Wormholes in space are shortcuts linking distant points -- a bit like that other sci-fi favorite, the star gate.

CNN: Time travel: Can it really be done?

Not only wormholes, but several other mechanisms have been found that, according to Einstein's theory, can be used to travel back in time.

CNN: Time travel: Can it really be done?

It's not uncommon for one last tweet before bedtime to lead to YouTube wormholes, which lead to a few emails, which lead to the inevitable 4 a.m.

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Which is fine, but someone either has to come up with a way to generate wormholes, or we still have to plan on a long space flight to find naturally occurring ones.

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If wormholes exist, they could be adapted to make time machines that send you into the future if you traverse them in one direction, but into the past if you go in the other direction.

CNN: Time travel: Can it really be done?

And after much talk of "wormholes" and "parallel universes, " came a conclusion: "We are still very far away from being able to entangle and teleport human beings and bulk inanimate objects, " reads page 46 of the report (PDF file).

MSN: ��Beam me up, general!��