What is the definition of space-time?

Answer 1

Space-time is the geometric model of physical reality put forward by Albert Einstein's theories of relativity consisting of three spatial coordinates and one temporal coordinate. It is what separates physical objects from each other and gives them their distinctiveness. Space and time give the universe complexity and diversity. The three spatial dimensions are length, width, and depth. Time is considered to be the fourth dimension. This framework hypothesizes a flat space warped or curved by the presence of mass or gravitation around it. Think of a Bowling ball placed in the center of a trampoline. Space and time are no longer considered separate and absolute as put forward by Issac Newton but fused together and relative depending on the observer's frame of reference. Gravitation is no longer considered a force that attracts bodies but the curving of this fabric by the presence of bodies. This four-dimensional framework is also known as the space-time continuum and it is the most generally accepted model of the universe today. However, there could be more dimensions than this as put forward by string theory. String theory postulates as many as eleven physical dimensions consisting of ten of space and one of time. Also, our universe may not be the only one we know of. There could be an infinite number of space-times or universes existing alongside ours in an even larger hypothetical space known as the multiverse.