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Comment by scoith | Hacker News Reader

This is not true. A wave propagates both in time and space. You're mixing these two. A negative frequency is like a wave travelling backwards in time, not left/right spatial direction.

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Not quite. A wave going left forward in time is equivalent to a wave 'going right' but backwards in time. Since it is further right in the past than now, it is actually going left.

There's a lot of similar effects in Physics, especially with time and/or antimatter.

Save me the trouble an learn some basic physics. Read Jackson's Classical Electrodynamics, Chapter 7. If it's too complicated for you, read about waves. See how they propagate in time and space, and pay special attention to what happens to the equation when you change the sign of t. If it's too difficult to imagine, try plotting using a program. And anti-matter is not matter travelling backwards in time. See my post below.

Could you be more condescending?

More seriously, explain to me how making the wave travel backwards isn't the same as changing the sign of t. Wave movement is linearly based on t.

Are we talking about the same thing? I'm talking about particle waves, or wave functions of particles, not a function which satisfies the wave equation (a photon happens to satisfy the wave function, but I'm trying to be general here) and with frequency, I mean energy. Try changing the sign of t in Schrodinger equation and see if it simply amounts to changing the sign of your momentum vector or not.

I guess not. I had an impression of you talking about particles from the start of your comment, but then you went into "read about waves" and said to make a plot, which made it sound like you were talking about basic math. I only understand a few of the effects of altering time on physics so I'll shut up.

From just the book title, I'd like to point out that we have something known as Quantum Mechanics nowadays.

...which unfortunately doesn't cover a photon. I think you meant quantum electrodynamics or quantum field theory.

Which is exactly why the book has that title. The book by Jackson is required reading for any physics graduate in a field where EM radiation plays a role.

I have seen a negative sign grouped with frequency. Which was used to distinguish directionality. Most of the time it is understood from context what is meant, if not the speakers fall back on to more something more formal to ensure understanding.

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