Private versus Public time

  1. fearthebeard
    fearthebeard
    I'm very fuzzy on how time slows down (or speeds up) as certain milestones (speed of light) is approached.

    From the little I know, time can either speed up or slow down depending on the velocity with which one is moving. The closer that velocity is to the speed of light the slower you age to observers at rest. But privately, you age the same amount.

    If person X was moving close to the speed of light for 50 earth years. They may have only aged a few days, whereas person Y on earth aged 50 years.

    Is this accurate? Also how does rotational speed of a planet and thus the gravity on that planet affect time?

    How do black holes factor in? Time infinitely slows down as you approach the event horizon?
  2. Q
    Q
    I'm very fuzzy on how time slows down (or speeds up) as certain milestones (speed of light) is approached.

    From the little I know, time can either speed up or slow down depending on the velocity with which one is moving. The closer that velocity is to the speed of light the slower you age to observers at rest. But privately, you age the same amount.

    If person X was moving close to the speed of light for 50 earth years. They may have only aged a few days, whereas person Y on earth aged 50 years.

    Is this accurate?
    Yes. Time is relative and can be stretched.

    Also how does rotational speed of a planet and thus the gravity on that planet affect time?
    Gravity and rotational speeds aren't interlinked. Venus for example has a mass very close to that of Earth but a very slow 'day'.

    Gravity does affect time. I suggest this article for more info. It was the knowledge of special relativity that actually makes GPS work for example.

    How do black holes factor in? Time infinitely slows down as you approach the event horizon?
    Basically, yes. For an outsider you appear 'frozen' just before entering the event horizon, eventually redshifting out of existence. For you however, it is unknown what exactly happens. A very likely scenario is 'spaghettification': The huge gravity differences between your different body parts that will pull you apart. But how your perception of time will happen is unknown. Physics theories break down near singularities.