# Intergalactic angst



## KenOC

I am collapsing in a heap of self-pity today. Just finished an online course on the nature of the universe that promised to answer all my deepest questions. It wasn’t to be! Turns out that:

- 70% of the “stuff” the universe is made of is “dark energy.” We can’t observe this and have no idea what it is. It doesn’t fit our standard model of particle physics. We only know it’s there because the universe is expanding faster than it should.

- Another 25% is “dark matter,” which again we can’t observe and is a total mystery to us. We only know it’s there through its gravitation effects, for instance spiral galaxies rotating faster than they should.

- Finally, that last 5%. That’s us and all the matter and energy we can observe or account for in the universe. Basically, as the instructor said, “pond scum.”

A pretty poor showing from our physicists and cosmologists, who perhaps need some re-education through labor to encourage them to work harder or, at least, be more clever. Meanwhile, if there’s anybody here who can make me feel better, please do so!


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## mmsbls

Just a slight correction - it's not that we can't observe dark energy or dark matter but rather that we haven't yet observed them.


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## KenOC

mmsbls said:


> Just a slight correction - it's not that we can't observe dark energy or dark matter but rather that we haven't yet observed them.


Not for lack of trying, certainly...


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## Guest

Did you have to pay for this online course, KenOC?


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## KenOC

poco a poco said:


> Did you have to pay for this online course, KenOC?


No, Coursera courses are all free, unless you want a certificate. Some interesting music courses as well.

https://www.coursera.org/learn/astronomy


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## Red Terror

KenOC said:


> I am collapsing in a heap of self-pity today. Just finished an online course on the nature of the universe that promised to answer all my deepest questions. It wasn't to be! Turns out that:
> 
> - 70% of the "stuff" the universe is made of is "dark energy." We can't observe this and have no idea what it is. It doesn't fit our standard model of particle physics. We only know it's there because the universe is expanding faster than it should.
> 
> - Another 25% is "dark matter," which again we can't observe and is a total mystery to us. We only know it's there through its gravitation effects, for instance spiral galaxies rotating faster than they should.
> 
> - Finally, that last 5%. That's us and all the matter and energy we can observe or account for in the universe. Basically, as the instructor said, "pond scum."
> 
> A pretty poor showing from our physicists and cosmologists, who perhaps need some re-education through labor to encourage them to work harder or, at least, be more clever. Meanwhile, if there's anybody here who can make me feel better, please do so!


And yet many of them claim to "know" that God doesn't exist. In our age, convenience dictates 'truth'. Pitiful.


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## Strange Magic

Red Terror said:


> And yet many of them claim to "know" that God doesn't exist. In our age, convenience dictates 'truth'. Pitiful.


It isn't that they claim to "know" whether a god or gods exist, or don't; it's that there is neither evidence nor requirement.

For Ken, there are at least three hypotheses for dark matter, and several hypotheses for dark energy--the latest Sky & Telescope magazine has an article on the latter. But unless scientists have an answer right here, right now!, people seem to get all bent out of shape.....

Come on down to Groups where we can further discuss these things in Science or Religion!


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## DaveM

Okay, we know the universe is expanding. What I want to know is what is it expanding into? There has to be somewhere for it to expand into. Inquiring minds want to know.


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## KenOC

DaveM said:


> Okay, we know the universe is expanding. What I want to know is what is it expanding into? There has to be somewhere for it to expand into. Inquiring minds want to know.


As I understand it, the universe is thought to be infinite. The collection of matter and energy born from the big bang is expanding into infinite empty space, plenty of elbow room there. But it seems that other opinions exist!


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## KenOC

Strange Magic said:


> For Ken, there are at least three hypotheses for dark matter, and several hypotheses for dark energy...


Of course, a hypothesis without observational evidence is just a speculation.


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## Strange Magic

KenOC said:


> Of course, a hypothesis without observational evidence is just a speculation.


Yes. But the observed rotation period of galaxies, in order to comport with well-established gravity theory, requires additional mass, as yet unseen. That is the observational evidence that triggers the speculating: Where, What, How about this missing mass? Pretty much science at work.......

We discuss these things additionally downstairs in the Science group:

https://www.talkclassical.com/groups/talk-science-d1428-ligos-latest-triumph.html


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## Room2201974

Way back in the early 70's I was doing some research for a composition I was writing and I got interested in element formation. This "research" required meeting with a university physics dean to discuss the matter (pun intended). Well, basically it turns out we knew a few things about element formation then....but now? HOLY COW! We know exactly which types of stars create the elements, and we know the sequence of their formation through the understanding of several types of nuclear reactions. So great progress had been made in that field!

And need I remind everybody that the expanding universe concept is less than 100 years old!

So have patience! Those things that one century cannot explain, and some attribute to a celestial power, turn out to be explained by a later century. (The gods move in the night sky. See, there goes Jupiter in retrograde!) (Laplace to Newton: "Yo, Isaac, having trouble with all the gravity calculations in the solar system? Hold my beer!")


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## mmsbls

DaveM said:


> Okay, we know the universe is expanding. What I want to know is what is it expanding into? There has to be somewhere for it to expand into. Inquiring minds want to know.


Technically, the universe (our region of spacetime) is not expanding _into_ anything but rather creating new spacetime as it expands. The actual extent of the universe is not known. It's a bit difficult to speak about these things because English phrases such as "before our universe" or "outside our universe" don't have a proper meaning in terms of the physics. There is no space "outside our universe" since the expansion of the universe created space (spacetime).


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## aleazk

I find the status of dark matter to be much more solid than that of dark 'energy'. Dark matter refers to actual observational anomalies that have been observed, galaxies seem to 'weight' much more than what their EM emissions suggest. So, there's definitely something going on there. There are several proposed solutions, some of them want to modify our understanding of gravity and some others want to postulate the existence of new kind of particles that, of course, interact little with anything else besides gravity. So far, none of the proposals seem to be 100% satisfactory in explaining all of the observed phenomena in a single stroke. But, if you ask me, I think some theory will explain it in the next decades since the actual experimental data exists, it's a well posed problem (unlike many other things going on right now in particle physics, like supersymmetry and string theory).

As for dark energy, I'm one of those that think we already have an explanation for it: it's just the cosmological constant in Einstein's equations of general relativity, it's one of the terms in the left side of them, side which deals with the spacetime geometry (the reasons why that constant appears there are purely geometrical). The observed data can be explained with just that. Now, some want to put that constant on the other side of the equations, the one that corresponds to matter. And, of course, the physical interpretation for the same constant will have to be as some sort of universal and ever present energy that permeates all of the cosmos and which has some bizarre properties. Even more, you can now throw yourself into wild speculations about the nature of that supposed 'energy', activity which pays good dividends in the academia's currency (i.e., publishable papers). But, to me, the accelerated rate of expansion of the universe is well explained in a purely geometrical way by standard general relativity.


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## joen_cph

Am just a layman, but one interesting, concrete path of research into this is the LIGO project, which apparently will be working on a more sophisticated level from 2021:
"_Could dark matter - the missing, unseen matter in our universe - be composed of as-yet-undetected primordial black holes?_"

https://aasnova.org/2017/09/27/can-ligo-find-the-missing-dark-matter/

https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves
"_The first direct observation of gravitational waves was made on 14 September 2015 and was announced by the LIGO and Virgo collaborations on 11 February 2016_"

https://en.wikipedia.org/wiki/LIGO#Advanced_LIGO:
"_It is aimed to achieve design sensitivity in 2021._[39]"


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## Strange Magic

^^^^I don't think we can "explain" the accelerating expansion of spacetime by the fact that Einstein's General Relativity incorporates/contains the cosmological constant math/geometry. Having the mathematics for generating a sphere, an ellipse (or anything else) does not itself require that an actual physical structure exist that embodies it. The strong evidence that spacetime is expanding at an increasing rate "legitimizes" Einstein's construct, rather than the other way round. I'm no expert on cosmology, but I recommend the May 2018 issue of _Sky & Telescope_ and the article The Dark Enigma by Marcus Woo. Woo discusses the full subject of dark energy, including both the evidence for accelerating expansion, the quality of the data of the rate of acceleration, the discrepancies between the predictions of quantum theory, Einstein, and the best-measured rate of acceleration, and also a whole bunch of current hypotheses seeking to explain what's going on. The latest S&T also addresses dark energy in an article titled What Came Before the Big Bang?.


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## aleazk

Strange Magic said:


> ^^^^I don't think we can "explain" the accelerating expansion of spacetime by the fact that Einstein's General Relativity incorporates/contains the cosmological constant math/geometry. Having the mathematics for generating a sphere, an ellipse (or anything else) does not itself require that an actual physical structure exist that embodies it. The strong evidence that spacetime is expanding at an increasing rate "legitimizes" Einstein's construct, rather than the other way round. I'm no expert on cosmology, but I recommend the May 2018 issue of _Sky & Telescope_ and the article The Dark Enigma by Marcus Woo. Woo discusses the full subject of dark energy, including both the evidence for accelerating expansion, the quality of the data of the rate of acceleration, the discrepancies between the predictions of quantum theory, Einstein, and the best-measured rate of acceleration, and also a whole bunch of current hypotheses seeking to explain what's going on. The latest S&T also addresses dark energy in an article titled What Came Before the Big Bang?.


It only means that the universe is fine tuned to be consistent with that value and no other. Fine tuning is a problem for some, not for me, since I consider it a pseudo-problem. You are not going to be able to explain everything unless you have a final theory (which I find an impossible pseudo-goal). So, as for the current theories concern, I consider it 'explained' by the cosmological constant. We could start asking what's the true nature of gravity then. Maybe there's some answer, but you will have to conform with general relativity in the meanwhile.


