Physicists Chip Away at a Mystery: Why Does Glass Exist? (wired.com) 79
For decades, physicists have dreamed of this perfect amorphous solid. They desire ideal glass not so much for its own sake (though it would have unique, useful properties) but because its existence would solve a deep mystery. From a report: It's the mystery posed by every window and mirror, every piece of plastic and hard candy, and even the cytoplasm that fills every cell. All of these materials are technically glass, for glass is anything that's solid and rigid but made of disordered molecules like those in a liquid. Glass is a liquid in suspended animation, a liquid whose molecules curiously cannot flow. Ideal glass, if it exists, would tell us why. Inconveniently, ideal glass would take so long to form that it may not have done so in all of cosmic history. Physicists can only seek indirect evidence that, given unlimited time, it would. Ramos, an experimental physicist at the Autonomous University of Madrid, hoped that after 110 million years of aging, the Spanish amber might have started to show glimmers of perfection. If so, he would know what the molecules in ordinary glass are really doing when they appear to do nothing.
Ramos's amber measurements are part of a surge of interest in ideal glass. In the past few years, new methods of making glass and simulating it on computers have led to unexpected progress. Major clues have emerged about the nature of ideal glass and its connection to ordinary glass. "These studies provide renewed support for the hypothesis of the existence of an ideal-glass state," said Ludovic Berthier, a physicist at the University of Montpellier who was centrally involved in the recent computer simulations. But the emerging picture of ideal glass only makes sense if we set aside one piece of evidence. "Indeed," Berthier said, "the amber work stands out as difficult to rationalize."
Ramos's amber measurements are part of a surge of interest in ideal glass. In the past few years, new methods of making glass and simulating it on computers have led to unexpected progress. Major clues have emerged about the nature of ideal glass and its connection to ordinary glass. "These studies provide renewed support for the hypothesis of the existence of an ideal-glass state," said Ludovic Berthier, a physicist at the University of Montpellier who was centrally involved in the recent computer simulations. But the emerging picture of ideal glass only makes sense if we set aside one piece of evidence. "Indeed," Berthier said, "the amber work stands out as difficult to rationalize."
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At least when a hooker isn't around....
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We eat the night
We drink the time
Make our dreams come true
And hungry eyes
Are passing by
On streets we call the zoo [youtube.com]
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One just never knows where advocacy of theism will take you.
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All things you absolutely need, and you don't have that much time.
You're -still- needing my cock daily? Again, -no-.
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Yes, you're totally owned, mod.
Forever.
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And there's nothing you can do no there's nothing you can do about it [youtube.com]
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What's your issue? This isn't any worse than Trump or Nazi ASCII banners, even given your zero perceptiveness.
Pure fear is the only rational conclusion. Due to your own evaluation of yourself, which is not my responsibility.
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This isn't any worse than Trump or Nazi ASCII banners
...and your posts are no better than Trump or Nazi ASCII banners either. they both contain about the same amount of useful information.
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Speaking of which...
Kick you 'round the world there ain't a thing that you can do [youtube.com]
Enjoy.
Reality denying as always (Score:2)
Right. It's my longer posts that completely destroy my opposition's positions, logically inescapably, every time.
You can always tell a Theist...
But you cannot tell him much...
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No, it's objectively true. Feel free to review any of my threads, ever, and do better. But you know this, that's why you're here, and responding.
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Might I recommend aschimothusia?
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Curious advice by someone who is insisting on their death all day, every day.
Old glass panes have flowed to the bottom (Score:1)
They are actually thicker in the lower parts.
I guess that's also why shot glasses have a thick bottom. :-)
Re:Old glass panes have flowed to the bottom (Score:5, Interesting)
That's an urban legend. Old glass panes are thicker in the lower parts because the glass that they produced in that era wasn't flat, and because usually (but not always), the uneven panes were installed with the thickest part at the bottom. It simply made sense to have the heaviest side of the pane at the bottom.
It would take far longer than the age of those panes for any noticeable change in their shape due to the passage of time to become evident.
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Not just an urban legend. I have heard this same claim in distinctly rural areas as well.
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I've looked at panes from both sides now, but still somehow...
Sorry, all those youtube posts up higher got me distracted.
I've heard the urban legend claim, but I have a question about it. How much thicker were the panes at the bottom? And how much work would it have been to find the thickest edge (assuming the panes to have been randomly packed) and possibly turn 3/4ths of the panes 90 or 180 degrees just to line up that edge? Would glaziers really so have gone to the trouble? According to the link here
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Also, I suspect (but don't know) that the windows would have been built lying flat on a workbench, so up and down would not have been so clear.
