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shminux comments on Open Thread, June 2-15, 2013 - Less Wrong Discussion

5 Post author: TimS 02 June 2013 02:22AM

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Comment author: shminux 05 June 2013 04:13:11AM 2 points [-]

Today I learned that there exist electromagnetic waves in vacuum with electric and magnetic fields parallel to each other. Freaky...

Comment author: Manfred 09 June 2013 03:43:05PM 0 points [-]

Sure it's not in plasma?

Comment author: shminux 09 June 2013 06:30:08PM 3 points [-]

Consider a circularly polarized standing wave with the electric field of the form E=E0cos(kz)(cos(wt)x-hat - sin(wt)y-hat).

Comment author: [deleted] 09 June 2013 10:49:24PM 1 point [-]

... oh.

Comment author: Manfred 09 June 2013 07:00:24PM 1 point [-]

Ah, I see. They're offset along the z-direction, rather than in the x-y plane.

Huh.

Comment author: shminux 09 June 2013 07:18:36PM 3 points [-]

My mind was blown when I saw it first, so ingrained was the "fact" that E and B are normal to each other for waves in vacuum. I had to recalculate B several times before I believed it. Which makes me worried that some other physics "facts" I now believe unquestioningly have similar holes.