[HN Gopher] Black holes might be defects in spacetime
___________________________________________________________________
Black holes might be defects in spacetime
Author : wglb
Score : 174 points
Date : 2023-05-22 13:08 UTC (9 hours ago)
(HTM) web link (phys.org)
(TXT) w3m dump (phys.org)
| friend_and_foe wrote:
| This is pretty badly written. Something looks like a black hole
| but doesn't have an event horizon? Isn't a black hole nothing but
| an event horizon to an outward observer? How does it look like a
| black hole if it doesn't bend light with gravity?
|
| You could hold it in your hand "if you survive the encounter"? So
| you can't hold it in your hand? *What would happen to you if you
| touched it?"
| 100721 wrote:
| I find a lot of posts from phys.org to be highly editorialized,
| with ambiguous and sensational headlines.
|
| It is a low quality source, imo
| eigenform wrote:
| I think implication is that there's a spectrum of related
| phenomena (and that "black holes" with an event horizon are an
| extreme case)
| elashri wrote:
| The Topological solitons would appear exactly like predicted
| black holes from a distance, with shadows, light rings, and
| gravitational wave signatures. It is not about the event
| horizon. It just telling you we would see them as black holes
| if we look to them from some distance. Remember that cannot
| observe the event horizon directly, the famous gravitational
| waves discovery in 2015 is an example of indirect black holes
| observation
|
| The other important difference is that they could form without
| mass which is not the case with black holes. So I am not sure
| that I would agree with you.
| zelphirkalt wrote:
| So if they form without mass, why would they bend light like
| black holes? If they don't bend light, then it seems to me
| that they would not really appear as black holes.
| davidgrenier wrote:
| "Since we know that infinite densities cannot actually happen in
| the universe"
|
| How do we "know" that?
| vitehozonage wrote:
| Yeah, I stopped reading when i got to that sentence
| echelon wrote:
| Infinity and singularity are mathematical constructs. They
| look great on paper, but we don't know if they have actual
| physical analogs. It could be that relativity and the physics
| around black holes, the big bang, etc. are wrong.
| bell-cot wrote:
| > Infinity and singularity are mathematical...
|
| THIS. That I've seen, the [astro]physicists are confident
| that there are no actual physical infinities nor
| singularities. With the public, they'll use those terms for
| situations "approaching" infinities and singularities. But
| in private, they're busy using all sorts of clever
| mathematics and calculations and arguments to avoid having
| any infinity or singularity occur, even on paper.
|
| A very basic example: https://en.wikipedia.org/wiki/Dirac_d
| elta_function#Motivatio...
| dandare wrote:
| Are you saying that we have evidence that universe is not
| infinite?
| swamp40 wrote:
| Because we exist. If infinite density existed, our atoms would
| be in there.
| danra wrote:
| Not true. For example we could be surrounded by a sphere of
| uniform infinite density, in which case our atoms wouldn't be
| pulled in either direction.
| cyberax wrote:
| Why? At a distance, gravity doesn't really care about
| density, only mass.
|
| An infinitely dense object would shred anything it touches by
| its infinitely high tidal force, but there's only a limited
| amount of material it can touch within a given time and the
| Universe is not infinitely old.
| [deleted]
| [deleted]
| nico wrote:
| What if black holes are a very thin shell and all the matter is
| just on the surface, orbiting so fast around a center that it
| cannot escape
| onlyrealcuzzo wrote:
| Sure, but wouldn't something need to be in the center for it to
| do that?
| [deleted]
| nico wrote:
| https://www.livescience.com/62547-what-is-center-of-
| universe...
|
| The universe has no center. Maybe nothing has a center?
| cthalupa wrote:
| I don't think black holes are what is being described here,
| but no, it would not fundamentally be all that different from
| a binary system orbiting around a shared center of gravity
| between the two objects.
| dandare wrote:
| > Since we know that infinite densities cannot actually happen in
| the universe...
|
| Lol, and how exactly do we know that?
| hk1337 wrote:
| Glitch in the Matrix.
| dukoid wrote:
| Something I was always wondering about black holes:
|
| Does there really have to be a singularity? If I understand
| relativity correctly, time slows down as mass increases. Couldn't
| this slowdown affect the contraction so that it never can
| actually reach an "actual" singularity point?
| fnovd wrote:
| You're right that from an observer outside of the event
| horizon, a black hole hasn't happened yet (and never will).
|
| There's a fun thought experiment to be had here. We're all
| familiar with the concept of "going back in time". Even though
| the math doesn't check out and our imaginations of what that
| looks like are totally impossible, it's something we can (and
| often like to) imagine.
|
| Now, what happens when you move backwards not in time, but in
| space? And I don't mean changing your direction 180 degrees,
| but moving backwards within the confines of space. So, if your
| present coordinates are (X, Y, Z), you move "backwards in
| space" 5 meters such that no matter what your direction of
| motion, if you move "forwards in space" by 5 meters you end up
| right where you started, at (X, Y, Z). You're basically
| creating an inverted bubble around (X, Y, Z) and making it so
| that all possible paths lead "outward" toward (X, Y, Z). Any
| point that is A meters away from (X, Y, Z) is actually A+5
| meters away from you.
|
| In a 2-D world this can be modeled with a third dimension. We
| all live on a flat plain but someone on a 5-meter hill is
| actually farther away than their 2-dimensional coordinates
| would imply. You're able to move away from a point in 2-D space
| without changing your 2-D coordinates (because you're actually
| moving in another dimension).
|
| For 3D space, this extra dimension is time itself. The only way
| to move "backwards" in a comprehensible sense within 3
| dimensions is by moving backwards within time. So, I'm not
| actually moving 5 meters "backwards" within space but moving
| backwards in time such that I will appear at (X, Y, Z) in 3-D
| space at precisely the same time it would take me to move
| forward 5 meters. I'm blipped out of space until such time has
| passed to allow me to reach (X, Y, Z) again, so I've
| successfully "moved backwards in space" by 5 meters. So, if I
| move "backwards in space", then I'm really putting (X, Y, Z) in
| front of me time-wise.
|
| So, what's the center of a black hole? We can imagine it has
| coordinates (X, Y, Z). And let's pretend it's actually moving
| _backwards_ into space, which we now conceptualize as putting
| its "present" coordinates forward in time. But, it's actually
| moving backwards in space (i.e. moving universally farther from
| every other point in space) at a speed faster than we can
| travel. The center of the black hole is always in the future
| and even as we move closer to the center, it's still infinitely
| far away. As we cross the event horizon, we ride the current
| and start moving faster than the universal speed limit, cutting
| ourselves off from ever interacting with the outside universe
| again. However, we're still never going to be able to reach the
| center, and indeed the center of the black hole has still not
| happened from our point of reference (and still never will).
| gizmo686 wrote:
| Time slows down from the perspective of an outside observer.
|
| From the perspective of a particle falling into a black hole,
| the singularity will be reached in finite time.
| dukoid wrote:
| That's true but from our perspective this state won't be
| reached anywhere in the universe -- so there can't be any
| singularity from our perspective?
| friend_and_foe wrote:
| And you don't actually see a singularity, you see only an
| event horizon, and more accurately, the matter trapped
| orbiting the event horizon.
| treeman79 wrote:
| https://youtu.be/351JCOvKcYw
|
| There are a number of theories on black holes not being
| singularities.
|
| PBS space time goes into a few of them
| simiones wrote:
| Well, I don't think any physicist believes that an actual
| singularity exists in the center of a black hole in physical
| reality. The mathematics of GR actually do predict a
| singularity, but this is typically viewed as a limitation of
| the theory, not an actual physical object.
|
| Instead, most physicists believe that a theory of quantum
| gravity (a theory which accounts for gravitational interactions
| between quantum particles in general) would slightly modify the
| equations of GR to arrive at a finite solution for the interior
| of the black hole. Of course, such a theory eludes us so far.
| nathan_compton wrote:
| This is actually a pretty tricky question. The standard black
| hole solutions are highly idealized in order to make them
| tractable. In particular, they have a lot more symmetry in time
| than you would expect a black hole to have. Actually forming a
| black hole from realistically distributed matter undergoing
| gravitational collapse is a more complicated problem to talk
| about in GR. So you pose a genuinely interesting question.
|
| I think the singularity theorems address it however:
| https://en.wikipedia.org/wiki/Penrose%E2%80%93Hawking_singul...
|
| The basic idea is that singularities are a very general feature
| of general relativity, not confined to specific solutions to
| the field equations but sort of inevitable for a large number
| of initial conditions. So while the standard black hole
| solutions are highly idealized, we have good theoretical reason
| to believe that singularities exist in non-trivial solutions to
| the Einstein Field Equations.
| giantg2 wrote:
| For some reason it really irks me that they are using the word
| defect. It's like they forgot that the rules/model we set
| _follow_ what happens in reality. If there is a defect, it 's not
| in spacetime, it's in our understanding.
| EamonnMR wrote:
| If your spacetime contains black holes you may be entitled to
| compensation from the manufacturer. Please retain this notice
| and your receipt. Known in the state of California to cause
| spaghettification. Offer not valid in worldlines crossing the
| event horizon.
| r2_pilot wrote:
| It's a commonly used word to describe irregularities in
| lattices, such as grain boundaries in metals or imperfections
| in crystals.
