Dark matter unnecessary?

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The uncertainty of science: A new analysis of the infrared data from 153 galaxies using the Spitzer Space Telescope suggests that dark matter might not be necessary to explain the rotation of galaxies.

First, this concise and nicely written explanation from the link of why dark matter has been proposed:

Newton’s laws of motion predict that planets that revolve closer to a star move faster than those that are farther away. In principle this should also hold true for stars circling the cores of galaxies, but for nearly a century, astronomers have seen that stars near the outskirts of galaxies orbit at nearly the same velocities as ones near galactic centers.

To explain why these outlying stars travel as quickly as they do without flying out into the void beyond, researchers came up with the idea of dark matter, a substance whose gravitational pull is thought to keep whirling stars in check. Scientists have largely ruled out all known particles as possible explanations for dark matter, and the consensus is that dark matter must be a kind of invisible, intangible material that is only detectable via its gravitational influence.

However, despite decades of trying, researchers have failed to capture a single mote of dark matter, even though it is supposed to make up roughly five-sixths of all matter in the universe. This raises the possibility that dark matter might not be real.

The new research, which I must admit I do not really understand, supposedly suggests that dark matter is unnecessary to explain the motions of stars.

Previous analyses of the orbital velocities of the stars in galaxies often depended on visible wavelengths of light. However, the stars that produce the most visible light are relatively short-lived and prone to fluctuations, and so may not provide the best picture of how matter is scattered overall throughout a galaxy. Instead, McGaugh and his colleagues analyzed near-infrared images collected by NASA’s Spitzer Space Telescope over the past five years. “The stars that generate the most near-infrared light are red giants, that are pretty stable in their output, and so are much better representative of a galaxy’s total mass of stars,” McGaugh said.

The researchers found an extraordinarily close association between the location of normal matter and the way it accelerates around the centers of galaxies. “We were surprised at how tight that relationship was,” McGaugh said. “It looks tantamount to a law of nature.”

Neither the article nor the scientists who did this research however explain clearly how this tight association negates the need for dark matter.


  • Andrew_W

    As I read it the argument is that by using the IR radiation from giants they are getting a more precise measurements on the distribution of normal matter within galaxies, and that the relationship between that distribution and the rotation speeds of stars between different galaxies is so consistent, so precisely matched, that they’re suspecting that that level of consistency would be unlikely unless the distribution of dark matter was precisely matched to the distribution of visible matter. This leading to the supposition that perhaps the greater galactic mass that star rotation rates implies is actually due to Modified Newtonian Dynamics (MOND).

    But then we’ve got Abraham Loeb saying that while MOND “seems to work very nicely, reproducing the observations we have of galaxies,” . . . “if you look at high-precision measurements of the large-scale structure of the universe and how the cosmos has evolved to the present day, the entire picture of cosmology all hangs together much better with dark matter than with MOND,” .

  • The argument for dark matter seems to be running along the lines of aether: something many well-educated people advocate. I’ve never been a fan of dark matter and dark energy: it smacks a bit much of ‘here be dragons’. It may be that there are other aspects of physics we haven’t rigorously considered.

  • Localfluff

    I understand it they find that normal matter behaves as if it were much heavier, or strictly co-located with dark matter inside galaxies. “Fat matter”. On interclustular scale this is nothing new. Baryons have fallen into the gravity wells of the dark matter filaments. But on an intragalactic scale I think it’s a new idea. Dark matter is supposed to exist in a halo encompassing a galaxy homogeneously.

    There are other proofs of dark matter, such as gravity lensing on galaxy cluster level and the Bullet Galaxies where mass is clearly separated from visual matter after galactic collisions that decelerated all visible matter but where the dark matter continued straight through like a ghost.

    Most astrophysicists seem to wish for super symmetry particles to explain dark matter because they like the math describing that.

    It is a funny thing that visual light comes from heavy young short lived stars which are not representative for the 99% of stars which are smaller and fainter. We cannot even see our nearest star with the naked eye because it is a common red dwarf. The sky is not what it looks like.

  • m d mill

    If this were climatology the dark matter theory would be settled science…ie the specific phenomenon(eg CO2 sensitivity feedback multipliers of 3 to 6) has not been definitively observed, but some other observations could be explained by it…case closed.

  • Wayne

    I’m going to counter-differ on your sentence—“that level of consistency would be unlikely unless the distribution of dark matter was precisely matched to the distribution of visible matter.”
    (I’m not hearing that myself, but it’s early sunday morning & I’m not quite awake…)

    Blair– (excellent vacation blogging, btw!)
    -Yeah, I tend to agree with your point, “here be dragons.” Anytime you need to insert “the invisible stuff, goes here…” into the equation, leads to problems.

    m d mill– Good one!

    Localfluff- interesting…

    The full paper is here:
    The Radial Acceleration Relation in Rotationally Supported Galaxies
    (I’m still drinking my coffee & haven’t read it yet.)

    some stuff on MOND is at–

    and a fairly good overview–

    Dark Matter & Modified Gravity – Sean Carroll

    And this whole lecture series is informative—

    The Standard Model | Lecture 1 (of 15)

  • Joe

    What difference at this point, does it MATTER any way!

