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Worldbuilding

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  • $\begingroup$ The question was very much inspired by Contact, yes (but I did my best to make sure that it could stand on its own). Frankly, this is exactly what I expected that the answer would be, but it's always interesting to see what the Worldbuilding SE community can come up with. I've been surprised before. $\endgroup$ Commented May 29, 2016 at 11:17
  • $\begingroup$ Have you ever looked at hologram? It makes us see light coming from point far beyond it's surface. Holograms can pass parallax test all right. $\endgroup$ Commented May 29, 2016 at 21:15
  • $\begingroup$ That's not how holography works. Holograms require a specially prepared surface so an observer can see different images from different angles. (Usually different views of same target object.) Holography needs a single observer at a single location turning a holographic surface to see different images. Parallax is when 2 observers at 2 different locations looking at the same object and seeing different backgrounds. $\endgroup$ Commented May 29, 2016 at 21:27
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    $\begingroup$ @DonaldHobson And when those satellites pass overhead at a kilometer per second, they will not be between the dishes and Vega. It would take from a few minutes to over an hour depending on the satellite's orbit. That's another reason why you can't fake an alien signal with a satellite, and I considered that as a different answer, but chose to post about parallax instead. You can post that as a separate answer. I recommend doing the math for satellite orbits first. Here's a site for that. physicsclassroom.com/class/circles/Lesson-4/… $\endgroup$ Commented May 30, 2016 at 16:37
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    $\begingroup$ @JasonK Transient signals are not useful signals. If you can't get other observatories to see the signal, and you can't even get a repeat of the signal after a few seconds, it's just noise that clutters up what you were observing in the first place. Astronomers consider most transient radio signals as Earth-based signals. $\endgroup$ Commented May 31, 2016 at 15:29