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## aleazk

DaveM said:


> Okay, we know the universe is expanding. What I want to know is what is it expanding into? There has to be somewhere for it to expand into. Inquiring minds want to know.


Given its name, the notion of 'expansion' seems an easy one to understand, but it's actually a more subtle concept. I prefer the notion of 'space dilation'. But, leaving names aside, the best way to understand it is to go to the actual math. This expansion is a type of 'intrinsic' expansion, something which must be understood in terms of the space itself, and using only elements inside it, rather than by embedding it in an external container in order to define or measure the expansion in relation to that latter exogenous element. This intrinsic view was a key step in the development of geometry around the end of the 19th century and which is now in the core of general relativity. Before it, all curved geometries were studied as curved surfaces embedded into a higher dimensional space. Now, regarding the expansion, space is considered to be a set of points E. On that set, a distance function D can be defined, so that, for any two points p and q in E, their distance is the number D(p,q). Of course, we have actual formulas for that. For a flat geometry, it's the standard 'Pythagoras theorem'. But the relevant thing here is that the set of points and the distance function are two different levels, and, also, that everything is done in an intrinsic way. Thus, after this, the intrinsic expansion is simply defined as the case in which the distance for any two points is a time-dependent and increasing function, i.e., D[SUB]t[/SUB](p,q), where t is time. In this way, for any two points in space, the distance that separates them is always increasing. This is why it's often said that, rather than expansion, it's as if space is constantly being 'created' between any two points. Of course, as with any metaphor, that should be taken with a grain of salt.


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## KenOC

The short course I mentioned, linked to in post #5, goes into the subject of fine-tuning. Fritz Kobus would be all over this one! An alternate explanation, of course, is that we live in one of an infinite number of universes, one where physical constants happen to be “just right” for life and even for matter and energy, as we understand them, to exist. And we ask these questions because we happen to have developed in that universe and not in another.

In the case of dark energy and more directly dark matter, the instructor notes that of the four forces we know, gravity is the only one for which we have no quantum theory. That’s inconvenient!


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## geralmar

As a kid I loved westerns so I remain loyal to the saddle-shape universe and all implied. At least it helps make the universe relatable. (It's all Gene Autry.) That said I take cosmology seriously. When I was in college to ask what came before the Big Bang invited a contemptuous glare from the professor. Now cosmologists treat the question openly and respectfully. Of course ultimately it's like asking who made God; but science is too young to demand final answer to every question. And at least the questions (and half-answers learned) are challenging and fun.

https://sciencedemonstrations.fas.harvard.edu/presentations/saddle-shape-universe


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## aleazk

KenOC said:


> The short course I mentioned, linked to in post #5, goes into the subject of fine-tuning. Fritz Kobus would be all over this one! An alternate explanation, of course, is that we live in one of an infinite number of universes, one where physical constants happen to be "just right" for life and even for matter and energy, as we understand them, to exist. And we ask these questions because we happen to have developed in that universe and not in another.


Yes, and that's why I don't tend to like such fine tuning questions, since the supposed answers make you doubt if we are still in the province of respectable science. How do we test that? Besides, you can apply that reasonig to anything that has a constant whose value must be fixed by experiment. Take Newton's inverse square law, with that pesky G. Of course, there must be uncountable infinite universes for it. What about Coulomb's law, with that k? Waiter! Another infinite set of universes for this table please. And so on. What encompassing mathematical structure is supposed to model all these universes, the landscape from string theory? That's just a bad joke.

Whoever that has done some science knows that there will always be parameters whose values are fixed by experiment when you try to fit a theoretical model with reality. That's always bound to happen due to the always approximate nature of science, you make simplifications. Sometimes, those constants from old theories are explained by new theories, like, say, the Rydberg constant from spectroscopy, whose value is explained by the Bohr model of the atom in terms of other more fundamental constants. But, in some other cases, it's not explained by the new theory. For example, in general relativity, you still have the newtonian constant G, and its value is as unexplained there as it was in Newton's time. What I'm trying to say is that to try to explain why some constant has certain value is not a very good motivation for looking for new science. That's why I said in my first comment that the status of dark energy as a problem to be explained is not as strong as dark matter, which is a real and pressing contradiction in the observed data.

In today's fundamental physics, there are some vigorous debates right now about that way of doing physics, since a lot of hypothetical particles (the supersymmetry particles) that supposedly were going to be observed at the LHC have not been observed. The only arguments that support the predictions for those particles are ones based on supposed explanations of certain fine tuning 'problems'. Supersymmetry and related topics have dominated the field for decades now, it's an utter failure. I recommend S.Hossenfelder's 'Lost in Math' for a critical take on all these issues. Here's an overview of the arguments there.



KenOC said:


> In the case of dark energy and more directly dark matter, the instructor notes that of the four forces we know, gravity is the only one for which we have no quantum theory. That's inconvenient!


Quantum gravity is another one of the problems which is well posed, albeit one whose solution will require some radical re-formulations of some notions.


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## KenOC

Here's a transcription of the lecture from the online course having to do with multiple universes:

"…but if one little tiny part of the universe underwent inflation to create our universe, what about the rest of the universe? What was happening with the rest of the universe during this time? And it turns out there's no reason why those parts of the universe shouldn't undergo their own inflation. 

And this is an idea, it's really almost inescapable. If you believe in inflation, you're almost sort of driven to accept the idea of eternal inflation. Meaning that parts of the universe are always undergoing inflation. So that means is that you don't end up with just one observable universe. There, every piece of the universe that undergoes its own inflation, its own little period of inflation, will end up as its own, what they call, pocket universe. With its own region of space-time that is independent of the other regions of space-time, essentially. And that has its own physical laws. So the, it's another region of space-time that underwent inflation. It's possible that you could have a different kind of electromagnetism. And then you can have a different kind of strong nuclear force. Maybe you wouldn't even have a strong nuclear force. All of it depends on the details of the physics that occurred during the inflationary epoch. So the eternal inflation leads to the idea of a multiverse. That there's not one universe, but that there are actually multiple, perhaps infinite numbers of universes, of these pocket universes. Each with their own physical laws. 

Now, for some people, this is an abomination. Right? There should only be one universe. Why are we talking about these other universes? Especially since it's not clear at all whether or not we can make any observations about these other universes. Whether or not, if we are, we are causally disconnected from them, such that they can have no influence on them. Then we can't know anything about them. So what's the status of a theory, like inflation? That gives us a great account of our own, the universe we can see, but multiplies infinitely the number of universes out there and says you never can see them. So there, that's kind of a problem for some people.

On the other hand, what internal inflation and the multiverse does do for us is it eliminates the problem of fine tuning. Remember, when we talked about the standard model of particle physics, we said that there are all these numbers that you gotta put in there by hand in order to get all the forces to operate exactly the way we see them today. And what we find is that those numbers are just slightly different. Those constants of nature which are set during inflation we think. If they're slightly different, we can never get life in the universe. So the universe seems to be fine tuned for our existence which, you know, seems a little crazy. So with the multiverse though, you're okay, because there are infinite numbers of universes. 

And so, it wasn't like the universe only happened once and just ended up with those numbers. There have been lots of universes and it's kind of a roll of the dice in each universe what the constants of nature will be. So, in our universe, we just happened to end up, of course, in the universe that is, has the numbers that allows life to form, or we wouldn't be here. But since there's lots of other universes, you had lots of chances and so the, the appearance of those numbers is not a mystery. It's only when you only get one universe that those numbers appear as a mystery. So different people have different feelings about this approach. I'm not a big fan of it, I have to say. I think there's probably a better way of or of, of solving the problem of fine tuning."


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## aleazk

Except inflation is another non-verified theory and which, again, was deviced to solve another fine tuning 'problem', the so-called 'flatness problem'.

Really, it's not at all by mere chance that all these theories designed to solve pseudo-problems have been utter failures with no experimental confirmation whatsoever. It's because their motivation was very weak in the first place. This has been going on for decades. It's a plague in modern physics. And it's simply the evidence the thing which is eloquently putting it.


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## Strange Magic

aleazk said:


> Except inflation is another non-verified theory and which, again, was deviced to solve another fine tuning 'problem', the so-called 'flatness problem'.
> 
> Really, it's not at all by mere chance that all these theories designed to solve pseudo-problems have been utter failures with no experimental confirmation whatsoever. It's because their motivation was very weak in the first place. This has been going on for decades. It's a plague in modern physics. And it's simply the evidence the thing which is eloquently putting it.


Though "truth" is never established merely by a show of hands, you would agree that inflation is currently the overwhelming favorite model of cosmologists, as it appears to answer so many questions. But since we're scrounging for scraps of consistent data at the edges of both speculation and experimentation/instrumentation, it will be a while before things come into clearer focus. Geology is undergoing a similar phase with trying to establish beyond reasonable doubt the actual existence of mantle plumes as the source for "hotspots", flood basalts, island chains, etc. Hominin paleontology/Paleoanthropology also in the same boat. Dynamic Science--what a time! Lots of questions.


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## philoctetes

I feel that theory has fallen far behind observation in cosmological science. Partly for reasons that theorists seem very quick to create new theories to justify, adjust, or abandon old theories just to lock down these arbitrary coefficients to their satisfaction. This seems to have a paralyzing effect on progress and conclusive results. Apparently we will not end this quest until we can justify the value of all natural constants, or prove they are not actually constant. etc... and one must wonder if that is really so important or even possible to resolve with so many theories that can't be tested.

