A campfire burns steadily and long. But when the wind blows, the flame flickers out, leaving only embers. A similar story plays out with the gravastar — a hypothetical object that was supposed to replace the black hole.
An ordinary black hole hides a singularity — a point where the laws of physics break down. A gravastar is an attempt to do without it: inside, instead of a void, there is dark energy, which pushes space apart and prevents matter from collapsing to a point. The result is a kind of bubble, stable on the outside but with a secret inside. The authors of the new study examined how reliable such a construction is from a thermal perspective.
It turns out — not reliable at all. A thermodynamic calculation showed that the gravastar spontaneously loses stability and transforms into a Schwarzschild black hole with a singularity. It's as if a stretched rubber membrane (dark energy) suddenly bursts at the slightest thermal breath. The reason lies in the very nature of thermal fluctuations: they rock the system, and it rolls into a more probable state.
This result is not just a mathematical toy. It tells us: avoiding the singularity with dark energy alone won't work. Nature chooses the path of least resistance, and that path leads to the familiar black hole. Gravastars might have been born in the early universe, but they likely didn't survive to our time.
The dark energy that was supposed to keep the gravastar from collapsing is what destroys it: thermal fluctuations make it 'deflate' faster than you'd expect.
In Peter Watts's novel 'Firefly,' the crew of a ship encounters an object resembling a gravastar: it also turns out to be unstable and threatens to swallow everything around it.