Flat spacetime

Flat spacetime is a concept from physics describing a universe without gravity or any dents or curves in the fabric of space and time. Imagine a perfectly smooth, flexible sheet that can extend infinitely in all directions. In flat spacetime, objects move in straight lines at constant speeds unless acted upon by a force. It serves as a simple model in special relativity where space and time are combined into a single, uncurved framework. Unlike curved spacetime caused by massive objects like stars or planets, flat spacetime doesn't have gravity or gravitational effects, providing a baseline understanding of motion and time in a universe without gravity.