| devmor wrote:
| I was wondering about this too, thank you for the insight!
| giantg2 wrote:
| That makes sense
| zaebal wrote:
| Think of it as an abnormality in spacetime.
| _Microft wrote:
| It's a technical term in crystallography/solid state physics as
| well.
|
| https://en.wikipedia.org/wiki/Crystallographic_defect
| dathinab wrote:
| Wasn't string theory very thoroughly "dis-proven" (as in you have
| to go through absurd hoops to make it still work which indicates
| it most likely is not the truth at all, even though you can not
| completely rule it out because some concepts are very resistant
| to be proven to not exist).
| phyzome wrote:
| Hmm? I've not heard of any such thing. The main problem I've
| heard is that it's hard to come up with a test that will
| confirm or reject the hypothesis, let alone distinguish between
| the different variations.
| BulgarianIdiot wrote:
| Defect means imperfection, shortcoming, flaw. This implies
| reality has a design, a plan, that it was executed according to,
| which execution can have defects in it, compared to the plan.
| Design & plan means designer & planner.
|
| So yeah, we should be careful what words we use.
| BulgarianIdiot wrote:
| Funny that I get downvoted. I'm curious what is pissing
| everyone off that much. Physics and spacetime have no "defect"
| unless you define relative to what. Our theories of physics are
| just models we work with for our benefit, reality is entirely
| unconstrained by our models and concerns. And our opinions of a
| "defect" with respect to our models.
|
| We've long known the singularity is only "singularity" with
| respect to General Relativity. It's the place where the model
| breaks down. The model, not reality.
| _Microft wrote:
| "Defect" has a different meaning here than it has in common
| language, so people disagree with the comment.
|
| If you are curious, then try articles like on "Topological
| defect", "Crystallographic defect", "Cosmic string", ... in
| Wikipedia to get an idea what defect is supposed to mean
| here.
|
| _> Our theories of physics are just models we work with for
| our benefit, reality is entirely unconstrained by our models
| and concerns._
|
| True but every student of physics is taught right from the
| beginning that every model only has a range of parameters in
| which it is valid.
|
| Example: you can easily calculate speeds non-relativistically
| just fine if you are aware that you will only get good
| approximations of reality if the speeds involved are a low (~
| single-digit) percentage of the speed of light. Outside of
| that, the results will be non-sense.
|
| We create the models after reality and use these models to
| predict things. After experiments, we know if the the model
| is still valid in a new range of parameters. Since we know
| that the laws of nature do not change (we can and do test
| that!), we can now assume that we have a model that fits well
| with reality in a wider range than before.
|
| What you see here in progress is exactly the attempt to find
| an alternative explanation for that what we expect blackholes
| to look like because we know that our models might not be
| right there.
| SAI_Peregrinus wrote:
| It also means an irregularity in an otherwise regular
| structure. It's jargon, which probably shouldn't be used in a
| popular science article, but it does not imply any sort of
| plan.
| furyofantares wrote:
| > which probably shouldn't be used in a popular science
| article
|
| Depends on if you're maximizing for 'engagement' I guess :/
| BulgarianIdiot wrote:
| Define "regular structure". So the center of the sun is as
| regular as my living room, but a black hole is a bit too much
| for someone. For whom though? And how did they decide this?
| rcme wrote:
| > Since we know that infinite densities cannot actually happen in
| the universe, we take this as a sign that Einstein's theory is
| incomplete. But after nearly a century of searching for
| extensions, we have not yet confirmed a better theory of gravity.
|
| Is it really true that infinite densities are impossible?
| Consider a function that measures the volume of an object with
| respect to time, say V(t). If the force of gravity is strong
| enough to overcome every other force, wouldn't V(t) approach 0 as
| t goes to infinity? Isn't that essentially having infinite
| density?
| grungegun wrote:
| the infinite density is actually after a finite amount of time,
| since black hole collapse has already happened, which is why it
| matters that they are predicted to have infinitely dense points
| at their centers. The key is that this isn't a limit, GR seems
| to expect that there are infinitely dense objects just floating
| around breaking space-time.
| vletal wrote:
| You just arrived to infinite density using a concept of
| infinite time. Now you need to justify existence of infinite
| time.
|
| The argument is that there is no infinite amount of _anything_.
| That is a fictional concept of 'too many parts to count'.
| rcme wrote:
| I guess my point is that there isn't really an infinite
| quantity in mathematics, either. What we think about as
| "infinity" usually involves some type of unbounded limit.
| soulofmischief wrote:
| It's what you would consider a mathematical limit. The limit is
| never actually reached. V(t) becomes vanishingly small, to the
| point that time effectively stands still, but mathematically it
| should still always remain a non-zero value, and thus density
| at the singularity isn't infinite. Anyway, at that point
| measuring things becomes exceedingly difficult and abstract.
| qubex wrote:
| You've just defined gravitational collapse.
|
| The real question is: is the volume infinitely compressible or
| is there something that would eventually oppose enough
| counterforce to halt the collapse?
| marricks wrote:
| The actual article linked has a better title and the abstract is
| probably sufficient for anyone interested in the subject:
| https://link.aps.org/doi/10.1103/PhysRevD.107.084042
|
| The given title is just flat out misleading.
| xwdv wrote:
| How can spacetime have a "defect"? Isn't this just a feature?
| ThrowawayR2 wrote:
| The same way computers can have a "bus" despite there being no
| large multi-passenger motor vehicle inside the laptop sitting
| on our desks. It's technical jargon that means something other
| than what the layperson thinks it means.
|
| It's probably easiest to visualize the sense in which "defect"
| is used in the article by the analogous concept of
| https://en.wikipedia.org/wiki/Crystallographic_defect , a
| disruption in what is otherwise an orderly, regular structure.
| magicalhippo wrote:
| In this case it's about topological defects[1], also known as
| topological solitons, which is explained rather well on SE
| here[2].
|
| Mathematicians and physicists try to give words to concepts,
| they don't always map well. As Wikipedia puts it:
|
| _Topological solitons arise with ease when creating the
| crystalline semiconductors used in modern electronics, and in
| that context their effects are almost always deleterious. For
| this reason such crystal transitions are called topological
| defects. However, this mostly solid-state terminology distracts
| from the rich and intriguing mathematical properties of such
| boundary regions. Thus for most non-solid-state contexts the
| more positive and mathematically rich phrase "topological
| soliton" is preferable._
|
| [1]: https://en.wikipedia.org/wiki/Topological_defect
|
| [2]: https://physics.stackexchange.com/questions/285731/what-
| is-a...
| Attrecomet wrote:
| Interesting. During my time in solid state physics and later
| quantum information, we just used "(topological) defects",
| not "topological solitons", though of course papers trying to
| sound cool could use that term. It takes about 2 uses to not
| conflate "defect" with anything deleterious, just the
| breaking of an otherwise functional symmetry.
| 0xblinq wrote:
| Do we happen to work at the same software company, by any
| chance?
| [deleted]
| techwiz137 wrote:
| It's not a bug. It's a feature.
| liotier wrote:
| Just update the specification with the observed behaviour and
| presto - black holes are no longer defective !
| lovemenot wrote:
| What I understood from the purported distinction when reading
| this article was that black holes result from physical activity
| _within_ spacetime. Wheras solitons are constructs resulting
| from the mathematical arrangement of the fabric of spacetime
| (involving those other dimensions posited by String Theory) .
| zgramana wrote:
| The real takeaway is that researchers may have found a potential
| test for string theory.
|
| Its presumed lack of falsifiability has been one of its drawbacks
| and has been the source of some of the controversy around it.
|
| Finding a potential test that could be conducted with telescopes
| instead of high energy particle accelerators would be a big
| moment in modern physics.
| jgeada wrote:
| I know it is the standard nomenclature, but I object to it
| being called string _theory_ , as it is at best a hypothesis,
| if not even just philosophical speculation with more math.
|
| It can make no predictions, it is not falsifiable, it meets
| none of the constraints that allow something to be science.
| behringer wrote:
| I think string theory is so pupular is exactly because it can
| make predictions that classical particle theory cannot.
| lo_zamoyski wrote:
| > just philosophical speculation with more math
|
| Speaking of nomenclature, this is not a good characterization
| of what philosophy is, if your intention is to reduce
| philosophy to what you seem to have in mind for
| "philosophical speculation". Metaphysical theory thoroughly
| supported by argument (hylomorphic dualism, theory of act and
| potency) is actually stronger than mere empirical science.
| Empirically testable predictions do not transcend reasoned
| argument as observation is interpreted though the body of
| propositions of prior theory and enters into scientific
| argument as argument.
| ravenstine wrote:
| Even if it were testable, and the test failed to validate
| string theory, I don't think that would convince string
| theorists one way or another. Strings are a de facto religion
| within physics.
| getcrunk wrote:
| Lol ... I think the technical term for this is "hater"
| MichaelDickens wrote:
| > Strings are a de facto religion within physics.
|
| I don't think string theorists are being unreasonable by not
| having changed their minds yet, given that no evidence has
| come out one way or the other.
|
| I don't think we can extrapolate from "string theorists
| didn't update when presented with no evidence" to "string
| theorists won't update when presented with evidence".
