This week's New Scientist has an article on possible quantum time travel. This does not break any of the rules of Einstein's theory of relativity but only permits time travel back to the moment the time machine is created. We therefore know that time machines haven't been invented yet because we haven't met any time travellers.
One of the fascinating phenomena that was mentioned in passing was a variation on the double slit experiment (see 12 Nov post) in which the detectors were telescopes positioned beyond the screen that shows the photons. Observing through such a telescope affected the outcome of the experiment and is an example of an effect that precedes its cause.
No comments:
Post a Comment