how Internet back in the copper wire days could still transmit data in seconds when Electrons flow through copper at a few metres per second.
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You’re implying here the model of electricity as a series of pipes carrying some kind of fluid (electrons) which supposedly do work by flowing around and exerting some analog to fluid pressure.
Which is just that, merely a model. When one considers questions of AC circuits and signal transduction, it doesn’t work well as an analogy. One needs to, in that case invoke the wave model of electromagnetism and consider electrical and magnetic fields, the Maxwellian-Gauss model instead.
Derek Muller of the youtube channel Veritassium made a pair of videos explaining how this model fails and the more accurate nature of the field model.
The motion of electrons themselves is only partly related. It’s only meaningful to the extent that electrons near the outer surface of the wire can move relative to those in insulating materials surrounding the wire which are mostly bound in their respective molecules. This results in a magnetic field which permeates the insulator and surrounds the wire.
Electrical signals in fact require the junction between a conductive metal and an insulator, even if that insulator is air or a vaccum. You cannot easily transmit a signal inside a conductive material without an insulating conduit.
They are carried in the electrical and magnetic fields that *surround* the wire. Technically, speaking, they are carried by photons traveling from the device transmitting the signal to that receiving it. This is why one needn’t even form a complete circuit, and you can transmit the same signals wirelessly through the air with a pair of sufficient sized antennae and a sufficient amount of amplification. The field inside the wire itself is negligable in the context of signal transduction and we only care about the surface of the conductor and the fields around it.
Therefore the speed of electrical signals is equal to the average speed of light in the materials surrounding the surface of the wire. Such as air and plastic. The individual drift velocity of electrons is largely meaningless to signal transduction.
You could in fact construct a signal transferring circuit by boring channels through a solid block of copper and filling them with an insulator. This would not conduct DC but it would have no problem conducting AC signals. This fact also explains why spacecraft experience a period of “radio blackout” when they reenter the atmosphere. The high speed of entry heats the thin air around the spacecraft until it becomes the fourth state of matter which is a plasma, which is electrically conductive. This makes it very difficult to send or receive signals to the ground because the spacecraft is embedded inside a conductor.
In the 1950’s some very smart physicists and engineers who were well versed in the fact that signals are carried in fields surrounding the wires , realized you don’t really need any wires at all and you can simply use photons themselves directly. This is much more efficient because it bypasses the electromagnetic limitations of a very long set of wires. Namely that such a system has a nontrivial value of inherent capacitance and inductance, which limits the maximum frequency that can be transmitted. In other words such a system has an inherent tendency to act as a *low-pass filter.* A long set of wires has greater capacitance and inductance thus the maximum frequency you can pass digital bits over, say, a transatlantic cable is appallingly poor.
Whereas simply transmitting electromagnetic waves (I.e. from a LASER) down an optical conduit such a a thin piece of ultrapure glass, the only limitation on bit rate is the frequency of the light itself. Inductance and capacitance isn’t a major factor.
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