Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Time and Size

  1. Jul 13, 2010 #1
    Im new to physics. I had this weird idea and was wondering if anyone could help me. either tell me if im right or wrong.... but i was wondering is time and size relate. would time be interpreted differently if we were much larger than we are?
  2. jcsd
  3. Jul 13, 2010 #2
    Time is completely independent from size.
    Things with very high gravitational forces (e.g. very high energy/energy-density) do experience time differently from alternate reference frames however.
  4. Jul 13, 2010 #3
    Although time is not directly related to size, how you measure size can differ depending on your relative rate of time. Just as it can differ with your relative rate of speed. It doesn't just change apparent size, it can also change the apparent geometry, or shape. This is in essence one way to view what is behind the curvature of space in General Relativity.
  5. Jul 13, 2010 #4
    Yeah, time would not, but interestingly enough, some distance measurement units probably would.
    For example, the "foot" measurement is considered to be roughly derived from the length of someones foot in the distant past(nobility, athlete?). So, if we were larger as a species, such that our feet were twice as long, it is conceivable that the development of that measurement might be 24 inches instead of 12.
  6. Jul 13, 2010 #5
    i have wondered this myself. If a being was the size of say our solar system would he percieve all things in the universe moving a lot faster. If this being lived for a million years wouldnt his perception of speed be much different. Almost like they way we perceive atoms. Having a much wider view would change everything
  7. Jul 13, 2010 #6
    A Lorentz transformation, within certain context, is sometimes referred to as a length contraction. Born rigidity and the relativity of rigidity are closely related to this question. You can work with the presumption that length contraction is real or it is an effect of time on how we measure it, not both at the same time, and it makes no physical difference. When a mismatch occurs when two observers return to a common local frame, it'll show as a mismatch in the passage of time. Your kids can actually grow older than you this way.

    Some people try to divide everything up into real effects and illusions, but what's real in relativity is the symmetries, not on some distinction between real and apparent relative properties. That's what makes them relative properties, because such properties don't exist at all in either observer alone.
  8. Jul 14, 2010 #7
    thanks. @ binbots

    Thats what i was basically shooting for... but on an even larger scale. i was thinking that maybe time and size relate sort of how time and space do... i also thought, that is this being were large enough, that it would veiw thing very much faster. maybe see the earth spinning extremely fast like a dradel... heres why i think this... lets assume that this being that were thinking of takes the shape of a human and is human like for all intensive purposes.... i was thinking of this being even larger than just the size of our solar system... lets think even bigger. lets say 10 times. our solar system is 100,000 light years. lets say he is 1 million light years in height.. i dont know how accurate this would be, but lets assume one of his arms is lets sayy 350,000 light years in length. for this being to strectch his arm out from his chest to directly in front of him, his arm would travel 350,000 light years. since nothing can travel faster than the speed of light, to see this, it would take us humans 350,000 years to watch. but for this being, wouldnt it seem to take him the same time as it seems for us to stretch our arm out as well. although it is natural, the concept of distance is man made. so what we consider to be very very far such 350k light years, wouldnt this being see it as only a foot or so relative to its body size? so if it took us 350k years to see something that is only perceived as a few short seconds to this being, its correct to assume he would see everything else at astronomical speeds? this gigantic being, with an altered perception of time, could have witnessed the big bang, and to him, it may of just happened yesterday?!?! just something i thought of. tear it to bits if you can! i like to learn and this has been bugging me for awhile now!
  9. Jul 14, 2010 #8
    Whoa, hellboundkid. those assumptions are entirely incorrect.
  10. Jul 14, 2010 #9
    yea im sure they are! i dont know much about physics, it just seemed to make sense to me. thats why i came on here because im sure everyone on me knows a whole lot more than i do.
  11. Jul 14, 2010 #10
    the assumption that our solar system is 100,000 light years is whats throwing this WAY off. Alpha Centuri is only 4 light years away.

