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?
From the point of view being near the distant supernova, we are moving away from them at relativistic speed, so as much slower as they appear to us, we should appear that much slower to them.
I’m struggling to wrap my brain around this