The highly infectious Delta has optimised yield of all the steps in replication and an infected person soon reaches a virus titer of 1200 times the previous titer, 2 days quicker. That means each particle shaken loose by panting, shouting etc has 1200 times as much virus. In adition high frequency child voices shed 10 times as much as adult voices on the vocal folds - thus children are prone to fast and intense spread and even though they have historically higher survival rates, it is not clear if the youth advantage will enable them to survive the 10,000 times the viral titer AND the extra spread = an abundance of caution to protect the kids.
Virus replication requires making virus sub-units and assembling them into a virus. When the cell gets full it ruptures and spills completed viruses as well as a sea of unused and partially used subunits. There will be a 'critical path' that ends up maximizing complete viruses and minimizing wasted sub units.
There has been a lot of work studying the Delta variant and why it leads to over 1000 times as many virus particles in the blood. 1000 times as many means any expelled particle of sputum holds 1000 times as many chances to infect a person. This greater efficiency explains why it peaks it's infectivity ( as measured by virus titre (measured number of particles in the blood)) 1-2 days faster and why it spread so much faster.
This paper, and others are exploring this aspect of virus kinetics. It also reports that the vaccine efficacy is maintained, so a booster is a very good idea.
https://www.biorxiv.org/content/10.1101/2021.05.08.443253v4....
A search under 'covid-19 delta variant replication kinetics' showed many similar papers.
I can not understand the hate? This is a true and valid situation.
>"In theory, most materials are capable of becoming metallic if put under enough pressure. Atoms or molecules can be squeezed together so tightly that they begin to share their outer electrons, which can then travel and conduct electricity as they do in a chunk of copper or iron. Geophysicists think that the centres of massive planets such as Neptune or Uranus host water in such a metallic state, and that high-pressure metallic hydrogen can even become a superconductor, able to conduct electricity without any resistance.
Turning water into a metal in this way would require an expected 15 million atmospheres of pressure, which is out of reach for current lab techniques, says Jungwirth.
But he suspected that water could become conductive in an alternative way: by borrowing electrons from alkali metals.
These reactive elements in
group 1 of the periodic table, which includes sodium and potassium, tend to donate their outermost electron.
Last year, Jungwirth and his colleague Phil Mason — a chemist who is also known for making science videos on YouTube — led a team that demonstrated a similar effect in ammonia. The fact that ammonia can turn shiny in such conditions was known to the British chemist Humphry Davy in the early nineteenth century, Edwards points out.
The team wanted to try the same approach with water instead of ammonia, but faced a challenge: alkali metals tend to react explosively when mixed with water. The solution was to design an experimental set-up that would dramatically slow the reaction so that it would not be explosive. The researchers filled a syringe with sodium and potassium, a mixture that is liquid at room temperature, and placed it in a vacuum chamber. They then used the syringe to form droplets of the metal mixture and exposed them to small amounts of water vapour. The water condensed onto each droplet and formed a layer one-tenth of a micrometre thick. Electrons from the droplet then quickly diffused into the water — together with positive metallic ions — and, within a few seconds, the water layer turned golden."
Could you please stop posting large chunks of articles like this? You've been doing it repeatedly, and it's confusing and adding more noise than signal to the threads. It's super hard to distinguish what you're quoting from anything you may be adding—I had to search in the article text to even figure out that this was all a quote.
If people want to read the material, the article URL is close at hand.
Copy-pasting in bulk is generally not a good idea on HN. Quoting bits that are relevant to what you have to say is of course fine!
Wow, I hadn’t even realized that this was all quotation before reading your response. To add a formatting tip: When quoting multiple paragraphs, it’s best to repeat the “>” marker at the start of every new one.
But, you should understand WHY I was doing this...
Oftentimes, when I read articles on the web from articles on HN, I take a set of notes.
My own notes; a set of notes which I believe cut to the core points of an article without significant information loss; that is, when I have these notes, I typically would read them prior to re-reading an entire article -- when revisiting old favorite articles at some point in the future...
You see, while HN offers users the ability to store interesting links/URLs as "favorites" -- it does not (at least to the best of my knowledge, and please correct me if I am wrong!) offer the ability for users to
attach their own personal notes to their favorite articles
...short of that note being a public comment.
