👉 In physics, "spacetime" refers to the three-dimensional space that surrounds objects and events in time. This concept is fundamental in understanding how physical phenomena such as gravity, motion, and energy travel through space-time. The universe is composed of a vast amount of matter and energy, which makes up spacetime. These particles can be observed from different points in spacetime at the same time, which is why we perceive them as moving relative to each other. The speed of light in a vacuum
