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?

  • Alvaro@lemmy.blahaj.zoneEnglish
    21·
    3 days ago

    I don’t actually know, but to my understanding…

    Firstly it would be impossible because of the doppler effect and the fact that at these speeds you would go around the earth in about the same time it takes to say “Hello” , but if you ignore that:

    At a difference of around 260,000 KM/S you could actually have a time dilation difference that would be perceived by the observer (the slow one) as 0.5x and anything said by the traveler would be heard by the observer in slow motion.

    Again, I have no physics background, so…