Is there any way on HN that I can attach my own personal set of notes to URLs that I like, that I favorite, on HN?
?
And, if not, would you consider passing the request for that functionality on to the appropriate HN administrative structure, and if so, if they approve of it, on to the HN software team?
If that functionality isn't there, then I think a lot of users, like me, could benefit from it -- and if it is there, then I really don't understand how to use it -- could you/would you -- help me out there?
We can consider adding such a feature, but I can't promise anything about when it would be ready. In the meantime please don't use comments for this; I'm sorry for the inconvenience, but it's really important to keep comments for public discussion.
"The researchers filled a syringe with sodium and potassium, a mixture that is liquid at room temperature, and placed it in a vacuum chamber. They then used the syringe to form droplets of the metal mixture and exposed them to small amounts of water vapour."
Why will it react slowly under these conditions? As I understand it this is just NaK + water (in vapour form), why isn't the reaction just as fast?
I wonder if it’s an [0] eutectic alloy? This property is used to make solders that melt more easily, and cast iron is easier to melt than wrought iron, which explains the name.
Because you add water more slowly, essentially atom by atom, otherwise you would have to add picoliter sized drops of water or small amounts of very fine dust of metal.
Probably the reaction is just as fast, but since they add very (very!) small amount of water, when the free electron bubbles collapse and the electrons interact with the H2O molecules the released energy is not enough to cause the usual macro scale effect (the phase change of water to steam, and thus the explosion).
Sort of related: you can also obtain "dissolved electrons" by putting chips of sodium or potassium in pure ammonia.
I forgot what I used this for back in the day, but the solutions were very very beautiful. Apparently electrons dissolved in ammonia are an intense, deep blue. Photos don't really do it justice:
Interesting question, considering that they're "wet" electrons in a dynamic environment, I'd say the effect would be not so much different from applying a magnetic field to any other solution with dissolved unpaired electrons. So: fun for doing electron spin resonance studies, nothing spectacular otherwise.
As a footnote, the underlying paper and research is by Phil Mason, who goes by Thunderf00t on YouTube. He posted a video of the experiment to his channel today[1].
He was always a scientist and also did debunking of crowdfunding projects that promised physically impossible stuff.
And while I agree about his toxic tone - he has some points regarding feminism. For example his critique of Feminist Frequency podcast was on point ("in this game women can be killed therefore it's sexist" meanwhile in that same game you kill thousands of men and that's fine).
Idunno... I guess what I was trying to say was that if it's just the "delivery", but the actual contents are actually correct, then can that really be called "toxic"?
I mean, if what he is saying is not "Black people / women / poor people are all inferior, and deserve to suffer!", but just "Hey assholes, black people / women / poor people are not inferior, and don't deserve to suffer just because they're black / women / poor!", then "toxic" doesn't feel like the right word to describe it. IMO. To me that feels like it should relate to the actual content of the message,as in "White supremacists are spreading their toxic views online" etc.
But but, guess I'm just arguing semantics, YMMV, so never mind.
thunderf00t is usually spot on / correct, but his videos are extremely demeaning to the people that are wrong.
It gives off an extremely elitist feeling, which usually gets everyone just to double down on their opinions.
He's just not actually trying to teach people why things don't work, he instead does long videos showing how dumb various people are to believe the bullshit they believe in.
I wish some of the people that valued musks corps would watch some of them, as their presentations are usually pure scify that's not doable with current technology, as can be shown by literally all their product launches.
(Tesla's arent going to be self driving cars. Not 3 yrs ago when he said he'd deliver it, nor anytime soon - remember how musk said each Tesla would earn their owner $30k per year? Vacuums for Hyperloops remain impossible at scale and the solar roofs are plain uneconomical, which is why they never shipped them.)
Ah, thanks. To get some sense of scale: If you have any experience (or anyone else who has, please chime in!), how much more down-putting is he than, say, SciManDan; how bad is he "on a SciManDan scale"? :-) An appropriate comparison IMO, seeing how Dan is also famous for debunking dumb stuff.
N.B: I think Dan is pretty darn nice, even when he's being what for him is snarky. As I recall, I was much more of an arrogant a-hole myself when I was younger. (Yup, that's my exc^H^H^Hstory: I've mellowed out now, all that was only when I was young.)
