Black hole, yep that sounds familiar and there are other cousins of it? They are the White and Worm holes.
I am not going to describe in detail about all the hole(s) stuff, except for the snippet.
Black holes - Anything that sucks, that does not allow any matter to escape from its tentacles like the monster squids. See the actual definitions in the links...
(also see this - http://hubblesite.org/explore_astronomy/black_holes/)
White holes - Reverse process of the black holes, they puke what ever they have. Can never hold on to stuff, worthless holes. See the actual definitions in the links...
(also see this - http://curious.astro.cornell.edu/question.php?number=108)
Worm holes - The one that gives a subway (not the place we eat, it is the structure that helps our transportation) kind off a infrastructure, which connects different points in space and time. Could not give a better definition like I did for the other holes.
(also see this - http://www.startrekdesktopwallpaper.com/wallpapers/32_warmhole_shuttle_StarTrek_wallpaper_e.shtml, http://en.wikipedia.org/wiki/Wormhole, http://www.hypography.com/topics/wormholes.cfm)
I got the insights in to this with the help of the amazing "History channel". And they talked about the small black holes theory of Stephen Hawking that caused a clash in the Quantum theory (one more) and the Gravitation theory or the theory of relativity (both). The first one deals with the smallest of known things and the later deals with the biggest of known things.
"White holes" are considered not in existence now. The body that could have been the single source for all of the existing particles today. They exploded/expelled everything they had in them. And coming to black holes it is considered that these masses are constantly drawing matters in to them, and there are hundreds in any given galaxy. And the small black holes partially agreed that during their formation emits radiations and almost always disappears. And the worm holes that could exist to form connections to different points in space. But they may not exist for a known unit of time, anyways.
The only accepted part in the above is the black holes. White holes and worm holes are a conception and only in theory now. As we understand anything that exists cannot be destroyed but could only be transformed from one form to the other. So as a source of drain is the black holes, the source of emission is the white holes and they are connected time to time by the Worm holes. The worm holes latch on to the sources of the black holes and white holes not known in definitive ways, but when ever they do so the white hole pulls the source for its emissions from the black hole and the black hole pulls its source of drain from the white hole. In a sense they do the opposite of what they are.
There is no way known so far to understand what happens on the other side of a black hole?, because of the fact that what ever goes never comes out, Is there any leak? No body knew it.
(But the energy transformations are only true w.r.t Quantum mechanics)
But what if the black holes are connected to infinitely smaller and infintely "time to time" changing worm holes that connects different black and white holes. This theory defines that the other side of a black hole is white and vice versa. This contradicts the existing theory on white hole, "the white hole is singular". The worm holes might be the connector to the white and black holes.. And also worm holes that connects black hole(s) to black hole(s)might vanish in the smallest units of time. Which depends on the contraction of the black holes which would produce a ripple effect the slightest of which would suffice to burst the worm holes.
It all boils down to:
So if you see a white whole from one side; the other side is black and vice versa
source of the picture: http://library.thinkquest.org/5653/pre_blk.htm