  • wayne

    Joe– most excellent!

    [If I say, “Dark Matter, Possibly… Doesn’t Matter,” am I a racist? (Isn’t All Matter, Equal?)
    (–something like that– sounded funnier in-my-mind… Point goes to Joe!)]

    This is, heavy-stuff, and I haven’t read the Paper yet so I must reserve judgement. (and I generally have an opinion on everything… har… but the Cosmology stuff is dense & I rely on other people to tell me if the Maths are correct.)
    While we do know, a-lot-of-stuff, to high degrees of certainty, the Astronomy & Astrophysics folks, could use bigger & better Telescopes, on & off Earth, and all wavelengths.
    (I would have wished, they hadn’t come up with the terms “dark matter,” & “dark energy,” to describe these ‘things.’ They are different concept’s, people confuse them, & dark-matter smack of “dragons go here,” and.. we are lacking a whole lot of data in certain respects, on both.)

    If I’m not mistaken– dark-energy is more of a Quantum Field thing, where-as dark-matter, in Fritz Zwicky’s thinking, was more rightly called “invisible matter,” or “we can’t account for it yet, matter.”

    Tangentially– What’s-Up with the TMT in Hawaii?

  • Joe

    Thanks Wayne, why is it that when I try to get my head around quantum mechanics, I get a headache? I like Blairs analogy, “there be dragons” it seems to be as plausible as anything that I am reading. Very much reminds me of Shrodingers cat. Great links Wayne!

  • wayne

    Feynman always quipped “no one understands Quantum Mechanics.”
    (as shorthand– just assume ‘all possibilities can exist but they don’t necessarily exist’ & it’s damn near impossible to visualize anything in more than 3 dimensions.’ And ‘entanglement’ is even worse.)

    What is amazing– is the high degree of agreement between Cosmology & Particle Physics in a lot of realms, and The Standard Model explains a lot, but Astrophysics needs more resources to collect more data.

    I would take this opportunity to shill for my preferred Cosmology Theory, from Dr. Penrose. (He’s also working on an even more abstract theory regarding “the biological basis of consciousness– quantum decoherence & superposition,” but that’s not ready for primetime.)

    His Cosmology theory is neat, tidy, elegant, and doesn’t violate the 2nd law of thermodynamics. (and he’s The Master with overhead projectors.)

    Conformal Cyclic Cosmology
    IST Lecture: “Before the Beginning and Beyond Eternity”
    Sir Roger Penrose

  • Joe

    Thanks Wayne, will check out the link before I go to sleep! Great catch on my sarcasm.

  • wayne

    Anyone interested in high quality visualizations (animation) of quantum effects & particles should check out this French quantum physics site–
    “Quantum Made Simple”

    Extremely well done, scientifically accurate, computer generated animation, on such things as; wave-particle action, laser excitation, scanning electron microscopes, quantum tunneling, spin, quantization, superposition, decoherence, etc.

  • mpthompson

    Wayne, I very much enjoyed the lecture by Sir Roger Penrose that you passed along above. The only issue I have with the lecture is that Penrose’s conjecture seems very much dependent upon information disappearing within black holes. This is the part of the lecture where he talks about Hawking at one time making such a claim, but later Hawking recanting that information disappears in black holes — with Penrose saying he believes Hawking was correct to begin with.

    This disappearance of information in black holes is the basis for Penrose’s explanation for how the universe gets from a very high entropy state back to a very low entropy state for the new “aeon” to begin. However, the disappearance of information is a huge violation of the laws of thermodynamics which are dependent upon information not being destroyed — whether inside black holes or anywhere else in the universe. This issue would seem to need to be resolved for Penrose’s cosmology to be more broadly accepted by the physics community which now seems to generally agree information doesn’t disappear within black holes.

    Regardless, it with still an enjoyable lecture. And Penrose is indeed the mast of the overhead projectors.

  • Localfluff

    mpthompson, I think expanding space is allowed to remove information. It happens in black holes and at a Hubble distance where spacetime expands faster than the speed of light. I don’t think that violates any physics. Information isn’t really gone, it is just inaccessible. If expansion reverses, it could come back.

  • mpthompson

    Localfluff, the edge of expanding space is very similar to the event horizon of a black hole in that in both cases, from our perspective, an object as it approaches the horizon will appear to become trapped on the horizon and we will never see the object actually cross the horizon no matter how long we wait. Also, the object will be so red-shifted and be smeared across the extent of the horizon it will be otherwise un-observable, but that is another issue. However, in both cases, information will eventually leave horizon and leak back into our universe due to quantum-level Hawking evaporation. Hawking originally proposed information was lost in this process, but eventually recanted that position. The information trapped on the horizon will, at a practical level, be scrambled beyond recognition, but scrambled information is not lost information. Information that falls into a black hole or crosses the expanding space horizon is no more lost than a drop of ink dropped into a warm bath tub becomes lost as it disperses to the boundary of the tub.

