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    Physics General Subjects Thread

    kvs
    kvs

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    Post  kvs on Wed Nov 04, 2020 6:22 pm



    Oops we did it again!

    So Betelgeuse was actually 25% closer than assumed and thus smaller. Some years later they may correct it to 33%, who knows.
    Lots of posturing BS from astrophysicists who talk like they know more than God. But when you scratch under the surface there
    is nothing there but hot air and ad hoc nonsense.

    Recall how UY Scuti "fell from grace" as the largest star in the known universe to 7th place. And these "experts" claim to measure
    black holes down to the last solar mass. You never hear these clowns giving error bounds on their "measurements" in any of their
    public pronouncements. They don't even give real error bounds in their papers. Funny how astronomy has always been linked with
    the occult. Seems this voodoo is still with us today.



    kvs
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    Post  kvs on Tue Nov 24, 2020 8:57 am



    kvs
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    Post  kvs on Wed Nov 25, 2020 8:19 am



    Video where actual imaging of modern CPU die structure is made.   The juicy part is at around 13 minutes.

    They cut through the cache which has a regular structure but which reflects the transistor process tech used
    in the rest of the chip.   Cutting through other parts of the chip would give different structures and complicate
    the comparison.

    So what we see is that 7 nm and 14 nm are marketing BS.   The gate lengths are over 20 nm and there is
    not that much difference between "7" and "14" nm.   The little rant by the narrator is misleading since the
    evolution of CPUs has clearly involved actual geometric change.   It simply can't be claimed that a 130 nm
    process is the same as a 65 nm process.   The whole 3D "FinFet" technology allows marketing departments
    to claim BS size numbers.  

    It is clear from these images that no structure in these 3D transistors is smaller than 10 nm.   In the real world
    having components as small as 7 nm and the much hyped 5 nm would result in failure of the IC to be functional.  
    Around 3 nm there is a transition to the molecular cluster regime where continuum thermodynamics and material
    properties break down.   It is physically impossible to make any FinFet at 3 nm.   And 5 nm would have so
    much quantum tunneling that these transistors would not be acting deterministically in response to
    voltages.  

    Moore's law is quite dead.

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    kvs
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    Post  kvs on Sat Nov 28, 2020 5:37 pm



    The fractal nature of reality.

    The video above is interesting but some of the analogies are hard to swallow. The water in the brain is a volume in which
    neurons and dendrites exist. It is not an energy. The dark voids between galaxies and the filaments linking them is space.
    Dark energy is not volume in the current cosmological theories, it is the attributed to the cosmological constant term in
    Einstein's GR equations which results in space-time solutions that are not static but expanding.

    https://en.wikipedia.org/wiki/Cosmological_constant

    There are attempts to attribute the cosmological constant to the quantum mechanical vacuum energy but as of now there
    are show-stopping issues. Dark energy is not volume and space, it is the change in the volume of space(-time).

    Unlike dendrites which grow away from the neurons to form a network, the large scale filaments seen in the universe linking
    galaxies are mass acting under gravity. This mass is not moving away from galaxies but towards them. These filaments
    are evidence that there were no galaxies in the past and mass was distributed more homogeneously. Over time small
    inhomogeneities grew resulting in the aggregation of mass into clumps and into sheets which collapse into filaments. So
    the filaments are slowly being mopped up by the galaxies (and galaxy clusters) but this process is much slower than the
    initial growth of matter(-energy) clumps. The amount of matter in the filaments is tiny compared to the amount in galaxies.
    As long as we are not talking about dark matter.

    Dark matter is believed to not condense into compact objects like stars and planets. It interacts basically just through
    gravity and has no or vanishingly small EM interaction. This means it does not radiate away its kinetic energy and acts
    like a perpetual gas since it cannot cool off. Dark matter could be orchestrating the regular mass filaments to some
    extent but even though it is supposed to be most of the mass in the universe (over three times more than regular
    mass that we can observe through spectroscopy) it is clearly not counteracting the aggregation of regular mass into
    galaxies. This makes sense since galaxies are potential wells for dark matter as well. So galaxy formation dynamics
    involve the gravitational contribution of dark matter. The large voids separating galaxies may be filled with dark matter
    but it is much more diffuse than in galaxy potential wells. Since there is a finite amount of dark matter it would be
    depleted from inter-galactic space by concentrating in galaxy potential wells.



    kvs
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    Post  kvs on Sat Nov 28, 2020 8:00 pm



    Never judge a book by its cover. Just because particle physicists act nice and are not total assholes all the time
    does not mean that they are holy and justified. Always look for the money motive. These people directly depend
    on the financing of bigger and bigger colliders. Because they do not really know a priori what the physical picture
    is. That is why experimentation is required. But their experiments are mostly flops so they spend a lot of time
    in pulling theories out of their rear ends.

    This does not mean that particle colliders are totally pointless. But we may require one deployed in space with length
    scaling in the thousands of kilometers. Are we going to spend tens of trillions of dollars and develop technology we
    do not have for an experiment that is not even likely to give results? I would think that letting time pass and
    doing such experiments in the future when they make economic sense is more justified.

    kvs
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    Post  kvs on Fri Dec 04, 2020 7:54 pm



    My favourite clickbaiter on YouCrap.

    Two trigger terms "free energy" and "graphene" = ad money.

    Brownian motion or molecular motion is also known as heat and is measured with temperature. This
    energy is not free by any measure. And predictability of particle trajectories is totally irrelevant and is
    not some spooky quantum mechanical effect but is purely classical and deterministic. Brownian
    motion requires a source of heat to maintain and will not just re-emerge spontaneously. Quantum
    mechanics does not override this fact.

    This is not zero point energy which is a sci-fi myth. ZPE cannot be extracted as a usable energy. It
    makes no sense to talk about the kinetic energy of particles at absolute zero. The internal energy of
    ground state atoms cannot be extracted. Molecules that are truly at absolute zero do not vibrate and
    rotate so these energy modes cannot be exploited either.

    There is no free lunch in this universe and most likely any other. All that graphene is doing is allowing
    thermal energy to be converted to electricity in a more direct fashion. Such material effects are not
    new.

    https://en.wikipedia.org/wiki/Thermoelectric_materials





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    GarryB
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    Post  GarryB on Sat Dec 05, 2020 6:04 am

    Would have interesting applications for cooling though would it not?
    kvs
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    Post  kvs on Sat Dec 05, 2020 6:34 am

    GarryB wrote:Would have interesting applications for cooling though would it not?

    Yes like with Peltier coolers. I am not dismissing graphene as not useful, but methinks the hype is over the top.
    Graphene is like the miracle cure and too good to be true. We had similar unrealistic expectations when
    high temperature superconducting materials were found during the 1980s. It's been over 35 years and little
    has come from it. Maybe there will be fruits some day.


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