Observations have improved thanks to advancements in material technologies that develop more sensitive sensors, devices, and developments in data processing platforms and algorithms that can take advantage of higher SNRs. Of all the developments in physics over the last few decades I think these have been more productive than those in particle or cosmological theory. But even though these applied technologists are doing most of the trailbreaking, much of the elite scientific community still dismisses them as inferior, which is the same problem that led me to make bad decisions in my own education. Unless I read things wrong, THAT aspect of physics education is still prevalent.


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## philoctetes

What is the universe expanding into? I remember when it was a loaf of raisin bread expanding in the oven. Later it was a rubber sheet and then a manifold with a metric... each step getting more abstract.... for purpose of theory and computation... while dismissing the question of "what is outside?"

The expert, faced with such a challenge, has two responses to make 1) call it a stupid question 2) simply grasp the nostrils, write the equation y(A)=y0(A) and forget about it.


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## aleazk

philoctetes said:


> What is the universe expanding into? I remember when it was a loaf of raisin bread expanding in the oven. Later it was a rubber sheet and then a manifold with a metric... each step getting more abstract.... for purpose of theory and computation... while dismissing the question of "what is outside?"
> 
> The expert, faced with such a challenge, has two responses to make 1) call it a stupid question 2) simply grasp the nostrils, write the equation y(A)=y0(A) and forget about it.


Well, the art of science lies in formulating things in such a way as to evade impossible metaphysical questions and, in this way, to obtain working concepts that can be tested in reality. Not that the metaphysical questions are not interesting, but we are unlikely to advance in their answer by a direct attack.

Manifold and metric provides an intrinsic and self-consistent definition, which makes the 'outside of space' unnecessary. That's what scientific genius do.


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## mmsbls

philoctetes said:


> ...Observations have improved thanks to advancements in material technologies that develop more sensitive sensors, devices, and developments in data processing platforms and algorithms that can take advantage of higher SNRs. Of all the developments in physics over the last few decades I think these have been more productive than those in particle or cosmological theory. But even though these applied technologists are doing most of the trailbreaking, much of the elite scientific community still dismisses them as inferior, which is the same problem that led me to make bad decisions in my own education. Unless I read things wrong, THAT aspect of physics education is still prevalent.


I don't know where things stand today, but when I was an experimental particle physicist, I never had the impression that theorists looked down on experimentalists. In general when we talked, they would express admiration for our collective ingenuity and great thanks for providing them with the necessary data to test their theories. To me it always seemed to be a collaboration of physicists trying to understand reality. We were different but not inferior.


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## mmsbls

aleazk said:


> Except inflation is another non-verified theory and which, again, was deviced to solve another fine tuning 'problem', the so-called 'flatness problem'.
> 
> Really, it's not at all by mere chance that all these theories designed to solve pseudo-problems have been utter failures with no experimental confirmation whatsoever. It's because their motivation was very weak in the first place. This has been going on for decades. It's a plague in modern physics. And it's simply the evidence the thing which is eloquently putting it.


I have a slightly different view of inflation and other theoretical work. As I understand it, Guth developed inflation primarily to deal with the "monopole problem." Magnetic monopoles had not been found (and still have not been), and many Grand Unified Theories (GUTs) predicted them. I agree that this was a non-problem since GUTs had no empirical evidence supporting them. Our best theory, the Standard Model, did not predict magnetic monopoles so there was really no reason to develop a theory to show why we don't see them.

The flatness problem (i.e. why do we observe the universe to be so flat rather than with strong positive or negative curvature) was considered another serious issue. One can consider that problem to be a fine tuning problem since the universe could have started out remarkably (incredibly, incredibly remarkably) flat though my understanding is that most cosmologists have trouble with that assumption.

I have more difficulty with the "horizon problem" (i.e. that the microwave background radiation is remarkably uniform in all directions). My understanding is that conventional non-inflationary cosmologies do not have a mechanism to allow bringing distant regions of our universe into thermal equilibrium leading to such uniformity. One can assume that the initial condition was in such equilibrium, but I have trouble understanding how quantum processes could have generated such a condition. Inflation does give a solution by greatly expanding an extremely small region that was able to reach equilibrium.

As an experimentalist,I personally don't believe theories that do not have at least some experimental verification. I think we do have some data that seems to support inflationary cosmologies over non-inflationary ones, and we will be getting more data in the not so distant future. It's a tough time for theorists. For the vast majority of the 20th century, theorists were catching up with unexplained data. That changed in the late 1900s with the standard model and general relativity doing an excellent job of explaining essentially everything we see. Now they simply don't have enough data to guide them.


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## aleazk

mmsbls said:


> I have a slightly different view of inflation and other theoretical work. As I understand it, Guth developed inflation primarily to deal with the "monopole problem." Magnetic monopoles had not been found (and still have not been), and many Grand Unified Theories (GUTs) predicted them. I agree that this was a non-problem since GUTs had no empirical evidence supporting them. Our best theory, the Standard Model, did not predict magnetic monopoles so there was really no reason to develop a theory to show why we don't see them.
> 
> The flatness problem (i.e. why do we observe the universe to be so flat rather than with strong positive or negative curvature) was considered another serious issue. One can consider that problem to be a fine tuning problem since the universe could have started out remarkably (incredibly, incredibly remarkably) flat though my understanding is that most cosmologists have trouble with that assumption.


Yes, the monopole 'problem' was another of the motivations. As for the flatness problem, and as with most fine tuning problems, they indeed have problems with those assumptions. But they only have aesthetic justifications for their angst. Please, check the paper I mentioned before.



mmsbls said:


> I have more difficulty with the "horizon problem" (i.e. that the microwave background radiation is remarkably uniform in all directions). My understanding is that conventional non-inflationary cosmologies do not have a mechanism to allow bringing distant regions of our universe into thermal equilibrium leading to such uniformity. One can assume that the initial condition was in such equilibrium, but I have trouble understanding how quantum processes could have generated such a condition. Inflation does give a solution by greatly expanding an extremely small region that was able to reach equilibrium.


But it's yet another fine tuning problem. What if the initial state was just that thermal equilibrium. In fact, as you know, it's a ridiculously simple state. Besides, I'll rather wait for quantum gravity to know what's the most likely initial state. Until that, we simply don't know. The problem with all these theories is, to me, that they consider as 'problems' things which are not problems according to our best current theories, they are just impartial input data. They are ad hoc hypothesis, true, but so what? They might get an explanation in the future... or maybe not. And that's the problem when you base your theory building with the only narrow aim of trying to explain those supposed problems. Check science history, it never worked. The greats were trying to solve things that were evident contradictions in the, at their time, current knowledge. Einstein invented general relativity because newtonian gravity was incompatible with special relativity, not because he wanted to know why G has the value it has (note that G is still an ad hoc data even in general relativity). The only current actual problems in fundamental physics are dark matter, quantum gravity and the measurement problem in quantum physics. They all arise from actual contradictions between different parts of our current knowledge.



mmsbls said:


> As an experimentalist,I personally don't believe theories that do not have at least some experimental verification. I think we do have some data that seems to support inflationary cosmologies over non-inflationary ones, and we will be getting more data in the not so distant future. It's a tough time for theorists. For the vast majority of the 20th century, theorists were catching up with unexplained data. That changed in the late 1900s with the standard model and general relativity doing an excellent job of explaining essentially everything we see. Now they simply don't have enough data to guide them.


Yes, I agree with that. But I also think that theorists made the hole in which they are trapped even deeper by throwing themselves to baseless speculation, rather than sticking to what we actually know for sure. And the result is eloquent. It's 2019 and no evidence of supersymmetry in the LHC. For decades they told that it would appear in the next generation collider. Now they are asking for a new collider! But they know it's over, the most promising energy limit was in the LHC. I don't think a new collider with a few TeV more will make any difference. It's time to go back to the drawing board and to discard the ideas and methods that didn't work.

Btw, about inflation. There are indeed some observations that seem to favor a phase of exponential expansion (certain correlations in the CMB). The problem is that the inflation models themselves are incapable of more specific predictions and in a pathological way. For some things there are models for all tastes, some predict x and some others the exact opposite of x.


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## Luchesi

"Could dark matter - the missing, unseen matter in our universe - be composed of as-yet-undetected primordial black holes?"

Decades ago Hawking wrote about this saying if a primordial BH ended its existence in a flash of gamma rays near enough to Earth so that the data was collected, he was confident that his published descriptions would earn him a Nobel. All he needed was the hard data..
He was commenting upon the state of theoretical physics (the lack of good evidence) and he was also being his humorous self (considering his condition).

from wiki;
General relativity predicts the smallest primordial black holes would have evaporated by now, but if there were a fourth spatial dimension - as predicted by string theory - it would affect how gravity acts on small scales and "slow down the evaporation quite substantially".[35] This could mean there are several thousand black holes in our galaxy. To test this theory, scientists will use the Fermi Gamma-ray Space Telescope which was put in orbit by NASA on June 11, 2008. If they observe specific small interference patterns within gamma-ray bursts, it could be the first indirect evidence for primordial black holes and string theory.'

-----
If string theory gets some confirming evidence like this, its Calabi Yau view of the universe will give a good answer to what Dark Matter is and why expensive experimental projects have not found Dark Matter.


----------



## mmsbls

aleazk said:


> Please, check the paper I mentioned before.


