Half Light Speed Probes: See What Earth Sees

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Discussion Overview

The discussion revolves around the implications of sending a probe into space at half the speed of light while transmitting continuous video footage back to Earth. Participants explore the effects of relativistic phenomena such as Doppler shift and time dilation on the received signal, considering both theoretical and practical aspects of data transmission.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant suggests that Earth observers would see the video footage as Doppler-shifted and time-stamped, indicating time dilation effects.
  • Another participant questions whether accounting for Doppler shift is necessary to understand the signal.
  • A different viewpoint discusses how the encoding of the data affects the reception, mentioning that older AM signals would result in a slower, deeper voice, while modern video streams might require different handling due to varying speeds.
  • Concerns are raised about the engineering challenges of receiving signals from high-speed transmissions and the need for different types of receivers for sufficiently high speeds.
  • One participant notes that prior arrangements for transmission would influence how signals are identified, likening it to challenges faced in SETI (Search for Extraterrestrial Intelligence).

Areas of Agreement / Disagreement

Participants express varying perspectives on the necessity of accounting for Doppler shift and the implications of data encoding, indicating that multiple competing views remain without a clear consensus.

Contextual Notes

Limitations include assumptions about the encoding standards for video transmission and the specific engineering requirements for high-speed data reception, which are not fully resolved in the discussion.

Mikec_vet
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You send a probe out into space at half light speed transmitting continuous video footage. What does the footage look like as seen on earth?
 
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It looks like video footage.
:) Welcome to PF

The Earth observers would see the carrier wave doppler-shifted.
If the footage was time-stamped, you'd see evidence for time dilation.
Was there something specific you were wondering about?
 
Am I correct in assuming you would have to account for the doppler shift to even understand the signal?
 
Depend on how the data was encoded.

If it was an old-style am signal, and it was just audio (say, the pilot reporting her position and time) then you'd just tune your radio receiver into whatever gets a strong signal and you'll hear her voice a bit on the deep side talking a bit slow. How big-a difference is 0.5c going to make?

If it was a modern wireless broadband video stream, I don't know the standard. I know it has to be able to handle streaming between different speed networks. I imagine you could work something out with the engineers so the receiver does not make assumptions about the incoming data's clock speed. That's just an engineering problem.

Of course, for sufficiently high speeds you may need a different kind of receiver completely.

In this example, the transmission was by prior arrangement - how you pick out a signal when there was no prior arrangement is a SETI problem innit :) Normally you'd know the relative speeds anyway.
 

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