| noslenwerdna wrote:
| There has been evidence though. All tests so far have been
| negative. Low energy SUSY, extra dimensions
| asdfman123 wrote:
| "Science advances one funeral at a time"
|
| - Max Planck
| Accujack wrote:
| Sadly, this is true of many things these days.
| SV_BubbleTime wrote:
| I don't think it's a these days thing at all.
|
| I think it's a human thing and every generation has to
| deal with the fanatics or believers or whatever you want
| to call it of their time.
|
| We're in a time where a great number of people are
| extremely religious without having any idea they are. The
| people that live by what their screen tells them. If you
| didn't see some of this in the last three years that
| there is religion without it being labeled as such, I
| don't know I'll be able to reach you now.
| mitchdoogle wrote:
| We all live by what our screens tell us. We don't know
| anything outside of our own direct experience without
| depending on others. And for the most part we choose to
| trust others and it usually works out ok. That's not
| religion - that's an efficient way to intake information
| about the world, because an individual doesn't have the
| resources to learn about everything or go every place. If
| someone abuses our trust, then it's not a problem with
| the delivery method, it's a problem with them. So the
| fact that we get a lot of information via a screen is
| irrelevant.
|
| Though I'm not sure what that has to do with the notion
| that bad ideas only die when the people who hold them
| die.
| asdfman123 wrote:
| I agree with your first sentence for sure.
|
| It's human nature for older people to be more
| conservative. Transcends time and culture.
| SV_BubbleTime wrote:
| Are you sure you're not emphasizing my second point by
| thinking what I wrote was an attack of one ideology vs
| another?
| asdfman123 wrote:
| I'm not sure what you're trying to say and I wouldn't go
| that far. But it's pretty straightforward to say, yes,
| older people like change less than younger people, even
| if they aren't fanatics.
| colechristensen wrote:
| This line of talk is way overplayed. Like people who have an
| enthusiast amount of knowledge follow a few people who have
| professional knowledge who are just unreasonably fixated on
| what other physicists pursue.
|
| Doubt and questioning are a part of science but this
| "religion" meme about string theory et al is silly. If you're
| really upset that somebody is pursuing something is a blind
| alley, go ahead and do some physics that shows results,
| otherwise I really wish people would tone the unhelpful
| criticisms down.
| senttoschool wrote:
| I agree. If every physicist quit string theory because we
| haven't thought of a way to test it, like what @ravenstein
| might want, then that would be a sad day.
|
| I don't see the problem with physicists working on or even
| promoting string theory.
| ravenstine wrote:
| No one is saying that string theory shouldn't be
| investigated.
| nathan_compton wrote:
| I don't see how this is testable, given what is written here.
| pdonis wrote:
| _> The real takeaway is that researchers may have found a
| potential test for string theory._
|
| Not really. All this paper is really saying is that they have
| found solutions in classical theories of gravity with extra
| dimensions that, in four dimensions, can look like standard
| black holes. So even observing effects predicted by these
| models would not be evidence for string theory. It would at
| best be evidence for possible extra dimensions of spacetime at
| the classical level.
|
| Also, the paper only compares its models with the standard
| Schwarzschild black hole. But first, most black holes are
| spinning so the comparison should be with Kerr, not
| Schwarzschild; and second, as the paper notes early on, there
| are many _other_ proposed models of compact objects that can
| look similar to standard black holes. Any given set of
| observations would have to be tested against _all_ proposed
| models, not just this one.
| noobermin wrote:
| >If the researchers can discover an important observational
| difference between topological solitons and traditional black
| holes, this might pave the way to finding a way to test string
| theory itself.
|
| This is a big if. For now they've just shown that once again
| something in the string theory landscape could look like
| something in real life.
| eikenberry wrote:
| > Its presumed lack of falsifiability has been one of its
| drawbacks[..]
|
| Given that the definition of a theory is an hypothesis that can
| be tested for falsehood, it isn't a theory by definition. It is
| a hypothesis.. but presumably "string hypothesis" doesn't sound
| as nice.
| simiones wrote:
| I think there are all sorts of other potential tests of string
| theory. The problem is that for all the _actual_ tests that
| were ever proposed, it failed (supersymmetry, various proposals
| for sizes of the extra dimensions).
| progrus wrote:
| Yeah, it's more they might have found a way to test the
| latest fix, than anything.
| sigmoid10 wrote:
| To be fair, what failed is low-energy Supersymmetry and large
| extra dimensions, because these things were actually
| accessible by current gen experiments. But there's a huuuge
| amount of room left unexplored.
| dcsommer wrote:
| Not without fine-tuning. The issue is that high-energy
| supersymmetry no longer removes the "ugly constants" of the
| standard model -- it just shifts them somewhere else.
| Disclaimer: not a physicist, but I learned a lot reading
| "Lost in Math: How Beauty Leads Physics Astray".
| Pet_Ant wrote:
| ...by Sabine Hossenfelder.
|
| I treat her like Jordan Peterson. Obviously smart, but
| also obviously bitter and if/when they have a valid point
| I'm sure someone else has said it in a less grating
| manner.
| gloryjulio wrote:
| Jordan Peterson now is so far gone into the far right now
| it's not remotely comparable.
|
| Maybe been you mean Jordan Peterson the year 1 edition
| where he was still talking about personal responsibility.
| runsWphotons wrote:
| Jordan Peterson has had many iterations. The year -5
| edition had good psychology lectures and I disagree with
| the above poster who says he doesn't know what he is
| talking about. Within his academic realm, I think he did,
| although there would be points other academics would
| contest (this is what academics do). He has then gone
| through at least two transformations.
| yarg wrote:
| His position regarding a lot of religious topics seems
| tainted by his personal beliefs.
|
| He makes frequent reference to judaeo-christian
| archetypes, which seems to me to grossly overstate the
| relevance of the belief systems.
|
| The fundamental archetypes represented in the human mind
| are far older than any current form of religion, to the
| extent that there's overlap then either the archetypes
| have been co-opted, or have been overlaid with a
| culturally mediated avatars.
|
| I don't think that you ever find him framing those
| underlying structures in a way that does not tie back to
| Christ.
| nyokodo wrote:
| > which seems to me to grossly overstate the relevance of
| the belief systems.
|
| It is hardly possible to overstate the relevance of those
| archetypes and beliefs. Nothing else has been more
| widespread on earth for as long to have anywhere close to
| the same influence on humanity.
| TheOtherHobbes wrote:
| Physics needs more insider critics. She's oppositional
| but - unlike Peterson - she does know what she's talking
| about.
| snapcaster wrote:
| I hear this a lot from people. As a non-physicist who
| enjoys her content, what am I missing? is she wrong on
| any specific physics? Without specific criticism this
| comes off as insiders being upset that a fellow insider
| is critical of the field
| s17n wrote:
| Hm, that seems like the opposite of Jordan Peterson (who
| is obviously an idiot, but has a good voice for TV)
| simiones wrote:
| That's my point: what experiments could be performed have
| been performed, and have failed.
|
| Also, it is a massive _weakness_ of the theory that it can
| be used to predict such varied values. This is a big part
| of why it is not exactly a scientific theory: it is not
| really falsifiable, since you can tweak it to predict any
| value you want. If we had the kind of particle accelerators
| needed to test high-energy supersymmetry, and if it failed
| again, it could be adjusted to predict _higher-energy_
| supersymmetry, and since the number line extends towards
| infinity, this would never stop.
| peteradio wrote:
| I think you are correct, ST is closer to mathematical
| abstraction than an actual physical theory. I think that
| makes it more useful than less useful though.
| mensetmanusman wrote:
| Wouldn't that mean it is just more useful in mathematical
| reality but less useful in physical reality?
| noobermin wrote:
| "low-energy Supersymmetry" oh, you mean 8 TeV wasn't
| enough? This kind of reasoning is just like the ether,
| people keep harping on a god of the gaps explanation for
| the failure of the search.
| eigenform wrote:
| (I'm not a physicist, but) from the paper:
|
| > All together, the Schwarzschild topological solitons have
| scattering properties very similar to Schwarzschild black holes.
| The main difference will be a residual faded glow that emerges
| from inside the would-be shadow.
|
| So basically, things fall in, bounce around, and come back out
| (albeit scrambled)? Seems intuitively more reasonable than
| singularities?
| supermatou wrote:
| The actual paper (no paywall):
| https://arxiv.org/pdf/2212.06837.pdf
| [deleted]
| gcgbcfy wrote:
| String theory like most of theoretical physics is just made up.
| Today our knowledge of atomic physics and the cosmos is no more
| improved little since 1945. There's a lot of theories, but
| ultimately they just add up to different kinds of particles
| interacting in non-verifiable ways. If you look at the actual
| advancements it's pretty laughable we're sitting here saying "Hey
| look this theoretical thing called a black hole, that easily
| could just be some type of unknown radio telescope interference?
| It maybe might exist for a different reason than we thought!"
| Your layman's understanding that a black hole is some kinda big
| suck-y thing in space is actually better then engineering an
| elaborate and probably incorrect theory.
| EGreg wrote:
| I think defects imply you know there is some purpose other than
| the phenomenon you are referring to as a defect
| Enginerrrd wrote:
| Not at all. Defects are typically just points of discontinuity
| or where a pattern breaks. These happen when something
| relatively continuous is forming but then the pattern breaks
| locally due to either global initial conditions or something
| unusual happening locally.
