Mysteries of the Universe : Re: What our fate may be

Black holes might be an example of spacetime curvature in the absence of matter. When matter falls into a black hole event horizon, a portion of its mass-energy is radiated away as gravitational waves (waves of spacetime curvature), and the remainder of its mass-energy contributes to the local spacetime curvature, and makes the black hole bigger. Whether the black hole crushes it into a point of infinite density or not is irrelevant, because from our perspective, the matter ceases to exist. Upon falling into a black hole, matter winks out of existence, converted entirely into spacetime curvature.

Under my hypothetical model, pure spacetime curvature without matter, is dark matter. It may, or may not, form an event horizon. Spacetime curvature from dark matter can also be transformed into ordinary matter, reducing the spacetime curvature. But if the same matter clumps together into a small enough volume, the local spacetime curvature is sufficient to form an event horizon, and the matter is destroyed. Thus, in the long term, black holes might restore the balance between dark matter and dark energy. This could either stop inflation, or collapse the universe entirely (big crunch).

An analogy to this spacetime model would be a solid material known as Low Thermal Expansion (LTE) glass ceramics. Development of LTE glass started "with the discovery by Hummel in 1951 that crystalline aggregates of β-eucryptite (Li2O-Al2O3-2SiO2) display a negative volume expansion." (Bach-Krause, Low Thermal Expansion Glass Ceramics 2nd ed., 2005). When prepared in the correct mixture, some components of the glass microstructure expand when heated, while other components contract. This leads to a range of temperatures throughout which certain compositions of LTE glasses, e.g. Zerodur, exhibit little or no thermal expansion. However, outside of this range, one or another component of the microstructure starts to expand or contract faster than the rest. Similarly, ordinary matter, dark matter, and dark energy form components of spacetime. These can be balanced, or unbalanced, depending on composition, or other factors (to be determined), resulting in inflation (early universe), contraction (galaxies), or steady-state (cosmic web). Whether this analogy is useful or not remains to be seen.