4 ms·

All objects and some questions

38 points by notpushkin 3y ago

kbelder 3y ago
Presumably it's just a coincidence we are pretty close to the middle?
- breezeTrowel 3y ago
  It's because we're not that big or small in terms of height and mass. That's why fleas are right in the middle.
- mike_hock 3y ago
  No, presumably it's about as hard to detect things on ever larger scales as it is on ever smaller scales, so we'd expect to always be approximately in the middle.
  - deleted 3y ago
    [deleted]
- ohwellhere 3y ago
  There's some interesting discussion of this in Wolfram's "The Concept of the Ruliad" article in his physics project. https://writings.stephenwolfram.com/2021/11/the-concept-of-the-ruliad/ https://writings.stephenwolfram.com/2021/11/the-concept-of-t...
- pphysch 3y ago
  Is it a coincidence that you are in the middle of your surroundings? No, they are directly related. All the objects, and measurements, are defined by humans according to human experience.
  - whatshisface 3y ago
    But the upper and lower limits are not defined by human experience.
    - pphysch 3y ago
      Of course they are! Very limited, derivative human experience, in the realm of squinting at numbers coming out of exotic research instruments and theories thereof -- but still human experience.
      - whatshisface 3y ago
        A being the size of the solar system would not be able to see any farther into the universe than we can with our telescopes, because it's about what light has reached the solar system and not at all about our sense of scale in interpreting it.
        pphysch 3y ago
        Yes, assuming this being is constrained to human senses + technologies. But why would we assume that?
      - deleted 3y ago
        [deleted]
  - Nevermark 3y ago
    “Creatures” in the Game of Life operate at roughly the level of that automata world’s minimum distance. Their is no a priori reason we would be in the middle.
l0b0 3y ago
Neat; it's a bit dense for non-physicists, though. Who's up for creating an SVG version of this with links for the words? I don't think I could do it justice with my very minimal understanding of physics and SVG.
- vinceguidry 3y ago
  The linked article goes into more detail. Still pretty dense, but better than this treatment.
lainga 3y ago
When plotted that way, it is indeed strange that the trend in density of large-scale structures (from Sun up to superclusters) is heading towards an intersection with the "black holes" line (Schwarzschild radius?)
- dvh 3y ago
  It's even stranger that when you calculate Schwarzschild radius for the mass of the universe, it is roughly the radius of the observable universe (1e53kg --> 15 billion ly)
  - beefman 3y ago
    The 1e53 kg estimate is based on the observable universe (radius 46 Gly) being flat, and ordinary matter being 4.8% of what's keeping it flat.[1] Is it meaningful that just this baryonic matter has a Schwarzschild radius near that of the Hubble (14.5 Gly) and Cosmic Event (16.7 Gly) horizons?[2][3] Then there's the question of how much baryonic matter we actually see...[4] [1] https://en.wikipedia.org/wiki/Observable_universe#Estimates_based_on_critical_density https://en.wikipedia.org/wiki/Observable_universe#Estimates_... [2] https://en.wikipedia.org/wiki/Cosmological_horizon https://en.wikipedia.org/wiki/Cosmological_horizon [3] https://physics.stackexchange.com/questions/60519/can-space-expand-with-unlimited-speed/63780#63780 https://physics.stackexchange.com/questions/60519/can-space-... [4] https://en.wikipedia.org/wiki/Missing_baryon_problem https://en.wikipedia.org/wiki/Missing_baryon_problem
dang 3y ago
We changed the URL from https://kottke.org/23/09/the-plot-of-all-objects-in-the-universe https://kottke.org/23/09/the-plot-of-all-objects-in-the-univ.... (Kottke is great but usually these are best changed to the original source. That URL is still a good place to start.)
whatshisface 3y ago
I am not sure whether I agree with the "Compton limit." A particle can be spatially localized as much as you want if you include high velocities in its wave function, and that can happen in tight bound states as well as in high energy processes. To offer an example of the former, the radius of the s1 atomic orbital shrinks as the nuclear charge increases, and if there is a limit on nuclear charge it is determined by processes unrelated to the electron itself. For the latter, the total energies of all particles eventually start acting like photons w.r.t velocity as their rest mass is overwhelmed, and the gravitation or inertia of a beam of light is impossible to rationalize as mass or put on that chart.
hirundo 3y ago
Why is it "sub-Plankian unknown" but "forbidden by gravity"? Are things smaller than the Plank unit not forbidden? I thought it was an absolute.
gaudat 3y ago
My brain keeps thinking the axes are in decibels than plain logarithms. I think I have never seen a graph with a log axis compressed so hard that the major tick interval is over 1.