|
| I think the term is probably borrowed from the theory of
| crystal lattices where defects are classified: dislocations,
| substitutions, and holes. As a crystal is forming, sometimes
| two contiguous regions can't come together in the same pattern
| because of initial conditions where the lattice won't line up
| right. These then form adjacent "grains". Alternatively,
| sometimes internal stresses result in a dislocation where a
| large section of crystal shifts along a line of symmetry. Or
| sometimes a stray impurity is hanging out and a crystal forms
| around it. Or holes happen where it's just like musical chairs
| as the crystal is forming and there's one too few atoms to go
| around.
|
| In none of those cases is there some "purpose", and yet there
| is a clear local discontinuity in an otherwise large scale
| pattern. The terminology fits pretty well to the situation here
| I think, only they're speaking about topological phenomena.
| b800h wrote:
| All my life, they've been hawking string theory; what feels like
| 40-odd years of breathless articles in New Scientist and on
| "Horizon". I don't really understand why it's still funded.
| [deleted]
| was_a_dev wrote:
| Most of the New Scientist is breathless articles. It's
| borderline science-fiction hooking in the very latest of
| publications
| ftxbro wrote:
| > All my life, they've been hawking string theory
|
| I see what you did there.
|
| Also, Sabine Hossenfelder was trained as a particle physicist
| and she doesn't like it either. She explains why it's like that
| and how it's bad and what they should be doing instead (like
| actively trying to reconcile the contradictory theories of
| gravity and quantum mechanics). She has changed career to
| professional youtuber
| https://en.wikipedia.org/wiki/Sabine_Hossenfelder
| EddieEngineers wrote:
| > like actively trying to reconcile the contradictory
| theories of gravity and quantum mechanics
|
| Isn't that exactly what string theory is trying to do?
| ftxbro wrote:
| She's mainly against research that tries to achieve
| naturalness for its own sake
| https://en.wikipedia.org/wiki/Naturalness_(physics)
|
| If someone is actually trying to get to the bottom of some
| contradictions in physics experiments I don't think she
| would be against this. I think she has observed that string
| theory has failed at it for so long and maybe some other
| methods can get a chance for funding instead of spending a
| hundred billion dollars on string theory and ten thousand
| dollars on other methods.
| [deleted]
| jjk166 wrote:
| No one has come up with something demonstrably better yet.
| gonzo41 wrote:
| It's cheap. A physicist I work with says it was a cheap way to
| have clout in the 80's in a physics department. Fundamentally,
| paying for a couple of people to do math on paper all day is a
| lot cheaper than doing what they do at cern.
| philipov wrote:
| And here I thought Hawking was a quantum field theorist.
| alecst wrote:
| String theory has been pretty useful outside of string theory
| proper. There are analogies to lots of other systems which I
| think continues to breathe life into the research. See:
| https://www.quantamagazine.org/string-theorys-strange-second...
|
| > "It's hard to say really where you should draw the boundary
| around and say: This is string theory; this is not string
| theory," said Douglas Stanford, a physicist at the IAS. "Nobody
| knows whether to say they're a string theorist anymore," said
| Chris Beem, a mathematical physicist at the University of
| Oxford. "It's become very confusing."
|
| I knew some string people who easily transitioned into other
| fields (like condensed matter) because the work was similar. I
| don't personally see it as a huge waste of time, and it's like
| the least expensive thing to fund.
| runsWphotons wrote:
| I find this funny as well. A lot of complaints about all the
| funding for string theory, but it seems like just funding
| mathematicians, which is dirt cheap compared to anything
| else.
| qubex wrote:
| Of course they don't know whether they're string theorists!
| Nobody knows whether theorists are made of strings or not!
| That's the whole point of lacking experimental verification!
|
| </humour>
| [deleted]
| [deleted]
| nathan_compton wrote:
| The basic thing here is that 1) we can guess from pretty basic
| physics that black holes have an entropy. 2) in order for a
| black hole to have an entropy it must have microscopic degrees
| of freedom. 3) String theory is one of the few ways we've ever
| come close to actually calculating from microscopic degrees of
| freedom the entropy we "know" black holes should have. I think
| most physicists, even string theorists (perhaps them more than
| others) understand that there are physical and philosophical
| problems with string theory, but I think most folks also think
| its the closest thing we have to a working theory and that it
| is probably a useful language in which to cast certain
| calculations in lieu of a more complete or rigorous theory.
|
| I'd also like to point out that the actual total funding for
| string theory is extremely tiny compared to scientific research
| funding in general since it is a theoretical discipline with
| very few practitioners. If you want to attach inefficiencies in
| scientific funding, the LHC is a much better target. I'm a
| physicist and have an interest in theory, and even I think that
| we spend too much money on particle accelerators given what we
| stand to learn from them and the other pressing problems the
| human race has. I'd be delighted to see all that money re-
| allocated to large scale public works building solar panels and
| infrastructure or just giving it to poor people.
| d0mine wrote:
| If we follow Pareto principle, then it doesn't make sense to
| optimize spendings that are close to zero if compared with
| something like military spendings.
|
| https://en.wikipedia.org/wiki/Pareto_principle
|
| Even if string theory is just pure math with no base in
| reality, it still can be useful (any math domain for that
| matter).
| _0ffh wrote:
| I don't think the spending is really a problem, but
| possibly the many work-hours of brilliant minds that might
| be more fruitfully employed working on different problems.
| dangerlibrary wrote:
| Let's not pick on the LHC for that. How many
| gobsmackingly brilliant engineer-hours have gone into
| optimizing ad targeting or fine-tuning purchase
| attribution?
| ecnahc515 wrote:
| Not to mention, the LHC is responsible for a lot of
| innovation in it's own right, just in terms of hardware,
| software, etc.
| [deleted]
| nbardy wrote:
| It's noble to want to help the poor but the economy isn't
| zero sum in that way.
|
| Almost all the surplus we have could be traced back to our
| discoveries in physics leading to machines.
|
| People lived much much poorer lives without modern physics
| discoveries.
|
| The expects return on physics is so great we should find ways
| to afford more long shot experiments not less.
| nathan_compton wrote:
| Sorry, but _even as a physicist_ I think the idea that the
| expected returns for society of discovering some other
| obscure standard model particle are trivial to nothing.
| Literally useless knowledge and only of interest to a tiny
| minority of people (of whom I am a part, I admit). Like
| seriously. Consider: how has _anyone 's_ life been improved
| by the discovery of the Higgs? By the absence of
| Supersymmetry?
| senttoschool wrote:
| We don't know yet. To be determined. But science has
| taken us pretty far.
| clarle wrote:
| Neural network algorithm research was considered more of
| an academic endeavor rather than something that could
| have practical implications from the 1960s to even the
| early 2000s, compared to other machine learning
| algorithms. Look at where it took us today.
| luxuryballs wrote:
| pun intended? :D
| indy wrote:
| Sunk cost fallacy.
|
| A lot of people have spent a lot of their time developing this
| theory
| b800h wrote:
| And I suppose given that it was exciting in the 1980s, these
| are the people in positions of power at the moment.
| chongli wrote:
| Tenure has its pluses and minuses. If a string theorist has
| tenure, they're going to be string theorizing for a very
| long time. Sunk cost fallacy plays a role but so does
| specialization. If you're leading string theorist and you
| walk away from string theory, what are you? A
| mathematician?
| bumby wrote:
| If you adjust your priors in response to data and end up
| walking away from a faulty theory, I think the term is
| "scientist". It sounds like the problem from your
| perspective is they identify themselves as "string
| theorists" first and "scientists" second.
| chongli wrote:
| Until now, there hasn't been any data around string
| theory whatsoever. It's been a purely mathematical
| exercise without even a hint of a possible experiment to
| test it.
|
| So walking away from string theory years ago, in my mind,
| would make you a mathematician.
| bumby wrote:
| I agree, it's impossible to completely divorce humans of
| their biases. One way is to create a system of diversity
| in rival ideas. So while a scientist is a noun, science
| should be viewed as a verb. The person may be biased, but
| the goal is that the process is not. (Still easier said
| than done).
| chongli wrote:
| I didn't really intend to convey the idea that I thought
| bias was the major factor. As a practical matter, if
| you're an expert in a field and your foundational
| theories are seriously challenged, it challenges your
| foundation as an expert.
|
| It's fun to talk about scientists as these staunch
| defenders of their theories and say "science advances one
| funeral at a time" but the reality of the situation is
| that sometimes scientists are faced with the realization
| that their entire life's work is in ruins. It's hard to
| imagine a more severe test of character than that. Harder
| still to imagine how one might pick up the pieces and
| move on to something else and still be able to contribute
| to science in a meaningful way.
| eep_social wrote:
| And yet, "science advances one funeral at a time"
| probably because scientists are people.
| runarberg wrote:
| I can't stop thinking about one the greatest scientific
| discoveries in this context.
|
| Kepler was convinced the planetary orbits around the sun
| were circular and could be described with the five
| Platonic solids. His theory was testable, and when he
| measured it against observation, it failed. He could have
| persisted, modified his theory, and continued on the
| wrong path, but instead, he discarded his theory and
| discovered elliptical orbits with his three laws of
| planetary motion.
