Widdekind

From Science Daily 2012, non-Ribosomal Proteins pre-date Ribsomes. Non-ribosomal protein (NRP) synthesis "resembles fatty-acid synthesis"; perhaps primitive pre-cellular life employed pathways, for the biosynthesis, of fats, carbs, & proteins, which were all similar, and all before the later evolution, of Ribosomes (Cells, Genes) ? NRPs are often "siderophores", i.e. "iron carriers", that "cradle" bio-valuable Fe+++ ions. By naive extrapolation, all primitive NRPs "cradled" bio-valubale metalic ions -- implying that they were bio-catalysts, i.e. enzymes, for other bio-chemical reactions. (Indeed, modern proteins are often enzymes.) NRPs are synthesized, individually & uniquely, by conventional proteins (called NRP-Synthetase enzymes), themselves assembled by ribosomes, from DNA-to-RNA "blue-prints". According to said article, the fact that the NRP-S sequences were "remembered", and re-encoded into DNA genes, is note-worthy. By what mechanism, would ancient NRP-S "proto-genes" have existed, to be remembered? Proteins || Ribsomes ===(mRNA)=== DNA || NRP-S || NRP By naive extrapolation, all primitive NRPs were enzymes (above), each "custom built", by its own NRP-S, coded by its own gene. If so, then Ribosomes centralized the assembly process; whereas before, myriad genes coded myriad NRP-S, bio-sythesizing myriad NRPs; after, myriad genes all "went to/thru the ribosome", which bio-synthesized the myriad Proteins. I.e. Ribosomes are a "universal NRP-S", capable of bio-synthesizing any Protein, so "stream-lining production", through a "central production hub". Now, again according to said article, Ribosomes have been evolving bigger & bigger, with larger & larger Proteins; and longer & longer RNA strands. Ipso facto, anciently, proto-Ribosomes were small clusters, of P+RNA. And, the "active site", where mRNA attaches, on arrival from the DNA, is not the oldest part of Ribosomes; ergo, proto-Ribosomes did not communicate, with mRNA / DNA: proto-Ribsome (P+RNA) || NRP-S || NRP Now, Ribosomes are composed of multiple "modules", each a conglomerate of P+RNA. And, before they joined, they were separate. Since we also need a "proto-gene" system, to "blue-print" all the NRP-S (which then, each individually & separately bio-syntheisze one unique NRP); we recognize, that bundles of P+RNA resemble primitive Viruses, i.e. "Protein-armored RNA". Perhaps ancient "proto-Genes", were "Protein-reinforced RNA" strands? Then ancient proto-life would have represented "armadas", of P+RNA molecules ("ships"), each the template, of a NRP-S Protein enzyme, each of which, in turn, assembled NRP "nano-tools"? (P+RNA)............(P+RNA)............(P+RNA) ||.....................||.....................|| NRP-S...............NRP-S...............NRP-S ||.....................||.....................|| NRP...................NRP...................NRP Then, by fortuitous conglomeration, (P+RNA) "proto-Genes" began sticking together, accreting into "proto-Chromosomes", one of which became the Ribosome? (P+RNA):(P+RNA):(P+RNA) -------> Ribosome At some point, DNA evolved, i.e. "ruggedized RNA" (via removal of an O) that no longer needed "Protein scaffolding"; DNA was, somehow, "spun-off". Perhaps "Ribosomes" date to the dawn of "cells", i.e. pre-ribosomal-proteins reflect pre-celular, molecular life? According to Science Daily 2008,

fission reactors "melt down", because they can generate sufficient heat, to melt metals. Perhaps fission reactors could be run "hot", to melt metal space-ores, w/o need for "fuel + oxidizer" ?

for an RNA-world scenario, primitive molecular "trans-life" could possibly have been self-catalyzing complexes of RNA + Protein, similar to Ribosomes; ergo perhaps Ribosomal RNA codes for Ribosomal Proteins ?

