Before one can attempt to understand what a wormhole is, one must first have knowledge of the black holes that comprise them. The basic definition of a black hole, according The Essential Cosmic Perspective, is, “A bottomless pit in spacetime. Nothing can escape from within a black hole, and we can never again detect or observe an object that falls into a black hole.” To further understand this concept, a few theories and terms must be explained.

Spacetime: According to The Essential Cosmic Perspective, spacetime is, “The inseparable, four-dimensional combination of space and time.” It is generally understood that space comprises three-dimensions of spacetime and that time comprises the fourth dimension. This time dimension differs in nature from the space dimensions.

Curved Space: Defined by The Essential Cosmic Perspective as, “A change in geometry of space produced in the vicinity of a massive object and that is responsible for the force we call gravity. The overall geometry of the universe may also be curved, depending on its overall mass-energy content.” The idea that space is in fact curved was introduced by Albert Einstein in his General Theory of Relativity. It solved the main problems that science had found with Newton’s laws of gravity by showing space and space-time’s structure to be influenced by matter and energy. The amounts of matter and energy determine the curvature of space in a given area, and this curvature in turn determines how the matter moves.

Event Horizon: The event horizon is defined by The Essential Cosmic Perspective as, “The boundary that marks ‘the point of no return’ between a black hole and the outside universe; events that occur within the horizon can have no influence on our observable universe.” The event horizon is essentially the point where the black hole’s gravity grows stronger than light, so that nothing may escape. This horizon is also referred to as the Schwarzschild Radius.

Point of Singularity: The point of singularity is defined by The Essential Cosmic Perspective as, “The place at the center of a black hole where, in principle, gravity crushes all matter to an infinitely tiny and dense point.”

Appearance of Time: According to The Essential Cosmic Perspective, if one was observing a clock as it moved closer to the event horizon, the clock would appear to slow down. If one moves with the clock, it appears to keep steady time. If one observes a clock looking out from near the event horizon, it appears to keep regular time. When the clock eventually reaches the event horizon, to the outside observer it appears to stop. To an observer with the clock there would be no discernable change as the event horizon was crossed.