    Leonard Susskind’s book, “The Black Hole War” describes the black hole information paradox in great detail. It’s an excellent read. The book describes how physicist over a twenty year period of time turned from believing as Hawking originally did, that information could be lost or removed from our universe, to eventually realizing that the laws of thermodynamics holds true even at the most extreme conditions at an event horizon of a black hole or at the equivalent horizon at the edge of expanding space.

    Of course, as Penrose demonstrates, not all physicists agree with this interpretation, but most seem to have accepted the arguments put forth by Leondard Susskind and Gerard t’Hooft that information is never lost or removed from our universe. As such, a cosmology that depends upon information loss in black holes is not going to gain much mainstream acceptance within the mainstream physics community.

  • Dave Williams

    Most excellent discussion. One of the best at BTB. Serves to illustrate how much we don’t know.

  • wayne

    you touch on something… I’ll get back to you on all that!

    Cool!. Most excellent input.

    Penrose, I believe, addresses your issue, but it’s not coming to me right now. (He IS the Master of Overhead Projectors!) I’ll have to get back to you, as well.

    -a slightly more recent presentation on Conformal Cyclic Cosmology:
    Sir Roger Penrose – November 2015
    ‘Einstein’s Amazing Theory of Gravity: Black Holes and Novel Ideas in Cosmology’

    I’m not a string-theory Guy myself, but I do enjoy all of Leonard Susskind’s lectures. I’ve been slowly watching/re-watching all his classes on YouTube the past year, and they have them all.
    (Susskind is the Master of filling up blackboards, and in contrast to Penrose he dislikes “electronic teaching aids,” analog or digital– he wants to use his chalkboards!)

    These two lectures in particular, touch on your/’fluff’s, comments, but not entirely…

    Dr. Leonard Susskind
    “ER = EPR” or “What’s Behind the Horizons of Black Holes?” – 1 of 2

    The Black Hole Wars: My Battle with Stephen Hawking
    Silicon Valley Astronomy Lectures (These folks have excellent presentations!)
    Prof Leonard Susskind

    And, Penrose touching on decoherence, superposition, and entanglement, as they possibly relate to biological consciousness.

    Sir Roger Penrose – “Consciousness and the foundations of physics”

    This is a fascinating topic!
    (I only play a Cosmologist on the interweb, but I am resolved to “understand” all this stuff, as-much-as-is-possible, before I die, so I’m highly motivated to do so!)

  • wayne

    Have a multi-link post awaiting moderation, and I should have thrown in these two as well:

    “Leonard Susskind of the Stanford Institute for Theoretical Physics discusses the indestructability of information and the nature of black holes in a lecture entitled The World As Hologram.”

    Leonard Susskind
    The World As Hologram & The Holographic principle

    Sir Roger Penrose, Aeons before the Big Bang
    (Copernicus Center Lecture 2010)

    And I would take this opportunity to shill for anything from “Gresham College Lectures,” they just started a new season, last week, of Public lectures for 2016-2017.

  • Localfluff

    It seems strange if there’s some kind of macro law which only works like forbidding information to be lost. Shouldn’t it be proven from the down up? If space expands, info can get lost. Thermodynamics were formulated before black holes and Hubble bubbles were known. Why couldn’t the discovery of bent spacetime change the conclusions from how matter and energy behaves in a Newtonian world? Why would thermodynamics override both Relativity and Quantum fluctuations? At the Hubble Horizon, information is certainly lost (unless maybe if spacetime crunches back again, which is not a popular hypothesis anymore).

    When we watch matter fall into a black hole, none of it ever enters it. It slows down to a halt before what would’ve become the event horizon. The matter should for ever stay at the surface of a neutron star asymptotically near the critical mass for collapsing to a black hole. From a local frame of reference, the matter does cross the event horizon, but never from our perspective. Still, black holes somehow exists in our reference frame anyway. LIGO recently proved it. How this adds up is beyond me.

  • wayne

    Localfluff– interesting stuff. Can’t speak to any of it right now, but will get back to you later. (Have actual real-work to perform today!)

    — just a brief babble–in brief generalities– Susskind handles the “increasing degrees-of-freedom” ‘thing, fairly well.
    Information gets scrambled beyond belief but never disappears.
    Penrose handles how-that-is-not-violated, with his Conformal Cyclic Cosmology, but I can’t speak to his solution in detail right now. (It’s In There, but I’ll have to find it.)

  • wayne

    Information Entropy—
    Leonard Susskind – Fast Scrambling (2008)

    “Abstract: Motivated by the consistency of black hole complementarity, Sekino and Susskind have conjectured that no physical system can “scramble” its internal degrees of freedom in time faster than (1/T) log S, where T is temperature and S the system’s entropy.

  • Brendan

    You might find this interesting…

    Mike McCulloch has used his theory predict the rotational speed of galaxies without the dark matter crutch. He’s talked about this issue before, and the new data actually supports his theory.