Follow-up: FWIW, now that I've seen a few of his videos, he doesn't seem all that mean to me. Could be that I watched the "wrong" ones: I saw two or three of the "Why do people laugh at creationists" series, but they were very old, some 12-13 years IIRC. Maybe he's gotten meaner since? But then I also watched a couple other ones -- also not totally new, but some two, three years old I think -- and they weren't particularly "toxic" in tone either, IMO.
Either I just happened to randomly miss his most typical toxic videos, or I have a very different -- higher -- threshold for what I consider toxic than you do.
Yeah -- he called it right. After her appearance on the Colbert show she started getting in to scamming people. Which was a very odd turn that I didn't see coming at all.
He debunks a lot of stuff, but debunking feminist-gone-crazy is very controversial so now he is considered sexist :/
As a guy living in conservative country where women actually are discriminated and have to fight for their rights I find it very sad that this pseudofeminist bullshit becomes the face of the movement.
It is very harmful to have a constant stream of "pacman is sexist" or "kill all men" from the west used by alt-right to point out "see this is where this whole feminism thing leads to - that's why you can't have legal abortion or civil partherships or anti-family-violence legislation".
I know there are always fringe groups in every movement, my problem is that you cannot criticize them without getting a label that instantly destroys your credibility for a lot of people. It's not sustainable, eventually this will discourage people from talking about women rights at all, even in the west.
It sounds like your description of those feminists came from his videos. You should try watching them so you have a more accurate take. Anita isn't nearly as much of a radical as she's painted.
I watched several podcasts of Anita and they were all pretty much the same. A game shows half-naked women = sexism. The same game shows half-naked men but that's ignored. A game shows tortured women = objectification. The same game shows tortured men (including by women) but that's ignored. The game allows you to kill women = sexism. The same game allows you to kill men, but that's fine. Now support us at ....
In my opinion if a game worked like they want it to (you can only kill/torture and see naked men) - only then it would be sexist.
Can you imagine that perhaps there are factors that make a man killing and torturing a man different from a man killing and torturing a woman? Surely you can, sexual dimorphism is a thing! What if I told you there is a type of sexual dimorphism that exists in society wherein women are treated entirely differently than men?
In fact, what if equality didn't mean murdering an equal number of men and women in video games, and instead that is just a silly distraction? I promise you no serious people are discussing the ratio of sexes killed in video games to do anything impactful.
> Can you imagine that perhaps there are factors that make a man killing and torturing a man different from a man killing and torturing a woman?
Sure, there's even a name for that kind of factors: sexism. That's the reason pay gap is a problem that is talked about but life expectancy gap isn't.
Feminism was supposed to fix sexism not to reinforce it, though.
> that is just a silly distraction
Well, yes, in the end it's just art critique. But even that should be a topic that you can discuss without being labeled as chauvinist the moment you disagree.
> Well, yes, in the end it's just art critique. But even that should be a topic that you can discuss without being labeled as chauvinist the moment you disagree.
Wow, it sounds like perhaps you have been called a chauvinist for expressing these same opinions before! Perhaps instead of blocking out that critique you can meditate on it. To be honest, you are hitting all of their talking points.
I didn't, as I said I live in a very conservative country and I'm considered extreme left-wing here :) I've been called communist and libtard on the other hand :) I don't particularly care because I don't depend on my reputation for living like scientists and youtubers do.
But I've seen people like Thunderfoot called such names and dismissed on first sight and I don't think that's fair.
Wonderful, thanks for sharing. I didn't know that ultra-concentrated electrons-in-ammonia solutions exist with a similarly golden hue.
10^-5 mbar atmosphere... hearing those pumps whirring and seeing those pressure gauges gave me painful flashbacks from troubleshooting leaky vacuum lines ;)
I find the tone he takes in his debunking videos pretty annoying (although I agree with him on almost all of his stances on what's a scam/vaporware and what not), but when he's actually talking about his own science/science in general he's very listenable.
The projects he goes after usually deserve some criticism, but he just keeps repeating points and generally is a little too convinced of his own superiority.
Hmm, so by adding extra electrons (and ions?) to water, the water gains reflective properties.
