So, multiply connected spacetime may exist or even does already according to current knowledge, right? And in which of the thousand of millions of books about GR, which every physicist seems to have to have written about at least once, ever you read about it, authors claim that, although it's in general possible, it would practically take unobtainably vast amounts of energy to realize it. Hm. Well lets assume we somehow got to aquire such amounts of energy and a device which, in some magic concealed way, can create a wormhole for us. What would it be like? Practically, I mean. Wormholes, once created, must curve spacetime in a way similar to a BH, just stronger. And as a BH does have an enormous gravitational field and an event horizon, shouldn't each wormhole have one, too? Meaning, that once going into the wormhole, you are behind an event horizon you may never emerge from? I think I'm confusing a little classical theory, plus rubber- and paper&scissors model with GR, but let me go on nonetheless and correct me at the appropriate places. So far, I reckon that WH would create an enourmous distortion of spacetime which is as little spatially limited as a BH's one. But let's assume we created the WH in a way that the gravitational effect in its proximity is limited and there is no EH, so it's actually feasible for going through (I hope you can explain why this can be). Let's say we created such a WH down hear on the planet (huge machinery and stuff, needs a planet, you know...) and connected it to somewhere out in space in the 18th century. Here I got a little question, just out of curiousity and less relevant to my actual problem: Is the time a wormhole is connected to somehow correlated to the targeted position, or can both arbitrarily "chosen"? Back to the WH: We used an enormous amount of energy - possibly depleted all reserves of oil and other fossil fuels, just for the kick (wait, what...) - and now we got a stable wormhole. Do we have to keep pumping energy into it? Where will that energy go? Will we retrieve it back, once the wormhole is "brought down"? A black hole doesnt require much energy to bend spacetime. It just requires mass. It just sits there and laughs at us while we are squeezing the last iota of oil out of the ground, to keep our spacetime distortion alive. Or did we use mass to create it, too? If so, that would again make me wonder how our WH can effectively not be a BH in appearance an behaviour and not swallow the planet while it... worms. So our oil, where does it go? Does our machine which creates the wormhole heat up? Can it be built a way that it wont heat up and conserve the energy? Seriously, where is our energy, and how can we get it back? I got it! I know how we can get it back! Aw wait... That doesn't make any... But well, let me tell my proposal: Since we created a tunnel into space, far away from earth, we eventually have invented a working perpetuum mobile! Yes! It's so simple, every child would get it: Throw a stone in the black hole here on earth and see it falling from the sky (or have your ancestors, offspring respectively seeing it fall down). There we go! Everything balanced out. If you think about it, its a good investment, though. Invest an incredible amount of energy and get an infinte amount back. Problem solved. But how do we convince the government to fund our project, as they still believe in such stupid things as "energy conservation" (lol) ?