Where do black holes go? According to many physicists, any matter near a black hole is obviously gravitated towards it, and transported to a parallel universe. As far as i know, black holes are made up of material particles, as is everything else in the universe, so why isn't it sucked up in the parallel universe? And if it is true that it sucks up everything and transports it to a parallel universe, shouldn't it be bright in that parallel universe, as light is also pulled into it? If so, why doesn't our universe have these?
 A: It's a common claim that certain types of black holes provide a gateway to a parallel universe, however there are two problems with this claim. Firstly, although it's true that trajectories can be traced through the event horizon and back out again, it isn't clear whether this is physically meaningful or just a mathematical trick. In fact if recent suggestions about firewalls are correct anything crossing the event horizon will simply be incinerated.
Secondly, even if the trajectories are physically meaningful and firewalls don't get in the way, the universe you reach is not a parallel universe but just a causally disconnected bit of the same universe you and I live in.
Lastly, even if you can travel through the black hole to reach a causally disconnected bit of the universe, for any observer outside the black hole the trip will take an infinite time. So we could only see something emerge from a black hole if the black hole was infinitely old. Clearly this isn't the case.
You might be interested to have a look at my answer to Entering a black hole, jumping into another universe---with questions where I go into more detail about the travel through a black hole. Also in that answer I mention the book The Cosmic Frontiers of General Relativity by William J. Kaufmann and this book deals with your question. From outside the event horizon you can't see anything travelling out of the black hole, but if you jump into the black hole then in principle once inside the event horizon you could see light coming from other parts of the universe, or from parallel universes if you wish to describe them so.
A: This model you are talking about, parallel universes and black holes connecting with them is a popularized version of a model  that is not mainstream physics.
Black holes exist because we have seen their influence, we have not seen any white hole sources of particles, this is an experimental fact. This is the reason that the black holes of mainstream physics are described as:

a region of spacetime from which gravity prevents anything, including light, from escaping.1 The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that marks the point of no return

The matter that falls in the black hole adds to its mass and its attractive strength.  There is no other universe where it leaks out. That is a science fiction view at the moment.
A black hole is not eternal, as quantum mechanics tells us that it slowly radiates away the energy it has accumulated.
