The Birth of a Gravastar: How a Star Escapes a Black Hole ⚡ экспресс
Physicists have for the first time simulated how a gravastar — a hypothetical object without an event horizon, akin to a frozen star — could form. Using the classic scenario of a dust ball collapse, they showed that with precise tuning, a microscopic region with vacuum energy (a de Sitter core) emerges at the center. It expands, but slows down at the Schwarzschild boundary, meets the infalling shell, and forms a static equilibrium. Unexpectedly, an upper limit on the compactness of the collapsar was found: if it exceeds 3/8, a black hole is inevitable. This discovery builds bridges between theory and the search for real candidates.
A dying massive star usually shrinks into a black hole—a trap from which even light cannot escape. But another finale is possible: a gravastar—a bubble of dark energy, the mysterious force pushing the cosmos apart.
Simulations of a collapsing cloud revealed: deep in the center, a tiny nugget of dark energy is born. It inflates, like a soap bubble in a vacuum. Upon reaching the critical radius where a black hole would normally appear (first calculated by Karl Schwarzschild), the expansion halts. Infalling matter hangs suspended on the bubble—a stable gravastar is born. The surprise: inside, space stretches as rapidly as in the first moments after the Big Bang—a whole mini-universe beneath the shell.
The trick doesn't always work. The star must be sufficiently 'fluffy': its mass-to-radius ratio (in special units) must be less than 3/8. Otherwise, collapse into a black hole is inevitable.
🎯 Inside a gravastar, space expands like a newborn Universe—a miniature cosmos hidden from us by a glowing shell.