    I’m not a physicist, just a lowly engineer, but I’ve never liked the dark matter concept. Since they’ve never found any trace of it beyond just using it to fill in where theories don’t work, McCulloch’s work seems particularly interesting…

  • wayne

    Brendan– I’ll check that out. I’m predisposed to enjoy British Scientist’s & he has an interesting-sounding specialty-field (“Geomatics.”) I got as far as his home page at Plymouth College.
    I’ll have to dig further (& I’ve never heard of Geomatics.) But… not locked-solid into Penrose and remain persuadable to all things Cosmological & Astronomical.
    You know of any Lectures he has available, off hand?

    (I’m just a lowly civilian, but I truly believe we are in for some fascinating Physics/Cosmology, in the next 20 years.)

  • Brendan

    Wayne –
    I think a lot of his detractors say that he’s not a real physicist, because of his field of specialization. I’ve been following his work because of his commentary on dark matter, but then he started to actually talk about the EM drive (his math seems to predict what is being seen, even though the errors are huge) and his ideas on inertia match what my professor used to hammer home in Physics 8D (inertia becomes infinite, not mass). I have to say that I’ve found a lot of physics to get really strange recently, from dark matter to infinite universes. Most are not provable. But if you can come up with a simple equation and theory that seems to properly describe what is going on, Occam’s Razor really needs to apply.

    Of course, I’m insane. So there’s that!

    I’ve been busy emailing my buddies at Lockheed today after the WashPost article. I was sure I found the culprit (he’s someone I regularly try to go drinking with when I and he are both in Colorado) but unfortunately he had an alibi… or so he says!

  • PeterF

    The simplest explanation is the best.
    The existence of dark matter was a simple explanation. Until it turned out that it may not exist. If it did exist, the random distribution of matter throughout the universe would have created galaxies consisting almost entirely of dark matter as well as galaxies with almost none.

    Perhaps the simplest explanation is that Newtonian physics doesn’t work on a galactic scale. Not hard to imagine since it doesn’t work on a quantum scale either.

    Or we could just keep on adding more circles to the theory until the theory matches observational data?

  • wayne

    I’ll give him a hearing. I am however, definitely not, into whacky-physics, at all.
    (Have enough trouble keeping track of what we do know, much less what we don’t.)
    And, I’m more of the big-picture guy, and have trouble with all the Maths. But the devil, is in the details.)
    I sample/consume, a lot, of this-stuff, and I like to think I’m pretty good at sifting out completely whacky material.

    PeterF– totally on board to a high degree.
    I would counter differ slightly with Newtonian physics & quantum-mechanics, in part, but I understand your point.
    ( no biggie and I’m not extremely well-versed, just highly interested, and moving slowly today…)
    I believe, the big problem (among a few), has been quantizing gravity, but I’ll defer. (The devil is in the details.)

  • Edward

    Wayne wrote: “Anytime you need to insert “the invisible stuff, goes here…” into the equation, leads to problems.

    I have some personal experience with this phenomenon. In geometry class I had some trouble doing proofs. I would start at the beginning and after a few lines I’d get lost. So I would try working backward from the end and try to get to some point before I got lost on the forward part, but I would get lost again. I once tried to insert into the middle “Then a miracle occurs” in order to link the two parts together.

    My teacher found it humorous but unconvincing.

    I have been pondering an alternate hypothesis to replace both dark energy and dark matter (although I am still open to the possibility of these “dark” phenomena):
    There are two forces of nature that work only on the microscopic scale, within atoms, the Strong Force and the Weak Force. Two others work at our scale, the Gravitational Force and the Electromagnetic Force. Perhaps there are more as-yet unknown forces that work only on the galactic/universal scale, and we are unable to directly detect them at our scale.

    On the other hand, what is the fun of having forces that we cannot detect. We might as well remain swayed by the dark side: dark matter and dark energy.

  • mpthompson

    From a local frame of reference, the matter does cross the event horizon, but never from our perspective. Still, black holes somehow exists in our reference frame anyway. LIGO recently proved it. How this adds up is beyond me.

    Localfluff, what you are describing is called Black Hole Complementarity whereby what is observed to happen to an object as it crosses the horizon depends entirely upon the frame of reference in which it is observed. From the outside, the object will be observed to never actually cross the horizon, but it will get within a plank length of the horizon. However, as you describe, if you were in the same local reference frame falling with object towards the black hole, you would observe the object crossing the boundary without a problem. Of course for stellar sized black holes the gravitational gradient is so great that even sub-atomic particles are ripped to shreds, but super massive black holes (think one as nearly as large as our galaxy in size) could have a gravitational gradient no larger that at the Earth’s surface so objects would be free to fall in without the extreme experience of spaghettification (is that a word???).