I read her book and thought it was quite interesting although I think she gives the slight impression that all of these physicists are a bunch of fools who are doing physics wrong. I don't think they are a bunch of fools so perhaps a slightly better understanding of why these physicists act as they do would have been helpful. I'm not a theorist so I don't have a feeling for what it's like trying to "guess" the nature of reality.



aleazk said:


> Yes, I agree with that. But I also think that theorists made the hole in which they are trapped even deeper by throwing themselves to baseless speculation, rather than sticking to what we actually know for sure. And the result is eloquent. It's 2019 and no evidence of supersymmetry in the LHC. For decades they told that it would appear in the next generation collider. Now they are asking for a new collider! But they know it's over, the most promising energy limit was in the LHC. I don't think a new collider with a few TeV more will make any difference. It's time to go back to the drawing board and to discard the ideas and methods that didn't work.
> 
> Btw, about inflation. There are indeed some observations that seem to favor a phase of exponential expansion (certain correlations in the CMB). The problem is that the inflation models themselves are incapable of more specific predictions and in a pathological way. For some things there are models for all tastes, some predict x and some others the exact opposite of x.


I don't see how a new collider makes sense. To make a reasonable increase in energy would be prohibitively expensive. I think they have to focus on significant increases in the integrated luminosity looking for slight deviations from the standard model. My understanding is that there is now an emphasis on calculating higher order loop effects to better understand standard model predictions.

Two stories about supersymmetry. I heard a theorist give a talk about supersymmetry, and he joked that there was a 95% chance that supersymmetry was true. He asked 20 theorists and 19 said they believed it was real. Once several of us were sitting around after a colloquium, and one of the experimentalists asked Paul Steinhardt if we would have to actually learn supersymmetry someday. He wasn't sure but thought probably yes. That was awhile ago.

I actually wanted to do a search for supersymmetric particles for my thesis, but my adviser steered me away because we wouldn't have enough data for a reasonable search at that time.


----------



## Luchesi

After the Higgs discovery they thought they had found another particle. It was a glitch. This is especially bad for physics because they were looking for more evidence in that predicted range of energy. Since they didn't find any - physicists started talking about the end of physics because of the huge ramifications of no deterministic constraints on the parameters of quadrillions (a lot more than that --- 10^400) of possible universes. 

They have the funding so they will be still looking with more energy but the hopes are less and less, I assume. It might be a question of being stuck with what we have which according to them seems to be a random outcome to dwarf all random outcomes. And this is where it gets into the realm of philosophy..

We're easily explained if you have enough new baby universes inflating out of the eternally inflating nested-hierarchy of multiverses.


----------



## philoctetes

Intead of trying to justify all the necessary parameters... someone might be able to determine if it is even a solvable problem... I suspect it isn't. 

I don't follow this stuff with such relish anymore, but I find the entropic theory of gravity by Verlinde to be an interesting idea... and physicists are quick to shoot it down.. yet they keep demanding that the gaps in their theories be tolerated...


----------



## mmsbls

philoctetes said:


> Intead of trying to justify all the necessary parameters... someone might be able to determine if it is even a solvable problem... I suspect it isn't.
> 
> I don't follow this stuff with such relish anymore, but I find the entropic theory of gravity by Verlinde to be an interesting idea... and physicists are quick to shoot it down.. yet they keep demanding that the gaps in their theories be tolerated...


I'm not sure what you mean by tolerating gaps in theories. My experience has been that any gaps, inconsistencies, or mismatches between theory and experiment are the focus of work by both experimentalists and theorists. For example, there is an enormous effort to understand both dark matter and quantum gravity. What gaps do you feel are tolerated?


----------



## Strange Magic

philoctetes said:


> Intead of trying to justify all the necessary parameters... someone might be able to determine if it is even a solvable problem... I suspect it isn't.
> 
> I don't follow this stuff with such relish anymore, but I find the entropic theory of gravity by Verlinde to be an interesting idea... and physicists are quick to shoot it down.. yet they keep demanding that the gaps in their theories be tolerated...


Come back in 100 years and see how things stand. But everybody seems to want answers now .


----------



## philoctetes

mmsbls said:


> I'm not sure what you mean by tolerating gaps in theories. My experience has been that any gaps, inconsistencies, or mismatches between theory and experiment are the focus of work by both experimentalists and theorists. For example, there is an enormous effort to understand both dark matter and quantum gravity. What gaps do you feel are tolerated?


Working together on these gaps is a form of tolerance, is it not? Just not as flattering to pose it that way.


----------



## mmsbls

philoctetes said:


> Working together on these gaps is a form of tolerance, is it not? Just not as flattering to pose it that way.


I'm sorry, but now I'm even more confused about what you mean by tolerance. When you said



> ..yet they keep demanding that the gaps in their theories be tolerated...


,

I thought you meant that when physicists find problems with their theories, they demand that others ignore these problems. In my experience, when physicists find problems, they work intensely hard to solve those problems. In other words they do the exact opposite of tolerating the problems.

When you say that experimentalists and theorists working together to solve the problems is a form of tolerance, I would ask tolerance of what? Do you think experimentalists and theorists are generally at odds with each other so it's nice to see them working together. When have they ever not worked together?

I suspect that we are somehow talking about very different things.


----------



## philoctetes

Strange Magic said:


> Come back in 100 years and see how things stand. But everybody seems to want answers now .


If I could do that I would have every physicist at my doorstep today. Some (perhaps most) would want all the answers now (truthseekers) but a few would see me as a threat to their careers and hire someone to cause an accident. Life is not what some kids think it is.


----------



## philoctetes

mmsbls said:


> I suspect that we are somehow talking about very different things.


I suspect it's my extreme cynicism that makes us different. My bad.


----------



## Luchesi

philoctetes said:


> If I could do that I would have every physicist at my doorstep today. Some (perhaps most) would want all the answers now (truthseekers) but a few would see me as a threat to their careers and hire someone to cause an accident. Life is not what some kids think it is.


Yes, imagine going back to Isaac Newton's study and telling him that his baseless assumptions about absolute time and space and mass etc. were wrong-headed. And that such bad guessing obstructs and derails progress in understanding physics! 
...He'd put a contract out on you!


----------



## aleazk

Luchesi said:


> Yes, imagine going back to Isaac Newton's study and telling him that his baseless assumptions about absolute time and space and mass etc. were wrong-headed. And that such bad guessing obstructs and derails progress in understanding physics!
> ...He'd put a contract out on you!


I think you have no understanding of what's being discussed... considering your blind belief in things like string theory and the multiverse, I'm not surprised...


----------



## aleazk

Strange Magic said:


> Come back in 100 years and see how things stand. But everybody seems to want answers now .


But those are precisely the ones that invent fantasy theories to solve pseudo-problems. They want to know now why those free parameters are what they are. I don't have any hurry for that. What many people in the field of fundamental physics do want to know now is why now that we know all of their predictions in the last 50 years were all wrong, they still act as if nothing happened, as if everything in their ideas and methods is just fine. It cannot be the fault of technology, since their predictions stated, for example, that the superpartners should have masses of around 1 TeV. The LHC can easily detect that and, indeed, they said that it would be an easy discovery. I have seen too much bullsh.it in talks and papers as to be impressed by these theories, sorry. But carry on.


----------



## aleazk

mmsbls said:


> I read her book and thought it was quite interesting although I think she gives the slight impression that all of these physicists are a bunch of fools who are doing physics wrong. I don't think they are a bunch of fools so perhaps a slightly better understanding of why these physicists act as they do would have been helpful. I'm not a theorist so I don't have a feeling for what it's like trying to "guess" the nature of reality.


They are not fools, of course. The causes are mostly sociological and I don't think it's her task to address them, it's a job for an expert on that.

I don't think it's a 'guess'. And thinking it's simply a guess is in part the reason why we ended with so many useless theories. Of course, there's some hypothesising about things we don't know yet, but that's a very different thing. Check this paper for more about the practices of the great theoreticians of the past, they didn't do what the modern gurus of susy, string theory and inflation tell us it's what science is about.



mmsbls said:


> I don't see how a new collider makes sense. To make a reasonable increase in energy would be prohibitively expensive. I think they have to focus on significant increases in the integrated luminosity looking for slight deviations from the standard model. My understanding is that there is now an emphasis on calculating higher order loop effects to better understand standard model predictions.
> 
> Two stories about supersymmetry. I heard a theorist give a talk about supersymmetry, and he joked that there was a 95% chance that supersymmetry was true. He asked 20 theorists and 19 said they believed it was real. Once several of us were sitting around after a colloquium, and one of the experimentalists asked Paul Steinhardt if we would have to actually learn supersymmetry someday. He wasn't sure but thought probably yes. That was awhile ago.
> 
> I actually wanted to do a search for supersymmetric particles for my thesis, but my adviser steered me away because we wouldn't have enough data for a reasonable search at that time.


In those jokes, it's clear they are about these very sociological issues I'm mentioning. It's not as if nobody noticed them, pretty much eveyone outside the small group of endogamic practitioners of those theories always perceived them.


----------



## Luchesi

aleazk said:


> I think you have no understanding of what's being discussed... considering your blind belief in things like string theory and the multiverse, I'm not surprised...


I wish I was your age again so I could be just like you.


----------



## Tikoo Tuba

Well , I see only two dimensions of space . What we deem 3-d is one , and then there is spatially another . I hope a future math will account for teleportation reality in this context . Math derived from finger counting will just not do , *pi* being pathetic and all . Oops . I'm gone again . Nah , just happened to me once ... and then a couple years later I witnessed it happen to someone who poof appeared in front of me . Learning is slow . I don't know much . Maybe in lifetime one can personally learn three little existence facts of god or something . This is my story of that so far . My life-expectancy is 130 .


----------



## aleazk

Luchesi said:


> I wish I was your age again so I could be just like you.


