The concept of compressing the fabric of the universe without affecting its mass/energy content is not well-defined within our current understanding of physics. In physics, the fabric of the universe refers to spacetime, which is intricately connected with the distribution of mass and energy. Any compression or alteration of spacetime would inevitably involve changes in the mass/energy content.
In general relativity, mass and energy determine the curvature of spacetime. The distribution of mass and energy throughout the universe influences the geometry of spacetime, and this curvature, in turn, affects the motion of objects within the universe. Compression of spacetime, without altering its mass/energy content, would require a fundamental change in our understanding of how mass and energy interact with spacetime.
It's worth noting that our current knowledge does not provide a complete understanding of the universe, especially in extreme conditions or at the smallest scales. The behavior of the universe under such conditions, including the fabric of spacetime, is an active area of research and remains a topic of investigation in theoretical physics.
Therefore, while we cannot definitively rule out the possibility of compressing spacetime without affecting its mass/energy content, it goes beyond our current understanding and would likely require new physics to explain such a phenomenon.