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“Rob Sheldon: On our universe “as a massive computer sim:

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As claimed here, he says:

The simulation is really quite bad. According to the article, they used 12 billion pixels in a cube 350 million ly across, for a resolution of 153000 ly per pixel (without adaptive meshing). Now our galaxy is about 100,000 ly across, so we basically have one largish galaxy per pixel. With 100 billion galaxies in the universe, then at a minimum we would need to have 100 billion pixels to simulate for our “universe simulation” if we used “adaptive meshing” to skip over the vacuum in between, so right away you can tell we have only about 10% of the necessary computer resolution. But they didn’t even come close to that. According to the article they simulated the formation of 41,000 galaxies. So their universe, despite trying to simulate the entire Big Bang, managed to get 41,000/100,000,000,000 = 0.000041% of the matter into its proper place.

The sad story of 21st century science:

“But does it ever look pretty! What are you doing with that calculator, just watch the movie!”

He also writes to say,

Its unfortunate that the overlap between being a teacher and being hired as a teacher is rapidly approaching the null set, because short-term, propaganda is always politically more powerful.

Darwin lobby court judgments help.

Look, it doesn’t matter any more what they are shouting as long as it is  the effect of such judgments. Why does no one realise?

6 Replies to ““Rob Sheldon: On our universe “as a massive computer sim:

  1. 1
    bornagain77 says:

    But if our universe is a computer simulation in the first place,,,

    The Physical World as a Virtual Reality – Brian Whitworth – 2008
    http://arxiv.org/abs/0801.0337

    ,,,then did they just run a computer simulation of a computer simulation??? Seems rather redundant. 🙂

  2. 2
    bornagain77 says:

    Planetary Collective presents a short film documenting astronauts’ life-changing stories of seeing the Earth from the outside – video
    https://vimeo.com/55073825

  3. 3
    bornagain77 says:

    Warning, heavy dose of environmentalism is tacked on at the end of preceding video:

    But along the line of beautiful imagery from space:

    View from the ISS (International Space Station) at Night – video
    https://vimeo.com/45878034#

  4. 4
    lukebarnes says:

    The embarrassment continues …

    * “a resolution of 153000 ly per pixel (without adaptive meshing)”

    But the simulation does use an adaptive mesh. (To be precise, it uses a moving unstructured Voronoi tessellation). The resolution in high density regions like galaxies is 157 light years. So rather than “one largish galaxy per pixel”, the paper describing the simulations states that that all galaxies are “resolved with more than 500 stellar resolution elements”.

    * “According to the article they simulated the formation of 41,000 galaxies. So their universe, despite trying to simulate the entire Big Bang, managed to get 41,000/100,000,000,000 = 0.000041% of the matter into its proper place.”

    The entire big bang?!?! Are you serious?

    Our universe, to the best that observations can tell us, is homogeneous. That means that it is statistically the same everywhere, above a certain scale. Thus, simulations do not need to model the entire universe in order to get a statistical sample able to be compared to observations. The simulations in question sampled a sufficiently large part of the universe – with sufficient resolution – to achieve this aim.

    You got one thing right … What *are* you doing with that calculator?

  5. 5
    phoodoo says:

    lukebarnes,

    I believe that if one is arguing that the world is a computer simulation, that disqualifies them from passing judgement on embarrassment.

    Even the Truman Show realized the need for building an actual set.

  6. 6
    lukebarnes says:

    Except that it isn’t arguing that “the world is a computer simulation”. The phrase “as a massive computer sim” quoted in the title of this post is not a quote from the linked article or the paper.

    It’s a simulation of how galaxies form in our universe, under the combined influence of the expansion of space, the attraction of gravity and the microphysics of matter (thermal pressure, radiation cooling, star-formation, angular momentum etc.).

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