    For me, Black Hole Complimentarity is what makes black holes such fascinating and surprising things — that two entirely different outcomes can be observed for the same object and both being equally as real. Just as fascinating is the realization that the same thing occurs at the boundaries of our universe where the expansion of space causes ordinary objects to experience the same type of dual existence — the one observed remotely and the one observed locally. For instance, there is a remote observer in our universe for whom our planet is just now just being pushed over their cosmic horizon and they see us slowing down, red shifted, flattened and smeared across a planck deep boundary at the very edge of their frame of reference. No matter how long they wait they will never actually see us leave their universe, but for all intents and purposes, we may as have well have as we, or the matter and energy that comprise us, can re-enter their reality other than as disembodied information slowly leaked back over eons. Yet, while this is happening we are none the wiser and it’s just another day in paradise.

  • Dave Williams:

    Concur. One of the best if not the best discussions on BTB. Much to process here.

  • Localfluff

    @mpthompson, are you sure about the Hubble horizon working like a black hole event horizon? Don’t galaxies actually leave when they cross a Hubble distance from us? When there’s enough space between us and the galaxy that the space expands faster than the speed of light, then the galaxy should disappear completely. Expansion of space happens everywhere between us and the galaxy, not at an event horizon with extremely curved spacetime as with a black hole. My impression has been that the far away galaxies simply fly away from us in a pretty straight forward way, kind of.

  • mpthompson

    Localfluff, I’m not positive about the Hubble horizon working like a black hole, but I’m pretty sure. I’m an engineer interested in physics, but we would need a physicist to weigh in on this. However, from my understanding and confirmed by references I don’t have access to at this moment, the red shift observed from receding galaxies come from two sources, the first being from the expansion of space in the intervening time between when light left the galaxy and when it finally reaches us, and the second coming from the object actually being an at actual relative velocity receding from us due to previous expansion of space prior to the light leaving the galaxy. The red shift we observe is the sum of the two, with the second source being akin to which would be observed as an object reaches the event horizon of a black hole. Likewise, imagine observing a rocket that magically has enough thrust to constantly inch closer to the speed of light (similar to a galaxy that is being pushed by the expansion of space), even if the rocket could reach the speed of light we would never observe it as it would disappear from observation of our frame of reference seemingly red-shifted out of existence, frozen in time and flattened to a plank level depth around the boundaries of our observation.

    However, I could be wrong, and would love someone to confirm my interpretation of such a thought experiment. I believe everything I describe is indeed consistent though on the same principals as Black Hole Complimentarity.

  • wayne

    mpthompson– I tend to think you are correct, but I’m no physicist or even an engineer. (I do however, love this stuff!)

    tangentially— these two Susskind lectures are extremely interesting

    Quantum Complexity Inside Black Holes
    Leonard Susskind

    More on-topic:
    Dr. Leonard Susskind on Dark Energy

  • wayne

    Blair– Most Excellent vacation-blogging!
    (I encourage everyone to check out your blog the past few days.)

  • mpthompson

    Something I would like to add is there are two very interesting aspects to objects as they approach an event horizon — either a horizon around a black hole or the edge of expanding space. The same holds true for objects with mass as they are accelerated to the speed of light — which to an outside observer is equivalent to observing the object approach an event horizon.

    The first is that as the object approaches the horizon is that it becomes more and more red shifted. The implication for this is that the wavelengths of light that we can use to observe the object with becomes longer and longer and our ability to resolve the object becomes less and less precise. As we see the object approach the horizon the wave lengths of light we must use to observe the object will become longer and longer until the wavelengths exceed the size of the horizon itself. To us, being the outside observer, the object will appear to become a 2 dimensional smear across the entire extent of the horizon — all particles that form the object would blend together and appear to be everywhere at once. However, in the local frame of the object, as it passes over the horizon, everything appears completely normal without any indication any horizon is being approached or passed. The object is at the same time both at a single location and everywhere depending on the frame of the observer.

    The second aspect, and this is more speculative based upon my reading from Leonard Susskind, is that as an object approaches the horizon, from our perspective time will appear to slow down for the object. Just as the object approaches the horizon the slow down becomes so great that sub-atomic quantum-level processes normally invisible to us (because they occur so fast and would require incredible frequencies of energy on our part to observe) would become visible. As such, ordinary matter which normally appears as point particles to us (electrons, quarks, gluons, etc…) will explode into detail that stretches in all directions (including time) far beyond their normal point-like appearance. Just before the object reaches the horizon we would be able to see quantum-level details of the object that extend to the very edge of our universe. Leonard Susskind uses a “propellers upon propellers upon propellers” analogy which I would invite others to read and comment upon.

    Unfortunately for us poor observers on the outside, these two phenomena are a cross purposes which thwart our efforts to see and understand the universe at it’s most fundamental levels — our ability to precisely measure an object becomes less in direct proportion as it approaches a horizon and slows down more. In our normal frame of reference, we need to use accelerators on galactic scales to create energies to attempt to discern what happens to objects at Planck scales. However, if we attempt to cheat and throw an objects into a black hole and observe what happens at vastly reduced time scales near the horizon, we need to create galactic scale sensors that can capture the red shifted photons to observe what happens to the object. We just can’t win… :-(

    What’s very interesting is that we normally expect event horizons to be extreme places where space-time is so warped that normal laws of physics break down. However, if we realize that we ourselves reside on such a boundary for some distant observer, then we must come to the conclusion that event horizons are no more radical or extreme than normal space we experience everyday. The laws of relativity and quantum mechanics operate exactly as one expects even at what appear to be extreme conditions.

