Posted June 12, 2016
![avatar](http://images.gog.com/85238c5442d71488fea1397151503e6ffda9cc4e82d7018bf558557f59628c80_avm.jpg)
And it is proven in multiple ways they exist i, they can't be obverved directly but their influence can.
As for the link you posted, whoever stated that rest-cores of the neccessary size couldn't exist either made a mistake by calculating it (happens to the best scientists sometimes, either by using the wrong calculation method or by observing numerical artifacts) or is just calling for attention.
If you know how big stars end it's obvious that an rest-core always remains which depends on the size of the actual star, the shockwave of the supernova is not created in the core (one shockwave is created close to the core but it is stoped by the force applyed by the radiation of the outer layers and that way the source of the actual supernova is somewhere in the outer layers) of the star but in one of the other layers around the core and it spreads in both directions destroying the outer layers and compressing the core.
And concerning the hypothesis of them leading to other universes:
It doesn't oppose the fact of them being a trap for everything, beyond the event horizon there are 2 layers, one which can be mathimatically described and a sigularity with multiple mathematical solutions, the hypothesis of the "portal" is one possiblility. It does not mean that you can just use it for traveling but that matter and energy can be transfered in a chaotic way.
There are also possiblities of "countering" or evading the destructive effects of the black hole in theoretical physics, those are just not possible to test with our technology yet.
Sounds more like the realm of sci-fi, but it may not be impossible, if Hawkings is correct, that energy or matter can travel between different universes through black holes, hence a sort of a portal. Wish I had a better understanding about these things, and had the knowledge and intelligence to better grasp it. Very intriguing stuff.