Science in Fiction: Faster Than Light Communication

What: Instantaneous communication over long distances.


Who invented it? I'm not sure if Gene Rodenberry gets the credit again or if this was a standard trope of the early sci-fi books.


What does it do? Through various gizmos and gadgets characters can communicate between planets or far-ranged space ships instantaneously. Thus allowing for witty banter between the pirates and our hero (or the intergalactic police and our hero depending on the story).


Does this exist? No.


Can it exist? No. Not with our current understanding of physics.



Why not? The speed of sound at sea level is 340.29 miles per second. That's pretty fast, but not fast enough for long distances. That speed decreases as temperature drops. And space is cold.

Not that characters regularly shout in vacuum.

Most, if not all, FTL communications rely on some form of mechanical contrivance. Currently all our vocal communications revolve around the use of radio waves.

When you talk into a microphone or cellphone the sound waves created by reverberating vocal chords hit the microphone in the form of sound pressure, causing vibrations...

From there it gets complicated.

A small movable induction coil, positioned in the magnetic field of a permanent magnet, is attached to the diaphragm. When sound enters through the windscreen of the microphone, the sound wave moves the diaphragm. When the diaphragm vibrates, the coil moves in the magnetic field, producing a varying current in the coil through electromagnetic induction. A single dynamic membrane will not respond linearly to all audio frequencies.

When all is said and done the communications array is still limited by the speeds of radio waves and sound waves.


What does this mean for me? This means that if you want to have some science in your science fiction that you will have to remember distance matters.

The further away your character is from something the longer the delay will be.

Jack Cambell's Lost Fleet series handles this very well. Even the battles are done with speed-of-light delays as part of the battle matrix. And it works.

Elizabeth Moon's Trading in Danger/Ky Vatta series also handles this very well. Although they find a way to overcome the problem.

Doyle and MacDonald's Price of the Stars uses this except in one scene where the villain is able to "phone home" across several star systems and have instantaneous communication.

Louis McMaster Bujold's Komarr handles this well, even remembering the delay between an orbital space station and the ground (small but noticeable).

Linnea Sinclair's Gabriel's Ghost has an epic failure. Two characters manage to exchange flirtatious banter in a casual rhythm but their ship's are out of weapons range. I don't know about you but I want my ship's to have a much better range than that.

Just remember that when you write sci-fi you have to know your audience. If you're writing sci-fi/rom you can probably get away with a few technical errors because the focus of the story isn't science but the romance.

If you're writing a hard-core science fiction book and throwing out numbers and formulas you better check your data before you hit the send key on your query.


Optic fiber with light.... Photo credit Neil Baril found HERE.