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- How does a particle accelerator work, and why are such large structures necessary?
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- Why is a bicycle easier to control when it’s moving?
- Why can’t I use a dimmer switch with a compact fluorescent bulb?
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Can we build a time machine?
An internationally renowned expert on general relativity says it’s a no go…By Deborah Halber
While some cosmic analysts have suggested that time travel is at least theoretically possible, MIT physicist Eddie Farhi, an internationally renowned expert on general relativity, says it’s a no go.
“I’ve given a lot of thought to the problem of time travel in recent years,” Farhi, director of MIT’s Center for Theoretical Physics, was quoted in the fall of 2007, “and everything I’ve ever looked at suggests that the laws of physics conspire to prevent you from going backward in time.”
Farhi and MIT colleagues considered Princeton astrophysicist John Richard Gott’s proposal of using cosmic strings to create a time machine, but “what we discovered was that you really could not construct such an object because the construction would require more than half the energy in the entire universe,” he said.
Furthermore, it was later shown that if you built such a device, before the would-be time traveler completed a voyage to his past, the universe would end in a Big Crunch. “So it really seems that time travel cannot happen,” Farhi said.
Posted: December 18, 2008