• Rivalarrival@lemmy.today
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    11 months ago

    it’s relative to the earth or tied up people, then A.

    If it is relative to the earth, they would be crushed at an atomic level.

    Imagine the trolley-portal is passing around a tape measure at 10m/s. The tape measure is stationary on the earth. After 10 seconds, 100m of tape has entered the portal in a straight line. For me to have 100m of tape in a straight line at the exit, the end of the tape has to be moving away from the portal at 10m/s. Given that “crushed into a singularity” is not an option, we can assume the velocity cannot be relative to earth, and must be relative to the portal.