Gravastar Model Avoids Black Hole’s Crushing Centre, Defying Physics As We Know It

Researchers are increasingly investigating alternatives to black holes to resolve the singularity problem at the heart of gravitational collapse. Shounak Ghosh from the Directorate of Legal Metrology, Rikpratik Sengupta from the Indian Institute of Technology Kanpur, and Kazuharu Bamba from Fukushima University, et al., present a novel gravastar configuration constructed within the Shtanov-Sahni braneworld scenario, featuring a timelike extra dimension. This work is significant because it demonstrates how braneworld dynamics can naturally prevent the formation of central curvature singularities, offering a fully analytic and stable, finite-thickness gravastar solution without relying on simplified assumptions. By solving modified Einstein field equations, the team reveals a mechanism where higher-dimensional Weyl corrections dynamically induce stabilizing pressure anisotropy and suppressed gravitational mass, establishing a physically viable compact object and a compelling alternative to the classical black hole paradigm.

This model, characterized by a timelike extra dimension and negative brane tension, naturally regularizes interior geometry through SS braneworld dynamics.

By solving the modified Einstein field equations on the brane, researchers obtained explicit interior, shell, and exterior solutions without relying on the idealized thin-shell approximation typically used in these calculations. The gravastar core is modeled as a Bose, Einstein condensate, while the intermediate shell comprises ultra-dense stiff matter, creating a unique structure distinct from traditional black hole models.
Bulk Weyl corrections induce anisotropic effective pressures on the brane, a feature that emerges intrinsically within this scenario and contributes to the overall stability of the gravastar. Detailed analysis focused on the active gravitational mass, energy, entropy, and proper thickness of the shell, establishing precise junction conditions at the interfaces between these components.

This work reveals that the SS gravastar exhibits suppressed or even negative effective mass, a direct consequence of the repulsive nature of the interior condensate. Stable equilibrium solutions consistent with established energy conditions further validate the model as a physically viable compact object and a compelling alternative to black holes.

A key innovation lies in the dynamic origin of stabilizing pressure anisotropy and suppressed gravitational mass, arising from higher-dimensional Weyl corrections rather than artificial sources or simplifications. This construction represents the first fully analytic realization of a finite-thickness, stable gravastar within the Shtanov-Sahni braneworld framework, highlighting a genuinely geometric mechanism for singularity avoidance in compact objects and offering new insights into the ultimate fate of gravitational collapse. The research provides a novel approach to understanding extreme astrophysical phenomena and potentially resolving long-standing theoretical challenges in gravitational physics.

Gravastar interior modelling incorporating braneworld cosmology and Weyl corrections

A detailed analysis of the interior geometry of a gravastar was undertaken within the Shtanov-Sahni (SS) braneworld scenario, characterized by a timelike extra dimension and negative brane tension. The research began by solving the modified Einstein field equations induced on the brane to obtain explicit interior, shell, and exterior solutions, circumventing the need for a thin-shell approximation.

The gravastar core was specifically modeled as a Bose, Einstein condensate, while the intermediate shell comprised ultra-dense stiff matter, allowing for a comprehensive description of the object’s composition. Bulk Weyl corrections were then incorporated, inducing anisotropic effective pressures on the brane and contributing to the overall stability of the gravastar configuration.

Researchers meticulously analyzed the active gravitational mass, energy, entropy, and proper thickness of the shell, establishing precise junction conditions at the interfaces between the core, shell, and exterior regions. This analysis revealed that the SS gravastar exhibits suppressed or even negative effective mass, a consequence of the repulsive nature of the interior condensate, and supports stable equilibrium solutions consistent with established energy conditions.

A key methodological innovation of this work lies in the dynamic origin of stabilizing pressure anisotropy and suppressed gravitational mass, arising from higher-dimensional Weyl corrections rather than artificial sources. This approach provides the first fully analytic realization of a finite-thickness, stable gravastar within the SS braneworld framework, demonstrating a genuinely geometric mechanism for singularity avoidance in compact objects. The study highlights the viability of the SS gravastar as a physically plausible alternative to classical black holes, offering a novel perspective on the nature of these enigmatic celestial bodies.

Shtanov-Sahni Gravastar Construction and Singularity Resolution via Braneworld Physics

Scientists have constructed a gravastar configuration within the Shtanov-Sahni (SS) braneworld scenario, demonstrating a mechanism to prevent central curvature singularities. This model utilizes a timelike extra dimension and negative brane tension to regularize the interior geometry, avoiding singularity formation unlike classical black holes.

Solutions were obtained for the interior, shell, and exterior without employing the idealized thin-shell approximation. The gravastar core is modeled as a Bose, Einstein condensate, while the intermediate shell comprises ultra-dense stiff matter. Bulk Weyl corrections induce anisotropic effective pressures on the brane, intrinsically contributing to the configuration’s stability.

Analysis of the active gravitational mass reveals a suppressed or even negative effective mass, reflecting the repulsive nature of the interior condensate and admitting stable equilibrium solutions consistent with energy conditions. This work establishes junction conditions at the interfaces, confirming the physical viability and self-consistency of the resulting gravastar solution.

The timelike extra dimension ensures the effective cosmological constant on the brane can vanish under fine-tuning, simultaneously allowing bulk corrections to regularize the interior geometry. Importantly, the induced anisotropy and suppressed effective mass are direct consequences of higher-dimensional corrections, rather than ad hoc assumptions.

These findings resonate with recent investigations of traversable wormholes in the SS braneworld, where curvature singularities can be avoided with matter satisfying energy conditions. The SS braneworld provides a consistent framework where diverse singular structures, including cosmological bounces, wormholes, and gravastars, can be rendered non-singular.

This strengthens the case for the SS model as a promising candidate for probing quantum-gravity inspired phenomena in astrophysics. Current and future high-precision gravitational-wave and electromagnetic observations may provide avenues for distinguishing gravastars from classical black holes, particularly within modified gravity frameworks like the braneworld scenario.

The analysis reveals a genuinely geometric origin for the stabilizing mechanism, with intrinsic pressure anisotropy dynamically generated by non-local bulk gravitational effects. The existence of an exact finite-thickness stiff-matter shell further distinguishes this construction from past works relying on infinitesimally thin shells.

Braneworld Gravastar Construction and Singularity Resolution

Scientists have constructed a gravastar configuration within a braneworld model, offering a potential alternative to black holes and resolving issues with singularity formation. This model, based on the Shtanov-Sahni scenario with a timelike extra dimension, demonstrates that the dynamics of the braneworld naturally prevent the formation of central curvature singularities, unlike classical black holes.

By solving modified Einstein field equations, researchers obtained solutions for the interior, shell, and exterior of the gravastar without relying on simplified thin-shell approximations. The gravastar core is composed of a Bose, Einstein condensate, while the surrounding shell consists of ultra-dense stiff matter, with stability supported by anisotropic pressures induced by bulk Weyl corrections.

Analysis of the gravastar reveals suppressed or even negative effective mass, consistent with energy conditions and suggesting a stable equilibrium. This construction represents the first fully analytic, finite-thickness, stable gravastar within the Shtanov-Sahni braneworld, providing a geometric mechanism for avoiding singularities in compact objects.

The authors acknowledge that the model relies on specific assumptions about the equation of state for the shell and the properties of the extra dimension, which could influence the results. Future research may focus on exploring the implications of different brane tensions and extra-dimensional geometries, as well as investigating the observational signatures of these gravastars to differentiate them from black holes.