Einstein's theory of general relativity, published in 1915, indeed introduced the concept that gravity is not merely a force but also the curvature of spacetime. According to general relativity, massive objects like stars and planets cause the fabric of spacetime to curve, and this curvature influences the motion of other objects nearby. This concept has been supported by various experimental observations, such as the bending of starlight by the Sun's gravity, which was confirmed during a solar eclipse in 1919.
It is true that space, in itself, is not a physical substance like matter or energy. Instead, it is a mathematical construct used to describe the geometry of the universe. However, according to general relativity, the presence of mass and energy can cause the geometry of space to be curved. This curvature is what we refer to as the bending or deformation of spacetime.
Regarding the possibility of warp drives, it is an area of speculative physics and hypothetical concepts. Warp drives, as popularized in science fiction, involve the idea of creating a local distortion in spacetime to achieve faster-than-light travel. However, the current understanding of physics does not provide a known mechanism to create such distortions or bypass the known limitations, such as the speed of light, as described by the theory of relativity. While scientific exploration and advancements are ongoing, warp drives remain speculative and not yet supported by empirical evidence or established scientific theories.
It's worth noting that the understanding of the universe is continuously evolving, and future discoveries may challenge or expand our current knowledge. However, as of now, the consensus among physicists is that the bending and deformation of spacetime as described by general relativity are well-supported by observational evidence.