Ohh FFS, give those craftsmen some credit. There would be the stiles and the sill and perhaps some brickmolding; all shaped the way they were because from the start of construction the window had a top and a bottom and the profiles required thereof. That's how, in part, the rain was kept out. By doing a little thinking first. FYI there was a great big functioning world long, long before Intel and WoW and Slashdot and Gwyneth Paltrow's vagina perfume...
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1) centrifugially spinning out a blob of glass (which would produce panes with ripple-arcs, and the "artful" circular blob type of window pane (which were just the cheaper parts of each spun sheet). Those panes were just plain irregular, and the irregularity wasn't even in straight lines. You'd build the window with the panes available. You might put the "blob" panes above the line of s
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no
im actually trying to find what the actual supreme properties and maybe practical application would be but these guys put the T& E in
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or window makers just mounted the thicker ends towards the bottom (and glass itself didn't "flow").
Re:Old glass panes have flowed to the bottom (Score:5, Insightful)
Unfortunately as cool as it sounds this is a myth. The reason why some old windows are thicker on the bottom is that glass production methods were much less accurate in the past than they are today, so the panes were uneven. I once heard that builders would intentionally put the thickest part at the bottom, maybe for structural reasons, but apparently that isn't necessarily the case either, in many stained glass windows as many glass panels will be thicker at the top as at the bottom
Source : The Corning Museum of Glass https://www.cmog.org/article/d... [cmog.org]
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They poured the glass windows thicker at the bottom to make them easier to extract from stationary forms. The glass production methods of the time used stationary forms, probably made of clay (this likely also helped temper the glass so it didn't cool too quickly and shatter) so extracting the glass without breaking it was easier if the glass was thicker at the base (the top side of the pour) and thinner at the bottom of the form (top of the pane), this made filling the form easier and reduced friction of e
Re:Old glass panes have flowed to the bottom (Score:5, Informative)
Most modern sheet glass is float glass. It's formed by pouring molten glass onto a bath of molten tin, ensuring it is extremely flat and smooth on both sides. There is no mechanical forming. The glass cools enough to be removed while floating, and then passed onto mechanical rollers to pass it through a kiln for annealing.
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"The glass production methods of the time used stationary forms..." Huh? I just read several treatises on how windows were made back in the 18th and 19th centuries, and they devote a good deal of space to how the glass itself was made, None of them mentioned molded glass; they all refer to it being blown into a cylinder, and then the cylinder was split (when still semi-molten, I guess) to form a sheet. Or later on a globe blown glass was spun so the centrifugal force flattened it out. Again, no mold.
Al
Re:Old glass panes have flowed to the bottom (Score:4, Interesting)
If glass flowed, telescopes would quickly become blurry. Even the smallest amount of flow would be enough to render a precision telescope mirror useless.
slow glass (Score:2)
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Didn't we already make that, a few years ago?
Re: slow glass (Score:2)
I seem to remember a âoeslowglass-likeâ experiment...
Is it April Fool's (Score:2)
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But where do you keep the cat?
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Until you press the button, the cat does not need to have (and we believe it does not have) an exact location.
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The next research topic (Score:4, Insightful)
After this mystery is solved, the next research topic is going to be magnets.
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Magnets: I don't know how they fucking work, but they sure help to keep notes on my fridge.
Re: The next research topic (Score:2)
No foolinâ(TM)!
I have asked many a physicist to explain why a weak little refrigerator magnet can resist the pull of gravity (which must require the expenditure of energy) for what seems to be âoeforeverâ.
No one so far has an answer.
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You're joking, right? Why would it require the expenditure of energy? Energy need only be expended if work is done, and since the refrig magnet is stationary, no work is done.
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In fairness, friction doesn't explain why a magnet will remain attached to the underside of a magnetic surface.
transparent aluminum is not a thing yet! (Score:2)
transparent aluminum is not a thing yet!
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Aluminium oxynitride != aluminum.
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The aluminum content of ALON (as referenced in your Wikipedia link) is only 30-35% aluminum.
Ideal Glass (Score:4, Funny)
Some would say Koyaanisqatsi, but I think the soundtrack to Mishima is his best work.