|
| Kepler was a scientist.
| ndsipa_pomu wrote:
| String theory is seductive as it is almost a natural
| progression to go from point-like particles to strings with
| different patterns of vibration. Also, it seems to have a
| natural handling of gravity and so promises the holy grail of
| unification. It's almost like a mathematical formula that's too
| beautiful to not be true (though there's plenty of examples of
| beautiful maths that fails).
| AmericanOP wrote:
| What I find curious is the "observed" properties of the
| whirlwinds within each and every proton & neutron are so
| phenomenally complex, I would not be surprised at all if the
| mathematical abstractions of strings represent another
| quantum ecosystem we may never be able to observe
| digging wrote:
| I don't understand why it wouldn't be?
|
| One of the most fundamental scientific facts is that quantum
| theory (the most precisely tested theory in human history) and
| general relativity are incomplete. There _must_ be a bridge.
| And we have no idea what that bridge is. It 's been this way
| for over a century; the lifespan of string theory is not so
| long in comparison. Until we find a way to falsify it, we have
| to keep trying, don't we?
| runarberg wrote:
| Why do you assume there is a bridge? Or even if there is one,
| why do you assume that descriptions of that bridge in a
| mathematical language is at all possible?
|
| We do know that mathematical frameworks cannot be at the same
| time totally complete and internally consistent. Would it be
| a stretch to assume descriptions of our physical reality
| could have the same restriction? General relativity and
| Quantum mechanics are relatively complete in describing our
| physical reality, however they are not consistent with each
| other. Perhaps if we ever find a description that is
| consistent, it won't be complete. Perhaps grand unified
| theories are simply a mathematical impossibility.
| eouwt wrote:
| > We do know that mathematical frameworks cannot be at the
| same time totally complete and internally consistent.
|
| I take it you're referencing Godel's theorems here, but
| "consistent" and "complete" have rather technical (and
| somewhat limited) meanings within that context, so it's not
| clear to me how they'd usefully map onto the potential
| relationship between QM and GR?
| simiones wrote:
| That's a very good point. In particular, "complete"
| refers to the ability of the mathematical-logical system
| to prove every statement that is true within that system,
| in terms of the system.
|
| This property is completely irrelevant to a theory like
| QM or GR - it is only relevant for a system that aims to
| be a universal foundation for mathematics (a formal
| language in which any mathematical statement whatsoever
| could be precisely formally encoded, and then proven or
| disproven).
| simiones wrote:
| The problem with this line of thinking comes from the way
| the problem is posed. The reality is worse for both GR and
| QM.
|
| QM is not a theory about small particles: it is a theory
| that describes the evolution of any object whatsoever. It
| just happens to be completely wrong for large objects. And
| even if we accepted that there is some objective cutoff
| points between "small objects" and "large objects" (the
| "objective collapse" interpretation), it would still be
| wrong, because it predicts effects like gravitational
| lensing don't exist.
|
| Conversely, GR is also a theory about any size of object;
| and it is also completely wrong when tested on small
| objects, as it predicts effects like the self-interference
| of particles don't exist.
|
| And again, even if some kind of objective boundary existed
| between the domains of GR and QM existed, that would need
| to be incorporated into the maths of both of them, and
| questions about behaviors close to that margin would arise.
| cthalupa wrote:
| >because it predicts effects like gravitational lensing
| don't exist.
|
| But we use gravitational lensing, and the amount of
| lensing is predicted by GR?
|
| I don't understanding this statement. Is there some
| additional affect around lensing we should see if quantum
| gravity is a thing?
| simiones wrote:
| No no; I'm saying that if you apply QM as it exists today
| to describe the motion of light beams around the sun, you
| will not get any effect similar to gravitational lensing.
| Since gravitational lensing is a real effect that we have
| clearly seen, it means that QM as it exists today is just
| wrong (in its predictions about how light moves around
| the sun).
|
| GR does of course predict gravitational lensing. However,
| if you used the formulae of GR to compute the motion of
| photons passing through a double-slit experiment, the
| solution would show two different bright spots,
| corresponding to the two slits; in reality, we see an
| interference pattern. So GR is also wrong.
|
| By definition, a (correct) theory of quantum gravity
| would predict both gravitational lensing and the way
| photons behave in a dobule-slit experiment (otherwise, we
| would say that either the theory is wrong, or it is not a
| theory of quantum gravity). However, no such theory
| exists today, at least none that doesn't contradict other
| observations.
| raattgift wrote:
| There are already experiments (and simulations) which
| show Raychaudhuri focusing and Einstein lensing in
| purely-quantum analog gravity (see e.g.
| <https://scitechdaily.com/bridging-quantum-theory-and-
| relativ...> for something moderately accessible that
| allows for attaching a causal cone at each point in a
| relevant analog spacetime), so
|
| > no; I'm saying that if you apply QM as it exists today
| to describe the motion of light beams around the sun, you
| will not get any effect similar to gravitational lensing
|
| falls down because we can describe such an effect purely
| quantum mechanically.
|
| Also, I think you should be put to proof with respect to
| a claim against quantum perturbative or canonical methods
| in the solar-mass lensing regime in which perturbation
| theory works great for classical GR, taking into account
| all sorts of beyond-leading-order (classical) effects
| like noncircularity, backreaction, helicity, you name it.
| The sun is a fixed enough background that it's a
| linearized gravity problem. What exactly in "QM as it
| exists today" breaks (or is broken by) this?
|
| > ... if you used the formulae of GR to compute the
| motion of photons passing through a double-slit
| experiment ... GR is also wrong.
|
| How exactly does taking the fully Lorentz-invariant QED
| or Standard Model to local Lorentz-invariance (with the
| radius of curvature significantly larger than the
| laboratory experiment) break the picture? We are nowhere
| near needing to consult Birrell & Davies.
|
| What do you think needs doing here if "you used the
| formulae of GR", beyond solving the EFEs and the geodesic
| equations for the whole (region of) spacetime, and then
| wondering what geodesic any given photon will couple to?
| What do you think the scale of the correction from
| Minkowskian geodesics will be? And how much of that do
| you impute to the apparatus?
| runarberg wrote:
| I see. So me and my parent are both wrong. The problem
| isn't about a lack of bridge, or
| inconsistencies/incompleteness, it is about a lack of
| well defined scopes for each theory.
|
| In a sibling post I talk about how this is not a problem
| in psychology, and ask what the difference is. This
| answers that question kind of well, the difference is
| that in psychology/sociology the scopes are well defined.
| We know what a population is and apply sociology to it,
| and we know what an individual human being is, and apply
| psychology to it.
|
| With quantum mechanics and general relativity the scope
| is supposed to be the cosmos, but both theories fail on
| some places in the cosmos. So either the theories are
| wrong, or the scopes are wrong. I'm leaning towards the
| latter.
| digging wrote:
| > So either the theories are wrong, or the scopes are
| wrong. I'm leaning towards the latter.
|
| Well, no. That's not really possible here. The scopes
| can't be adjusted. The theories are wrong. They both
| _must_ explain all physical phenomena, but neither does,
| therefore a more accurate theory exists which we have not
| found yet.
|
| I just don't know if there's much value in trying to make
| an analogy to psychology here. Currently it seems to be
| getting in the way of understanding.
| jakeinspace wrote:
| It's sort of incomprehensible that there wouldn't be, even
| if that bridge is forever incomprehensible to us. There are
| boundaries between where GR and QM are predictive, so
| presumably, unless there's some strange smooth transition
| of equations between those two regimes (which would itself
| lend itself to a mathematical theory), then there must be a
| consistent set of equations which explain both regimes
| consistently and simultaneously.
| runarberg wrote:
| Coming from psychology this feels alien to me. In
| psychology there is a definite boundary between
| individual behavioral dynamics and population behavioral
| dynamics. There is no smooth transition between the two,
| either you describe the individual or you describe a
| group, you cannot do both (even thought debates about IQ
| here on HN will have you believe otherwise) and there is
| certainly no smooth transition.
|
| How is the boundary between GR and QM different from the
| boundary of psychology and sociology?
| jakeinspace wrote:
| Im neither a psychologist nor a physicist, but I think
| one can analogize population vs individual behaviour to
| condensed matter physics versus particle physics.
| Condensed matter physics finds emergent behaviour in
| large clumps of stuff that would, in principle, be
| totally predictable from first principles (the standard
| model), but which in practice are quite difficult to
| guess a priori. Different scales lend themselves to
| different tools, since nonlinear dynamics (chaos) makes
| it intractable to apply bedrock reductionist formulae to
| large systems. The higher order behaviour of complex
| systems is in no way less interesting or true, I would
| argue, than the seemingly simpler behaviour of very small
| systems.
|
| In contrast to condensed matter vs the standard theory
| (QM basically), QM vs GR has fundamental incongruities,
| since both theories make claims about what happens at the
| same scale. Only one (or most likely neither) can be
| correct at the event horizon and center of a black hole.
| raattgift wrote:
| > In psychology there is a definite boundary between
| individual behavioral dynamics and population behavioral
| dynamics.