Is that supposed to be some sort of ageist insult or something? Maybe you should start giving arguments rather than silly one-liners...  If not, bye, I have nothing to discuss with you.


----------



## Luchesi

Tikoo Tuba said:


> Well , I see only two dimensions of space . What we deem 3-d is one , and then there is spatially another . I hope a future math will account for teleportation reality in this context . Math derived from finger counting will just not do , *pi* being pathetic and all . Oops . I'm gone again . Nah , just happened to me once ... and then a couple years later I witnessed it happen to someone who poof appeared in front of me . Learning is slow . I don't know much . Maybe in lifetime one can personally learn three little existence facts of god or something . This is my story of that so far . My life-expectancy is 130 .


"Maybe in lifetime one can personally learn three little existence facts of god or something . This is my story of that so far ."

That's what I'm working on too. I started long ago and it hasn't matured or advanced very much. So far, 'just a focus of gratitude.

I ask other people, especially online, but I think they're stumped too.


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## Tikoo Tuba

Well , yes , I am thankful to hold a better story than institutions provide . There's no existential angst in it . My story may be spare yet its extraordinarily sure and inspires me to patience .


----------



## mmsbls

aleazk said:


> I don't think it's a 'guess'. And thinking it's simply a guess is in part the reason why we ended with so many useless theories. Of course, there's some hypothesising about things we don't know yet, but that's a very different thing. Check this paper for more about the practices of the great theoreticians of the past, they didn't do what the modern gurus of susy, string theory and inflation tell us it's what science is about.


I'm pretty sure there are no particle physicists that believe theorists guess at theories. My "guess" was a shorthand for the extremely complex process of developing new ideas and hypotheses that extend or modify current physics but conforming with the extremely strict constraints of data and very basic principles such as relativity and quantum mechanics.

I read the paper and have read other papers or books that discuss philosophy in physics. I don't believe that physicists _actually_ ignore the philosophy of doing science, and I agree that the process of doing science must and does evolve. So I think the argument is more subtle than often described. I think there are two issues. First, how do we know that our theories are "right", and second, how should we proceed with developing new ones (or maybe what is a proper theory?). I believe physicists do a good job on the first. The second is much harder to nail down. Perhaps physicists would do well to take a step back and evaluate that process to see what has succeeded and what has not, and maybe philosophers could add useful thoughts there.

The paper seemed to assume that many or most physicists agree with Kuhn's Structure of Scientific Revolutions. It has been my experience in reading and talking with physicists that most (all?) feel that Kuhn's hypothesis may be trivially true in a very general sense but the details disagree with how science is actually done.

Personally I think SUSY, string theory, and inflation were initially brilliant ideas that were useful attempts to solve particular problems. Some problems were more philosophical than others. SUSY simply has not found the experimental confirmation the theory predicted. Maybe some form will turn out to be real, but it does not appear to be a promising area now. String theory is a beautiful mathematical idea that might have some potential relationship to physics. Theorists have been working very hard for a long time to find that relationship as yet to no avail. If someone can take the theory and calculate results that both agree with present data and make testable predictions, that would be interesting. I can easily understand people questioning why 90% (or whatever the number) of theorists work only on string theory. Inflation seems still in play. I don't understand the theory well enough to know how well formed it is, but people seem to agree there is data that does not agree with standard cosmological models (yes, initial conditions are an issue) but does agree with calculations based on inflation. We need some more data and perhaps a more finalized theory.


----------



## aleazk

mmsbls said:


> The paper seemed to assume that many or most physicists agree with Kuhn's Structure of Scientific Revolutions. It has been my experience in reading and talking with physicists that most (all?) feel that Kuhn's hypothesis may be trivially true in a very general sense but the details disagree with how science is actually done.


I think he refers to the current generation of researchers. What he says about how they take a one liner version of Popper and Kuhn in their theory building is spot on, since I have seen it in many conferences. Some people think that we should constantly look for a radical paradigm change. Thus, they lucubrate very extravagant ideas and pretend it's valid science just because it gives some remotely falsifiable prediction (experimentalists, good luck now in trying to find some supposed entangled primordial black holes...) Of course, it's not valid science, since it's completely alien to our main verified theories, it's just a shot in the dark. They all want to be the next Einstein, but he never worked in that way. His shots always tried to stick to the accepted theories and only departed when it was strictly necessary. The reasons why in that way and not other were brilliantly stated. His ideas were radical, yes, but when you read his 1915 paper on general relativity, and particularly the part in which he justifies why the gravitational field must be the spacetime metric, you don't even notice how radical it is because the argument just flows naturally. No aesthetic considerations, just plain physical argumentation.



mmsbls said:


> Personally I think SUSY, string theory, and inflation were initially brilliant ideas that were useful attempts to solve particular problems. Some problems were more philosophical than others. SUSY simply has not found the experimental confirmation the theory predicted. Maybe some form will turn out to be real, but it does not appear to be a promising area now. String theory is a beautiful mathematical idea that might have some potential relationship to physics. Theorists have been working very hard for a long time to find that relationship as yet to no avail. If someone can take the theory and calculate results that both agree with present data and make testable predictions, that would be interesting. I can easily understand people questioning why 90% (or whatever the number) of theorists work only on string theory. Inflation seems still in play. I don't understand the theory well enough to know how well formed it is, but people seem to agree there is data that does not agree with standard cosmological models (yes, initial conditions are an issue) but does agree with calculations based on inflation. We need some more data and perhaps a more finalized theory.


To be honest, I was never very impressed by string theory as a theory of quantum gravity. In its current and only concrete formulation, it's not background independent. Thus, it's not a true theory of quantum gravity. You cannot pretend you are quantizing the metric when you are doing that on a given classical background spacetime! In quantum gravity you quantize the very variability of the metric, therefore you cannot assume a fixed classical background metric while doing that and do ordinary perturbative/particle qft, that's the whole conceptual issue which makes it so hard. Thus, whatever string theory is, I consider it more similar to an ordinary qft of particles on some curved classical spacetime background. At best, that could be a low energy limit of quantum gravity, when the quantized metric can be approximated as a quantized perturbation (gravitons) of a classical background. But that's evidently not a fully quantized metric. That's why I prefer LQG, since they at least try to quantize the full metric.

Furthermore, string theory as a theory of unification of the forces seems to be in deep trouble today with the landscape. I vastly prefer Connes' spectral standard model, where he describes the standard model in a unified way by showing how all of its aspects arise from a single geometric framework, it's a geometric unification, exactly what Einstein wanted (it's based on a slight non-commutative extension of the standard spacetime, it's the metric there the one that gives all the fields of the standard model). It doesn't assume extra-dimensions nor susy. And, finally, it's 100% mathematically rigorous, everything is proved as rigorous theorems that anyone can check (unlike string theory, which is full of conjectures and non-rigorous argumentations).

String theory, to me, has failed to deliver its physical promises and the alternative approaches (of which string theorists mocked in the early 2000s) are proving to be much more robust.


----------



## Tikoo Tuba

I thought it interesting to see pictures of the galactic center . On one occasion some energetic black hole activity gave the sense a butterfly (the Mayan butterfly) lives there .


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## Luchesi

Tikoo Tuba said:


> I thought it interesting to see pictures of the galactic center . On one occasion some energetic black hole activity gave the sense a butterfly (the Mayan butterfly) lives there .


In my field the butterfly is the enemy for the customer and it's the rationalization everyone understands for why we consistently miss by 50 to 100 miles in terminal forecasts. It's a real dose of reality for both sides. And it's been extensively studied.

We understand enough to confidently forecast 16 days in advance most places in the world, surface to 40k ft, knowing we'll be off by 50 to 100 miles. And we've reached that limit which the physics allows, ...again, it's well-studied now.


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## Tikoo Tuba

Peace to the chronic angst , then we can experience the truly weird and original wonders without worry .


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## DeepR

The information given by the OP wasn't new to me, but the rest of the thread quickly turned too technical. I wouldn't dare contribute without thorough education. Me, I'm just watching shows like How The Universe Works. I do recommend it, if not only for the enthusiasm of the scientists involved. Season 7 just started. Very basic, elementary, simplified. Exactly what I need.  It really does increase my appreciation and fascination on anything space. Maybe some day, I will learn more.


----------



## Red Terror

Some interesting posts, but why worry about the universe when we can’t even manage our home planet? We’ll never understand the universe because our time is limited. We’re doing a great job expediting our own destruction.


----------



## Luchesi

Red Terror said:


> Some interesting posts, but why worry about the universe when we can't even manage our home planet? We'll never understand the universe because our time is limited. We're doing a great job expediting our own destruction.


Since Beethoven wrote a lengthy development section in his Second Symphony one major critic said it was a "monstrous snake biting at its own tail, consuming itself".

Beethoven - Applause, my friends, the comedy is over!

Most likely, he didn't say that. According to the book by his composer friend, he and Johanna van Beethoven were there.

LvB didn't know, like we know, that we live precariously in a false vacuum state. Every day that passes the probability goes up that we will be collapsed into nothingness, because black holes are growing and new ones are forming. As I understand the theorists, these black holes disturb the tiny stabilizing force of universal gravitation holding up the current state of things.

As we speak, aliens are racing toward us to stop our tinkering at the LHC. After all it's their universe too. Hiigh energy collisions in nature haven't been disastrous so far, but who knows what will happen in the compartments at the LHC. Outside physicists have sued the LHC in court, but they couldn't prove legally that there was an understandable danger.


----------



## philoctetes

Luchesi said:


> We understand enough to confidently forecast 16 days in advance most places in the world, surface to 40k ft, knowing we'll be off by 50 to 100 miles. And we've reached that limit which the physics allows, ...again, it's well-studied now.