From a bit of googling, I'm reading that reflectiveness comes from having small "band gaps" (gaps between allowed electron energy levels) for electrons to cross. Metals have small/no band gaps, while non-metals have larger ones that (if I understand correctly) don't match with the energy levels of visible light. So I assume this means that adding electrons to water changes its band structure and reduces the gap.
So is it generally true that any non-metal which gains electrons is able to absorb and release visible-wavelength photons more easily, i.e. is reflective?
So is it generally true that any non-metal which gains electrons is able to absorb and release visible-wavelength photons more easily, i.e. is reflective?
Bill Beaty has a nice ELI5-style essay on the subject at http://amasci.com/elect/charge1.html , where he discusses what electric charge is (and isn't):
"Here is a way to see charge directly: look at the surface of a wire. Metals look metallic because they contain a 'fluid' composed of movable electrons. This electrical 'fluid' is an excellent reflector of light waves, and it causes the surfaces of metals to act like mirrors. It's these same electrons which flow during an electric current. The 'silvery' stuff of a metal is the charge. What is charge? It is a 'silver liquid' which is found in all metals, and which can be forced to flow.
"Even though the charge is visible, its flow is not. Look carefully at wires in an operating electric circuit and you won't see anything moving along. This is not very mysterious: stir a glass of water and then look for the flowing motion. You'll see moving bubbles and perhaps moving specks of dirt, but you won't see the water move. The silvery charge-fluid in a wire has no bubbles or dirt, so even though the charge is visible, we cannot tell if it is moving or still."
> This electrical 'fluid' is an excellent reflector of light waves
Thanks, though I'm actually wondering about a deeper question: why is this so? Why do loose plasma-like electrons make metals reflective (or, roughly equivalently, how does adding extra electrons make a non-metal like water more reflective)?
To continue on this topic, the 'bands' I referred to are clusters of energy levels corresponding to the orbitals of the atoms. (I found this neat explanation: https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/... ). Apparently, metallic reflectivity comes down to the fact that metals have overlapping "valence" and "conduction" bands. This allows electrons in the lower "valence" band to be excited to the higher "conduction" band and then fall back down and emit photons - which is reflection.
Therefore, in the case of water with extra electrons, the additional electrons may be causing the valence and conduction bands to come closer together - maybe by filling up the valence band and bringing the top of the band closer to the conduction band?
Just wanted to speculate on the chemistry of this discovery a bit, I've always found the science interesting.
Because the electrons in the shared "metallic" electron cloud are in a myriad of quantum states, thus they are able to interact with myriad of "kind" of photons. (Of course the important thing is the wavelength = frequency = energy of the photon.) In particular for metals (like mirrors) where there's a lot of "free" electrons this interaction is through the EM field of all those electrons, not through "isolated" photon-atom pairs. The incoming photons are themselves traveling excitations of the EM field. The electrons - as charged particles - are nudged by the EM field. The moving charges then cause new EM waves, the outgoing photons.
In opaque stuff, let's say a black cloth, the bound electrons are able to absorb almost all of visible light and then emit it as lower frequency (infrared) photons.
In mirrors and shiny stuff, the electrons are able to scatter most of the photons. (So the conversion to infrared photons - heat - is usually negligible.)
Quite interesting - the details get ever more complex as you dig deeper. So the incoming photons interact with the oscillations of the free electrons (i.e. "plasmons"), causing new EM waves to be emitted. I take it that this interaction between photons and plasmons is equivalent to the changing of energy states of electrons and the release of photons as electrons fall to lower states.
So in non-metals, does the band gap between the valence and conduction bands get crossed by electrons excited by incoming photons? You said a black cloth is able to absorb and emit virtually all visible light, but as infrared, but how do band gaps work there?
I guess this is too advanced for a casual conversation with a layman like me, so thanks for the explanations. In the end, maybe it just boils down to "free electrons reflect light because that is what they do".
>So in non-metals, does the band gap between the valence and conduction bands get crossed by electrons excited by incoming photons?
It is an active area of research and they started exploring 'metallic ammonia' last year. recent paper looking at metallic ammonia using synchrotron x-ray PES in a refrigerated liquid microjet setup: https://science.sciencemag.org/content/368/6495/1086
They are currently known as 'metastable' nanostructures exhibiting plasmonic effects similar to noble nanoparticles.
