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So sound is a wave and is basically just vibrations, an atom vibrates causing another next to it vibrate and so on until it finally reaches our ears to become sound.

If that's normally how waves behaves, what about light? I understand it's also a particle but something must have caused its starting point to influence its next point in space thereby allowing it to travel through space. what is the cause and effect relationship that allows light to propagate through space? I ruled out matter because most visible light is blocked by matter.

Qmechanic
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Mike
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1 Answers1

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The process of light propagation is described by the Maxwell equations.

$$ \nabla\cdot{\bf D} = \rho $$ $$ \nabla\cdot{\bf B} = 0 $$ $$ \nabla\times{\bf E} = - {{\partial{\bf B}}\over{\partial t}} $$ $$ \nabla\times{\bf H} = {\bf J} + {{\partial{\bf D}}\over{\partial t}} $$

These equations say (in simple terms) that: change in the electric field is causing a change in magnetic field, while change in magnetic field is causing a change in the electric field.

The original source of electromagnetic waves is some oscillating charge (for instance an electron) which has an electric field around it. This field is changing (because the charge is oscillating). Therefore (according to the fourth equation) a magnetic field $H$ is formed. But the creation of magnetic field is in fact a change in magnetic field. This leads (according to the third equation) to creation of new electric field $E$. But this change in $E$ leads to $H$, which leads to $E$, etc.

mpv
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