Flying saucer
"Flying saucer" is the term commonly used to describe Unidentified flying objects, (UFOs) particularly those that are alleged to be alien spacecraft. The origins of the term lie in the report of a UFO sighting by Kenneth Arnold on June 24th 1947, near Mount Rainier, Washington. The nine objects he saw were not saucer-shaped: drawings showed something more resembling a "flying wing" style aircraft. However, he described their movement as a kind of skipping, like a saucer skimmed over water; press reports picked up the "like a saucer" phrase, and reported it as a "flying saucer".
Since that day, the number of different shapes, sizes and configurations of reported UFOs has been large, with accurate descriptions of chevrons, equilateral triangles, spheres, domes, diamonds, shapeless black masses, eggs and cylinders being amongst the reports. The fact that there are so many different shapes, size and configurations is in favor of the socio-psychological paradigm.
See also : George Adamski, UFO
One possible explanation of flying saucers is based on the theory of parallel universes. As these parallel universes fold and twist in their higher dimension, occasionally they come in contact with one another. Using a two-dimensional analogy, imagine bedsheets hanging side by side on a clothes line, wafting in the breeze. The two-dimensional creatures that inhabit this two-dimensional bedsheet world are constrained by some force that prevents them from moving into the third dimension. When two bedsheets come in contact, this constraining force causes the point of contact to assume a minimal surface two-dimensional object, a circle. The dimension-constraining forces interact, causing an emission of light. The intersection could effect bizarre motion - sudden acceleration, abrupt turns, and suddenly disappear as the two bedsheets separate. The behavior of this "object" would be unexplainable by the laws of physics as understood by the two-dimensional beings.
Moving up to three-dimensional universes, when two come in contact, the region of contact again assumes a minimal surface area object, a sphere or ellipsoid of revolution. The dimension-constraining forces cause the emission of light around its perimeter. Bizarre motions are evidenced by the object of intersection, and it suddenly disappears as the two universes separate their point of conjunction.
This theory raises many questions. Is it possible, for example, for the inhabitants of a universe to force a wrinkle in their universe such that it intentionally comes in contact with a parallel universe? Could they then use this intersection to travel from their universe to the adjoining one? What if the intersection of two universes takes place at a location in one of the universes at the center of a star? There would likely be a sudden infusion of star-interior matter flowing into the other universe.
Some may criticize this hypothesis as attributing one unexplained phenomenon to yet another, the theory of higher dimensionality and parallel universes. However, many scientists believe that physical dimensions higher than three could explain numerous phenomena we observe in our universe.