Could it be that black holes don’t exist after all? Stephen Hawking may have to rewrite his books.
A new theory proposes the existence of "gravastars" that solve many of the theoretical problems traditionally associated with black holes:
"It would be surrounded by a thin spherical shell composed of gravitational energy, a kind of stationary shock wave in space-time sitting exactly where the event horizon of a black hole would traditionally be. The formation of this condensate would radically alter the space-time inside the shell. "
Most intriguing of all is this speculation:
"Mottola says that if you scale the size of a gravastar up to around the size of the visible Universe, the pressure of the vacuum inside roughly matches the pressure that seems to be accelerating the expansion of the Universe. So our Universe might be one big cosmic gravastar: a giant shell trapping the Milky Way and all the other galaxies we see. "We might be able to entertain the really radical notion that we — and everything we see in the Universe — could be inside such an object," Mottola speculates. "