ELI5: How much would a human age travelling a light year at the speed of light?

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ELI5: How much would a human age travelling a light year at the speed of light?

Comments

  1. parentheticalobject Avatar

    Not at all. The journey would be instantaneous for them, and they’d be exactly as old as they were at the start of the journey.

  2. KamikazeArchon Avatar

    A human cannot travel at the speed of light. It is impossible to answer the question because the premise is impossible.

  3. stanitor Avatar

    Well you are made of matter, and matter can’t travel the speed of light. But for your question, that doesn’t really matter. Even traveling near the speed of light, you will age one year. Your time always feels normal to you, whatever speed. It will be longer from the perspective of someone else who is not traveling that fast

  4. SalamanderGlad9053 Avatar

    Humans have mass, so they can’t travel at the speed of light, you get a divide by zero in the equations, and it doesn’t work.

    You can get arbitrarily close to the speed of light, for example, at 0.999c, you will to an observer appear to be passing through time 22x slower as compared to a stationary observer. At 0.9999c, it is 70x and so on.

  5. Abridged-Escherichia Avatar

    0

    It would require an infinite amount of energy for a human to travel at the speed of light, but if they did no time would pass for them.

  6. cornsnicker3 Avatar

    From the perspective of the human (let’s assume massless to allow for speed of light travel), it would occur instantly and no aging at all. This would be true of ANY distance. To the outside observer, one year would elapse per light year.

  7. Dbgb4 Avatar

    In this thought experiment the travel time would be instantaneous.

  8. DrClawizdead Avatar

    Massless blah blah blah.

    One year. Time is relative to the observer.

  9. DontH8DaPlaya Avatar

    To make this question simple, “How long would it take to go a mile at one mile an hour?”

    The answer to both is One, year or hour.

  10. netuser247 Avatar

    I love the fact that so many replies seem to think that you do not understand that a human cannot travel at the speed of light and are asking a hypothetical question. 1 light year is how far light travels in one year so if you travelled for one year, you would age one year, The people you know who are not travelling at the speed of light however would age much faster relative to you.

  11. Jaymac720 Avatar

    Aside from the fact that that’s not possible: nothing. Traveling at the speed of light, time stops. If you left earth and traveled to some distant planet at C, it would feel instantaneous to you

  12. norrinzelkarr Avatar

    Real question is, a year in whose time, ours or theirs?

  13. Liambp Avatar

    It is weas possible (which it isn’t) the human wouldn’t age at all.

  14. Gaersvart Avatar

    If I understand it correctly, from your perspective the distance change to zero (distances shrinks the closer you get to lightspeed) and no time passes for you since the distance is 0. for a stationary observer looking at you a year would pass, they would age one year. You traveling at light speed would age 0