Last weekend's 3-day forecast errors where I live were far greater than that.


----------



## KenOC

Tikoo Tuba said:


> I thought it interesting to see pictures of the galactic center . On one occasion some energetic black hole activity gave the sense a butterfly (the Mayan butterfly) lives there .


It's difficult to see the Milky Way's core because we're looking edge-on through a lot of stuff. This is the best picture I've seen.


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## Tikoo Tuba

There's some sort of radio telescope that has an eye on it . An image of the galactic center from that info has been presented in a documentary film . I found it memorable .


----------



## aleazk

At some point in this year it's expected that the Event Horizon Telescope will deliver its results, which may include the first image ever of the 'shadow' of a black hole. It is, of course, an image made from EM emissions outside the visible spectrum but which will be translated to visualizable forms.


----------



## Luchesi

philoctetes said:


> Last weekend's 3-day forecast errors where I live were far greater than that.


What did the forecast say, and what happened where you live?


----------



## Tikoo Tuba

aleazk said:


> Event Horizon Telescope[/URL] will deliver its results, which may include the first image ever of the 'shadow' of a black hole.


The first image ever ? I cannot accept that . The first images depicted a black hole , going on and on being black , but then oh!discharging energy . Perhaps that information has been deleted as unacceptable .


----------



## aleazk

Deleted by whom? The President of Physics?


----------



## Luchesi

KenOC said:


> It's difficult to see the Milky Way's core because we're looking edge-on through a lot of stuff. This is the best picture I've seen.


I can see where the galactic center is hiding. Antares is a large star directly above the smaller structure (four or five lengths of the smaller structure straight up). Bisect a line extending from Antares down to the top of the larger structure. That's the position of the galaxy's center.

Or look from the bottom of the Dark Pipe Nebula across the riff down toward the brightest bulge. It's in the riff between the Pipe and top of the bright bulge.


----------



## DeepR

Did you know that... Chuck Norris can do pushups on a neutron star?
Nah really, such unimaginable objects.


----------



## Luchesi

DeepR said:


> Did you know that... Chuck Norris can do pushups on a neutron star?
> Nah really, such unimaginable objects.


Did you know that Norris married a girl younger than his own kid and believes that the world will end soon - even though his Bible says nobody can calculate that.

You'd think that Newton would've been smart enough not to waste his time with this, but he believed that absolutes were everywhere to be helpful -- ...he's been proven embarrassingly wrong about all of this.


----------



## philoctetes

Yet another Luchesi post about how a great scientist was stupid and looks bad today. If only Newton knew Luchesi back then we'd be much better off now.


----------



## Tikoo Tuba

aleazk said:


> Deleted by whom? The President of Physics?


Well , obviously the angstrom has been weaponized . Our Dr. Eileen Dover is suspect of believing in and employing this necessary evil . People suffering angst is considered by leadership to be the cost of an orderly advancement in knowledge .


----------



## Luchesi

philoctetes said:


> Yet another Luchesi post about how a great scientist was stupid and looks bad today. If only Newton knew Luchesi back then we'd be much better off now.


No, we're better off now because he was ahead of his time. But he was a nasty person and he made assumptions in his fields that a scientist shouldn't make. Why? A huge ego? Superstitious beliefs? Most people tend to gloss over his negatives, and they're BIG ones.


----------



## Room2201974

Luchesi said:


> Most people tend to gloss over his negatives, and they're BIG ones.


My good friend who has a piled-high-and-deeper in Astrophysics had a sage remark about Sir Issac: He called him the Bobby Fischer of physics. You have to put up with a lot of bs before you get to a brilliancy!


----------



## aleazk

It's true that Newton did a lot... and, really, a _lot_... of pseudo-scientific studies (by today's standards). Most of that was in alchemy. Of course, modern chemistry barely existed so one could argue that the poor man just wanted to understand the elements and resorted to the only knowledge available at that time and that, also, the scientific method wasn't still fully clarified. But that's only defensible to some extent, considering that Newton himself wrote a series of guidelines in his Principia for doing research in 'rational mechanics'. By that time, the standard of rationality in mechanics was quite high and any 'divine principle' wasn't allowed. In fact, Leibniz once mocked Newton because the latter made a vague suggestion that perhaps 'god' made regular 'interventions' to keep the planets from gradually dispersing due to perturbations. Thus, it seems he was much more willing to embrace the irrational than his contemporaries.


----------



## Luchesi

Room2201974 said:


> My good friend who has a piled-high-and-deeper in Astrophysics had a sage remark about Sir Issac: He called him the Bobby Fischer of physics. You have to put up with a lot of bs before you get to a brilliancy!


Yes, negative experiences in childhood. Fischer and Newton and LvB and JsB. We can look up what's been written about them. Abuse by or loss of a parent and poverty. Newton's father died before he was born and his mother married a man he didn't like, she sent him off to his grandmother. When he became old enough his mother wanted him to make money for her in farming, which he disliked because he wanted to pursue academics ...but poverty.

These people were blessed with a natural intelligence and there's only 24 hours in the day. They became fixated on what was available to them, at the cost of other experiences which we would consider normal.


----------



## philoctetes

Tikoo Tuba said:


> Well , obviously the angstrom has been weaponized . Our Dr. Eileen Dover is suspect of believing in and employing this necessary evil . People suffering angst is considered by leadership to be the cost of an orderly advancement in knowledge .


If John Updike had written one more novel - "Rabbit is Weaponized"...


----------



## philoctetes

Room2201974 said:


> My good friend who has a piled-high-and-deeper in Astrophysics had a sage remark about Sir Issac: He called him the Bobby Fischer of physics. You have to put up with a lot of bs before you get to a brilliancy!


Also true for about 95% of all music...


----------



## aleazk

aleazk said:


> At some point in this year it's expected that the Event Horizon Telescope will deliver its results, which may include the first image ever of the 'shadow' of a black hole. It is, of course, an image made from EM emissions outside the visible spectrum but which will be translated to visualizable forms.


Update on this:


----------



## Zofia

KenOC said:


> I am collapsing in a heap of self-pity today. Just finished an online course on the nature of the universe that promised to answer all my deepest questions. It wasn't to be! Turns out that:
> 
> - 70% of the "stuff" the universe is made of is "dark energy." We can't observe this and have no idea what it is. It doesn't fit our standard model of particle physics. We only know it's there because the universe is expanding faster than it should.
> 
> - Another 25% is "dark matter," which again we can't observe and is a total mystery to us. We only know it's there through its gravitation effects, for instance spiral galaxies rotating faster than they should.
> 
> - Finally, that last 5%. That's us and all the matter and energy we can observe or account for in the universe. Basically, as the instructor said, "pond scum."
> 
> A pretty poor showing from our physicists and cosmologists, who perhaps need some re-education through labor to encourage them to work harder or, at least, be more clever. Meanwhile, if there's anybody here who can make me feel better, please do so!


I do believe very much in Science so please do not hold my faith against me. Saying so there is little proof for Dark Matter and Dark Energy (two different things I believe). Expect they are needed in order to explain away why things do not work out as was predictable no?

If I play the wrong note I cannot say I played the right note. When teacher says it does not match the sheet music I simply say dark energy did it it would be like saying...









I think perhaps we do not understand it or mistake was made.


----------



## Roger Knox

As a child, if I heard a strange sound my Mom said, "That was Inky." There is no photographic proof, but I believe in Inky!


----------



## Zofia

Roger Knox said:


> As a child, if I heard a strange sound my Mom said, "That was Inky." There is no photographic proof, but I believe in Inky!


Sounds like a Demon...


----------



## Roger Knox

Zofia said:


> Sounds like a Demon...


A minor demon, only at home, like a house cat ... never went outside. Inky would take away one sock, that kind of thing.


----------



## Jacck

if you want some intergalactic anxiety, then watch how huge the Andromeda galaxy is





and how many galaxies there are in the universe


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## Kjetil Heggelund

Oh no! What's this? I just live on the hillside with a view to the fjord and stars at night.


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## Jacck

another interesting discovery from LHC - a mysterious asymmetry between matter and antimatter
https://www.symmetrymagazine.org/article/lhcb-discovers-matter-antimatter-asymmetry-in-charm-quarks
https://home.cern/science/physics/matter-antimatter-asymmetry-problem


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## Luchesi

Our DNA is one of the biggest and rarest molecules in the whole universe.

We are the "music heard so deeply
That it is not heard at all,

but you are the music
While the music lasts."

TS Eliot - from Dry Salvages


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## Luchesi

For the first time the VLBA has directly measured a star forming region all the way across our galaxy!


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## aleazk

aleazk said:


> At some point in this year it's expected that the Event Horizon Telescope will deliver its results, which may include the first image ever of the 'shadow' of a black hole. It is, of course, an image made from EM emissions outside the visible spectrum but which will be translated to visualizable forms.


Tomorrow is the day! Some background here.


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## KenOC

aleazk said:


> Tomorrow is the day! Some background here.


Very informative article. Thanks!


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## aleazk

Well, here it is!










Such a beauty!

A shame that Hawking is not alive to see this, since he was the person that did most to advance our knowledge of black holes. At least Penrose is alive, another person that did lots of work in this field.


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## senza sordino

aleazk said:


> Well, here it is!
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Such a beauty!
> 
> A shame that Hawking is not alive to see this, since he was the person that did most to advance our knowledge of black holes. At least Penrose is alive, another person that did lots of work in this field.