|
| > either you describe the individual or you describe a
| group
|
| In gravitational physics, with respect to a flow in a
| dynamical system (an example is galaxies in an expanding
| universe) we can use a Lagrangian observer (e.g., one
| galaxy, drifting along with the flow, tracing out a
| pathline/worldtube that depends on features like its
| mass-evolution and proper motion within a cluster of
| galaxies) or a Eulerian observer (e.g. a notional
| observer with no spatial motion at all, watching alllll
| the galaxy clusters jiggle, swirl, turn, and age a little
| differently in relation to her). One can convert
| observations of each type of observer to the other in a
| rigorous mathematical procedure, since they are just two
| (families of) the infinity of different observers allowed
| by even just Special Relativity. See e.g. <https://en.wik
| ipedia.org/wiki/Lagrangian_and_Eulerian_specif...> for
| more detail.
|
| >> There are boundaries between where GR and QM are
| predictive
|
| > this feels alien to me
|
| You can do both quantum matter and classical General
| Relativity in one of several effective field theories,
| which I'll return to below.
|
| GR and relativistic quantum field theories (QFT) purport
| to make accurate predictions in strong gravity, which one
| only finds deep within black holes (i.e., not on our side
| of any horizon), but they make _very different_
| predictions in that regime pretty generically.
| Generically in the sense that choosing different
| behaviours of particle-particle interactions (and self-
| interactions) do not really move the needle on GR 's
| prediction of a collapse to a core of _infinite_ density.
| However, in various approaches which convert GR 's
| classical gravitational waves into large number of
| gravitons, one can write down a matter QFT in which
| charged particles' self-interaction can lead to a
| degeneracy pressure (a repulsive force) that increases at
| higher particle energies such that they overwhelm
| gravitational collapse at very high but _finite_ density
| in black holes of arbitrary mass.
|
| In weak gravity, like we have in our solar system, QFTs
| allow us to prepare significant masses in superpositions
| of (spatial) position. General relativity does not allow
| for such superpositions. We are approaching lab-
| testability, with results from sensitive accelerometers
| allowed to point at tiny superposed masses.
|
| However, in regimes far from (non-negligibly) gravitating
| superpositons and strong gravity, GR and QFT are usefully
| (and possibly fully) compatible. We get good results in
| astrophysics from semi-clasical gravity, where the
| classical curved spacetime of General Relativity couples
| with the expectation value of QFT matter (i.e., we
| average out some quantum weirdness and justify this by
| the weak gravitational effects of the "lumpy" weirdness
| being practically impossible to measure; superpositions
| and ultra-high-energy/ultra-high-denisty systems might be
| _too_ lumpy).
|
| We also get good results from perturbative quantum
| gravity and canonical quantum gravity, for example.
| Neither of these latter two is really classical General
| Relativity so they can deal with the gravitation of
| superposed matter (otherwise they give for all practical
| purposes the same answers as semiclassical gravity).
| These approaches do not work in strong gravity, however.
| Essentially they become calculationally intractable or
| they crash into unresolved problems splitting spacetime
| into space and time (in order to do time-dependent
| quantum mechanics).
| PopePompus wrote:
| I would say it is completely different. In physics,
| quantum mechanics gives extremely precise and verifiable
| predictions of the outcomes of experiments within a
| certain range of physical conditions. So does general
| relativity. In contrast, psychology has no mathematical
| model that will, for example, accurately predict what I
| am going to eat for lunch, nor is there a model that
| predicts the exact outcomes of elections. Since physics
| has two models which are exquisitely precise in different
| size regimes, but which are mutually incompatible, you
| have a definite puzzle about what happens in situations
| where the effects of both theories should be important.
| There are no exquisitely precise and accurate
| mathematical models of anything in the social sciences,
| as far as I am aware.
| balfirevic wrote:
| If you could precisely and reliably describe and predict
| individual behavior for any individual, then population
| behavior would follow directly from those laws.
| dotnet00 wrote:
| The difference would be that the laws of physics are much
| more rigorous than the 'laws' of psychology/sociology.
|
| Outliers in the latter aren't necessarily indicative of
| anything wrong with theory in general, while even a
| single outlier in anything in the former is indicative of
| an incomplete model.
|
| There are various results in physics which should be
| predictable via both GR and QM independently. The results
| should be the same as both models are supposed to be
| describing the same thing, so it follows that there
| should be some sort of gradual transition as one set of
| effects gradually comes to dominate over the other.
| Otherwise we'd see a single point in the data where QM
| stops being accurate and GR takes over, but despite
| investigating so many different scales, we have not seen
| any such cutoff point.
| digging wrote:
| > In psychology there is a definite boundary between
| individual behavioral dynamics and population behavioral
| dynamics.
|
| I'm aware of my own behavior as an individual being
| influenced by social context, is that not the kind of
| bleed over you might look for? Maybe you're referring to
| specific concepts I'm not actually even understanding.
| runarberg wrote:
| You still use theories from psychology to describe the
| interaction. This is precisely what social-psychology
| does (admittedly spectacularly often without
| replication). And a good social psychology theory is
| consistent with other fields of psychology, like
| cognitive, or--more often--behavioral psychology. You
| don't use population statistics to predict how you as an
| individual will behave in a certain situation.
| simcop2387 wrote:
| Yep, or at least until we find something else that is
| explaining things better and testing better and looks like a
| better path forward. As much as I dislike ST because of the
| ambiguity/vagueness that means it's so hard to nail down as a
| single concrete theory, the alternatives so far still also
| have a lot of those same issues (e.g. too many parameters,
| effectively impossible to test, etc.) so there's no reason to
| drop ST just yet as useless or an invalid theory.
| joaorico wrote:
| Opportunity costs. The real debate has been whether it makes
| sense for string theory (whatever the prevailing definition
| is) to _dominate_ funding for theoretical research of the
| "bridge". There are alternatives besides strings for the
| bridge, and there should be even more, in theory...
| digging wrote:
| I don't know enough about the history of funding
| theoretical physics research to comment on that one way or
| another. However, neither did the comment I was replying to
| reference any actual facts about the distribution of
| funding that might suggest any of them had been wasted.
|
| The fact is, we have no falsifiable theories that can unite
| GR and QM. Should every theory be abandoned that doesn't
| quickly lead to a resolution? No, clearly not. So the
| question is what kind of criteria we could use to determine
| that string theory is a dead end or is otherwise stifling
| true progress.
|
| And that's pretty much what I was trying to ask
| previously... is ST actually sucking all the air out of the
| room? I'm a layperson and not just going to assume that
| hundreds of experts have blown their careers doing
| pointless calculations on a theory that "obviously" isn't
| worth the resources put into it. But the comment I replied
| to seemed to be making that assumtpion,
| scotty79 wrote:
| The bridge is "simply" doing the math of quantum mechanics in
| the curved spacetime of general relativity instead of the
| flat one.
| simiones wrote:
| > Until we find a way to falsify it, we have to keep trying,
| don't we?
|
| By that same token, we should keep looking for the fountain
| of eternal youth in El Dorado until it can be conclusively
| proven it doesn't exist.
|
| A theory which is not falsifiable is not a scientific theory,
| at least in principle, and it is hard to tell why it should
| be entertained for quite so long.
| atoav wrote:
| While I agree with the general premise, don't you think
| that if we were to find a simple explaination that
| elegantly explains many things at once, it would be at
| least worth a try to find ways of falsifying that
| explaination?
|
| Not at any cost of course, but the falsifications gathered
| e.g. in trying to disprove the string theory might also
| help us figure out what is actually going on.
| simiones wrote:
| Sure, but once it keeps failing for a few decades, and
| given that ST is significantly more complex than either
| QM or GR, not simpler, there has to come a time where it
| simply is abandoned, even if it hasn't been disproven.
| senttoschool wrote:
| A few decades...
|
| How long did it take to go from Principia to General
| Relativity?
| kneebonian wrote:
| Science progresses one funeral at a time.
| rhacker wrote:
| Pretty much. We can't get past the big wigs until the big
| wigs are no longer enforcing beliefs that make little sense.
| candiddevmike wrote:
| What causes them to do this?
| tinideiznaimnou wrote:
| Being apes, I guess.
| pvaldes wrote:
| A structure build painfully to get money. With enough
| time each scientist learns to became an entertainer or a
| politic.
| some_furry wrote:
| What causes dictators to cling to power?
|
| What causes political parties to prioritize their donors
| over their constituents?
|
| What causes corporations to disregard the safety and
| health of the public if the worst they'll face is a fine
| for negligence?
|
| These questions, while superficially unrelated, all point
| to the same underlying mechanism in the nature of
| societies.
| luxuryballs wrote:
| they might be cosmic whale blow holes too
| metanonsense wrote:
| If I am not completely wrong, this headline has nothing to do
| with the linked article. The article is about "topological
| solitons" that - according to the article - look "to outside
| observers" like black holes.
| wrycoder wrote:
| The phys.org article isn't worth spending time on. It's better
| to read the original arxiv paper that @supermatou linked in a
| peer thread.
| kadoban wrote:
| I think the headline just doesn't do enough work specifying how
| unlikely this is. The article otherwise seems to match.
|
| We are "outside observers", correct? So black holes we see
| "might" (theoretically, in an unproven and maybe unprovable
| system of physics) be defects in spacetime.
