5 ms·

If you a single type that counts the number of Plank Time units (10^-44 s) from the big bang until the heat death of the universe, how many bits would you need?

If you a single type that counts the number of Plank Time units (10^-44 s) from the big bang until the heat death of the universe, how many bits would you need? If the heat death of the universe is 10^100 years, that's 6*10^150 plank times [1]. log_2(that) ~ 500 bits. So you'd probably go with 512 bits for a maximally-precise time type that will never need to be updated for either size or precision. [1]: http://www.wolframalpha.com/input/?i=convert+10%5E100+years%2Buniverse+age+to+Planck+times http://www.wolframalpha.com/input/?i=convert+10%5E100+years%...

repsilat 12y ago
Two points: - Quantization of time is not a part any widely accepted physical theory, and the evidence we have so far is consistent with time being continuous. Timekeeping with Planck time units would be "nice" (well, "overkill" and "impossible" are two good words to come to mind as well), but there's no reason in theory that you can't go finer. - When your time is this fine, you also need to talk in very specific ways about reference frames. Time passes at different rates at different altitudes, and relative velocities also screw with you. Where's your reference clock? In some inter-galactic space, stationary relative to the CMB?
- infogulch 12y ago
  To be fair, this is more an exercise in taking "future-proofing" to a logical extreme than something practical (or even possible). With that context I (arbitrarily) chose plank time to be the smallest possibly-ever usable (maybe not practical) time scale for timekeeping. That's a good point about location. If we're going for extremes, we should put it in one of the especially large spaces between galaxy clusters: supervoids[0]! If there were a clock made at plank time frequency, I wonder how much of an effect structures would have on it at interstellar, intergalactic, and void space distances. At this accuracy (and these distances) I imagine the clock's own gravity would be a major source of time dilation. Perhaps the best setup would be an extremely small (think the size of a virus) clock with a small support station that provides energy to it and reads ticks back, kept a few hundred thousand light-years away to avoid gravitational influence. Another thing. 10^100 years is a long time. So long that if the time from the big bang to the heat death of the universe were one second long, the universe isn't even 1 plank time old yet. 10^100 years is so long it starts making sense to talk about the half-lives of elements that are considered perfectly stable. To make any clock that is designed to operate continuously for that long would be a crazy undertaking even for an interstellar civilization. [0]: https://en.wikipedia.org/wiki/Void_(astronomy) https://en.wikipedia.org/wiki/Void_(astronomy)

repsilat 12y ago

Two points: - Quantization of time is not a part any widely accepted physical theory, and the evidence we have so far is consistent with time being continuous. Timekeeping with Planck time units would be "nice" (well, "overkill" and "impossible" are two good words to come to mind as well), but there's no reason in theory that you can't go finer. - When your time is this fine, you also need to talk in very specific ways about reference frames. Time passes at different rates at different altitudes, and relative velocities also screw with you. Where's your reference clock? In some inter-galactic space, stationary relative to the CMB?

infogulch 12y ago
To be fair, this is more an exercise in taking "future-proofing" to a logical extreme than something practical (or even possible). With that context I (arbitrarily) chose plank time to be the smallest possibly-ever usable (maybe not practical) time scale for timekeeping. That's a good point about location. If we're going for extremes, we should put it in one of the especially large spaces between galaxy clusters: supervoids[0]! If there were a clock made at plank time frequency, I wonder how much of an effect structures would have on it at interstellar, intergalactic, and void space distances. At this accuracy (and these distances) I imagine the clock's own gravity would be a major source of time dilation. Perhaps the best setup would be an extremely small (think the size of a virus) clock with a small support station that provides energy to it and reads ticks back, kept a few hundred thousand light-years away to avoid gravitational influence. Another thing. 10^100 years is a long time. So long that if the time from the big bang to the heat death of the universe were one second long, the universe isn't even 1 plank time old yet. 10^100 years is so long it starts making sense to talk about the half-lives of elements that are considered perfectly stable. To make any clock that is designed to operate continuously for that long would be a crazy undertaking even for an interstellar civilization. [0]: https://en.wikipedia.org/wiki/Void_(astronomy) https://en.wikipedia.org/wiki/Void_(astronomy)