What I don't understand about this photo is that it's a like a flat disk, and we are looking at it from the top. It's as if we are looking at the top of a table with a hole in it and stuff falling into that hole. Isn't space three dimensional? Wouldn't stuff fall into the black hole from all directions essentially making the black hole invisible to us from way beyond the event horizon? All we would see is illuminated matter falling into the black hole with the black hole inside cut off from our view.

I think I have an answer to my own question and please correct me if wrong. As matter spins into the black hole that matter forms a disk like a spinning solar system that naturally flattens as if revolves about the event horizon. And so in this picture we are fortunate to see the top view of this disk spinning about the event horizon.


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## Guest

aleazk said:


> Well, here it is!
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Such a beauty!
> 
> A shame that Hawking is not alive to see this, since he was the person that did most to advance our knowledge of black holes. At least Penrose is alive, another person that did lots of work in this field.


Ah yes, what a beauty!!!!
Have you seen the film "Interstellar", Aleazk? Should they re-edit the shots of the black hole Gargantua in light of this recent photo?


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## KenOC

aleazk said:


> Well, here it is!
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Such a beauty!
> 
> A shame that Hawking is not alive to see this, since he was the person that did most to advance our knowledge of black holes. At least Penrose is alive, another person that did lots of work in this field.


News reports say that the ring of glowing matter surrounding the black hole, something never before observed, is of the size predicted by Einstein's general theory of relativity a century ago. Good going Al!


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## KenOC

senza sordino said:


> I think I have an answer to my own question and please correct me if wrong. As matter spins into the black hole that matter forms a disk like a spinning solar system that naturally flattens as if revolves about the event horizon. And so in this picture we are fortunate to see the top view of this disk spinning about the event horizon.


One article I read says that the matter circling the black hole does indeed flatten into a disk, without explaining the exact mechanism. I suspect your explanation is right or close to it.

Anyway, to paraphrase Jack Handey: "If you drop your car keys into a black hole that big, don't bother going in after them because, baby, they're gone!"


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## Luchesi

I remember reading that there's a very old jet, quite faint now, coming out of our galactic center and detectable far behind the stars of Cassiopeia. We're heading that way, but as the galaxy rotates the jet and its potential resurrection will be staying ahead of us. This jet reached that far out, almost to the Perseus Arm, so that's probably when a quasar was last somewhat active in this galaxy. It's good if it's so far ahead of us..


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## aleazk

senza sordino said:


> What I don't understand about this photo is that it's a like a flat disk, and we are looking at it from the top. It's as if we are looking at the top of a table with a hole in it and stuff falling into that hole. Isn't space three dimensional? Wouldn't stuff fall into the black hole from all directions essentially making the black hole invisible to us from way beyond the event horizon? All we would see is illuminated matter falling into the black hole with the black hole inside cut off from our view.
> 
> I think I have an answer to my own question and please correct me if wrong. As matter spins into the black hole that matter forms a disk like a spinning solar system that naturally flattens as if revolves about the event horizon. And so in this picture we are fortunate to see the top view of this disk spinning about the event horizon.


To interpret images of black holes can be rather tricky because they heavily distort the trajectory of light rays. For example, the gravity near the event horizon can be so strong that a light ray can describe a circular orbit around the black hole (and circle it many times), like a planet around a star, before leaving it and be captured by (radio-)telescopes.

The galaxy M87 in consideration has a jet that points roughly in the direction of our galaxy. The jet comes from the vicinty of the central black hole and is perpendicular to the accretion disk. Thus, what we see in the image is indeed the black hole roughly from above, the top view. But, because of the extreme gravitational light bending effect of black holes, the actual radio waves that we see come from many places around the black hole, even zones below it, that we couldn't normally see if it were a normal object because the object obviously would block that light.


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## aleazk

TalkingHead said:


> Ah yes, what a beauty!!!!
> Have you seen the film "Interstellar", Aleazk? Should they re-edit the shots of the black hole Gargantua in light of this recent photo?


Actually, the black hole there is correct. It is based on calculations by famous relativist Kip Thorne, who won the Nobel for the detection of gravitational waves. But the perspective is different there, we see the black hole from the horizontal plane, that is, on the same plane of the accretion disk. In that case, the light bending is notorious and one can see the part of the accretion disk that is behind the black as light above the black hole.

In this picture, the black hole in the real image was seen in a perspective like the first figure, while the one from the movie corresponds to the second.


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## Jacck

cosmology and black holes are fascinating, but not nearly as fascinating as the microscopic world for me. GTR is still more or less a classical theory and you can picture it in your mind (as warped space time). On the other hand the quantum mechanics is completely mind-bending (though much more difficult to explain to lay people)


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## philoctetes

Well, much of Hawking's early work on black holes had to do with quantum pair production at the event horizon and its thermodynamic effects. Ho hum.

What happens to matter when it enters a black hole? Maybe GTR can't tell you, but that doesn't make the question uninteresting.


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## Jacck

philoctetes said:


> Well, much of Hawking's early work on black holes had to do with quantum pair production at the event horizon and its thermodynamic effects. Ho hum.
> 
> What happens to matter when it enters a black hole? Maybe GTR can't tell you, but that doesn't make the question uninteresting.


it is interesting, but I think that Hawking is overrated as a physicist (by the lay public). He was more a popularizator of physics. There are easily 20 other physicists in the 20th century alone that are ahead of him in terms of contributions. 
The evaporation of black holes due to production of quantum pairs is interesting, but there are more interesting results concerning the black holes, such as their entropy


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## aleazk

philoctetes said:


> Well, much of Hawking's early work on black holes had to do with quantum pair production at the event horizon and its thermodynamic effects. Ho hum.
> 
> What happens to matter when it enters a black hole? Maybe GTR can't tell you, but that doesn't make the question uninteresting.


Something I wrote elsewhere regarding Hawking.

His work is very important and influential in the following fields:

(classical) General Relativity;

QFT in curved spacetime;

His work provided serious hints to the kind of phenomena we should expect from a theory of Quantum Gravity.

In a more detailed way:

Classical work (classical General Relativity), 1960s:

Together with Penrose, he proved what is considered the single most important mathematical result in General Relativity: the Singularity Theorems. These theorems show that the theory predicts spacetime singularities in physically realistic situations (in particular, at the beginning of the universe and as the final result of general stellar collapse, i.e., the collapse is realistic, not necessarily spherically symmetric). The well known singularities in the Robertson-Walker and Schwarzschild solutions are physically meaningless because these solutions have exact symmetries and so it was not known if these singularities were just a mere consequence of this idealization. So, whenever you hear on TV that "physics predicts that there are singularities in the center of black holes" and things like that, that's Hawking's theorem in action. Also, the existence of these theorems is considered as one of the most imperative reasons about why we need a theory of quantum gravity.

The (very elegant, concise, and far reaching) mathematical techniques he used and developed to prove these theorems are an interesting (and very innovative for that time) array of general topology and lorentzian differential geometry. They are called "global methods" and comprise a big chunk of the material covered in advanced GR courses. The techniques are also very useful for many other results and they completely revolutionized the mathematics of GR, since they allowed to tackle problems that were considered intractable before (the singularities issue being, of course, one of them; Kip Thorne, a well known general relativist/astrophysicist and friend of Hawking, gives, in one of his pop books, a nice historical testimony, and in first person, of the impact that these methods had at that time, since, simultaneously, a soviet team was trying to settle down the problem with more conventional methods).

For example, with them one can prove another of Hawking's famous results in black hole physics, the "area theorem", which states that the area of the event horizon of a black hole/s never decreases in time (clearly resembling the 2nd law of thermodynamics if we make the identification area-entropy). In fact, this theorem is one of the classical "laws of black hole mechanics", a set of laws (derived all of them from General Relativity) that govern some fundamental aspects of the dynamics of black hole processes. The remarkable fact is that these laws strongly resemble the laws of thermodynamics if one makes the identification: mass-energy; area-entropy; surface gravity-temperature. But, with the exception of the first one (mass-energy), the others are pure speculation at this stage.

So, basically, Hawking is really the main figure in most of the big results of advanced General Relativity, he really is the boss there. All of these results can be found in his monumental technical monograph

_The Large Scale Structure of Space-Time (Cambridge Monographs on Mathematical Physics): Stephen W. Hawking, G. F. R. Ellis._

The years that elapsed between the 1960s and 70s are known as the "Golden Age of General Relativity", because of the intense wave of interest and research that occurred at that time, and, of course, the very important results that were obtained. After Einstein, Hawking is probably one of the main contributors to General Relativity.

QFT in curved spacetime, 1970s:

If all of the above is not enough, his next key result is very important: the Hawking radiation of black holes and related problems/developments. He proved, using a theory that was not completely settled down at that time (QFT in curved spacetime backgrounds), that black holes emit thermal radiation. This result put QFT in curved spacetime backgrounds in the map and launched a wave of interest and research in this field.

What's more, according to this result, then black holes indeed have a temperature and the calculation shows that this temperature is indeed proportional to the surface gravity. This is incredibly intriguing, since it suggests that the mentioned analogies with the laws of thermodynamics are an actual identification (since it allows to define a temperature for the black hole, and this strengthens the interpretation of the entropy as being indeed proportional to the event horizon area) and thus giving clues of a very deep connection between gravity-geometry, statistical mechanics and quantum mechanics.