    Furthermore, once one accepts that what comprises the vast majority of our universe lies outside our observable 3D buble of expanding space-time and that that ALL that stuff (the rest of the universe) is compressed to a 2D Plank-depth boundary at the edge of our universe, the idea that we live in a holographic universe actually begins to make sense. For instance, consider this. That everything we observe as normal 3D space-time (with point like particles) for us, for another distant observer in our universe, is actually occurring smeared across a 2D Plank-depth boundary for them. For me, realizing that both our observations and the observations of the distant observer are equally real, is the very heart of the holographic universe hypothesis.

    Anyway, very fun stuff to ponder.

  • wayne

    Most interesting. You raise many good points. (I appreciate your effort.)
    Yes, most interesting to ponder. I’ve made a concerted effort to try and get a grip on all-this in the past few years. (highly enjoy the astrophysics & astronomy end of Cosmology)

    Good information, presented well, is hard to find

    I’d recommend the Perimeter Institute in Canada; they will be starting their 2016-2017 Public Lecture series soon & have a large archive of interesting material.
    As well, Gresham College in the UK has great material, on a wide variety of topics
    and for Space & Rocket-Science– highly recommend JPL’s Von Karman Lectures.

  • Localfluff

    I still don’t get how black holes form when nothing can ever fall into them to form them. From our point of view, nothing can fall into them to form them. Still, we are shaken by their gravity waves.

  • wayne


    –Stuff does fall into black-holes. mpthompson is touching on that apparent paradox, with the Frame of Reference thing.
    Every particle/photon/wave that gets too close, is trapped, and the black hole increases in size.
    (With Hawking Radiation, they do eventually dissipate, on massive time-scales, but that’s a whole other ball-of-yarn.)

  • mpthompson

    Localfluff, a way to think about black holes is that they represent the absolute maximum amount of stuff (ie. information) that can be packed into a given unit volume of space. However, as Wayne describes, when it comes to black holes we need to be very careful by what we mean by “the black hole increases in size” when stuff is added to it.

    Here is a very strange thing about black holes. It has been demonstrated mathematically that the maximum amount of information that can be packed into a black hole is proportional to the surface area of the black hole, not the volume of the black hole. This is absolutely counter intuitive with regards to how we normally consider 3 dimensional objects. It’s as if discovering a type of jar where the absolute maximum number of marbles a jar can contain is defined by the number of marbles that can be stuck to the outside area of the jar which is much less than the number of marbles that can actually fit into the jar.

    Once you understand that we, as outside observers, can never observe an object actually crossing over the event horizon of a black hole, this starts to kind of begins to make sense. A black hole can only contain as much information as fits around the area of the horizon, not what can actually fit within the volume of the black hole. It is my understanding is that this strange fact is now an accepted given within the physics community.

    Another way of perhaps looking at this is that from one perspective a non-rotating black hole is an absolute perfect 3D sphere — from our outside perspective it must have what we consider volume in normal 3d space-time. However, it demonstrably behaves as a 2D object when information is added to it in that its surface area increases direct proportional to the information added, not it’s volume. Very bizarre.

    Something to consider is that this 3D vs. 2D dichotomy of black holes may be an important clue as to the true nature of our universe. If the maximum amount of information that any 3D region of space can contain is defined by the 2D outside area of the region, perhaps the fundamental nature of our universe is itself 2D rather than 3D. This once again points to our universe being holographic in nature. Where what we perceive as 3D space + time is actually an illusionary artifact of lower dimensional fundamental building blocks from which our universe is actually built up from.

  • mpthompson

    Wayne, I’ll investigate the links you refer to. They look very promising. It is indeed very hard to find information about cutting edge cosmology theories that are accessible to a lay person.

    I love thinking about thought experiments that make these concepts more clear to me, but I myself lack the mathematical background to really distill my thoughts to rigorous mathematical analysis. Rather, in my reading and research I try to develop a gut level understanding with regards how the universe might work at a fundamental level and then look to validate or invalidate my gut level understanding with actual mathematical calculations or real experiments performed by others.

  • wayne

    I suspect you would enjoy Susskind’s Stanford classes. The total upside is you get grad-school level Physics info, with no grades/homework, & you can fast-forward. “priceless”
    (it is technical.. something like “Physics 541” but he walks you right through it pretty well)
    The Perimeter, Gresham, and von Karman lectures are more “public” in nature, but not dumbed down.

    Empathize and agree with your comment on the search for knowledge. I’m not a big maths-guy. Know stats & linear-algebra, but then things get fuzzy…but it’s interesting!
    (Gresham in particular, has a whole series on Maths.)

    I’m not big on string theory or m-theory, but I totally buy into “extra-dimensions,” just not 11 of them…
    (I believe there is a variant of string theory that only requires 6-7 dimensions(?))