The important thing is that the sea of electrons in metals are able to interact with EM waves coherently, so phase is conserved, so the classic ray optics happens, an that's why we can see things in a mirror, while in case of a white non-mirror surface we have the absorption-emission, and in that case the emitted photons are going everywhere, so we just see a big homogeneous surface.
> I take it that this interaction between photons and plasmons is equivalent to the changing of energy states of electrons and the release of photons as electrons fall to lower states.
Yes, except "better", because it keeps the phase.
> band gap
So there's the optical band gap and the electric. (The electric is required for charge transport, so it's sometimes also called transport gap.)
So a cloth is an insulator, in an insulator the band gap is pretty big. The incoming photon does not lead to transport, but it leads to optical excitation. And then an emission of a photon with a lower energy.
In some instances the relatively high energy of the incoming photon gets converted through various radiationless processes into other forms of energy. For example molecular rotation and vibration (usually photons in the infrared and microwave range do this to matter). These also lead to at least one quantum number change [as every interaction in a quantum theory must], but in case of UV or visible light the electron getting excited and jumping to a higher atomic orbital shell is in an atom that's bound in a molecule. The incoming EM field wave is not high energy enough to "penetrate into" the atom, it interacts with the whole sum of the EM field of the molecule. (And the energy basically gets transferred into the molecular bond: https://en.wikipedia.org/wiki/Ultraviolet%E2%80%93visible_sp... )
Might be a useful technique to be exploited in camouflage research. Combine this with drop-stiched expandable, and we might have Predator-level hidden baddies to deal with ..
I don't know if I really don't understand this or there is a confusion in the title. The shiny-metal-ness is from an already shiny metal that is forming the drop, right? The interesting thing is perhaps the fact it is golden as the water interacts with the surface, but frankly that looks very similar to other thin-film surface interactions, some of which are due to oxidisation in other reactions. Now, that this isn't the normal O2 reaction is interesting, and that there isn't a violent H2O oxidation process that normally occurs is interesting, but it just feels like 'Look! Water is shiny and metal now' is a bit ... misleading?
The title is not misleading, and the golden layer formed is metallic water and not any of the metals used -- where electrons are delocalised/shared between water molecules. They have strong evidence that the layer is indeed metallic water and not something else:
> Experiments at a synchrotron in Berlin confirmed that the gold reflections produced the signatures expected of metallic water.
In my opinion, the ingenious part of the experiment is the following part, and I'm glad that they were lucky enough to find the right conditions:
> The key to avoiding an explosion, Jungwirth says, was to find a window of time in which the diffusion of electrons was faster than the reaction between the water and the metals.
I forgot to say that what you said is perfectly reasonable and not too different form my initial reaction. This is indeed very weird (but cool) science. :)
I agree. The original explanation is a good guess but it's not what is happening in the OP.
There is experiment to detect some sugars, that is somewhat similar to this alternative explanation (and unrelated to the experiment in the OP). More details in:
This is fucking crazy-go-nuts. This is what real-life mad science looks like. Scientists decided "yeah, water is great and all but what it really needs is a nice metallic sheen" and found a possible way to make that happen based on a technique with sodium, potassium, and ammonia. Only problem is, sodium and potassium explode in water! So now the problem became getting the metallic sheen without the explodey drawbacks... and they invested effort and funding to actually do it! Utterly mad, and brilliant.
The author of the research paper is Phil Mason (Thunderf00t on YouTube). He has another paper[1] and video[2] about making sodium+potasium explode in water.
67 comments
[ 3.2 ms ] story [ 126 ms ] threadVirus replication requires making virus sub-units and assembling them into a virus. When the cell gets full it ruptures and spills completed viruses as well as a sea of unused and partially used subunits. There will be a 'critical path' that ends up maximizing complete viruses and minimizing wasted sub units. There has been a lot of work studying the Delta variant and why it leads to over 1000 times as many virus particles in the blood. 1000 times as many means any expelled particle of sputum holds 1000 times as many chances to infect a person. This greater efficiency explains why it peaks it's infectivity ( as measured by virus titre (measured number of particles in the blood)) 1-2 days faster and why it spread so much faster. This paper, and others are exploring this aspect of virus kinetics. It also reports that the vaccine efficacy is maintained, so a booster is a very good idea. https://www.biorxiv.org/content/10.1101/2021.05.08.443253v4....
