Why is light assumed to travel in straight lines?

AstrophysicsX · Apr 25, 2011

Explain why it's accepted that light is rectilinear. It doesn't really seem like it.

turbo · Apr 25, 2011

AstrophysicsX said:

Explain why it's accepted that light is rectilinear. It doesn't really seem like it.

Details? What is your objection?

pergradus · Apr 25, 2011

well its a transverse wave - the direction of energy flow is always perpendicular to the plane containing the e-field and b-field, so the energy has to move in a straight line, albeit infinitely many straight lines.

jtbell · Apr 26, 2011

What about diffraction?

sophiecentaur · Apr 26, 2011

The E and H fields are only at right angles to the energy flow in the 'far field'. When you introduce an obstacle, the fields are disturbed (diffraction) and need to travel a reasonable distance to settle down again. The term Rectilinear was originally to describe the fact that you see shadows. I don't think there's really any conflict here - just a bit of history.

Why is light assumed to travel in straight lines?

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