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Timeflow, light, spatial speed, quarks & anti-matter questions

  1. Jun 23, 2005 #1
    hi all. im new, and am bursting with questions about everything. ive always been interested in quantum physics, however, have never had enough knowledge to do anything about it. But im in high school! :smile: and after getting bored in our energy and machines physics course, i decided to do some heavy researching on quantum physics. Especially the area revolved around 'time'.

    Ok, so ive done the research and get alot of it... but some of the fundamentals i still cant get my head around, such as, IS time a constant..? i mean.. time can be discribed as a 'line' - and a line can be discribed as a sequence of dots... is the number of 'dots' finite? or in a different sense, 'infinite' with gaps in between the dots. where each dot holds all 'present spacial information' (i am talking on a quantum level here)

    Also, would it be correct to say that as ones speed increases - density increases. And therefore, IFF ones spatial speed reaches lightspeed (c) ones density would become infinite, therefore altering the space-time continuum to such an extent that the result would be time flow slowing to 0. If this is true.. why doesnt 'light' itself have no time? is it becasue light is a form of EM enery and has no mass? or does energy have mass also? (im new.. remember)...

    Next question revolves around particles and anti-matter.
    here is a table
    It basically says anti-matter cannot exist without time. for, anti-matter is simply matter, however, going 'backward' in time? yes?
    In addition to this, apparantly anti-particles have a charge. can some kind person please explain this 'charge' idea to me. Is it related the number of spatial dimensions that are absent in a void?
    And continuing further from this, how are quarks related to atoms?

    And finally.... did the universe have to be 'created'? i always thaught 'creation' was a function of man, could it be true that the universe and everything has simply always existed and always will. for example, humans build a chair, and say they have 'created' it. Could the universe on othe other hand have just 'been', i.e. all the dimensions were simply 'infinite', however, by definition, something infinite needs a start? so could perhaps in the case of this theory i have, could it bend the rules of math?

    As you can see.. my knowledge is fairly small - as i have just started research. I work with a friend every tuesday after school on this subject, i find it works really well critiquing other people theories, and it allows my mind to expand.

    I really hope you super dooper smart people can help out with a few of my simple questions. otherwise i have to ask my evil physics teacher (and i think he just makes stuff up).

    Keep in mind generalized replies are wanted.

    Thanks in advance. And i hope i have a good future here at physicsforums.com!!! rok on!
    Last edited: Jun 23, 2005
  2. jcsd
  3. Jun 23, 2005 #2

    Kane O'Donnell

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    Not true, consider the set of integers - it goes to infinity in both directions, position and negative, so it doesn't have a start. No matter where you choose the start to be, there are an infinite number of smaller numbers and an infinite number of bigger ones.

    We don't know. At this stage of our physical understanding of the universe we only know that the Universe was at some time in the past very, very, very small and dense. What happened 'before' this is not something we have good theory on at the moment, and the question may not even make sense.

    This is not strictly correct. In almost all quantum theories time is a continuous parameter, so sort of like your 'line'. However, a line *can't* be described by a sequence of dots in every case. For example, take a parabola. If you plot a finite number of points on a graph according to the formula [itex] y = n^2 [/itex] say, where n is a discrete parameter, you get a bunch of dots that follow a parabola. But you could join the dots up in any way you like - there are an infinite number of curves that can join the dots. Therefore, the sequence of dots doesn't uniquely describe the parabola. Only the formula [itex] y = x^2 [/itex] with x as a *continuous* parameter does this.

    It's been hypothesised by mathematicians that the 'number' of numbers on a line segment (like the line from 0 to 1 on the x-axis of a plane) is not just infinite but a 'bigger' infinity than the infinity of counting numbers. What 'number of' and 'bigger' mean are a bit more complicated though, so don't worry about that. What I'm trying to convince you is that there are more dots than you can count. :smile:

    Also, 'spatial speed' doesn't really mean anything, because speed (well, velocity) is the *time* rate of change of position.

    That's enough of my answers :smile:

  4. Jun 23, 2005 #3
    so do you mean to say that time is infinite in both forward AND backward directions? doesnt this just prove that the universe has and always will exist?

    but wait a second... if time has an infinite backward direction, it therefore cant even get a milisecond older... and therefore, time MUST have had a start in order to have a future.
    Last edited: Jun 23, 2005
  5. Jun 23, 2005 #4

    Kane O'Donnell

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    No, I'm not saying time is infinite in both forward and backwards directions, all I'm saying is that just because something is infinitely long doesn't mean it has to start somewhere. It's just mathematics, don't read too much into it.

    This makes no sense. It's like saying just because there are an infinite number of negative numbers, you can't count to 1. It's just not true. Be careful when you try and deduce things that each step is actually implied by the previous.

  6. Jun 23, 2005 #5
    It may be helpful to think of the line as a sequence of segments joined end to end. The segments become 'dots' as their length shrinks smaller and smaller.

    You asked about the information contained within each dot on a quantum level. Going back to the 'segments' picture, think of the information contained within each segment of time. The Heisenberg uncertainty principle gives us this equation:

    [tex]\delta t \cdot \delta E \ge \hbar/2[/tex]

    Roughly speaking, if we measure a system's energy for a duration of time, dt, then the above equation limits dE, the accuracy of the energy measurement. As the time interval gets shorter, the energy measurement is less and less accurate, so you could say that less information about the system is available. When the time segments shrink to dots (dt = 0), we find that no information about energy is present at all in a single dot.
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