    but back to your question. being next to a large object, you would see everything away from you moving much faster due to the gravitational effects on time in relation to mass. so there you are correct. but i think what you are really asking is could this being said "Let there be light" 7 days ago in that beings time. and the answer is yes. what is a day to God? but we wont know until he comes and tells us so i tend to stick with stuff my professors can prove to me in the short hours i have with them in a week.
  12. Jul 16, 2010 #11
    i read somewhere that it was 100k light years so i was just going on that. but im an athiest, im not saying this person might have influenced the bb, just wondering if it would percieve time in the manner i suggested. that thousands of years to us may be only a seconds to it. if anything, i think that a being like that couldnt even know we exist, let alone create us, considering how small we would be to it.
  13. Jan 16, 2011 #12
    This is a very interesting topic. It has been bugging me for a long time now too. The question of time actually being relative to size. When I talk about size, I think it is important to start by defineing the size variation, ie the scales varying from "atomic" to that of "our world" and to that of the "solar system". If for example it were possible to stand back and see the earth and our solar system from a distance say, for example atleast a million light years away, what would we see. Firstly, we would have to change how we were looking, the wavelength of light we look at the world would be to small, and the wavelenght would have to be nearer the scale of what we were looking at, so we too would have to be much much bigger..... so in this world would time be running at a different scale.
  14. Jan 16, 2011 #13


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    Before we make such speculation, there has to be some physics that's involved here. And when we talk about "physics", we can't simply wave our hands and claim that that is science. Physics just doesn't say "everything that goes up, must come down". Physics also must say WHEN and WHERE it comes down.

    So when one is claiming "size" is related to "time", one must first of all established (i) the connection and (ii) the QUANTITATIVE relationship between the two. You will note that so far, in this thread, these have not been established.

    I will warned those who are proposing such a thing to re-read the https://www.physicsforums.com/showthread.php?t=414380" that you had agreed to, especially on our policy on speculative post. Unless you can based your ideas on established physics (and actually show that you've understood what we currently know right now, especially on Special Relativity in this case), then you will be in violation of the rules. Typically, nasty things happen to people who do such things.

    Last edited by a moderator: Apr 25, 2017
  15. Jan 17, 2011 #14
    As the person who first started this thread, i am in no way saying anything i said was fact. i dont know much about physics, but was merely asking a question in hopes that people with a physics backround could answer my question which has yet to be answered whether it is or is not possible. i cant prove anything, nor am i claiming it can be proven to be true. i am only wondering if what i suggested is possible within the laws of physics. if it were possible that an intelligent organism was so large, that it would see time and speed at different rates... slower in this case..
  16. Jan 17, 2011 #15
    I think this is just a case of which units of time/space that are chosen.

    It doesn't matter for physics if a large being (with a "slower" brain) chooses a different unit of time and space than us, since the laws of physics are the same in any case.

    Also, it doesn't matter for physics if a large being percieves the revolution of planets in the solar system to be slow or fast. A large being with an expected lifetime of 10.000 years might consider it very fast, but in any case it doesn't affect Newton's gravitational law.
  17. Jan 17, 2011 #16
    I too was only adding comment to an idea that i too had been thinking about for several years now. I did think that this was however a forum for discusion of ideas in physics, and a place to ask questions that might stimulate discusion.

    I would not like to say that I'm totally verse with the Special Theory of Relativity, but it does throw up some interesting things, like time slows for an object that is moving.... which can be seen in experiments, such as the natural half life of sub atomic particles like neutrons can be extended if they set into motion in a particle accelerator, and an atomic clock will lose time if it is taken at speed on an aeroplane.

    I still find that size or distance interests me and the implications that it might have on time.
  18. Jan 18, 2011 #17


    User Avatar

    I think we have to introduce the theory of evolution here. Our sense of time is shaped by evolution, we are "conscious" of time intervals that were important for our survival over the past x million years. We are not intuitively conscious of intervals that are too slow to affect our survival, things that happen on these time scales are "slow". We are not intuitively conscious of intervals that are too fast for our nervous system to respond to, things that happen on these time scales are "fast". This is the bottom line. I would expect the same to hold true of an organism that was 1 light year in size. If it is an organism shaped by evolution, you have to ask: What time scales must it respond to in order to survive? These time scales are what will seem not excessively fast or slow to that organism.
  19. Jan 18, 2011 #18


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    Er.. this is no longer the same topic. And if it is, then this is not a physics issue, but rather a biology issue.

    Someone needs to come up with the mechanism (with valid references) where the physical time is affected by a 'size' of an object, and also define what one means by 'size'. For example, my size affected by the fact that I'm touching the earth? What is the boundary of my size? What is the size of a galaxy?

    Does that mean that a cesium atom has a different frequency by itself then when it is measured attached to something the size of the earth? We know that gravity affects time, but nowhere in this thread is gravity invoked as the result of a size. So this has nothing to do with time as defined within Special and General Relativity.

    For this thread to not be locked in violation of our Rules, these issues MUST be addressed and clarified. If not, then the simple answer to the question if time is affected by size, is no, it doesn't, and we put this issue to rest.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook