Democritus, an ancient Greek philosopher, posited that space is a void, or emptiness, through which atoms move and interact.

The Big Bang theory suggests that the universe originated from a singularity, an infinitely dense and hot point, from which space, time, and matter expanded.

Gottfried Wilhelm Leibniz, a German philosopher, maintained that space is not a substance with independent existence but rather a relation between objects, akin to time.

In general relativity, spacetime is a four-dimensional continuum that combines space and time into a single entity, with the curvature of spacetime determining the motion of objects.

Spatialism, a philosophical school of thought, asserts that space is the fundamental reality and that time is secondary or derivative.

The 'block universe' concept in the philosophy of space and time refers to a static, four-dimensional spacetime continuum, where all events are fixed and predetermined.

The theory of quantum gravity seeks to unify space and time into a single entity, known as spacetime, where the properties of space and time are intertwined.

George Berkeley, an Irish philosopher, posited that space is a mental construct, existing only in the mind and not as an objective reality independent of the mind.

The concept of 'absolute space' in the philosophy of space refers to a fixed and immovable reference frame against which all motion and position are measured.

The Steady State model, proposed by Hermann Bondi, Thomas Gold, and Fred Hoyle, suggests that the universe is infinite in size and has no boundaries, with new matter continuously being created to maintain a constant density.

Cosmological horizons are boundaries in spacetime beyond which information cannot travel, due to the finite speed of light and the expansion of the universe.

Immanuel Kant, a German philosopher, maintained that space is a necessary condition for the possibility of experience, as it provides the framework within which objects can be perceived and organized.

Spacetime foam is a concept in quantum gravity that describes the fluctuating structure of spacetime at the Planck scale, where the laws of physics are believed to break down.

The Inflationary Universe model proposes that the universe underwent a rapid expansion in its early stages, causing it to expand and accelerate continuously.