Ribosomes are molecularly massive structures, composed of 3 RNA strands, cradled in a cluster of 56 proteins. Those 3 RNA strands (16S + 5S,23S), and their corresponding complimentary anti-strands (16S + 5S,23S), code for what poly-peptides, i.e. would generate what proteins, if "fed" to other ribosomes ?

Biomedical animator Drew Barry states that mosquitoes are normally vegetarians, and only pregnant female mosquitoes drink blood; and only for "special nutrients". Perhaps people could construct "mosquito feeders", that "smelled like animals", and contained said special nutrients, so that the mosquitoes would be attracted to the bait, over actual people ?

On earth, sub-marine volcanoes erupt under many atmospheres of pressure, which limits their "explosiveness". How would thicker atmospheres, e.g. Venus, affect eruptions ?

if fiber-glass is similar, in strength, to many metals; then could rail-road tracks be "extruded", from fiber-glass? In analogy to "extruded" PVC piping, such rails could be continuously created, from traveling trucks, into which the appropriate ingredients could be continuously poured, so that continuous rails could be extruded, vaguely like line-painting-trucks on roads, capable of creating continuous road markings.

What about synthetic aperture arrays, that can mimic ultra-long baselines ([math]D[/math]), for resolution ([math]\theta[/math]), at the cost of some sensitivity ?

http://www.physorg.com/news/2012-02-planetary-accretion.html

I understand, that a "glass" is an amorphous semi-solid, whose molecular monomers have not self-assembled, into an ordered crystalline structure. A "glass" is a kinetically locked, rapidly cooled state, wherein the material was "flash frozen" before it could self-assemble, into an ordered, structured, crystalline, solid state. I.e. in contrast to the amorphous liquid state, wherein the molecular monomers "stick & slip"; in an amorphous semi-solid glass, the molecular monomers "stick & grip" or "stick & lock". For example, glass is (essentially) amorphous semi-solid silicon dioxide (SiO2) (chemically identical to carbon dioxide (CO2), but much more massive, which is why the former is a solid ("sand"), whilst the latter is a gas, at terrestrial S.T.P.). And, the crystalline structured solid form of SiO2, i.e. quartz crystal, is an ultimately-lower energy state, than the amorphous semi-solid form, i.e. glass. Therefore, given sufficient time, e.g. geologic 'deep time', would not glass slowly solidify, into quartz crystal ? Would not small regions become aligned, and 'nucleate' the crystallization process, reminiscent of 'zone growth' in ferromagnets, albeit ultra-slowly ? And so, if quartz crystal is a common constituent, of continental crust, on earth today; then would not those crystals have derived, from amorphous glasses, billions of years ago, on the early earth ? Also, if quartz is the most common constituent, of planetary crusts, then could not fiber-glass be generatable, in situ, from "ground up regolith", on any rocky world, e.g. moon, mars ? Could "concrete & fiber-glass" help build habitats, on other worlds, or remote regions of earth ? Were anyone willing to delve into the details, I suspect, that there is some connection, between glass formation, and latent heat of fusion. I.e. a glass is a "flash-frozen" super-cooled melt, in a non-crystalline amorphous state, below its melt/freeze transition temperature Tm; and, even below its colder glass transition temperature Tg < Tm; but, above its theoretical Kauzmann temperature Tk < Tg < Tm, at which the "entropy", i.e. internal energy, of the super-cooled, flash-frozen "glass" would reduce to the value, of the true solid state. I suspect, that all of that entropy, i.e. internal energy, difference, corresponds to the latent-heat-of-fusion, released during solidification / crystallization, under "normal" conditions. If so, then the glass state would truly be transitory, although the transition, from amorphous liquid, to crystalline solid, could take ages & aeons, for some materials. For example, when water freezes to form ice, it would, then, briefly transition through a "glassy" state. I understand, that, unlike in an amorphous liquid state, in an amorphous semi-solid glass state, covalent bonds do form, albeit "haphazardly". The stronger the bonding affinities, of the molecular monomers, in the initial liquid-phase "melt", the higher the glass transition temperature Tg ----> Tm. Conversely, non-interacting monomers would never "vitrify", i.e. become glassy, Tg ----> Tk. Naively, I intuit, that a "glass" is a possible condition, of a super-cooled liquid, which "should be solid", but hasn't given up (all) of its internal energy, i.e. latent heat of fusion, and so retains a liquid-like amorphous unstructuredness. On other, colder, worlds, could dry ice, i.e. solid CO2, exist in glassy, as well as crystalline, (semi-)solid forms ?

