[Editor: We're very far away from ever creating a wormhole, but I would imagine that if our understanding of physics ever resulted in the controlled creation of such a phenomenon, then yes it could be controlled. Think about electricity. It was only about 200 years ago when we figured out how to control electricity in a rudimentary way. Now we can control it in very marvellous ways, such as the way you are reading this text right now. The thing is: at the present moment there is no evidence that scientists will ever be able to create a wormhole, so everything we say about it now would be about the same as Shakespeare talking about electric lights or cellphones. It's all imaginary at this point in time. The exact answer to your question is: we have no idea.]
Boy, what optimism! I mean, that we'll still be around millions of years from now. Actually SF authors have been propping wormholes open with "exotic matter" for decades, and this notion is based on the speculations of some theoretical physicists. However, when John Archibald Wheeler showed that wormholes always "pinch off" before you can send anything through them (even a light signal), I stopped considering the possibility, attractive as it was.
I forget exactly what "exotic matter" is supposed to be, but I think it has negative mass or something crazy like that. So far nothing we've seen has negative mass (antineutrons do not fall up). And the science fiction dreamers ignore something very important: the energy required to produce such a space warp in the first place. I don't know the numbers, but I expect that, at the very least, we'd need to use all the energy in a supernova to "build" one.
Good luck engineering THAT!
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