A search under 'covid-19 delta variant replication kinetics' showed many similar papers.
I can not understand the hate? This is a true and valid situation.
Turning water into a metal in this way would require an expected 15 million atmospheres of pressure, which is out of reach for current lab techniques, says Jungwirth.
But he suspected that water could become conductive in an alternative way: by borrowing electrons from alkali metals.
These reactive elements in
group 1 of the periodic table, which includes sodium and potassium, tend to donate their outermost electron.
Last year, Jungwirth and his colleague Phil Mason — a chemist who is also known for making science videos on YouTube — led a team that demonstrated a similar effect in ammonia. The fact that ammonia can turn shiny in such conditions was known to the British chemist Humphry Davy in the early nineteenth century, Edwards points out.
The team wanted to try the same approach with water instead of ammonia, but faced a challenge: alkali metals tend to react explosively when mixed with water. The solution was to design an experimental set-up that would dramatically slow the reaction so that it would not be explosive. The researchers filled a syringe with sodium and potassium, a mixture that is liquid at room temperature, and placed it in a vacuum chamber. They then used the syringe to form droplets of the metal mixture and exposed them to small amounts of water vapour. The water condensed onto each droplet and formed a layer one-tenth of a micrometre thick. Electrons from the droplet then quickly diffused into the water — together with positive metallic ions — and, within a few seconds, the water layer turned golden."
[1] https://en.wikipedia.org/wiki/Solvated_electron
[2] https://en.wikipedia.org/wiki/Birch_reduction
If people want to read the material, the article URL is close at hand.
Copy-pasting in bulk is generally not a good idea on HN. Quoting bits that are relevant to what you have to say is of course fine!
You have my most humble apologies!
I will stop doing this...
But, you should understand WHY I was doing this...
Oftentimes, when I read articles on the web from articles on HN, I take a set of notes.
My own notes; a set of notes which I believe cut to the core points of an article without significant information loss; that is, when I have these notes, I typically would read them prior to re-reading an entire article -- when revisiting old favorite articles at some point in the future...
You see, while HN offers users the ability to store interesting links/URLs as "favorites" -- it does not (at least to the best of my knowledge, and please correct me if I am wrong!) offer the ability for users to
attach their own personal notes to their favorite articles
...short of that note being a public comment.
Is there any way on HN that I can attach my own personal set of notes to URLs that I like, that I favorite, on HN?
?
And, if not, would you consider passing the request for that functionality on to the appropriate HN administrative structure, and if so, if they approve of it, on to the HN software team?
If that functionality isn't there, then I think a lot of users, like me, could benefit from it -- and if it is there, then I really don't understand how to use it -- could you/would you -- help me out there?
?
Why will it react slowly under these conditions? As I understand it this is just NaK + water (in vapour form), why isn't the reaction just as fast?
I enjoyed "Can we have the balcony for explosions"!
[0] https://en.m.wikipedia.org/wiki/Eutectic_system
I forgot what I used this for back in the day, but the solutions were very very beautiful. Apparently electrons dissolved in ammonia are an intense, deep blue. Photos don't really do it justice:
https://ssl.c.photoshelter.com/img-get/I0000lH1LMamRdV8/s/86...
https://en.m.wikipedia.org/wiki/Electron_paramagnetic_resona...
1: https://m.youtube.com/watch?v=Vdz18ibX7rE&t=16s
And while I agree about his toxic tone - he has some points regarding feminism. For example his critique of Feminist Frequency podcast was on point ("in this game women can be killed therefore it's sexist" meanwhile in that same game you kill thousands of men and that's fine).
(Genuinely asking, haven't looked at him yet. Just seems to stand to reason.)
(Not agreeing or disagreeing either way, as I know nothing about Thunderf00t.)
I mean, if what he is saying is not "Black people / women / poor people are all inferior, and deserve to suffer!", but just "Hey assholes, black people / women / poor people are not inferior, and don't deserve to suffer just because they're black / women / poor!", then "toxic" doesn't feel like the right word to describe it. IMO. To me that feels like it should relate to the actual content of the message,as in "White supremacists are spreading their toxic views online" etc.
But but, guess I'm just arguing semantics, YMMV, so never mind.
It gives off an extremely elitist feeling, which usually gets everyone just to double down on their opinions.
He's just not actually trying to teach people why things don't work, he instead does long videos showing how dumb various people are to believe the bullshit they believe in.
I wish some of the people that valued musks corps would watch some of them, as their presentations are usually pure scify that's not doable with current technology, as can be shown by literally all their product launches.
(Tesla's arent going to be self driving cars. Not 3 yrs ago when he said he'd deliver it, nor anytime soon - remember how musk said each Tesla would earn their owner $30k per year? Vacuums for Hyperloops remain impossible at scale and the solar roofs are plain uneconomical, which is why they never shipped them.)
N.B: I think Dan is pretty darn nice, even when he's being what for him is snarky. As I recall, I was much more of an arrogant a-hole myself when I was younger. (Yup, that's my exc^H^H^Hstory: I've mellowed out now, all that was only when I was young.)
Either I just happened to randomly miss his most typical toxic videos, or I have a very different -- higher -- threshold for what I consider toxic than you do.
As a guy living in conservative country where women actually are discriminated and have to fight for their rights I find it very sad that this pseudofeminist bullshit becomes the face of the movement.
It is very harmful to have a constant stream of "pacman is sexist" or "kill all men" from the west used by alt-right to point out "see this is where this whole feminism thing leads to - that's why you can't have legal abortion or civil partherships or anti-family-violence legislation".
I know there are always fringe groups in every movement, my problem is that you cannot criticize them without getting a label that instantly destroys your credibility for a lot of people. It's not sustainable, eventually this will discourage people from talking about women rights at all, even in the west.
In my opinion if a game worked like they want it to (you can only kill/torture and see naked men) - only then it would be sexist.
In fact, what if equality didn't mean murdering an equal number of men and women in video games, and instead that is just a silly distraction? I promise you no serious people are discussing the ratio of sexes killed in video games to do anything impactful.
Sure, there's even a name for that kind of factors: sexism. That's the reason pay gap is a problem that is talked about but life expectancy gap isn't.
Feminism was supposed to fix sexism not to reinforce it, though.
> that is just a silly distraction
Well, yes, in the end it's just art critique. But even that should be a topic that you can discuss without being labeled as chauvinist the moment you disagree.
Wow, it sounds like perhaps you have been called a chauvinist for expressing these same opinions before! Perhaps instead of blocking out that critique you can meditate on it. To be honest, you are hitting all of their talking points.
But I've seen people like Thunderfoot called such names and dismissed on first sight and I don't think that's fair.
10^-5 mbar atmosphere... hearing those pumps whirring and seeing those pressure gauges gave me painful flashbacks from troubleshooting leaky vacuum lines ;)
From a bit of googling, I'm reading that reflectiveness comes from having small "band gaps" (gaps between allowed electron energy levels) for electrons to cross. Metals have small/no band gaps, while non-metals have larger ones that (if I understand correctly) don't match with the energy levels of visible light. So I assume this means that adding electrons to water changes its band structure and reduces the gap.
So is it generally true that any non-metal which gains electrons is able to absorb and release visible-wavelength photons more easily, i.e. is reflective?
Bill Beaty has a nice ELI5-style essay on the subject at http://amasci.com/elect/charge1.html , where he discusses what electric charge is (and isn't):
"Here is a way to see charge directly: look at the surface of a wire. Metals look metallic because they contain a 'fluid' composed of movable electrons. This electrical 'fluid' is an excellent reflector of light waves, and it causes the surfaces of metals to act like mirrors. It's these same electrons which flow during an electric current. The 'silvery' stuff of a metal is the charge. What is charge? It is a 'silver liquid' which is found in all metals, and which can be forced to flow.
"Even though the charge is visible, its flow is not. Look carefully at wires in an operating electric circuit and you won't see anything moving along. This is not very mysterious: stir a glass of water and then look for the flowing motion. You'll see moving bubbles and perhaps moving specks of dirt, but you won't see the water move. The silvery charge-fluid in a wire has no bubbles or dirt, so even though the charge is visible, we cannot tell if it is moving or still."
Thanks, though I'm actually wondering about a deeper question: why is this so? Why do loose plasma-like electrons make metals reflective (or, roughly equivalently, how does adding extra electrons make a non-metal like water more reflective)?
To continue on this topic, the 'bands' I referred to are clusters of energy levels corresponding to the orbitals of the atoms. (I found this neat explanation: https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/... ). Apparently, metallic reflectivity comes down to the fact that metals have overlapping "valence" and "conduction" bands. This allows electrons in the lower "valence" band to be excited to the higher "conduction" band and then fall back down and emit photons - which is reflection.
Therefore, in the case of water with extra electrons, the additional electrons may be causing the valence and conduction bands to come closer together - maybe by filling up the valence band and bringing the top of the band closer to the conduction band?
Just wanted to speculate on the chemistry of this discovery a bit, I've always found the science interesting.
In transparent stuff the electrons are bound to nuclei, and almost all of the photons in the human visible energy range just go through without interacting with the electrons. ( https://www.lehigh.edu/imi/teched/GlassProp/Slides/GlassProp... )
In opaque stuff, let's say a black cloth, the bound electrons are able to absorb almost all of visible light and then emit it as lower frequency (infrared) photons.
In mirrors and shiny stuff, the electrons are able to scatter most of the photons. (So the conversion to infrared photons - heat - is usually negligible.)
See this for more details: https://www.reddit.com/r/askscience/comments/1zi5hg/how_do_a...
So in non-metals, does the band gap between the valence and conduction bands get crossed by electrons excited by incoming photons? You said a black cloth is able to absorb and emit virtually all visible light, but as infrared, but how do band gaps work there?
I guess this is too advanced for a casual conversation with a layman like me, so thanks for the explanations. In the end, maybe it just boils down to "free electrons reflect light because that is what they do".
It is an active area of research and they started exploring 'metallic ammonia' last year. recent paper looking at metallic ammonia using synchrotron x-ray PES in a refrigerated liquid microjet setup: https://science.sciencemag.org/content/368/6495/1086
They are currently known as 'metastable' nanostructures exhibiting plasmonic effects similar to noble nanoparticles.
The important thing is that the sea of electrons in metals are able to interact with EM waves coherently, so phase is conserved, so the classic ray optics happens, an that's why we can see things in a mirror, while in case of a white non-mirror surface we have the absorption-emission, and in that case the emitted photons are going everywhere, so we just see a big homogeneous surface.
> I take it that this interaction between photons and plasmons is equivalent to the changing of energy states of electrons and the release of photons as electrons fall to lower states.
Yes, except "better", because it keeps the phase.
> band gap
So there's the optical band gap and the electric. (The electric is required for charge transport, so it's sometimes also called transport gap.)
So a cloth is an insulator, in an insulator the band gap is pretty big. The incoming photon does not lead to transport, but it leads to optical excitation. And then an emission of a photon with a lower energy.
In some instances the relatively high energy of the incoming photon gets converted through various radiationless processes into other forms of energy. For example molecular rotation and vibration (usually photons in the infrared and microwave range do this to matter). These also lead to at least one quantum number change [as every interaction in a quantum theory must], but in case of UV or visible light the electron getting excited and jumping to a higher atomic orbital shell is in an atom that's bound in a molecule. The incoming EM field wave is not high energy enough to "penetrate into" the atom, it interacts with the whole sum of the EM field of the molecule. (And the energy basically gets transferred into the molecular bond: https://en.wikipedia.org/wiki/Ultraviolet%E2%80%93visible_sp... )
See also: https://en.wikipedia.org/wiki/Hot_band
> Experiments at a synchrotron in Berlin confirmed that the gold reflections produced the signatures expected of metallic water.
In my opinion, the ingenious part of the experiment is the following part, and I'm glad that they were lucky enough to find the right conditions:
> The key to avoiding an explosion, Jungwirth says, was to find a window of time in which the diffusion of electrons was faster than the reaction between the water and the metals.
Edit: added "in my opinion".
There is experiment to detect some sugars, that is somewhat similar to this alternative explanation (and unrelated to the experiment in the OP). More details in:
https://en.wikipedia.org/wiki/Tollens%27_reagent
Random quick video: https://www.youtube.com/watch?v=21PHoxlukME
NileRed video with more technical details: https://www.youtube.com/watch?v=nGmxHLHyUPc
[1] https://www.nature.com/articles/nchem.2161
[2] https://www.youtube.com/watch?v=LmlAYnFF_s8