I’m asking this because there is a scifi book I’m reading, and in the book there’s a scene where someone is communicating with a person in a spacecraft moving at lightspeed. I know their ability to communicate would probably not be possible, but let’s just put that aside for a second. Hypothetically, if you could communicate with someone moving lightspeed, would the time dilation make it so that they would appear to be moving and speaking very slowly relative to you?


In principle you could have equipment that cancels out any doppler effect, no?
That’s awesome, let me know if you find anything interesting
To cancel the effect of someone moving away from you, the equipment would simply hold the transmission until you received the whole thing.
Like waiting for someone to finish leaving a message on an amswerimg machine before hitting play.
I see