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Evidence for String Theory? 258

Posted by CowboyNeal from the quarks-and-stuff dept.
Izeickl writes "PhysOrg.com is reporting that scientists working at a neutrino detector nicknamed AMANDA at the South Pole report that evidence for string theory may soon be coming. Extra dimensions predicted by string theory may affect observed numbers of certain neutrinos and this is what the scientists will be looking for. The article further states 'No more than a dozen high-energy neutrinos have been detected so far. However, the current detection rate and energy range indicate that AMANDA's larger successor, called IceCube, now under construction, could provide the first evidence for string theory and other theories that attempt to build upon our current understanding of the universe.'"
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Evidence for String Theory? More

Evidence for String Theory?

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  • new dimensions (Score:5, Funny)

    by joe 155 ( 937621 ) on Saturday January 28, 2006 @09:31AM (#14587736) Journal
    I heard that there was only one other dimension... and the only difference was we are all wearing mexican hats... I thought this was general knowledge - perhaps the scientists here should have checked the facts before they started considering 24 dimensional super gravities and the like

  • well is it (Score:2, Insightful)

    by lubricated ( 49106 )
    so will string theory finally be falsifiable and be more than a religion?

    • Re:well is it (Score:2, Interesting)

      by musonica ( 949257 )
      Or perhaps provable and evidence of religion? Oh save us from thy noodley jokes that are yet to be posted... Still this will be great to actually have some idea if the beautiful http://en.wikipedia.org/wiki/String_theory/ [wikipedia.org] has validity!

      • Re:well is it (Score:3, Interesting)

        by l2718 ( 514756 )
        Actually, this research will say next to nothing about string theory. The "string theory" mumbo-jumbo there is just hype. The IceCube experiment will (hopefully) see physics beyond the Standard Model [wikipedia.org], but it's a far cry from that to saying "this will test predictions of string theory". There are literally hundreds of models (many of them string-theory based) for what could happen. More importantly, the energy scale of the experiment will never detect anything "stringy" directly. It can only see the eff

    • Comment removed (Score:5, Insightful)

      by account_deleted ( 4530225 ) on Saturday January 28, 2006 @09:59AM (#14587826)
      Comment removed based on user account deletion
      • >> Just because you don't know how to falsify it doesn't mean it's not falsifiable.

        If nobody has any idea on how to even begin to falsify it, what's the difference?
        >>Religion is by definition not falsifiable.
        String theory by construction is unfalsifiable.
        • Well what about this experiment? If it fails, then that disproves a certain version of it.
          • ok, so certain versions are falsifiable, the thing as a whole is not.

            • Re:well is it (Score:4, Informative)

              by ceoyoyo ( 59147 ) on Saturday January 28, 2006 @11:03AM (#14588059)
              "String theory" isn't a theory, it's a collection or class of competing theories. Kind of like "celestial mechanics." You can't falsify celestial mechanics, but you CAN falsify the geocentric model, thereby realizing that the heliocentric model is better.

        • Re:well is it (Score:3, Insightful)

          by Dashing Leech ( 688077 )
          "If nobody has any idea on how to even begin to falsify it, what's the difference?"

          It's a huge difference. But beyond that, if a theory/model makes predictions about how the universe works, and it is impossible to ever prove it wrong (falsifiable), by definition you've just demonstrated that it is a perfect model of the universe. That is, after all, the goal of the Theory of Everything, to have a model that explains and can predict everything.

          Religion is not falsifiable because it makes no predictions

          • Re:well is it (Score:2, Insightful)

            by Scarblac ( 122480 )

            It's a huge difference. But beyond that, if a theory/model makes predictions about how the universe works, and it is impossible to ever prove it wrong (falsifiable), by definition you've just demonstrated that it is a perfect model of the universe. That is, after all, the goal of the Theory of Everything, to have a model that explains and can predict everything.

            No, if it is impossible to test any of its predictions, then it doesn't actually predict anything at all, and it's perfectly useless. With your "

          • Re:well is it (Score:5, Interesting)

            by Valdrax ( 32670 ) on Saturday January 28, 2006 @02:15PM (#14588883)
            Put yet another way, if string/M- theory is not falsifiable then it is not making any predictions about reality and hence it is useless as a model to tell us anything. That's hardly the case.

            No, that really IS the case [sfgate.com] from a lot of physicists' POVs.

