What do electro-magnetic waves consist of?

I’m watching a variety of YouTube videos trying to understand how a signal from a Wifi router, TV broadcast antenna, and cell phone towers create and send a signal to the receiving devices. All I can find is that the tower/device creates an “electro-magnetic” wave (very simple explanation and nothing further) OR something way too complex for me to understand as a non-engineer.

So are these electro-magnetic waves simply “vibrating” nearby electrons and the wave continues to the next nearby electrons and so forth (like the waves in a still pond that created when you drop a pebble in the middle of it)? Or, are they actually sending the same electrons out from the source until they hit something? Or something else?

I’m not any sort of an expert… but the question you’re asking is equivalent to “what is light”?

All of “reality” is held together by four fundamental forces. Gravity and electromagnetism are the two we’re most familiar with in day to day interactions. The other two are more related to what holds matter together.

Human understanding of what is gravity and light is not that advanced. In many ways you’re asking the question “what is light?” Light behaves like a wave and like particles, depending on how you measure it.

That is what sound does. Magnetism can pass through the vacuum of space… as can gravity… I don’t think we have a good explanation for this propagation. There are quantum theories but they’re unproven so far as I know. (The grand unification and string theories and other theories are all in this area.)


You’re getting into some pretty deep questions that can’t really be abstracted down very well imo. If you really want a grasp on this stuff you should look up the author Carlo Rovelli. He’s an Italian physicist with a real gift for explaining modern physics concepts. His book “Seven Brief Lessons of Physics” is a great one to start with, but my personal fav is “The Order of Time.” That was a real mind-bender.


Thanks to both for the explanations above. I will digest the answers over the next day or so.

But if we really don’t know what they are exactly, how do we built receivers that actually can receive the waves and then translate them into video, sound, data, etc.??

We may not know precisely what they are, but we know enough to be able to effectively observe and predict the effects in a consistent way, consistent enough to build a television broadcasting/WiFi/LTE standard based on what we do know.

All of science is theory based on supposition and observation. So we accept these theories until we observe that the accepted theory is wrong.

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In a word: physics. Physics is the study of the physical world trying to understand its properties and make “laws” to predict how the world works. It’s a bit like driving a car… you don’t really need to know how a car works to be able to operate one. So it is with radio waves. We don’t fully understand all of their nature, but we do know that that they have certain properties, such as the inverse-square law, and we are able to make devices to exploit the properties at the level of understanding we currently have.

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Akin to the way lots of men navigate marriage. :rofl: