**Ask a monkey a physics question thread**

[OngBonga]

My mate was underwhelmed, asking if I'd seen it. I hadn't and asked him to show me. He asked me what I expected to see. To his surprise, I described what the image showed... a circular halo with a bright side. He asked why the bright side? I told him Doppler. We're looking at very fucking hot matter, probably plasma, orbiting at a significant fraction of light speed, slowly being consumed by the black hole. Half of what we see is moving away from us, half towards us. The bright side is moving towards us. I also told him the hole we see is 2.6 times the radial size of the actual event horizon, and told him to dig more. Now he isn't underwhelmed, he finds it interesting.

I saw a youtube guy predict what it would look like, based on what GR would predict. So I knew what to expect.

Mind still blown.

[CoccoBill]

It's big.

[OngBonga]

So big that despite it being ridiculously far away, we get a better image of it than the much smaller black hole in the centre of the Milky Way, our own galaxy.

Black holes are crazy. All the entropy of a black hole is, apparently, on the event horizon. But if things keep falling closer to the singularity, then that means the entirity of the black hole is described by information at the surface. That has holographic implications for the nature of the universe. It could mean that everything we know is an inward projection from the 2D surface of the edge of the universe... the information that describes the universe is infinitely far away.

Or maybe there isn't anything beyond an event horizon, maybe black holes are essentially hollow. The event horizon is the black hole. That's no more ridiculous than all the matter occupying a singularity. Why not a singularity for every base unit of energy, forming a sphere with a surface area determined by its total energy value?

[OngBonga]

At 1:45, thee's a visualisation of what it would look like if we viewed it from different angles. Pure fucking porn.

[MadMojoMonkey]

My mate was underwhelmed, asking if I'd seen it. I hadn't and asked him to show me. He asked me what I expected to see. To his surprise, I described what the image showed... a circular halo with a bright side. He asked why the bright side? I told him Doppler. We're looking at very fucking hot matter, probably plasma, orbiting at a significant fraction of light speed, slowly being consumed by the black hole. Half of what we see is moving away from us, half towards us. The bright side is moving towards us. I also told him the hole we see is 2.6 times the radial size of the actual event horizon, and told him to dig more. Now he isn't underwhelmed, he finds it interesting.

I saw a youtube guy predict what it would look like, based on what GR would predict. So I knew what to expect.

Mind still blown.

FWIW, you know physics better than any other non-physicist I've met. I wonder if you could actually parlay that interest into a science communication career... or even a paying hobby.
There are certainly people with worse explanations on YouTube talking about physics.

I kinda doubt you're interested in this, if I'm on my game, that is. But if you are... go for it. Drop me a link so I can laugh at you swearing at black holes for being so fucking awesome.

I don't think that's doppler. Doppler would change the color of the light, not the intensity. I think it's frame dragging. The black hole's spacetime is distorted around it. The warped spacetime changes how straight lines look on either side of the rotating BH. Lines on one side of the BH can shoot past it, with some bending. Lines on the other side are bent so much that they go to the BH.

[MadMojoMonkey]

This is awesome news, and will surely bring new findings about black holes, but having a picture is more a PR boon than a boon for physicists.
Physicists have been 100% of the existence of black holes for decades, albeit from indirect evidence. We'd plotted the orbits of stars near the Milky Way's center, and could definitely see where the focus or barycenter was which they are orbiting around. We could also calculate the mass that was acting at that focus, and compare the mass to the star's closest approach and determine that mass, with a radius smaller than that has to be a black hole.

Having a direct image is great for quelling the naysayers who could correctly point out that we had no direct evidence for black holes existing. Hollywood hasn't helped the notion that just because evidence is circumstantial doesn't mean it's invalid, or not compelling.

Here's an excellent history of our knowledge of black holes by Dr. Becky, of Sixty Symbols fame.

[OngBonga]

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

Relativistic beaming, aka Doppler boosting.

[OngBonga]

How do two objects with zero volume actually merge? I'm really struggling with the idea of a singularity, I suspect that all of the mass of a black hole is actually in orbit around it's common centre of mass. That's all the singularity actually is... the common centre of mass.

I like this hollow black hole idea. Beyond the event horizon is a perfect vacuum.

[OngBonga]

I think I talk too much shit for a youtube channel. It'd be 5% interesting, 10% funny and 85% cringe. Maybe cringe can be funny if it's done right.

[MadMojoMonkey]

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

Relativistic beaming, aka Doppler boosting.

Oh. Cool. TIL.

[MadMojoMonkey]

How do two objects with zero volume actually merge? I'm really struggling with the idea of a singularity, I suspect that all of the mass of a black hole is actually in orbit around it's common centre of mass. That's all the singularity actually is... the common centre of mass.

I like this hollow black hole idea. Beyond the event horizon is a perfect vacuum.

IDK. I suspect [some quantum force that we cannot directly observe because it only manifests at energy densities beyond an event horizon] prevents the formation of a true singularity, but I'm just speculating.

It could be even weirder. The axes on a spacetime diagram flip when you cross an event horizon. So on this side of an event horizon, we are free to move in any of our spacial dimensions, but constrained to only move forward in time. On the other side of an event horizon, we'd be free to move about in time however we like, but we can only move in 1 direction in space (toward the center of the BH). At least, that's what the math says... what that means or how it would be experienced is beyond me.

That center could always be infinitely far away for all I know. Expanding spacetime could mean that there is ever increasing distance between you and the center, despite you always moving toward it. IDK.

[OngBonga]

Another way of thinking about the hollow black hole is to think of a bubble with enormous surface tension. Where does the surface tension come from? Gravity. Each particle is so close to the next particle that they are basically gravitationally bound to one another. The stream of particles moving at near light speed around the event horizon could be thought of as an unbreakable sheet of paper, that as far as the particle is concerned the universe is two dimensional... forwards in time. There's no falling downwards because of the kinetic energy making you go forwards, and the enormous gravity of the particles occupying almost the same location in spacetime, much closer to one another than in atoms where EM dominates. The only effect the downwards gravity of the entire system has it to create the curvature rrequired to maintain the sphere.

Another problem with singularities is that as they approach one another, their velocities will exceed light speed. We have a problem here if the singularities are where the mass is.

[MadMojoMonkey]

I think I talk too much shit for a youtube channel. It'd be 5% interesting, 10% funny and 85% cringe. Maybe cringe can be funny if it's done right.

None of that matters. All that matters is that you'd have fun doing it.

I mean... I think you're underestimating the appeal of a layman who's interested in a complicated topic. Sure, you'll make mistakes and say dumb things, but c'mon. You just corrected me about Relativistic Doppler effect, and you're right. That's something.

[MadMojoMonkey]

Another way of thinking about the hollow black hole is to think of a bubble with enormous surface tension. Where does the surface tension come from? Gravity. Each particle is so close to the next particle that they are basically gravitationally bound to one another. The stream of particles moving at near light speed around the event horizon could be thought of as an unbreakable sheet of paper, that as far as the particle is concerned the universe is two dimensional... forwards in time. There's no falling downwards because of the kinetic energy making you go forwards, and the enormous gravity of the particles occupying almost the same location in spacetime, much closer to one another than in atoms where EM dominates. The only effect the downwards gravity of the entire system has it to create the curvature rrequired to maintain the sphere.

Another problem with singularities is that as they approach one another, their velocities will exceed light speed. We have a problem here if the singularities are where the mass is.

Sounds a lot like my "not yet known quantum force" hypothesis, IMO.

I mean, it's not gravity. Gravity is so, so much weaker than electromagnetism and piddly compared to the strong force. Ever seen a water droplet hanging from the underside of a surface? It has a whole planet's worth of gravity pulling on it, and only the surface tension interactions of E&M to hold up its entire volume. E&M wins despite the unfathomable ratio of interactions by gravity being overwhelmed by a paltry number of E&M interactions.

The gravity of particles occupying "almost the same space" will be nothing compared to their E&M interactions from being that closely packed.

We'd need to consider the wave functions, though. Superfluid helium cannot boil because the wave functions for the atoms have spread out so much due to cooling that they overlap each other. In effect, the fluid condenses into a single quantum bulk. It's no longer mathematically clear "which" atoms should be boiling, so they perfectly conduct heat through the volume. The He still rapidly evaporates off the top of the surface, but it can no longer form localized hot spots which could turn into bubbles (boil).

This is because even though the He atoms are made of fermions (which have non-integer spin and therefore obey the Pauli Exclusion Principle), the atoms themselves contain an ensemble spin which is an integer. This means that while the constituent parts of each atom still obey the PEP, the atoms themselves do not. This means that the atoms can exist in the same state in the same quantum system at the same time.

So the idea that the particles may overlap is acceptible, so long as the collection of fermions comes together to form a particle that is itself a boson.

[oskar]

I think black holes are overrated.

[OngBonga]

Yes, but I had to watch the link above again to remind myself what it was actually called. Doppler is easy to understand, lots of people understand the physics behind it, or at least will do if explained to them.

I think the reason we don't see red and blue shift is because we're looking at x-rays... light of a very high frequency. For it to change colour, it needs to not be x-ray. This is the Doppler effect of light of a constant frequency.

[OngBonga]

I think black holes are overrated.

Racist!

[OngBonga]

I mean, it's not gravity. Gravity is so, so much weaker than electromagnetism and piddly compared to the strong force.

What is r squared in the equation for the force of gravity between two bodies? The force of gravity is inversely proportional to distance squared. What's the force of gravity if distance between two bodies is zero? EM dominates atoms, where the distance between particles is much greater than those at the event horizon of a black hole, assuming all the mass of the black hole is at the event horizon.

[MadMojoMonkey]

Yes, but I had to watch the link above again research to remind myself what it was actually called. Doppler is easy to understand, lots of people understand the physics behind it, or at least will do if explained to them.

FYP.

What sets you apart from the average layman is that you don't think watching the link was "boring" or any synonym for "waste of time." You thought that part was interesting enough on its own to pursue. That's not how most people operate.

I think the reason we don't see red and blue shift is because we're looking at x-rays... light of a very high frequency. For it to change colour, it needs to not be x-ray. This is the Doppler effect of light of a constant frequency.

What we're seeing is definitely red shifted by climbing up out of a deeper gravity well to get here than they fell back into once they got here. Not to mention the fact that the photons traveled through expanding spacetime to get here, which would also redshift.

X-Rays are still photons, and follow the same physics (Maxwell's Equations) as radio, microwave, visible or gamma rays.

[MadMojoMonkey]

Racist!

Kettle!

[OngBonga]

I guess the point I was making is that a shift of frequency would mean we're no longer looking at x-rays, but they can still shift slightly and still be x-rays. But the idea they are "redder" is alien, since x-ray is a range of colours we can't perceive!

[MadMojoMonkey]

What is r squared in the equation for the force of gravity between two bodies? The force of gravity is inversely proportional to distance squared. What's the force of gravity if distance between two bodies is zero? EM dominates atoms, where the distance between particles is much greater than those at the event horizon of a black hole, assuming all the mass of the black hole is at the event horizon.

There's a 1/r^2 in both equations.

The Coulomb Force and Newton's Law of Gravity look the same.

F = [constant] * [amount of 1]*[amount of 2] / r^2

For Gravity,
F = GMm/r^2

For E&M
F = kQq/r^2

The GMm's are about 0.5% as intense as the kQq's.

[OngBonga]

What sets you apart from the average layman is that you don't think watching the link was "boring" or any synonym for "waste of time." You thought that part was interesting enough on its own to pursue. That's not how most people operate.

PBS Spacetime, Vertasium and Suspicious0bservers is pretty much all I watch. If there's something I want to dig more, I usually look at the wikipedia page and leave it at that. This is the opposite of boring to me.

[OngBonga]

The Coulomb Force and Newton's Law of Gravity look the same.

Good point. Ok, but as two particles approach one another, gravity and EM approach parity.

[OngBonga]

Perhaps at the event horizon, gravity and EM are unified.

[MadMojoMonkey]

PBS Spacetime, Vertasium and Suspicious0bservers is pretty much all I watch. If there's something I want to dig more, I usually look at the wikipedia page and leave it at that. This is the opposite of boring to me.

My point exactly.
They're probably easy to consider experts in the field. Matt (PBS Spacetime) and Derek (Veritasium) have PhDs in physics, but I'm not familiar with Suspicious 0bservers.
What they bring to the table is stuffy experts tooting their own horns to a lot of people.

What you'd bring is a very down-to-Earth understanding that lacks all the stuffiness and pretense of higher learning.
IDK. Maybe I'm wrong, but I feel like there's an audience for that.

I'm not trying to convince you to do it if you don't want to, though. Just putting it out there that it could be fun and maybe in the long run also earn you a buck or 2.
(Or whatever... you don't call them "bucks" do you?)

Good point. Ok, but as two particles approach one another, gravity and EM approach parity.

Perhaps at the event horizon, gravity and EM are unified.

Maybe. Not under "normal" conditions, but at an event horizon... maybe.

I'm pretty sure no one knows how GR and QM come together.

I really shouldn't simplify things down to Newton and Maxwell when we're talking GR and QM. That was kinda dumb. It's a good approximation, but we're far from the "low energy" physics regime where they are effectively just as good. There are more complicated ways to compare the relative strengths of the forces, but they all agree that gravity is pretty useless on the particle scales. Quantum Electrodynamics and GR are both going to have to give a little to try to really understand what you're hypothesizing. Maybe that "give" is a unification of forces that many speculate.

[OngBonga]

I'm not familiar with Suspicious 0bservers.

Ben Davidson. Mostly a sun guy. He might be regarded by some as "fringe", but that's really not very fair. He uploads daily vlogs with solar and space weather updates, and extreme weather and seismic events here on earth. His area of expertise other than the sun is in the theory of electric earthquakes, casued by solar events, with the potential to predict earthquakes by identifying electromagnetic precursors. But he occasionally dips his feet in mainstream physics, in particular black holes and dark matter. He knows what he's talking about. Not sure about his qualifications though.

I'm pretty sure no one knows how GR and QM come together.

Hold my spliff.

[OngBonga]

I'm pretty sure no one knows how GR and QM come together.

Quantized inertia?

It's easy to imagine that an object is surrounded by an enormous information horizon. For an object that is not accelerating, it's a sphere... beyond the sphere, light can never reach the object. But what happens at the horizon? At the event horizon of a black hole, we have Hawking radiation... virtual particle pairs that become separated Well, the same is true for this information horizon... from the pov of the object, virtual particles become separated, giving rise to real particles... a type of Hawking radiation.

Now, an object that is not accelerating is surrounded by a sphere, but what if the object accelerates? In the direction of acceleration, the horizon will expand, while behind the object, it will contract. This creates an imbalance which can be thought of as similar to a Casimir effect, only on a universal scale... certain wavelengths of particles will be accessible to the object in front, but not from behind. This creates a radiation pressure that is greater in the direction of acceleration. Inertia is born! This pressure manifests itself as a resistance to acceleration, the very definition of inertia.

For reasons I don't understand, this theory implies a minimum acceleration, which in turn might explain the motion of galaxies without the need for dark matter. Essentially, the outer edges of the galaxy has lost inertial mass, and so can move faster than Newtonian dynamics would expect them to.

There are problems with this theory, the biggest one is that it completely violates the equivalence principle. At very low acceleration (below the minimum threshold mentioned), gravitational mass and inertial mass are not the same. But some people seem to think that this theory is a promising one, in that it might unify GM and QM. I'm not so sure about that, but it's definitely interesting.

Here's a 20 minute clip if you an be bothered...

[OngBonga]

Another problem is it seems to imply radiation is relative, that one observer might observe radiation, while another does not. I can't even begin to wrap my head around that.

[MadMojoMonkey]

Just before 10:15 he says we don't understand inertia. IDK exactly what he means there.
Inertia is defined as resistance to change in motion i.e. resistance to acceleration. We use the letter m to indicate this, for mass (but let's not get ahead of ourselves).
F = ma
is describing the relationship between a Force, F, acting on some object with property m, and the associated acceleration, a, of that object.

Ignoring for the moment whether or not we think we know what causes m, that relationship is simple enough to easily grasp the affect of m on the relationship between F and a. m is a constant of proportionality between them. I.e. F and a are proportional to each other and the constant multiple between them is F/a = m.

So mathematically, it's easy to understand "What is m?"

Physically, understanding "What is m?" leads us to put a label on it. We'll call it mass.
*brushes hands* My work is done here.


Seriously, though.
Via QM, energy conservation, and application of what parts of GR can be wed with QM, we were able to mathematically predict the masses of compound particles, specifically nucleons (protons and neutrons) to quite good precision. (I can't find the exact numbers on it right this second). We know that almost all of the mass of a proton or neutron comes from the binding energy of the quarks that make up those compound particles. Even without knowing the mass contribution of the quarks themselves, we can use E = mc2 and write m = E/c2, then plug in the binding energy due to the Strong Nuclear Force, divide by c2, and get almost exactly the empirical value.

The Higgs helps show how the quarks and electrons have "intrinsic" mass, even when not in a bound system. However, it's well worth noting that the mass of an atom is largely due to the mass of the nucleus (over 99%). An electron's mass is about 1/1800 that of a proton or neutron. For Hydrogen (no neutrons), that's 3 quarks and an electron not accounted for, so (pulling some numbers for quark and electron masses from a table) 19/1800 ~= 1% of the mass of Hydrogen needs the Higgs to explain. The rest is simply the binding energy of the quarks inside the proton, which is mathematically known. Far all larger atoms, that ratio is even smaller, due to the presence of neutrons in the nucleus of the atom contributing much more binding energy per quark than quark mass.

***
Moving on... It sounds like he's saying, "We haven't studied the effects of accelerating at obscenely high rates up close, yet." I mean... IDK... the LHC at CERN is pulling some pretty extreme accelerations on objects moving a significant fraction of c.
Maybe he's postulating there's some kind of emergent property of inertia on bodies as large as stars, or maybe only very massive stars and up.
I didn't really follow that.


PBS Spacetime on Unruh Radiation

[OngBonga]

Just before 10:15 he says we don't understand inertia. IDK exactly what he means there.

The impression I got from that is we know the effect inertia has, but we don't know why it happens. All Newton did was tell us inertia is a measure of mass.

Will watch that video right now, thanks.

[OngBonga]

Nice, that does sort of explain the "relative radiation" conflict I referred to. Not that I understand it.

[MadMojoMonkey]

The impression I got from that is we know the effect inertia has, but we don't know why it happens. All Newton did was tell us inertia is a measure of mass.

The problem with that complaint is that "What will happen if [...]?" is what physics is good at answering, but "Why does [...] happen?" is really beyond the scope of the field.
Ergo, it's not a fair criticism of one particular field or result of physics to say, "We don't understand why this happens," because there are no statements produced by physics that answer "why" questions.


EDIT: at the bottom, I mean. A student can ask why? and receive answers for years, but eventually those answers run out... because at the bottom, we can only describe and predict, but not explain.

[OngBonga]

The problem with that complaint is that "What will happen if [...]?" is what physics is good at answering, but "Why does [...] happen?" is really beyond the scope of the field.

Fair enough, but understanding why something happens is surely within the scope of science. I get the predictions are the primary goal, but that's a lot easier if you understand why. For example, Einstein told us why gravity happens. That made it much easier to predict the orbit of Mercury.

[MadMojoMonkey]

Fair enough, but understanding why something happens is surely within the scope of science. I get the predictions are the primary goal, but that's a lot easier if you understand why. For example, Einstein told us why gravity happens. That made it much easier to predict the orbit of Mercury.

Not really, no.

Einstein didn't tell us "why" anything. He only better described what we observe.

I can't speak for all sciences, but "why" doesn't reasonably seem provable in any way that doesn't dilute the meaning and relevance of scientific methods.

[OngBonga]

I suppose. I mean he sort of did explain why, he said inertia causes gravity. But that doesn't tell us why inertia happens, or why inertia has this effect. So I guess the question "why" is always present one way or another.

But striving to answer the question "why", if that's not the realm of science, what is it? Philosophy?

[MadMojoMonkey]

I suppose. I mean he sort of did explain why, he said inertia causes gravity. But that doesn't tell us why inertia happens, or why inertia has this effect. So I guess the question "why" is always present one way or another.

But striving to answer the question "why", if that's not the realm of science, what is it? Philosophy?

For all the "whys" that have answers, they are built upon "whys" that have no answers... so all we're really doing in that sense is pushing the whys further off, but never making any of them truly go away.

I'm more comfortable just dispelling the illusion that any "why" was ever offered, though. It's a tough one. I'd say it is ridiculously common for any research to begin as a scientist wondering why something isn't what they expected. Or wondering why something "obvious" has never been confirmed. It's a common motivator for a scientist to have a curiosity about "why."
However... I don't think any cold, calculating view of the results of scientific research would ever really be considered to address "why" something happens, so much as describe "what" happens.

I think it's a worthy topic of discussion among physicists and philosophers to address our position. There's certainly a sense of derision that comes openly from the wider physics community directed at any physicist whom starts pondering these deeper questions behind physics. Sean Carrol has opined that part of the reason for our roadblocks in String Theories is contributed to by our lack of any attention to questions of why. He's said that maybe the stagnation is due to us asking entirely the wrong questions, and we need to step back and look at the kind of questions we've been asking. Obv. that's pure speculation, but I think it's interesting.

However, I don' think it's in the cards. Not any time soon. There's a snootiness to physicists when it comes to softer sciences. It's probably not healthy and often at least partially in jest, but it's there. People attracted to physics are probably often attracted by the "hardness" of the science. There's certainly an attraction I feel toward the quest to find things upon which all intelligent people can agree. If anything, it kinda sucks that none of it includes any "whys" but there it is.

[OngBonga]

That's interesting, because what attracts me to physics is wanting to know why.

On a slightly (vaguely) related note, I watched a veritasium vid the other day and it infuriated me, because it demonstrated how dumb people are at problem solving. Rather than link it to you, I'll present it to you and see if you're as dumb as the fuckers I was shouting at.

So... I'll give you three numbers, and they all follow a rule. The idea is for you to figure out the rule. All you can do is either guess the rule, or give me another three numbers and I'll tell you if they follow the rule. Let's see how long it takes you.

The numbers... 2 4 8

[MadMojoMonkey]

I've seen it. It's pretty old, but I'd obviously guess 16 32 64, etc. if presented.
The fact that the only rule is that each successive number is greater than the prior number is even simpler.
It's just the fact that the 3 numbers he gives are powers of 2 leads me to see that pattern.

[OngBonga]

Yeah obviously "powers of 2" is the first thing I thought. But I instantly figured out how to approach this problem. They just kept fucking going with stupid shit like "100 200 400". I was thinking "they could be even, they could be in ascending order" so I was shouting at them to stop giving correct answers. They didn't figure out that they need to get one wrong, until then they're getting nowhere! I was literally shouting "STOP GIVING NUMBERS IN ASCENDING ORDER YOU FUCKING IDIOTS". I wanted them to go 1, 2, 3 and then 3, 2, 1, which would tell me if even numbers or ascending order was the solution. It took much longer than it should have done.

I found it relevant here because there's a scientific method hidden there. You learn fuck all until you get something wrong.

[CoccoBill]

https://writings.stephenwolfram.com/...its-beautiful/

MMM thoughts?

[MadMojoMonkey]

Holy F-ing crap that's a lot to read!!!

Reading...
Reading...



Phah. This is such a weird mix of hand-waving, injected assumptions, weird asserted correlations... and good-sounding reasoning.

I can't honestly tell if it's wishful thinking akin to any string theorist or not.

For everything I can poke holes in, I'm reminded of that feeling as an undergrad where the professor starts talking about some abstract mathematical object or concept and I'm just thinking, "This can't possibly stand up to experimentation." And then somehow these weird mathematical properties connect in the ether outside my brain and then I'm using them to solve problems.

Not because I understand the connection, but because many layers of abstraction are just too much to keep track of at once.

Like, his assertion that the thing creates time. I'm like, "No. You have an iterative function. That process of iteration means it changes in time and that implies that time is happening to it. You can't say it "created" time when you're injecting time from outside of it, right?"

He says, you have to foliate the graph in a way that is causally invariant. Then he says, "Look, since it's causally invariant, it creates GR!" Again, it feels like he injected the rule, then got all excited because it has the rule.


IDK. I'm not quite finished reading the whole thing, but I need a break.

[Poopadoop]

[MadMojoMonkey]

Pretty much.

EDIT: I want that picture in a framed glossy print on my office door.

[MadMojoMonkey]

:/

At the end, it's all... so this is just promising speculation, and we need your help to brute force this.

If they can't reproduce F = ma, then I'm holding out for something more.

[CoccoBill]

https://www.smbc-comics.com/comic/2012-03-21

Wondering if relevant.

[jackvance]

I appreciated the comic, made me chuckle, but probably too deep for most of the numbskulls.

[MadMojoMonkey]

I stumbled across /r/physics, and I found where the article and comic came from when I was googling for responses to the paper.


Basically, AFAICT, Wolfram is full of himself. Also, the claims he made about what his algorithm can accomplish are literally impossible to even the remotest degree of value.

In short... he says it can reveal all of physics. That means it has to explain all of chemistry, biology, etc. There are so many open, non-computable, problems in all of these fields. Like, not "we haven't found a way to compute them." But Halting Problem levels of proving that they cannot be computationally solved.

It's like... what he showed was all hand-waving and speculation. The amount of computation to get past the hand-waving and speculation needed to actually make a prediction seems not computationally possible.


That said. There is sometimes value in examining a simpler, similar system and seeing what is "nearby" in its description. If that nearby thing can be conceptualized as a new prediction, then that's good enough.

But that just describes string theory, pretty much. What Wolfram has done is not new or revolutionary (except maybe the images). The mathematical field of Cellular Automata has been around for a long time.I'm sure we're all familiar with Conway's Game of Life. If not, google it. It's a bit of fun for 20 minutes.

[oskar]

https://www.smbc-comics.com/comic/2012-03-21

Wondering if relevant.

^^

[MadMojoMonkey]

He's more of a Computer Scientist than a Physicist.

Far as I can tell, he's always been pretty full of himself.

Even Feynman thought so. Feynman not exactly known as being a humble person.

[CoccoBill]

I stumbled across /r/physics, and I found where the article and comic came from when I was googling for responses to the paper.

Can't remember exactly but I saw a link to the article somewhere, then the comic on slashdot after some digging.

Basically, AFAICT, Wolfram is full of himself. Also, the claims he made about what his algorithm can accomplish are literally impossible to even the remotest degree of value.

In short... he says it can reveal all of physics. That means it has to explain all of chemistry, biology, etc. There are so many open, non-computable, problems in all of these fields. Like, not "we haven't found a way to compute them." But Halting Problem levels of proving that they cannot be computationally solved.

It's like... what he showed was all hand-waving and speculation. The amount of computation to get past the hand-waving and speculation needed to actually make a prediction seems not computationally possible.

So basically comic strip confirmed accurate. When I skimmed the article and some discussion about it, as a layman I thought it's either one of the most revolutionary insights of all time, or a load of bollocks. Even my razor suggested the latter is more likely.

That said. There is sometimes value in examining a simpler, similar system and seeing what is "nearby" in its description. If that nearby thing can be conceptualized as a new prediction, then that's good enough.

As a concept, from what little I understood of it, it seemed really interesting and on some level compelling. Wouldn't it be great if he was right?

I'm sure we're all familiar with Conway's Game of Life. If not, google it. It's a bit of fun for 20 minutes.

Am not, will do, thanks.

[CoccoBill]

https://www.sciencealert.com/the-mat...d-the-universe

[MadMojoMonkey]

Link to a web page that lets you draw your own shapes on a grid, then animates it in Conway's Game of Life.

https://bitstorm.org/gameoflife/

[CoccoBill]

https://www.biorxiv.org/content/10.1...596v1.full.pdf

Explain.

[MadMojoMonkey]

I'm no biologist. They're talking about nervous systems, AFAICT.

[CoccoBill]

I think it's something about how neurons communicate, in plasmon-polariton waves and not electric signals, whatever the difference may be. How is this not physics?

[OngBonga]

We propose a new model of the saltatory conduction in myelinated axons.

I think what they're trying to say is some words than I don't know, and lots of stuff I didn't read because I assume it's got lots more words that I don't know. In conclusion, it's time for a spliff.

[OngBonga]

Surface plasmon polaritons are electromagnetic waves.

[MadMojoMonkey]

It is physics, but everything's physics until you get to levels we just don't currently understand as physics, like psychology.
Physiology is physics, psychology is ... idk ... probably still physics, but we don't have a physical model for psychology and AFAIK, there isn't one on any horizon.

This is physiology, and so it's physics.

Basically all I can make out is something like,
The old model was to treat neurons like an electrical cable, but the numbers just don't add up, so the model is bad.
Ditch it.
Here's a new model that seems better.

[MadMojoMonkey]

I'll post this in another community I'm in with more biologists and chemists and see if they have a better take on on it.

[CoccoBill]

I saw people (local skeptics society fb group) discussing the article and claiming that if true, it'd fundamentally change our understanding of how brains work. Apparently something like the neuron signals can't be detected by an outside electromagnetic field measurement, and conversely an outside electromagnetic field cannot affect the signaling. They seem to think this is a big deal.

[Poopadoop]

I saw people (local skeptics society fb group) discussing the article and claiming that if true, it'd fundamentally change our understanding of how brains work. Apparently something like the neuron signals can't be detected by an outside electromagnetic field measurement, and conversely an outside electromagnetic field cannot affect the signaling. They seem to think this is a big deal.

It might be a big deal for some measures of brain activity that rely on electical-magnetic signals, such as electroencephalography (though that's not a very influential method tbf). And, some means of disrupting brain activity to measure its function rely on introducing localized magnetic fields that disrupt brain activity (e.g., transcranial magnetic stimulation). If this is true, then these methods would not work on myelinated axons, but only on non-myelinated axons, limiting their robustness.

To explain the biology of the cited article a bit, the neurons' main way of communicating with one another involves chemical-electrical signalling. If a neuron's cell body reaches a certain level of electrical polarisation, it causes a chain reaction of chemical-electrical effects in the axon, which flows as a wave of changes in the electrical polarity between the inside vs. outside of the axon, ultimately leading to the release of neurotransmitters that then influence the neuron(s) that cell connects to, and so on.

Myelin is a fatty sheath that coats the axons of some cells, acting as an electrical insulator. When an axon is myelinated, the signal can travel much faster.

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

A lot of axons have myelin sheaths. In fact, multiple sclerosis is a disease where these sheaths get attacked by the immune system, and the brain eventually stops working because of it. So, they're pretty important.

The cited article seems to suggest (can't really follow the physics) that conventional electrical signalling theory can't explain the speed of transmission through myelinated axons. This, if true, implies as I said that certain conventional magnetic-electrical methods for measuring and/or manipulating brain states are unreliable, or at least are only measuring/manipulating the activity of unmyelinated axons.

Incidentally, fMRI would not be impacted by this because it measures blood flow, not brain activity directly.

[CoccoBill]

Thanks, while I obviously don't grasp a large part of that there's enough to understand roughly what we're talking about.

[wufwugy]

Hey Monkey,

When do you think all our computer stuff will be based on something other than silicon?

What do you think that material will be?

[MadMojoMonkey]

It's hard to answer, because I'm not neck deep in the design of computer chips.

From a physics standpoint, silicon is great because it's a semi-conductor. Not only that, but doping silicon is "easy" and silicon's crystal structure allows for more doping than other semi-conductors (but not all).
Pure silicon conducts at 0.7 V, which is a decent sweet spot between not so sensitive that random noise or thermal motions will trigger it, but still "pretty low."
Silicon oxides are also "easy" to make and are used as electrical insulators which are stable against degradation by water / steam and resilient at temperatures in the many hundreds of degrees.
The Earth's crust is basically made of it, so it's readily available.
It's chemically stable and non-toxic.

It's kind of a miracle element for making electronic devices.
It's also hard to say how much more we can do with it. Seems like every few years, there's a new use for silicon in the electronics manufacturing industries, which only increases its utility.


So that's a lot a new material has to compete with.
I'm pretty confident that whatever replaces silicon will not be a pure element. It'll be some breakthrough from materials scientists finding some lattice of different atoms that allows for a significant improvement in some desirable property.

[CoccoBill]

https://www.makeuseof.com/tag/moores-law-silicon-chips/

[wufwugy]

Do you have insight on how dense silicon transistors can get?

I know TSMC has 2nm in the works, and I've heard that 1nm *could* be the theoretical limit. They say the problem is quantum tunneling at too close of proximity.

Speaking of Moore's Law, this shit really has slowed down. The density doubling per 1.5 - 2 years is long gone, but it does appear that enterprise products are still doubling in total transistor count at that pace (by making them bigger, much bigger).

Our User Experience may still have a Moore's Law type of effect, but we're now doing, what, 15-20% increase in transistor density per year?

I found this fun (looks like it's about volume, not density, so not technically Moore's Law). I could be reading that wrong, though. I'd love for Moore's Law to not be dead.

[MadMojoMonkey]

I don't have any insight into how dense silicon transistors can get.

I'm just not an expert in the materials science that is used in current computer chips, and even those who are can't predict what breakthroughs will come from their field.


Carbon nanotubes and graphene sheets seem promising, but have seemed promising for a while, now. I've heard of great improvements in the manufacturing processes for graphene, but IDK what's holding it back from use in computer chips.


I'm way out of my understanding to even talk about a theoretical limit to quantum tunneling. Creating any material with infinite electrical resistance is off the table. I don't know of any upper bound to limit how high resistance could theoretically go, though. Atomic sizes and crystal structures will play a role in how thin an insulator can be.


I just can't answer these questions with any confidence.

[wufwugy]

Even though this isn't your domain, it's still good information. Thanks.

[OngBonga]

I suspect that the next generation of computers will be deliberately delayed, as the security implications are immense. I'm obviously thinking about quantum computers here, but any advance that increases processing needs to be coupled with similar advances in security technology.

Perhaps this is why graphene has been promising for some time without progress.

[OngBonga]

Anyway, I came here to talk about the heat death of the universe, something I've always been uncomfortable with. The latest episode of PBS Spacetime has some pretty cool ideas. The natural end state of the universe is pure radiation, ie light. That's a massless, timeless universe, and is indistinguishable from the beginning of the universe when everything was compacted into a singularity. This might not seem obvious at first, after all the beginning of the universe is infinitely small and the end is infinitely big. But without time, there is no spacetime. Photons do not experience time, because they travel at the speed of light. So a universe with only photons is a universe without time, and is therefore a universe without spacetime. The universe of photons, for all intents and purposes, is a singularity.

Head bending stuff, but it kinda makes sense, and more than that it's much more comforting (whatever that even means in this context) to believe the universe works in cycles.

[MadMojoMonkey]

Quantum computers are not likely to be used in consumer computers any time soon.

You lose rigorous determinism with quantum computing.

I don't see any immediate application to consumer needs like office software, sending / receiving data over the internet, and video gaming.
Maybe we'll find uses for the extreme speed bump from quantum computing.

I doubt anyone wants a calculator that only usually says 2+2=4, is all I'm saying.

[MadMojoMonkey]

Re. PBS spacetime
"It's outrageous and probably wrong"
Nice intro.

"rest mass energy was essentially negligible"
The difference between 0 and non-0 mass is effectively infinite in terms of traveling at light speed. Not trivial at all.

"so far no evidence of that, but wouldn't it be cool if [...]"
nice outro



Not sure if that all sounded like pure speculation because it actually is or because of my mood.

[CoccoBill]

I suspect that the next generation of computers will be deliberately delayed, as the security implications are immense. I'm obviously thinking about quantum computers here, but any advance that increases processing needs to be coupled with similar advances in security technology.

No one in the history of the world has done that wrt any technology as far as I know, I remain skeptical. Like with AGI, half the people still don't think there's any meaningful risks. I rather think there's a harder and harder push to create our Great Filter.

[MadMojoMonkey]

Gov'ts limit the spread of technology all the time.

Just one example
Confidential / Top Secret tech is in the nose of nearly all of our military aircraft, and the detection and avoidance hardware and software we sell to our allies is many years behind the current tech we're using ourselves.