  • Edward

    Even if the material never falls into the black hole, proximity increases the overall mass of the system. The rings and moons of Saturn increase its apparent mass from anywhere farther out. Similarly, the matter that is falling into the black hole increases the mass that generates the gravitational force. As mpthompson wrote, “but it will get within a plank length of the [event] horizon” and as wayne wrote, “and the black hole increases in size.” The black hole engulfs the material anyway.

    Once inside, it is hard to know what happens, but if the matter “never” makes it to the center but stays near the event horizon — at least from our own point of view — then that would explain that 2D phenomenon. This suggests that the material “covers” the surface of the black hole.

    Dave Williams and Blair Ivey,
    Yeah, this is a good discussion.

    You wrote: “However, I could be wrong, and would love someone to confirm my interpretation of such a thought experiment.”

    I’m also not an astrophysicist/cosmologist, but my understanding is that you are correct. We cannot see/detect anything that is going away from us at or faster than the speed of light.

    There is a thought among (some?) physicists that if the universe continues to accelerate its expansion (the dark energy thing), then eventually galactic clusters will appear to us to approach — then exceed — the speed of light (don’t worry, this will take trillions of years) as space expands them away from us. They will not be actually travelling through space at this speed, but the space between us and them will be expanding at a rate that gives them this speed relative to us (and us relative to them).

    Once all other galactic clusters disappear from our view, our view of the universe will look like it did a century ago: a stable universe spinning around a center of mass. By then, our local cluster may even have formed a single galaxy, just as we thought our universe was before figuring out that there were other galaxies.

  • mpthompson

    They will not be actually travelling through space at this speed, but the space between us and them will be expanding at a rate that gives them this speed relative to us (and us relative to them).

    When one considers 3D space, there is no absolute frame of reference so the phrase “traveling through space” would only have meaning if there was some absolute reference to travel “through”. However, as described Einstein, space-time does form an absolute reference upon which objects can be measured against.

    Space-time is why a toroidal space station in an otherwise absolute empty universe could still generate artificial gravity by rotating and creating a centripetal force equivalent to gravity. However, one might ask, if the space station is in an otherwise absolute empty universe, what is the space station rotating relative to? Newton himself answered this thought experiment (he used two rocks tied together with a rope which is functionally equivalent) by creating the concept of absolute space which can be thought of as a base reference from upon which all other motion can be measured against. For Newton, the space station would be rotating through absolute space. However, Einstein effectively killed the concept of Newton’s absolute space with the special theory of relativity which stipulates there is no preferred base frame of reference by which all other motion in the universe can be measured. But what Einstein takes away, he also give back. With all velocities, distances and time itself being relative, Einsteins theories still postulate an absolute space-time which conceptually the space station rotates against its own space-time history and centripetal force can still be found on a rotating space station in an otherwise absolutely empty universe.

    Getting back to galaxies receding from each other due to the expansion of space, at great distances they still experience relativistic effects even though neither can be said to be moving “through” local space at anything near relativistic speeds. This relativistic effect mandates that in the entire history of the universe that absolutely nothing, no particle of matter or photon of energy, has ever actually “left” our bubble of space-time by traveling beyond the horizon of expanding space-time. And, no matter how long we wait whether 10^100 years or 10^100^100 years, nothing can ever be observed to leave our universe. Instead, everything that we can no longer observe has accumulated and is smeared across the Planck deep boundary that defines the expanding edge of our local bubble of space-time.

    What is fascinating to me is the realization that while we may consider everything outside our own expanding bubble of space-time to now be part of this 2D boundary that surrounds us, we ourselves are effectively 2D entities living on the same boundary for every other region of space-time we consider to now be part of the boundary.

    Now comes the super speculative and freaky part. I propose that the rest of the universe that held within this 2d boundary will eventually evaporate at the quantum-level via process similar to Hawking radiation and leak back into our bubble of space-time. In this manner, on extremely long time scales the entirety of the universe will be forever be recycling itself through our own bubble of space-time. The freaky part is that we ourselves, at this very instant are no special exception to this this process. Right now, the bits of information that form our own existence within our space-time bubble, by being part of the 2D boundary for other pockets of space-time, are now undergoing this evaporation process and entering other pockets of space-time. This happens simultaneously while being part of our own existence. And it get’s stranger still. This process is iterative so that bits of information may participate not just in our bubble of space-time and one other bubble of space-time, but in an infinite or near-infinite number of other space-time bubbles that stretch across the entire boundary. It literally could be turtles all the way down. :-)

    I could speculate further, but I’ll stop here for now. I think everything I describe is consistent with the theories of relativity, quantum mechanics and thermodynamics, but the piece I’m least sure of is whether objects stuck at the boundary of expanding space undergo Hawking evaporation in the same way objects stuck at the boundary of an event horizon of a black hole do. I don’t see why not since I believe both instances are equivalent to each other (in the same way acceleration due to gravity and acceleration due to changing velocities are demonstrated by Einstein to be equivalent), but perhaps there is some fundamental difference I’m overlooking. Also, what I’m describing is contingent upon the premise that thermodynamics hold under ALL conditions in our universe and information can never be destroyed or removed from our universe.

