TEACHER-GUIDE-VERIFIED · TG-V9-003

3. Explain why a spacecraft message cannot travel instantly between Earth and an outer planet.

Verified solution

Answer: Radio signals travel at light speed, so the large distance creates a one-way delay; a reply requires another light-time interval.

Source: Teacher Guide V9 · English V9. Match the numbers and wording in your printed question before using this solution.

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These pages reproduce verified solution steps for the registered V9 questions. It does not diagnose learning needs or replace instruction from a qualified teacher or tutor.