38 points by notpushkin 3y ago

kbelder 3y ago

Presumably it's just a coincidence we are pretty close to the middle?

breezeTrowel 3y ago
It's because we're not that big or small in terms of height and mass. That's why fleas are right in the middle.
mike_hock 3y ago
No, presumably it's about as hard to detect things on ever larger scales as it is on ever smaller scales, so we'd expect to always be approximately in the middle.
- deleted 3y ago
  [deleted]
ohwellhere 3y ago
There's some interesting discussion of this in Wolfram's "The Concept of the Ruliad" article in his physics project. https://writings.stephenwolfram.com/2021/11/the-concept-of-the-ruliad/ https://writings.stephenwolfram.com/2021/11/the-concept-of-t...
pphysch 3y ago
Is it a coincidence that you are in the middle of your surroundings? No, they are directly related. All the objects, and measurements, are defined by humans according to human experience.
- whatshisface 3y ago
  But the upper and lower limits are not defined by human experience.
  - pphysch 3y ago
    Of course they are! Very limited, derivative human experience, in the realm of squinting at numbers coming out of exotic research instruments and theories thereof -- but still human experience.
    - whatshisface 3y ago
      A being the size of the solar system would not be able to see any farther into the universe than we can with our telescopes, because it's about what light has reached the solar system and not at all about our sense of scale in interpreting it.
      - pphysch 3y ago
        Yes, assuming this being is constrained to human senses + technologies. But why would we assume that?
    - deleted 3y ago
      [deleted]
- Nevermark 3y ago
  “Creatures” in the Game of Life operate at roughly the level of that automata world’s minimum distance. Their is no a priori reason we would be in the middle.

l0b0 3y ago

Neat; it's a bit dense for non-physicists, though. Who's up for creating an SVG version of this with links for the words? I don't think I could do it justice with my very minimal understanding of physics and SVG.

vinceguidry 3y ago
The linked article goes into more detail. Still pretty dense, but better than this treatment.

lainga 3y ago

When plotted that way, it is indeed strange that the trend in density of large-scale structures (from Sun up to superclusters) is heading towards an intersection with the "black holes" line (Schwarzschild radius?)

dvh 3y ago
It's even stranger that when you calculate Schwarzschild radius for the mass of the universe, it is roughly the radius of the observable universe (1e53kg --> 15 billion ly)
- beefman 3y ago
  The 1e53 kg estimate is based on the observable universe (radius 46 Gly) being flat, and ordinary matter being 4.8% of what's keeping it flat.[1] Is it meaningful that just this baryonic matter has a Schwarzschild radius near that of the Hubble (14.5 Gly) and Cosmic Event (16.7 Gly) horizons?[2][3] Then there's the question of how much baryonic matter we actually see...[4] [1] https://en.wikipedia.org/wiki/Observable_universe#Estimates_based_on_critical_density https://en.wikipedia.org/wiki/Observable_universe#Estimates_... [2] https://en.wikipedia.org/wiki/Cosmological_horizon https://en.wikipedia.org/wiki/Cosmological_horizon [3] https://physics.stackexchange.com/questions/60519/can-space-expand-with-unlimited-speed/63780#63780 https://physics.stackexchange.com/questions/60519/can-space-... [4] https://en.wikipedia.org/wiki/Missing_baryon_problem https://en.wikipedia.org/wiki/Missing_baryon_problem

dang 3y ago

We changed the URL from https://kottke.org/23/09/the-plot-of-all-objects-in-the-universe https://kottke.org/23/09/the-plot-of-all-objects-in-the-univ.... (Kottke is great but usually these are best changed to the original source. That URL is still a good place to start.)

whatshisface 3y ago

I am not sure whether I agree with the "Compton limit." A particle can be spatially localized as much as you want if you include high velocities in its wave function, and that can happen in tight bound states as well as in high energy processes. To offer an example of the former, the radius of the s1 atomic orbital shrinks as the nuclear charge increases, and if there is a limit on nuclear charge it is determined by processes unrelated to the electron itself. For the latter, the total energies of all particles eventually start acting like photons w.r.t velocity as their rest mass is overwhelmed, and the gravitation or inertia of a beam of light is impossible to rationalize as mass or put on that chart.

hirundo 3y ago

Why is it "sub-Plankian unknown" but "forbidden by gravity"? Are things smaller than the Plank unit not forbidden? I thought it was an absolute.

gaudat 3y ago

My brain keeps thinking the axes are in decibels than plain logarithms. I think I have never seen a graph with a log axis compressed so hard that the major tick interval is over 1.