Skip to main content
Worldbuilding

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Required fields*

3
  • $\begingroup$ What about @richS' s comment on his answer regarding holograms? $\endgroup$ Commented May 30, 2016 at 7:33
  • $\begingroup$ @JDługosz Hologram creates wave front as if it came from arbitrary shape. Point is simplest case. If "surface" is otherwise transparent, this "point" will look exactly as a light source placed where you want it to. Look here at one angle, stick is behind squirrel. At another, it is visible. As if these objects were there. Two observers, everything looks real. Limited to single wavelenght, but for purpose of one signal, that's enough. $\endgroup$ Commented May 30, 2016 at 9:17
  • $\begingroup$ @Mołot Several problems. A holographic surface does not emit radio waves; a hologram only exists by reflected light. Your "surface" would have to be thousands of kilometers across to fool the hundreds of radio dishes on Earth that are sensitive enough to receive alien radio signals. Such a surface would be visible to the unaided eye. $\endgroup$ Commented May 30, 2016 at 16:48