The key conceptual advance concerns the physical meaning of the event horizon. In standard General Relativity, the horizon is the boundary beyond which no information can return to an external observer.

In the NTU framework, the horizon corresponds to complete gravitational rigidification.

The effective 4D openness factor is:$$\chi_{\mathrm{4D}}(r) = 1-\frac{r_s}{r}$$

while the gravitational closure factor is:$$\zeta_G(r) = \frac{r_s}{r}$$

At the horizon:$$r=r_s$$

we obtain:$$\chi_{\mathrm{4D}} = 0$$

and:$$\zeta_G = 1$$

meaning that all gravitational pre-link surfaces accessible to a 4D observer have become fully rigidified.

In NTU language:$$\boxed{ \text{The event horizon is the surface of complete gravitational closure.} }$$

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The most radical consequence concerns the nature of the singularity itself. General Relativity predicts a breakdown of spacetime at:$$r=0$$

Traditionally interpreted as a point of infinite density.

The NTU framework suggests a different interpretation. Inside the horizon, the standard 4D projection progressively loses validity and the open NTU sector becomes dominant.

Defining the normalized internal NTU openness:$$\chi_{\mathrm{NTU}}^{\mathrm{int}}(r) = 1-\frac{r}{r_s}$$

we obtain:

At the horizon:$$\chi_{\mathrm{NTU}}^{\mathrm{int}} = 0$$

and at the classical singularity:$$\lim_{r\to0} \chi_{\mathrm{NTU}}^{\mathrm{int}} = 1$$

Therefore:$$\boxed{ \text{The classical singularity corresponds to complete NTU openness rather than infinite density.} }$$

In this picture, the singularity is no longer viewed as a physical divergence. Instead, it represents the complete failure of the 4D projection and the emergence of a permanent connection to the underlying NTU substrate.

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Matter, light, and information

This interpretation naturally leads to a new view of black-hole physics.

Matter and light are not destroyed after crossing the horizon.

Rather, their 4D particle description is progressively replaced by a topological description in terms of NTU pre-links.

In NTU language:$$\text{Matter} \longrightarrow \text{Pre-link topology}$$

and:$$\text{Photon} \longrightarrow \text{Pre-link topology}$$

Consequently, information is not lost.

The event horizon marks the loss of 4D observability, not the destruction of physical information. The NTU interpretation can therefore be summarized as:$$\boxed{ \text{A black hole is not an information sink.} }$$

but rather:$$\boxed{ \text{A black hole is a converter between 4D spacetime representation and NTU topological representation.} }$$