First, that assumes surveillance, at optical frequencies. Our universe is most transparent, at radio frequencies, near 1-50cm in wave-length. And, hypothetical star-sized; or star-system sized telescopes; or, arrays of telescopes; would still be no more luminous, than our own asteroid belt, Kuiper belt, or Oort cloud, which we cannot directly detect, i.e. "'big' need not mean 'bright'". Therefore, hypothetical vast "arrays", of asteroid-sized telescopes, are already invisible to humans, at trans-stellar ranges, i.e. Oort cloud. Er go, hypothetical aliens, in nearby star systems, could have deployed vast "artificial Oort cloud" space telescope arrays; and humans would know nothing "from next door". We do not have "good glasses" for space.

May I please "kibitz" for clarification ? I understand, that "mass tells space-time how to curve; and curved space-time tells mass how to move" (Wheeler. Journey into Gravity & Spacetime). Er go, different mass distributions, generate different space-time curvatures. So, I understand, that in "gravitationally bound" structures, e.g. galaxies, space-time is non-expanding; whereas, in deep space between the galaxies, space-time is expanding. From this understanding, I would say, not that "gravity inside galaxies 'offsets' expansion"; but rather that bound objects have fundamentally different space-time curvatures, where-with-in the fabric of space-time is non-expanding. Your use of the word "offsets" suggests some sort of "internal struggle", between a vaguely "Schwarzschild-like" space-time, attributable to local galaxy masses; and a Hubble-expanding "Friedmann" space-time, attributable to the global cosmological mass distribution. Is there such a "struggle" of competing factors, within the fabric of space-time, within galaxies ? The vaguely "Schwarzschild-like" space-time, inside a galaxy, as numerically calculated, in isolation, would presumably be vaguely "static" (on galactic scales). But, in real life, galaxies are embedded into the expanding space-time fabric of our universe. So, is your use of the word "offsets" an accurate description ? E.g. does the Hubble expansion "tug at the edges" of galaxies ??

If gravity is a fictitious (pseudo) force, cp. centrifugal & Coriolis forces; then how could 'gravity' be exerted, through force-ful interactions, via boson exchanges, i.e. 'gravitons', any more than there are 'centrifugal-ons' or 'Coriolis-ons' ? The only actual forces, mediated by bosons, are the S,W,EM, of the Standard Model ? If so, why would quantum gravity be any other, than "solving the Schrodinger equation on a curved coordinate grid-mesh" ?

perhaps, considering photons, E = pc = mc2, i.e. "there is only one fundamental substance, energy-momentum-mass" ? Via such explanation, energy can do work, i.e. exert forces, i.e. alter momentum, [math]W = F d = \frac{\Delta p}{\Delta t} d[/math]. Intuitively, I like the definition, that "energy is that which is capable of exerting forces, i.e. force-fully influencing its environment", i.e. energy represents a "battery-storage" of force.

from earth, humans cannot directly detect, i.e. observe, exo-planets & exo-moons. Er go, hypothetical world-sized telescopes could exist, in our nearest neighboring star systems, and we would not know. We do not have "good glasses" in space.

Humans cannot resolve dwarf planets, in our own star system, e.g. pluto; any planets, in any other star systems, i.e. exo-planets; or stars, beyond our local stellar neighborhood, i.e. in our galaxy, or others. Er go, hypothetical planet-sized, or even star-sized, space telescopes, far far away in space, are beyond human capability to detect. To develop & deploy such systems, would require billions to trillions of dollars.

