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May21-09, 07:13 AM
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Quote Quote by benk99nenm312 View Post
√(1- v2/c2) has two solutions, just like every other square root. It would be possible to get a negative solution.
Yes so slower-than-light particles can travel either forward or backward in time.

But tachyons can't their time dilation is imaginary (and minus imaginary is still imaginary )
As I stated, tachyons have some odd properties. One, they go backwards in time
No they don't

If we see a tachyon going from A to B, another observer may see it go from B to A that's all!
Two, they accelerate when they lose energy. How would this exotic property be possible without going backwards in time?
Nooo energy = m0/√(1 - v2/c2), so either the energy of tachyons is also imaginary, or their rest-mass is.