Hints to Quantum Gravity:

The previous result has completely convinced physicists that black holes have entropy and that this entropy is proportional to the event horizon area. But the argument is indirect. A satisfying calculation of this entropy would requiere knowledge of the microscopic degrees of freedom of the black hole at the quantum level, and this is only possible in a theory of quantum gravity. But it's, still, one of the few concrete hints we have to the kind of phenomena we should expect from such a theory. Several attempts have been made in the candidate quantum gravity theories (e.g., String Theory, LQG. and Hawking also tried it with the Euclidean path integral approach which he used to favor) to obtain this result from fundamental principles, i.e., it is considered by the researchers themselves as a crucial test for the plausibility and significance of their theories. Of course, the merits of these theories (and reported claims) are part of the current debate in today's theoretical physics, so it's still open.

Another consequence of the emission of radiation by black holes is that this fact ultimately provokes their (complete?) evaporation because of backreaction effects and thus we reach the well known "information paradox", one of the most puzzling open problems in today's theoretical physics. Again, it's believed that this problem will only be solved in the context of a theory of quantum gravity. Several claims have been made, it's still highly debated.


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## philoctetes

Two of my favorite Hawking quotes

"A naked singularity has no hair"

"Whenever I hear of Schrodinger's Cat, I reach for my gun"

aleazk: "A satisfying calculation of this entropy would requiere knowledge of the microscopic degrees of freedom of the black hole at the quantum level, and this is only possible in a theory of quantum gravity."

Well stated, makes sense. And what if that isn't enough? How can we test the calculations?

Sorry Jack I'm just not into bashing scientists in hindsight all that much. Not at Hawking's level.

However, for the worst take on this black hole image, see so-called astrophysicist Neil Degrass Tyson on Twitter


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## aleazk

I forgot to mention that he also proved a key step (spherical topology for the horizon and axisymmetry) and the most difficult one in order to finally obtain, after the work of many others, a complete proof of the black hole no hair theorem, which states that the only stationary general black hole electrovacuum solutions to Einstein's equations are the charged Kerr black holes. That theorem is crucial for the current understanding of black holes and was literally observed in the LIGO detection of gravitational waves for the merging of two black hole as the ringdown of the signal at the end of the event.


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## KenOC

Probably not the best place for it, but I was very impressed today by SpaceX's Falcon Heavy and its launch of ArabSat. This was a totally privately-funded launch. The main booster and the two strap-ons generated five million pounds of thrust, two-thirds the thrust of the vaunted Saturn V. Both strap-ons retuned to Florida and landed tail-down in unison on twin landing pads. The main booster core landed nicely on an offshore drone ship charmingly named _Of Course I Still Love You_.*

The second stage continued on to release ArabSat into the desired orbit.

You can watch the whole thing at spacex.com.

*The SpaceX drone ship in the Pacific is named _Just Read the Instructions_.


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## Jacck

philoctetes said:


> Sorry Jack I'm just not into bashing scientists in hindsight all that much. Not at Hawking's level.


I am not bashing him. I quite like him. He brought me to physics, when I read his book The Short History of Time as a high school student. But I believe there were physicists in the 20th century, who contributed more than him and are not nearly as famous. He is probably more famous than Feynman among the general public, but not in the same league with Feynman in terms of genius and contribution.


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## aleazk

Jacck said:


> I am not bashing him. I quite like him. He brought me to physics, when I read his book The Short History of Time as a high school student. But I believe there were physicists in the 20th century, who contributed more than him and are not nearly as famous. He is probably more famous than Feynman among the general public, but not in the same league with Feynman in terms of genius and contribution.


That's your view and I respect it. Feynman was certainly a key figure for the development of the modern standard model with his work in QED. I would say he was quite popular due to his numerous popular books, his personality and his involvement in the investigation of the Challenger accident. But he died 30 years ago. So, unless you are Einstein, popularity naturally fades a bit. In Hawking's case, he lived in a different epoch, the internet revolution, etc., and his disability certainly added some spice to his public persona as some sort of enigmatic "oracle" that gave clues to the universe. He also evidently liked to be famous.

Now, in my opinion, he's right there at Feynman's level if not more. Consider the following. In 1965, Penrose presented a general theorem about the formation of singularities in the collapse of matter that is not necessarily symmetric (i.e., the theorem applied to the real universe, where the collapse has irregularities instead of perfect spherical symmetry.) That, togheter with Chandrasekhar's limit on the hydrostatic equilibrium of degenerate matter, gave the first clues that black holes could actually form in the real universe, rather than being mathematical curiosities of some very special solutions to Einstein's equations, since it indicated that a catastrophic and unstoppable collapse was a real physical possibility. Hawking took that theorem and realized that some of the techniques could be applied to the origin of the universe. He proved that in our actual universe, there's a singularity in the past. Now, one must interpret that in its historical context. At that time, it was accepted that the universe expanded, but nobody believed in the singularity of the Robertson-Walker solution because it assumes perfect symmetries. Authorities like Hoyle believed in an infinite universe, with no beginning and no end and that it was always expanding. Hawking's result was a blow to that view. Hawking deserves the full credit for proving that GR predicts that the real universe was in a very hot and dense state in the distant past, the Big Bang. After that, Penzias and Wilson discovered the CMB which was a definitive experimental proof of that. They won the Nobel prize and Hawking didn't. If you ask me, the Nobel should have been shared between the three men. I mean, we are talking about proving that the universe had a beginning, if that's not an epoch marking discovery then I don't know what such a discovery is... and we are living in that epoch now, where the Big Bang origin of the universe is common knowledge and even part of the popular culture, featured in movies, series, cartoons, etc. It's even more widespread knowledge in the general public than some other effects from GR, like gravitational time dilation.

I think part of the reason why he didn't get the Nobel was because GR was becoming a rather specialized field and the techniques were rather new. For example, if you compare Feynman's lectures on gravity, written around that decade, they are very rudimentary in comparison to the revolution that was happening in the field, his knowledge of GR doesn't go beyond Einstein's original papers from 1915. Even today, not many physicists know exactly what those theorems say, particularly those in the high energy community.

I also think Hawking deserved a second Nobel because the LIGO discovery confirmed (or can be used to confirm after more observations) several of his theorems about the general qualities of the dynamics of black hole processes (in particular, the no bifurcation theorem, the area theorem, and the no hair theorem; the area theorem is the key result that gives credibility to the interpretation of the horizon area as an entropy.)


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## Luchesi

I would have liked to be a fly on the wall when they were deciding what colors to use for the picture.

greens, blues?, no, too spooky

black and white, no, not dramatic enough

If we use yellows and reds we'll be giving the wrong impression.

Oh well, we're limited..


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## tdc




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## philoctetes

Jacck said:


> I am not bashing him. I quite like him. He brought me to physics, when I read his book The Short History of Time as a high school student. But I believe there were physicists in the 20th century, who contributed more than him and are not nearly as famous. He is probably more famous than Feynman among the general public, but not in the same league with Feynman in terms of genius and contribution.


Both general public and scientific community knew about Feynman long before Hawking emerged. So you're seeing things from a certain generational perspective. We all are, just like we do with music. But Hawking never really over shadowed Feynman over the long run.

I too was drawn to physics by Hawking mainly because I got a late start in my education. The 3-volume Feynman course was already legendary but was rarely used as a standard textbook anymore.Unfortunate! Meanwhile black holes were the rage and so was Hawking et al. So it wasn't until later that I appreciated Feynman's unique way of understanding physics.

^^^^
Pretty much how I see it. That image could be of just about anything and contains little useful information. Please correct me if I'm wrong but I am simply underwhelmed. Indeed, it could be a testimonial to the negative side of the popularization of science that Hawking contributed to...


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## KenOC

philoctetes said:


> ...That image could be of just about anything and contains little useful information. Please correct me if I'm wrong but I am simply underwhelmed. Indeed, it could be a testimonial to the negative side of the popularization of science that Hawking contributed to...


The photo is not without scientific merit. At the very least, it supports a previously untested prediction of general relativity:
-----------------------------------------------------------------
"You can see the ring Einstein's relativity predicts," said Vincent Fish, a research scientist at MIT's Haystack Observatory in Westford, who was one of the 200 scientists who worked on the project. "You know exactly how big that ring should be. This was the first opportunity to test that hypothesis."
-----------------------------------------------------------------
There's actually a bit more than that, described in the article _Astronomers Reveal 3 Things the Historic Black Hole Photo Confirms About Space_ .​​


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## Luchesi

I think the object is one ten thousandth of an arc second. The star Alpha Centauri A is about one hundredth of an arc second.


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## aleazk

Lots of things can be inferred from the data that was used to build the image. You can check the papers for details, they are open access.


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## Luchesi

Luchesi said:


> I think the object is one ten thousandth of an arc second. The star Alpha Centauri A is about one hundredth of an arc second.


Another source said that it is only 50 microarcseconds.


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## geralmar

"Universe" (1960), 27 min., National Film Board of Canada. Obviously dated; but still impressive visually and narratively.


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## Jacck

there are the large galactic scales, but the small scales are fascinating too


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## geralmar

"Powers of Ten" (1977), nine minutes. An educational film created for IBM also dealing with size scales.


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## Luchesi

I recommend this for folks who are interested in the devastating real-world ramifications of quantum mechanics (unknown to science until recently).


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## Luchesi

geralmar said:


> "Powers of Ten" (1977), nine minutes. An educational film created for IBM also dealing with size scales.


Thanks. Dr. Morrison had an interesting voice for narrating. I remember seeing this on TV a few years before I bought a Zenith (Z80) IBM PC. Soon after that I wanted to program some graphics like this with the data I had collected for these distances. I never finished it because I was overloaded with solar observatory programming priorities, but it was a very educational project.

The reason I wanted to program it was so that I could make the sizes of the squares and the speed of the program selectable by the user.


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## Jacck

Mystery of the Universe's Expansion Rate Widens With New Hubble Data


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