    As I said earlier. Very fun stuff to think about.

  • wayne

    Don’t want to overload people with links, but this 3-parter is pretty good.

    Messenger Lectures at Cornell

    “Leonard Susskind | Lecture 1 of 3:
    Boltzmann and the Arrow of Time”

    [Theoretical physicist Leonard Susskind delivered the first of his three Messenger Lectures on “The Birth of the Universe and the Origin of Laws of Physics,” on April 28, 2014.]


    “Does Hope drive the expansion of space?”
    J.A.W. (hint:from one of his last journal entries)

    I love this stuff! I feel like I have taken a toke or two but actually didn’t.


    Hint #2
    “We live on an island surrounded by a sea of ignorance. As our island of knowledge grows, so does the shore of our ignorance.”


    When every photon is forever isolated behind its own cosmic horizon, who or what could still be left around to make use of any information? If you can’t have a clock, how can you have information?

    ORCH, CCC, Holographic Principle, Information Paradox, Computational Complexity, this sole thread has it all!

  • Localfluff

    mpthompson, Edward and others,
    Very enlightening posts here!
    Could one say that the gravity wells of masses around a black hole’s event horizon conspire interferometically (sort of) to create an event horizon although they will never reach it, from our view point? (I guess it’s not that simple either, oh well, go away intuition from the Garden of Earthly Delight, that competence isn’t useful in real space).

    Gravity waves lose their power LINEARLY with distance, not by the square law. If I got that right. Does that have something to do with this holographic reduction from 3D to 2D of what a black hole is in our frame of reference?

  • wayne

    you might find this enlightening–

    General Relativity Lecture 6
    Dr. Susskind

    (October 29, 2012 Leonard Susskind presents the physics of black holes including the event horizon, the photon sphere, and the singularity.)

  • Localfluff

    A few links to lectures which confuse me about astronomy, since someone asked above. Not all easily accessible, but all serious and at least sometimes they are accessible to the interested public:





    With fat archives on whatever astronomy topic fascinates you right now.
    Put them in your bookmark list for inspiration on a rainy day or lazy Sunday.

  • wayne


    har– we have “recreational organic matter” on the Ballot this November, until then, one needs a “medical card.”

  • wayne

    one last link…

    This, is amazingly understandable. Gives a good overview of cosmology on a pretty high level.

    Cosmology for Particle Physicists – Part I (of 4)
    Six Fundamentals of Cosmology

    “Edmund Bertschinger lecturing to particle-physics graduate students at TASI in June, 2012.”

  • wayne


    Some interesting animation on Black Holes, (and with a page on Penrose Diagrams.)

  • Edward

    Mpthompson wrote: “there is no absolute frame of reference so the phrase ‘traveling through space’ would only have meaning if there was some absolute reference to travel ‘through’.

    I had intended that to mean that the other galaxy clusters would not violate the speed of light limit. But I agree with your analysis; these clusters would see themselves as stationary as our galaxy would see itself, or as the toroidal space station sees itself. Although there are no absolute reference frames, we can still create our own reference frames, so while I am sitting still at my computer and you are sitting still at your computer, we are actually moving relative to each other due to the rotation of the Earth. From the Earth’s (non-rotating) inertial reference frame, I am travelling at about 800 miles per hour in this direction, and you are travelling about 800 miles per hour in a slightly different direction.

    Now comes the super speculative and freaky part.

    Youza! You speculate BIG!

    A different “turtles all the way down” thought is that when there is enough nothing in an area of the universe, something springs forth, because nothingness is unstable. The book is called “A Universe from Nothing: Why There Is Something Rather than Nothing” and one of the author’s speculations is that as the galaxy clusters that I described above move away from each other, a void forms that has nothing in it, so another universe springs forth – such as our universe – and repeats the process through all eternity.

    I feel compelled to warn you, though, that the author spends some time in his book to “prove” that God doesn’t exist, although it turns out that, under the boundary conditions he chooses, he concludes only that God is unnecessary for the formation of the universe.

  • wayne

    Are talking of Lawrence Krauss? There’s a number of his lectures at YouTube.

  • Edward

    Yes, that is Krauss.

  • wayne

    Is Krauss into infinite expansion and/or the multiverse, string theory or what? I’m unclear on that.

    You might enjoy the material at–
    Perimeter Institute for Theoretical Physics (Canada– they have some heavy-hitter Physicists & a public lecture series in the Fall/Winter. Nice facilities, great video.)

    Yow… I see they just had a lecture tonight, “As We Enter the New Quantum Era.”
    Which I think I shall take a look at.

    Great input from everyone!

  • Edward

    wayne asked: “Is Krauss into infinite expansion and/or the multiverse, string theory or what?”

    I only read the one book of his, and he mentions a whole lot of possibilities. Which ones he thinks are most probable or that he is into was not clear to me.

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