travel as a foundation for stories. The LOST version of time travel was puzzling because it lead to no where.
As the PBS science show NOVA explained, Sir Issac Newton's most important contribution to science was his mathematical definition of how motion changes with time. He showed that the force causing apples to fall is the same force that drives planetary motions and produces tides. However, Newton was puzzled by the fact that gravity seemed to operate instantaneously at a distance. He admitted he could only describe it without understanding how it worked. Not until Einstein's general theory of relativity was gravity changed from a "force" to the movement of matter along the shortest space in a curved spacetime. The Sun bends spacetime, and spacetime tells planets how to move. For Newton, both space and time were absolute. Space was a fixed, infinite, unmoving metric against which absolute motions could be measured. Newton also believed the universe was pervaded by a single absolute time that could be symbolized by an imaginary clock off somewhere in space. Einstein changed all this with his relativity theories, which was much broader than one iconic equation, fundamentally changed our understanding of time and space.
Modern sci-fi has demonstrated some of these principles in how a hero changes time. Superman speeds around the earth's gravitational axis in order to reverse time; Star Trek used a similar method to go back in time.
But in LOST it was not a single event or construct which shows how time changed. We were led to believe that the frozen donkey wheel somehow controlled the island's space time position, and when it got dislodged by Ben's travel, the island began to time skip. This would infer that the island itself contained a time travel engine at its core, which would have to be different than the light source which was only described as "life, death and rebirth."
The island must be sitting on the edge of a space gravity well. A gravity well is the pull of gravity that a large body in space exerts. The larger the body (the more mass) the more of a gravity well it has. The Sun has a large (or deep) gravity well. Asteroids and small moons have much shallower gravity wells. Anything on a planet or moon is considered to be at the bottom of the gravity well. Entering space from the surface of a planet or moon means climbing out of the gravity well, something that often takes a huge amount of energy. The larger a planet or moon's gravity well is, the more energy it takes to achieve escape velocity and blast a ship off of it.
A black hole is a "gravity well" that is so strong that NOTHING escapes from it, not even light. It sounds like that can't possibly be true, but it is.
Gravity is the common resistance against motion. In sports, every athlete is competing against
gravity. For example, a baseball player who hits towering home runs is
exerting more force on the ball than someone who hits little ground
balls. Sports is all about throwing, hitting, running, and moving
faster. If someone could figure out a way to reduce their own personal
gravity, they would have a distinct advantage.
In space travel, it is possible to escape the
earth's gravitational force and launch a rocket into "outer" space. The
amount of force required to escape the gravitational force is called the
"escape velocity".
At sea level , sound travels at a speed of 769.5
miles per hour (1238 km/h), depending on other factors such as
atmospheric conditions, wind, etc. Modern jets can "outrun" the speed of
sound quite easily. But for purposes of the black hole discussion, it
is important to understand that the biggest force or resistance to the
speed of sound is gravity, just as it is with solid objects.
Similarly, the speed of light is affected by
gravity. Light travels at a speed of 186,282.397 miles per second, which
is 670,616,629.4 miles per hour, 983,571,056.4 feet per second, roughly
one foot per nanosecond! Nothing man-made can outrun the speed of
light.
The island appeared to be in constant motion and not fixed to the Earth's core. That is why some fans believed it to be a alien spacecraft disguised as a tropical island. Because of its movement, the time on the island was in flux. Like all time mechanisms, it needs to be regulated like clock gears. A reset every 108 minutes could be that regulator which gave the island some form of space time stability.
But it also appeared that the island's time differential was highly localized. It would be hard to imagine how this localized time field could be monetized by powerful men like Widmore. People still aged on the island so it was not the fountain of youth (the exception was Jacob and Alpert who may have been "special" as in spirits).
Gravity was described as a "weak force" in terms of the vacuum of space itself. But it must be in vast quantities that it can affect so many things such as light and sound waves. Gravity itself could be viewed as its own unique space element which may have properties that we have not yet understood.
It may have the property of building up pressure in resistance to energy forces (like the island's EM field) so that it needs to be "released" at timely intervals (again, another possible purpose of the Hatch).
Is it possible that the resistance of a gravity well was the trap that kept both the smoke monster and Jacob in prison on the island? If that is the case, and the island survived their final battle, than that same gravity well would have kept them on the island forever.
It would have been nice if the writers would have given a clearer explanation of their view of time and space as it related to the island events.
