Gravity, as described by Einstein's theory of general relativity, is not like other forces in classical physics. Instead of being a force transmitted through space, gravity is understood as the curvature of spacetime caused by mass and energy.
In the presence of a massive object, such as a planet, star, or black hole, spacetime is curved. The curvature of spacetime tells matter and light how to move in its vicinity. When an object moves through curved spacetime, it follows a path that appears to us as being influenced by the force of gravity.
The curvature of spacetime caused by a massive object also affects the passage of time. In regions of stronger gravitational fields, the curvature is greater, leading to a slowing down of time. This effect is known as gravitational time dilation.
The connection between gravity and time dilation can be understood through the equivalence principle, a fundamental concept in general relativity. According to the equivalence principle, an observer in a gravitational field cannot distinguish between the effects of gravity and the effects of acceleration. This means that an observer in a gravitational field experiences time dilation in a similar way to an observer in an accelerating frame of reference.
In simple terms, the curvature of spacetime caused by gravity affects both the motion of objects and the passage of time. This is why gravity can cause similar effects on space and time, such as the bending of light and the time dilation observed near massive objects. It is important to note that this understanding of gravity and spacetime is quite different from the classical Newtonian view of gravity as a force acting between objects.