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Are we somewhere in the middle of everything?

  1. Sep 22, 2005 #1
    Alright, I'll try my best to use words for what I am thinking about but it may be a mess.

    Are we stuck in the middle of two worlds? The two worlds being the big, and small world. I don't know the proper name for them but lets just call them the Atomic World, and the oh I don't know, Galactic World. When I say we I mean like as small as an ant, and as big as a blue whale...thats a nice range I guess. Now for a second can we forget about infinity big and infinity small..not that it really matters but I think it will make things easier. Pretend for a second that an atom, and its electrons are fundemental building blocks, and galaxies are as big as it gets. So are we in the middle of these two worlds? Are we as small as we are compared to the galactic world, and as big as we are compared to the atomic world? Or do we fall more towards one of the two in terms of size?

  2. jcsd
  3. Sep 22, 2005 #2


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    I think you mean the quantum world and the relativistic world, called so due to the theories that best describe them, and the governing forces.
  4. Sep 23, 2005 #3
    Yup I knew I had the names wrong but you understood didn't ja. Thanks though. I still hope someone will answer my question though. It's really bothering me.
  5. Sep 23, 2005 #4


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    People tend to "categorize" everything and using two categories is always simplest. No matter what were true about the physics, we would notice that there are somethings smaller than us and some larger- and I think that's about all you are saying.

    As for whether we are close to "the galactic world" or "the atomic world", that depends on how you make the calculation. Do you want to compare sizes by subtracting or dividing?
  6. Sep 23, 2005 #5


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    I guess I can see it: Humans themseleves live in the macro world at low speed - the one governed by Newton's laws. QM is mostly relevant to the micro world of atoms, molecles, and photons. And Relativity takes hold at high speed in the macro world.
  7. Sep 23, 2005 #6


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    Nature doesn't really care how we define big and small. For us though, our standard unit of measure for size or distance is the meter. It's a nice size for us, the size of daily objects around us. (If we were the size of guinea pigs, the meter would've been a lot shorter).
    The atomic world takes place in relevent distances that are one ten billionth (10^-10)the size of a meter. If I remember correctly, the age of the universe is like 15 billion years, so the relevant distance is somewhat 15 billion lightyears or 10^26 meters.
    We cn go to much smaller distances than atoms though, the nucleus of an atom is about 10^-15 m. And we can go even further to smaller scales.
    So you decide, are we in the middle or not? As I said, nature doesn't care.
  8. Sep 23, 2005 #7
    i believe attometer's are about 1x10^-18...
    i assume that means the smallest things are probably smaller than 1x10^-30, seeing as an atom's nucleus in an atom is like a fly in a church...
    Did you just say that the universe is probably 1x10^26? so i think that stands up to say that we are closer to the size of the universe than we are a quantum particle...
  9. Sep 23, 2005 #8
    (about mozarts original post)
    basically you think we are a blip between a tiny universe and a gigantic universe that share the same dimensions? in that case yes. we are made up of billionss upon trillions of atoms while the univers is billionss upon trillions of times larger than us. we are just a blip in the middle
  10. Sep 27, 2005 #9
    If we take the human to be ~ 1 meter length, then as shown from the chart below, we tend to be closer to the galactic, than the atomic--info from this link:
    (for fun, this site lets you also calculate using area and volume)

    10-35 Planck-Wheeler length | space no longer "flat"
    10-18 am
    10-15 fm
    10-12 pm
    10-10 A | atoms
    10-9 nm | atoms
    10-8 bigger molecules
    10-7 virus
    10-6 um | hc/1eV | bacteria
    10-5 eukaryotic cells | blood cell
    10-4 eukaryotic cells
    10-3 mm | grain of sugar
    10-2 cm |
    10-1 foot | light-nanosecond |
    10+0 m meter | human
    10+3 km
    10+4 ocean & atmosphere thickness
    10+6 Mm
    10+7 Moon | Earth
    10+8 light-second | Jupiter
    10+9 Gm | Sun | to Moon
    10+11 to Sun
    10+12 Tm
    10+13 to Pluto
    10+15 Pm | to Oort Cloud
    10+16 light-year | pc (parsec)
    10+17 local stars | star cluster
    10+18 Em
    10+19 kpc | to Betelgeuse
    10+20 galactic disk - width | to Crab Nebula
    10+21 galactic disk - diameter | to LMC | galaxy
    10+22 to M31 | Mpc (megaparsec)
    10+23 Local group | galaxy cluster
    10+24 to Virgo Cluster | galaxy cloud | supercluster | voids | filaments
    10+25 to Coma Cluster
    10+26 ~ visible universe
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