• Rivalarrival@lemmy.today
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    1 年前

    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.