@xxporkxsodaxx – In general relativity, black holes are, indeed, infinitely small. The event horizon, the point at which you cannot escape the gravitational pull, can be large. These are important distinctions. Size is distinct from mass, however, and the event horizon is a marker of mass, not of size.
@psyla – I have no idea where you’re coming from with the idea that a black hole can crush the universe. We have observational data that supports that black holes are common, and they are not currently “crushing the universe.” Also, energy and gravity aren’t the thing. They are related, but again, they are distinct concepts
@xyzzy – While I was meaning wormholes as devices for travel (the force of gravity should rip apart any organism unlucky enough to pass in), wormholes are mathematically valid in general relativity, but there is no observational data to support their existence, nor is it believed by the greater astronomical community that we will discover any.
Besides, even in general relativity it requires exotic matter – things that have negative mass – that is on the edge of theory and we absolutely no data to support.
There is an excellent cover story in the May 20, 2008 (today’s) of Physical Review Letters that argues that singularities themselves are simply approximations required by “our insistence that space-time should be described as a continuum.” It’s fascinating stuff, really.