            One problem with the theory is that according one physicist's paper, string theory offers 10 to 500th power different universes all with different physical properties and with many different kinds of forces. String theory practioners -- dare I say worshippers -- use this to say that our universe is merely one out of 10 to the 500th power different possible universes. Some flakes, like Michio Kaku, think we can colonize a new universe through a wormhole with light-speed traveling single-atom nanobots containing the technological and cultural seeds of a new civilization to avoid the heat death of our own universe. [sfgate.com] (This article is why I'll never respect Michio Kaku's words ever again. How did this man ever get a reputation for understanding physics?)

            Other physicists rightly point out that if they theory can handle an almost uncountable number of alternate universes with alternate sets of forces and physical constants, then it doesn't actually predict anything useful since you can't figure out how to predict anything about our own specific single universe has and that its not falsifiable because any new observations we find can be retrofitted into the theory by playing with and changing the math as has happened numerous times since the theory's inception.

            Of course, string theory may be right. The philosophical problem is that many of our best minds are spending all their time on a theory that can't be proven or disproven with current technology. Some of the experiments needed to confirm or deny string theory will take super-colliders capable of generating energy on a scale far beyond even a type I civilizaions' resources (the theoretical energy densities needed to tear matter down to its component strings).

            Since its practioners frequently disdain the necessity of experimental verification, since it's useless as a predictive tool, and since it can be retrofitted for any information that conflicts with it that we'll be able to achieve in the forseeable future, string theory is for all practical purposes nothing more than a math-based religion.

            • Re:well is it (Score:2, Interesting)

              by Anonymous Coward

              (This article is why I'll never respect Michio Kaku's words ever again. How did this man ever get a reputation for understanding physics?)

              And what in that article violates known physical facts? It's speculative, but theoretically possible in string theory, which is a physical theory.

              Since its practioners frequently disdain the necessity of experimental verification,

              Really? Please, name these practitioners and give examples of their "frequent disdain". It's not true of any string theorist I've met.

              I large

      • Falsifiable (Score:3, Interesting)

        by Cybersaint2k ( 828867 )
        Religion that hides so far from rationality and logic that it become non-falsifiable, unproven and unprovable, is hardly the robust Christianity I find in the Bible.

        If you find internal consistency (within the dogma of a religion, including their trusted documents) and external consistency with the outer (earth/cosmos) and inner (conscience/mind) world, then you can start taking it seriously.

        Ordinary Christianity has its share of mystery and hyper-rational statements (that is, statements that seem to be bey
        • Comment removed based on user account deletion

          • Re:Falsifiable (Score:2, Interesting)

            by crazyeddie740 ( 785275 )
            >>has dedicated the last thirty years to showing that theism in general and Christianity in particular is provable.

            There is a difference between "provable" and "falsifible". Science never *proves* something right. It only fails to prove something wrong. Only mathematics and philosophy prove anything, and even those proofs are founded on unproven axioms with unknown truth value. (Sure, 2+2=4 is true, but is 2 true? When's the last time you saw a free-range two?)

            The current body of scientific theory at

        • Re:Falsifiable (Score:5, Insightful)

          by Lifewish ( 724999 ) on Saturday January 28, 2006 @12:38PM (#14588450) Homepage Journal
          If you find internal consistency (within the dogma of a religion, including their trusted documents) and external consistency with the outer (earth/cosmos) and inner (conscience/mind) world, then you can start taking it seriously.
          Thanks for validating my acceptance of Flying Spaghetti Monsterism. May you always be touched by His Noodly Appendage!

          No seriously. The filter you propose wouldn't even catch the travesty that was epicycles. There's a reason why Occam's razor is such an integral part of scientific philosophy.

          [/flamebait]
          • There's a reason why Occam's razor is such an integral part of scientific philosophy.

            Which I assume you take to mean: "All things being equal, the simplest explanation tends to be the correct one."

            When in reality, Occams Razor states: "Though shalt not pluralize needlessly."

            The former is what everyone assumes to be Occam's Razor. It's a travesty, really.
          • Do some research on epicycles. One of the reasons Galileo had a hard time gaining a hearing was that the "epicycle theory" worked for reliably predicting crop planting times and such.

            Which is not to say that it's the best theory; just that the Galileo affair was not a simple matter of obvious truth v. obvious falsehood.

