The concept of spacetime having viscosity or behaving like a fluid, such as a superfluid or a non-Newtonian fluid, goes beyond the current understanding of physics. In conventional physics, viscosity is a property of fluids that relates to their resistance to flow and deformation. However, it's important to note that spacetime is not a conventional fluid but rather a mathematical framework that describes the fabric of the universe.
In the context of general relativity, spacetime is described by a four-dimensional manifold with curvature that is influenced by the distribution of matter and energy. It does not possess the properties of viscosity or fluid-like behavior in the way we understand them in classical fluids. Rather, the curvature of spacetime is determined by the distribution of mass and energy within it.
The nature of spacetime is explored and understood through the principles of general relativity, which provides a mathematical framework to describe the behavior of gravity. It does not treat spacetime as a fluid but rather as a geometric structure influenced by matter and energy.
While there are theories and conjectures in physics that explore exotic ideas like fluid-like behavior of spacetime, such as the holographic principle or models based on string theory, they are still speculative and not yet confirmed by empirical evidence.
In summary, the current understanding of physics does not support the idea of spacetime having viscosity or behaving like a fluid. The concept of spacetime as a fluid, superfluid, or non-Newtonian fluid is largely hypothetical and speculative at this stage.