| metanonsense wrote:
| I share your understanding but when the article does not even
| mention that possibility, a link text seems to be an odd
| place to make such a claim.
| digging wrote:
| I don't understand how you didn't take that away from the
| article... it was clear to me what it was saying.
| metanonsense wrote:
| Can you give me some pointers where you read this?
|
| I mean, at the end they even write "It's only once you
| got close would you realize that you are not looking at a
| black hole." I take from that that they are aware that
| black holes are different from topological solitons. And
| I read at no place that they consider black holes
| actually being topologial solitons.
|
| So, when the authors think that those two things are
| different and they classify solitons as "defects in
| spacetime", wouldn't this directly contradict the
| headline "Black holes might be defects in spacetime"?
|
| I would be glad if you showed me where my reasoning is
| wrong.
| kadoban wrote:
| Maybe the disconnect is that there's an implicit "[What
| we see as] Black holes might be defects in spacetime" in
| front of the headline.
|
| We can't get close to black holes, maybe ever but
| certainly not currently, so the difference between what
| the article is saying and how you're reading it is a bit
| philosophical IMO.
|
| The article glossed over it a bit, but from the sounds of
| it, every observation we know of from our position (and
| current technology level) would match.
| digging wrote:
| I see. My reading was that black holes don't exist. That
| there is an alternative, topological explanation for the
| phenomena we've observed and so far classified as black
| holes.
| fnordpiglet wrote:
| Only if you don't look at it through the lens of selling
| advertisements based on impressions.
| thrill wrote:
| The only defect is in our understanding.
| NHQ wrote:
| People understand this dogma perfectly well, no reasoning or
| critical thinking required. Literal, to be under the standing
| of another mind.
|
| No logical basis exists for black holes, they are a
| rationalization for the faulty foundation upon which they lie,
| a fantasy to explain condescending pseudotheory.
|
| The defect is defending a false doctrine, accepting as truth a
| scientifically evident hoax.
| briantakita wrote:
| Has anyone considered that black holes may be defects in the
| model? There's an old phrase, "the map is not the territory".
| Some old maps show the edge of the world with giant sea monsters
| & ships falling off the ocean.
| gizmo686 wrote:
| Einstein originally thought that black holes were simply an
| mathematical artifact, and not possible in reality.
|
| Since then, we have observed objects that look a lot like we
| would expect black holes to look. There are theories, such as
| this one, that describe those objects as something different
| than what GR proposes, but thus far no testable prediction has
| contradicted GR's version.
|
| Part of the problem is that many of the differences are about
| the interior of the event horizon. At least under GR's model,
| such differences are nit observable, even in principle.
| vletal wrote:
| What if black holes are NaNs in the simulation we live in.
| Maybe it was written by a phd student as an experiment for his
| thesis.
| skirmish wrote:
| More like a half-baked elementary school science project.
|
| Consider:
|
| * Lazy evaluation was used to reduce computational costs.
| Unless an event is observed, it never collapses into reality.
| Cannot use up all household's hyper-electricity supply,
| parents will be mad.
|
| * Make GR and QM work nicely together? Nah, too hard, the
| show-and-tell is tomorrow morning.
|
| * Intelligent beings on multiple planets? Just a single
| planet will do for a C, maybe a C+. And no time left to make
| them interestingly different anyway.
|
| Be ready, once the project grade is announced, this
| simulation will just blink out of existence. Hyper-CPU power
| will be needed for billions of years (our time) of hyper-
| Minecraft.
| zelphirkalt wrote:
| The article has some pop-science feel to it:
|
| > But we do have candidates, including string theory.
|
| Oh no, you mean the theory that physicists say we see no evidence
| of at all? Great, if that is the basis, ... lets see what
| follows.
|
| > In string theory all the particles of the universe are actually
| microscopic vibrating loops of string. In order to support the
| wide variety of particles and forces that we observe in the
| universe, these strings can't just vibrate in our three spatial
| dimensions. Instead, there have to be extra spatial dimensions
| that are curled up on themselves into manifolds so small that
| they escape everyday notice and experimentation.
|
| Right, it would most definitely escape the experiments I have in
| my garage ... Who talks about "everyday experimentation" when
| talking about string theory? I mean, in "everyday
| experimentation" we don't even see atoms and most of us in their
| "everyday experimentation" do not even see molecules. Really
| makes you wonder what "everyday experimentation" they are going
| on about.
|
| > That exotic structure in spacetime gave a team of researchers
| the tools they needed to identify a new class of object,
| something that they call a topological soliton. In their analysis
| they found that these topological solitons are stable defects in
| space-time itself. They require no matter or other forces to
| exist--they are as natural to the fabric of space-time as cracks
| in ice. The research is published in the journal Physical Review
| D.
|
| But cracks in ice do consist of something: Usually air that fills
| the gaps. And even if we put ice in perfect vacuum somehow, there
| is still space between the parts of the ice. It is not like there
| is nothing. Seems like a bad analogy. At least they would have to
| go into what "fills" the gaps like with ice. Some space-time-
| vacuum?
|
| On top of that, the article tries to explain things by using even
| more in my vocabulary undefined terms like "soliton".
|
| > Because they are objects of extreme space-time [...]
|
| Ah, they are "of extreme space-time"! Now I know ... nothing.
|
| I don't feel like I understood anything valuable, but more like
| reading a sci-fi novel. Although, sometimes sci-fi novels do make
| more sense in their own invented universe than this article. Was
| this article perhaps generated by some language model?
| [deleted]
| marricks wrote:
| Article states that solitions are not black holes but only seem
| like black holes from a distance. Also they are hypothesized from
| string theory but haven't ever been seen, probably because they'd
| appear the same as black holes except up close?
|
| Title should be updated to something like: "A theorized defect in
| space time that appears to be a black hole"
| denton-scratch wrote:
| It's a really thin article. It fails to say how "topological
| solitons" are different from wave-mechanical solitons, nor does
| it explain why they look like black holes, or why they lack an
| event horizon.
|
| I'm routinely disappointed with phys.org. It's pop-sci with the
| "-sci" component reduced to a remnant.
| marricks wrote:
| 100% agree. It does link to an actual paper which is a step
| up from blogspam
|
| https://link.aps.org/doi/10.1103/PhysRevD.107.084042
| arisAlexis wrote:
| Or proof of a simulation... :)
| b800h wrote:
| "But we do have candidates, including string theory. In string
| theory all the particles of the universe are actually microscopic
| vibrating loops of string."
|
| Actually string. Brilliant exposition this.
| jiggawatts wrote:
| I've been keeping my brain occupied on long drives by trying to
| come up with a theory of everything, because... why not?
|
| My current pet hypothesis is that all fundamental particles are
| sort-of like tiny black holes, and that the space-time distortion
| caused by black holes is precisely the same thing that ordinary
| matter causes. All matter and energy are space-time distortions,
| which is why mass-energy bends space time. It's not a secondary
| effect, the bending is what everything _is_ , not a property that
| things _have_. (This is essentially just a variant of Kaluza
| Klein theory, or others like it.)
|
| Particles are kept apart by their spin, same as in well-
| established physics. Matter is still mostly empty space, same as
| normal.
|
| In this toy model, neutron stars are like a boba tea, with the
| black holes of particles close-packed but still not touching.
|
| When forced into forming a black hole, the event horizons of
| individual particles begins to merge, forming a "super-particle"
| that expands out. When fully-formed, the black hole is hairy,
| with a very dense packed crust of still-separate particles
| layered over a very lumpy surface, inside which there is...
| nothing. Not even space-time. The surface is where space-time
| _ends_.
|
| It's like... imagine if we lived on a knitted jumper or a space-
| time like woven cloth and could only follow threads. If someone
| were to poke a hole in the weave with a finger, pushing aside the
| threads, then it would be meaningless to ask what threads are
| inside that hole. There aren't any. The "weave space" doesn't
| extend into the hole.
|
| This simultaneously satisfies a long list of requirements
| gathered from modern physics:
|
| 1. Black hole formation is a gradual, continuous process at both
| microscopic and macroscopic scales. This model can start all the
| way down with the first pair of particles that got squished
| together and then can be extended all the way up to something the
| size of a star.
|
| 2. Black holes are hairy instead of smooth, satisfying
| thermodynamics and quantum information theory.
|
| 3. There's no paradox of what happens when you go past the event
| horizon. There's no singularity. The event horizon is a surface,
| essentially just a highly red-shifted neutron star. Hitting it is
| the same as hitting a neutron star. You do _not_ go through. You
| get squished.
|
| 4. There's no need for complex maths to explain black hole
| evaporation. In a sense, black holes don't exist, they're just a
| very time-dilated neutron star, and their evaporation is just an
| ultra-slow-motion explosion of a neutron star.
|
| 5. A well-established theorem is that many properties of a black
| hole grow in proportion to their surface area (2D), not their
| volume (3D). This theory matches that. There _is no volume_ ,
| there's only the surface. The inside doesn't exist. When
| approaching from normal flat 3D space, space _gradually_ becomes
| fractal (2.x dimensional), smoothly transitioning to a 2D space,
| which is the event horizon.
|
| 6. It is time-reversible. Seen backwards in time, "fingers" of 3D
| space invade into the event horizon, splitting it up into smaller
| and smaller chunks that bud off to form small, stable spheres
| that evaporate away. These are the particles that made up the
| black hole.
