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According to many physicist what ever goes near to a black hole is pulled by it sucked up in a parallel universe. As far as i know black holes are also made up of material particles as any other thing is made up of so why isn't it sucked up in the parallel universe. And if it is true that it sucks up everything and teleport's it to a parallel universe so it should be very bright on the other side as also pulls light towards it. So why don't our universe have those type of white holes?

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I'm confused, I was under the impression that a black hole was just a point of extremely high gravity, to a point causing a singularity in the Einstein field equations, and that a wormhole was the theoretical object OP (and everyone else so far) referred to. –  Matt Scott Feb 20 '13 at 16:17
If the black hole is rotating or charged it is possible to follow a timelike path through the event horizon and back out without hitting the singularity. However the bit of the universe you re-emerge into is causally disconnected from your starting point because there is no way back without travelling faster than light. See the question I linked to in my answer above for a detailed discussion of this. –  John Rennie Feb 20 '13 at 16:38
BTW, black holes are, for most intents and purposes, not made of anything but pure gravitational influence. The event horizon is just a surface in spacetime - it is not a solid object. Also, black holes are not vacuum cleaners - they are really no better than stars or planets or anything else with mass at sucking things in from a distance. –  Chris White Feb 20 '13 at 17:07
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2 Answers

up vote 4 down vote accepted

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.

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Yes you are right that the black hole needs to be of an infinite age so that we can see something coming out of it but in this universe of uncertenity can,t we have one because unverse is much older thn my grand grand mother. –  Akash Feb 20 '13 at 16:34
Observers outside the event horizon would have to be able to observe the event horizon for an infinite time to see anything coming out through it. Basically this means the black hole and the universe it's in would have to be infinitely old. You may have heard that infalling matter takes an infinite time to reach the event horizon, and the infinite time taken to emerge from the event horizon is just the corollary of this. –  John Rennie Feb 20 '13 at 16:44
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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.

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that,s my point if we haven,t seen one so far than how can we say that there is one on the other side of the black hole because whatever id there should be here. If there any correction to made to my statement please do and then answerme back :) –  Akash Feb 20 '13 at 16:41
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protected by Qmechanic Aug 5 '13 at 7:07

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