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A group of us were going to drop acid and go see 'Koyaanisqatsi', holy crap was I ever glad we couldn't find any that day. Being stoned and seeing/hearing that gigantic heap of negativity was enough.
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Oh, I prefer Akhnaten and Satyagraha.
Your post got at least 1 smile!
Ideal Glass is... (Score:5, Informative)
*sigh
Please define/explain novel concepts that can't readily be googled, what is "ideal glass"? (Aside from a good name for various glass making studios, windshield repair places, etc.) ...the definition of "ideal glass" they are using is a material created over infinite time where the molecules have been able to reach the least entropy.
Their premise is glass's heat absorption reflects this, and some researchers "built" glass practically molecule by molecule slowly allowing each to align with the previous before cooling/hardening (to get around needing infinite time to cool glass). Their "dense glass" showed different heat absorption near absolute zero than regular glass.
However old amber that has become more dense over time does not reflect this similar property near absolute zero.
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the whole article is an explanation of what "ideal glass" is. How about you try reading it
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Extrapolating the trend, Kauzmann realized that if you could cool a liquid slowly enough, you could cool it all the way down to a temperature now known as the Kauzmann temperature before it fully hardened. At that temperature, the resulting glass would have an entropy as low as that of a crystal. But crystals are neat, orderly structures. How could glass, disordered by definition, possess equal order?
Isn't the question the other way around? (Score:5, Interesting)
That is, why, given the distances between particles, does color exist?
That is, why can light NOT pass through things at our relatively low density?
The answer is that it can - but our evolution specialized our sight to be in a range that we can make sense of the world that matters the most to what we do.
So - we consider the 'visible light' portion of the light spectrum to be important, because that's the width of light wavelength that gets affected by the stuff around us the most.
Some liquids/latices just end up being transparent for that.
Seems like a normal exception to an arbitrary selection of light wavelengths to me.
The more interesting mechanics are the way light fits through spaces between things - and what paths it takes in terms of 'resolving' compared to potential paths. Lots of interesting experiments, where 'quantum' like effects seem the best explanation.
https://en.wikipedia.org/wiki/... [wikipedia.org]
Ryan Fenton
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Stop being deliberately obtuse. There is nothing illusory about wavelength, and animal visual systems respond differently to different wavelengths, and that is color.
It's common practice in physics to assign a rest mass to photons based on e=mc^2. e is inversely proportional to wavelength.
A related question is "What does an annoying fool sound like?" Some questions are invalid because they're based on erroneous assumptions, others because th
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Visible light also happens to be the wavelength of EMF that the Sun mostly radiates and which most easily makes it through our atmosphere. IR too, and a little UV, but sunlight at sea level peaks in what we call the visible (nice diagram here: http://thevirtuosi.blogspot.co... [blogspot.com]; the red regions are the wavelengths that make it to sea level).
Radio waves, otoh, are not strong at sea level (until Marconi, at least). Radio waves can, at least in some wavelengths, pass through your body; but don't stand in fron
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Some of your questions involve a detailed understanding of electromagnetics and atomic physics. If you really want to know the answers, you'll need to study.
There are additional reasons that the visual spectrum is limited to roughly 4000 to 7000 angstroms. Below 4000 the photon energy is high and would tend to damage photosensitive cells over time (in fact, human photosensors can detect some UV, but the eye's lens filters it out.) Above 7000 we start getting into the tail of blackbody radiation where most t
Where's my transparent aluminum? (Score:1)
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I ponder why stiwmid exist. (Score:2)
Once I have defined a term to include so many disparate things, I cant find any unifying characteristic. The only way to solve the mystery of why they exist is to answer the question, why universe exists.
Add corona virus too to the definition of glass, more click baits.
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Re: Not completely suspended animation (Score:2)
Kauzmann paradox (Score:5, Informative)
This article is poorly named. The article should have at least referred to the Kauzmann paradox.
cf. wikipedia for more information: https://en.wikipedia.org/wiki/... [wikipedia.org]
As a liquid is supercooled, the difference in entropy between the liquid and solid phase decreases. By extrapolating the heat capacity of the supercooled liquid below its glass transition temperature, it is possible to calculate the temperature at which the difference in entropies becomes zero. This temperature has been named the Kauzmann temperature. If a liquid could be supercooled below its Kauzmann temperature, and it did indeed display a lower entropy than the crystal phase, the consequences would be paradoxical. This Kauzmann paradox has been the subject of much debate and many publications since it was first put forward by Walter Kauzmann in 1948.