"mom-energy" = [ "space-time 4-displacement" between events A,B ] divided by [ "proper time" ] I understand you to be telling me, that "proper time" -- which, in my mind, is specific to that reference frame "threading through" both events A,B -- is better thought of, as the "invariant interval [math]dS = \sqrt{dS^2} \approx \sqrt{t^2 - x^2}[/math]. In my mind, "universally invariant interval" dS between events A,B is distinct from "proper time" which is limited, to that special reference frame, in which the whole entire invariant interval dS is "perceived" to be "elapsed time" dS = dtp, i.e. in every other reference frame, the invariant interval, although constant, is composed of a time part and a space part, whose difference remains invariant. In my wordage, I understand you to be telling me, that "momenergy" = "4-displacement" / "invariant interval dS" Intuitively, that seems a better definition, on the 'grounds' that the invariant interval dS is "directly accessible" to every reference frame, without any naive notions, of the perceived-to-be-moving particle somehow "reporting its proper time". To my mind, distinguishing "invariant interval" (same for all observers) from "proper time" (specific to a special reference frame) helps clarify this concept.

Please ponder "mom-energy", in curved space-time. Particles residing near massive bodies experience gravitational time dilation. Accordingly, for a distant observer, dividing by the particle's proper time, induces a "gravitational gamma factor", [math]m \rightarrow \frac{m}{1-\frac{2GM}{c^2 r}}[/math]. Note, this relation can also be derived, from [math]g_{\mu \nu}p^{\mu}p^{\nu}=\left(mc^2\right)^2[/math], using the Schwarzschild metric, on a stationary test charge [math]p^{\mu} = \left( \begin{array}{cccc} E & 0 & 0 & 0 \end{array} \right)[/math], which "picks out" the time-time component, of the metric tensor, [math]g_{00} = 1 - \frac{2GM}{c^2r}[/math]. If so, then particles residing near massive bodies, are perceived, by remote observers, to have a gravity time dilation; and a gravity gamma-like factor, which increases the effective mass, i.e. "time slows & mass increases, for fast-moving particles; and for particles in gravity 'wells'". principle of equivalence: Whether in "flat" space-time, or "curved" space-time, particles "prefer" to propagate along "straightest possible paths", i.e. geodesics, through space-time. Per Newton's first law, each & every deviation, from the "desired" geodesic "free fall" path, must result from forces; and are all experienced equally as accelerations. Is this accurate ? I understand, that, ultimately, all force-ful interactions arise, from the three fundamental forces, i.e. Strong, Weak, EM, via boson exchange. E.g. standing on earth is, ultimately, an EM interaction, between electrons, via virtual photons; whereas standing on a neutron-star would, hypothetically, be a Strong interaction, via virtual pions. Is that accurate ?

I understand, that the "mom-energy" 4-vector is calculated, from quantities, derived from two different reference frames. First, the observer measures a 4-displacement, [math]\Delta x^{\mu}[/math], between two events, on the trajectory, of some particle, propagating through their laboratory rest frame. Then, that 4-displacement is divided by the proper time, [math]\Delta \tau[/math], elapsing between those two events, in the particle's own rest-frame. I.e. "the observer measures the displacement, but the particle reports the time". The "mom-energy" is the velocity 4-vector, multiplied by the particle's mass. What about 4-acceleration ? I understand that If the 4-velocity "points" in the direction of the particle's time-axis, i.e. "is the tangent vector to the particle's world-line"; then must the orthogonal 4-acceleration "point" in the direction of the particle's space-axis ?? I observe, that, indeed, in a particle's own rest-frame, the 4-acceleration has no time component, and so is wholly space-like. More generally, in (2+1)D, I suspect, that the 4-acceleration must lie in the "tilted (x'y') plane" in the particle's reference frame.