| simiones wrote:
| While I understand these are just idle musings, you should note
| that this is failing to address the biggest problems that
| actually "require" a theory of everything.
|
| Most importantly, it doesn't explain how quantum fields
| interact with a non-flat space-time. If you try to combine QM
| with the space-time-deforming characteristics of mass from GR,
| you quickly get infinities all over the place, which is
| obviously not what we observe.
|
| Secondly, the object that you are calling a black hole is
| simply different from the object called a black hole in GR.
| That object, by definition, has a huge mass in an extremely
| small volume. All the other descriptions of it are derived
| properties of how GR says masses affect the structure of space-
| time. And it should also be noted that the event horizon of a
| black hole is much wider than the size of the object just
| before collapse, as far as I know - which sounds different from
| what your model would predict (but perhaps not?).
| pantulis wrote:
| Your first point sounds a lot like the Schwarzschild Proton
| conjecture by Nassim Haramein, don't know if you were aware of
| it. Alas, I need to point out that it is basically considered
| pseudoscience!
| jiggawatts wrote:
| I got the original concept from the quite famous "black hole
| electron" theory, but I'm not saying that particles are
| _exactly_ like tiny black holes.
|
| PS: My toy theories are not to be taken seriously, they're a
| product of idle musing only.
|
| My method however, I think is sound: try and come up with
| something that _simultaneously_ satisfies as many known
| experimental and theoretical constraints as possible, poke
| holes in it (hah!), fix, rinse, and repeat. Or discard as
| necessary. Whatever.
|
| A motivation that has been bugging me is: What sets the
| _scale_ of particles? How does the universe know that a
| proton _here_ should be the same size as a proton _there_?
| Why can 't we have giant protons?
|
| A simple geometric argument could be something like assuming
| that particles are black-hole-like things as described
| previously, and that they are _solitons_. They 're the
| smallest units of spin, where their rotation and size is
| balanced such that some aspect moves at the speed of light.
| They can't get smaller because then their rotation would have
| to increase past the speed of light. Hence, all particles
| have their sizes fixed by the constancy of the speed of
| light.
|
| That's why I pasted my rambling thoughts in response to this
| article, my original idea started off thinking of particles
| as solitons that are also somewhat like black holes, which is
| the topic of the article.
| simiones wrote:
| Some other notes from what I understand of current
| mainstream physics:
|
| - elementary particles have no defined size in QM
| (electrons, quarks, neutrinos, photons etc); there is no
| known lower-bound on how small they could be, and there are
| serious mathematical issues both with assuming a non-0
| radius, but other problems with assuming a radius of 0
|
| - composite particles like a proton or a hydrogen atom have
| a size because of the relative strengths of the forces
| holding together their components; for example, the three
| quarks making up a proton must exist at a certain distance
| from one another because of the properties of the strong
| force; the electron of a hydrogen atom must "orbit" the
| proton at a certain distance because of the properties of
| the electrical force
|
| - QM spin is not a rotation speed of any kind; QM particles
| are not little balls rotating around their center; quantum
| spin has no known relation to the speed of light
|
| - replacing one constant of nature (the size of a proton,
| or at least of an elementary particle) by another constant
| of nature (the speed of light) is not really simplifying
| the theory; one could just as easily go the other way, and
| say that the speed of light is derived from the size of
| elementary particles in some other way
| duncan-donuts wrote:
| I don't have anything to add other than I enjoy reading
| your idle musings. I'm not a physicist and don't really
| know any real physics passed 101 college courses. I have
| similar idle musing with the speed of light so it's nice to
| read another layman's thoughts.
| cdelsolar wrote:
| Your ideas are intriguing to me, and I wish to subscribe to
| your newsletter.
| codethief wrote:
| From
| https://journals.aps.org/prd/abstract/10.1103/PhysRevD.107.0... :
|
| > We show that topological solitons are remarkably similar to
| black holes in apparent size and scattering properties, while
| being smooth and horizonless. Incoming photons experience very
| high redshift, inducing phenomenological horizonlike behaviors
| from the point of view of photon scattering. Thus, they provide a
| compelling case for real-world gravitational solitons and
| topological alternatives to black holes from string theory.
|
| This is certainly interesting but so far they have only looked
| into Schwarzschild black holes (the simplest kind of black
| holes). Their case would be much more compelling if they also
| found soliton solutions that looked like non-static (Kerr) or
| even non-stationary/dynamic black hole solutions (<-> black hole
| formation). I know far too little about solitons, unfortunately,
| to estimate how easy/difficult it would be to find/construct
| those.
| raattgift wrote:
| > only looked into Schwarzschild black holes
|
| What plane is the authors' "equatorial plane"? Shortly after
| their eqn (31), "One should a priori do a similar computation
| out of the equatorial plane to obtain the total size of the
| solitons. Due to the complexity of the geodesic equations, this
| is only possible numerically. However, we will see in the next
| section that the outer photon shell is actually almost
| spherically symmetric and slightly flattened at its poles".
| (ETA: "... the Schwarzschild topological solution is not
| spherically symmetric ...", just before section A.
| Methodology).
|
| Central SMBHs' spin appears to be largely far from parallel to
| their host galaxies' angular momentum[1]. Spin gives us an
| equatorial plane for the SMBH. Is there physical motivation for
| picking an equatorial plane if we found an SMBH with negligible
| J (and no jets)? I don't doubt that people would land on some
| convention (e.g. equatorial plane parallel to host galaxy's
| north if available, our galaxy's north if not), but do doubt
| that the convention would reflect physics (i.e., that there
| _is_ such a plane where J = 0 or even that such a plane is
| relevant where J <<< 1, even if the plane is thereby picked
| out) rather than useful coordinates.
|
| I scanned the paper only briefly (I'm not really interested in
| black holes out of a cosmological or at least astrophysical
| context and am in no hurry to jump ahead of further EHT
| results) but found myself curious about the authors' "these
| solutions can be embedded in string theory" as their ref [17]
| at first glance seems to be about AdS, an acronym which is
| found only once in this paper.
|
| What provokes my wondering is in particular, "and so an
| asymptotic observer will barely notice the difference between
| the parallax angles" (among other references to an asymptotic
| observer), drawing a comparison with a distant Schwarzschild
| observer, again around eqn (31). "Barely notice" is, at least
| qualitatively, interesting wording. Can an observer at infinity
| more than barely notice the difference between a cold
| noncompact spherically symmetric uncharged nonspinning central
| mass and a Schwarzschild BH?
|
| [1] This is especially true for Sgr A*, see EHT paper
| https://iopscience.iop.org/article/10.3847/2041-8213/ac6674
| which is wildly "tilt"ed (to use authors' expression).
| flkiwi wrote:
| From a layperson's perspective, "discovered" is doing a LOT of
| work in the linked article given it appears to be a hypothetical
| construct (topological soliton) within a hypothetical construct
| (string theory).
| nathan_compton wrote:
| It is perfectly reasonable to use the word "discovered" for
| purely mathematical facts for which the demonstration is non-
| trivial.
| bashinator wrote:
| I guess that depends on how much of a Platonist you are :-D
| nathan_compton wrote:
| I am an anti-platonist but still think its reasonable to
| say one discovered a mathematical fact. All this amounts to
| is discovering that you can reach a sentence in a formal
| language using the rules of the language and the axioms.
| One can believe that a recipe for pancakes exists without
| believing it does so via participating in an unseen ideal
| world.
| flkiwi wrote:
| If it were phrased as "discovered a mathematical solution in
| string theory that would, if confirmed, represent a
| topological soliton" that would strike me as more accurate.
| But this is the reason I stated up front that I'm a
| layperson: I can certainly imagine that within the community
| there are conventional uses of language that differ from a
| layperson's use. That's certainly the case in my own. But the
| way it is phrased appears, to a layperson, to indicate that
| the thing has been found to exist.
| airstrike wrote:
| From another layperson's perspective, it sounds like you are
| arguing it is "perfectly common" whereas the parent is
| arguing "it is unreasonable, even if it is common"
| flkiwi wrote:
| Parent here. That's the implication, but my intent was
| somewhat gentler, along the lines of "Using what appears to
| be professional language shortcuts common in an industry is
| sometimes suboptimal when communicating with interested
| laypersons." I'm making a few assumptions there (first that
| "discovered" has a commonly accepted meaning in the field
| and second that that's how it's being used ... and I guess
| third that there are probably more laypersons than
| theoretical physicists on HN). I just don't want to hear
| from my curious but uninformed cousin that "hey did you
| hear that black holes are just space knots??!!" any more
| than I have to.
| livinglist wrote:
| I just was interested enough to look up what's the nearest known
| black hole to Earth, and it's Gaia BH1 which is 1560 light years
| away from us...can I still get my hope up that during my lifetime
| I can witness some significant breakthrough regarding our
| knowledge of black hole?
| dustingetz wrote:
| if AGI 2030 then presumably singularity shortly after at which
| point physics is immediately solved subject to the
| computational limits of the amount of energy available in our
| solar system (beyond which we start paying speed of light
| delays to move compute to energy dense regions of the galaxy,
| unless warp drives are solved too).
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