If the Einstein "mom-energy" relation [math]p_{\mu} p^{\mu} = m^2[/math] implicitly involves the Minkowski metric matrix, [math]m^2 = \vec{p}^T \cdot \tilde{\eta} \cdot \vec{p}[/math]; and if, in the presence of matter-and-energy within the fabric of space-time, that Minkowski metric matrix "evolves" into the GR metric matrix, i.e. [math]\tilde{\eta} \rightarrow \tilde{g}[/math]; then could application of the QM operator ansatz, to [math]\vec{p}^T \cdot \tilde{g} \cdot \vec{p} = m^2[/math] represent relativistic QM, on a non-matter-free space-time ? If so, would the "mom-energy" operators act on the metric matrix elements; or would they "slide through" to act only on quantum particle WFs ? edit: According to Hyman 1989; and acknowledging one "minus sign" for reversing that author's choice of metric, from (-+++) to (+---); and acknowledging another "minus sign", arising from eq.11, when setting the source at the coordinate origin, so that [math]r^a \rightarrow -x^a[/math]; then the Schwarzschild metric, in cartesian-like coordinates, is: [math]g_{00} = 1 - \kappa[/math] [math]g_{0a} = \kappa (x^a/r)[/math] [math]g_{ab} = -\delta_{ab} - \kappa (x^a/r)(x^b/r)[/math] where [math]\kappa \equiv \frac{2GM}{c^2r} = \frac{R_S}{r}[/math]. The presence of such "cross terms" would make the KGE, in a Schwarschild space-time, much "messier".

I recall Prof. Icko Iben telling our class, that stellar ages are predicted, from 1970s-era, 1D, spherically-symmetric, hydro-dynamics simulations; incorporating no magneto-hydrodynamics; incorporating no stellar rotation; incorporating mass-loss as an artificial factor, numerically imposed as if by "numerical fiat". From Carroll & Ostlie's Intro. to Mod. Astrophys., I learned that, when simplifying assumptions are involved, astrophysical calculations are expected to be accurate, only to within "a factor of a few". Er go, if a simple 1D star code estimates some stellar life-time to be, e.g. 10Gyr; then I would expect that the corresponding actual star life-time to be 3-30Gyr. Are star-codes more accurate, than in my stated understanding ?

The last equation says "mom-energy = mass x displacement / proper-time". So, some hypothetical CR, impacting earth's atmosphere at high energy, is perceived by "outsiders", e.g. earth observers, to have high mom-energy; whilst perceiving "internally" a small amount of proper-time elapsing ? So, there is a connection, between what the particle perceives (proper-time); and what other observers perceive (mom-energy)? If a high-energy particle is perceiving little proper-time elapsing, then is that why such particles are difficult to accelerate, i.e. you apply what you think is a large force, but the particle perceives the force applied for only a brief moment ??

Wouldn't that definition of [math]j^{\mu}[/math] be invariant, under [math]\phi \rightarrow e^{\imath \theta} \phi[/math] ? I don't understand, how the conventional current, is invariant, under that transformation.

Vaguely, the application of "rocket thrusters", by the traveling twin, somehow "drives them against the grain of space-time", so that they are "shoved along a short-cut" through space-time ?? Somehow the artificial force "cut corners off" the would-have-been geodesic arc-length-path ?? Vaguely, I intuit "maximizing arc-length" as "maximizing proper time" as implying that, in the absence of artificial forces, particles "lackadaisically take their time" through space-time ??

A coin, or a weight-lifting "plate", would be a better analogy (2D weight, on 2D membrane), than a bowling ball. I offer, that an even better analogy, would be some kind of "flat bag full of lead shot", in lieu of a rigid coin. For, the "rubber sheet" of space-time can, and does, deform, inside of gravitating bodies, i.e. the "flat bag of lead shot" would "slump & sag" towards the middle (until outward pressure forces offset gravity-like compressions).