          • The filter you propose wouldn't even catch the travesty that was epicycles.

            Sure it did. Not immediately, but eventually:

            external consistency with the outer (earth/cosmos) ... world

        • Re:Falsifiable (Score:5, Funny)

          by Schemat1c ( 464768 ) on Saturday January 28, 2006 @12:42PM (#14588471) Homepage
          ...the robust Christianity I find in the Bible.

          Yeah, I especially liked the part where Jesus went around hiding dinosaur bones to test our faith. He's such a scamp that Jesus.
      • Until you know how to make it falsifiable, it fails to be science.

        Just because it has equations or big ideas or lofty goals or the support of intelligent people does not mean that one can make the leap "this has potential" to "this is right." By insisting that you have found the one true theory when it is not CURRENTLY falsifiable means that you are following a religion.

        One day, we may discover a God who can attest that the god of the Christians does not exist, or who brings other elements of the supernatu
    • > so will string theory finally be falsifiable and be more than a religion?

      Do you know of anyone teaching their children that they will go to Hell if they don't believe in string theory?

      And if the day ever comes that we get observations that conflict with the claims of string theory, will physicists dismiss the observations as manifestations of God's inscrutable will?

      Even the most speculative branches of science very different from religion.
    • String theory would be provably false if there exists a phenomenon that string theory cannot explain without coming up with an entirely new theory that it's based upon (which, given the nature of string theory, would destroy a fundamental premise of it). This does not mean that the possibility that a myriad of other (perhaps individually simpler) explanations exist for all the phenomena that string theory can explain implies or even begins to imply that string theory is actually false.

      So no... it's no

  • Uh oh... (Score:5, Funny)

    by TheNoxx ( 412624 ) on Saturday January 28, 2006 @09:42AM (#14587763) Homepage Journal
    Great, now we'll be able to see Cthulhu and he'll get all embarassed because he'll be like, in a shower or something when that thing's turned on, and he'll eat the goddamn earth. Can't we be happy with *our* dimension of existence? Wasn't invading Iraq enough?

    • Re:Uh oh... (Score:3, Funny)

      by Jugalator ( 259273 )
      Hmm, and here I thought Cthulhu had been spotted [slashdot.org] already...
    • This makes me wonder how many /.ers are familiar with Lovecraftian mythology and the nature of early 1900s style extra dimensional occurrences.... and when did UFO phenonmenon take over as the predominant explanation for supernatural sightings?

      Someone should do a survey...

  • South Pole (Score:2, Funny)

    by 42Penguins ( 861511 )
    Is this in any way related to the Fifth Dimension, and Let the Sun Shine?

  • Don't get your hopes up (Score:5, Informative)

    by Anonymous Coward on Saturday January 28, 2006 @09:48AM (#14587785)
    This is not the only experiment which could probe large extra dimensions; the Large Hadron Collider at CERN is another notable experiment. However, this article is not implying that AMANDA (or any other experiment) has found evidence for string theory, or even that they are likely to.

    Normally, string physics is thought to appear at the Planck scale (far beyond what we will ever be able to probe directly), because that is thought to be the size of the "curled up" extra dimensions. However, it's possible that the dimensions aren't actually that small, that they could be much larger — possibly not much smaller than a millimeter. (They could even be infinitely large, not curled up at all, and we could be living on a 4-dimensional "brane" close to another one.) In those cases, stringy behavior is brought down from the Planck scale to as low as 1 TeV (tera-electron volt), which is the energy that corresponds to a distance somewhat below a millimeter. (By the Uncertainty Principle, higher energies correspond to shorter distances that can be probed.)

    The problem is, there isn't a lot of reason to believe that these scenarios ought to be true; they are highly speculative (even relative to string theory as a whole!). To a large extent, they are just hopeful thinking — that stringy physics might occur at in an energy regime we can probe. They could be helpful in understanding the hierarchy problem (the question of whether and why there is an absence of new particles between the electroweak and Planck scales), but when you get down to it, most high energy physicists are not betting on large extra dimensions. So these experiments might very well not show up any evidence of string theory (even if string theory is true).
    • Of course, just a couple weeks ago there was a story [slashdot.org] about people at RHIC thinking they saw evidence for micro black holes. And presumably if RHIC can do it, IceCube might be able to as well.

    • Re:Don't get your hopes up (Score:5, Informative)

      by Roger W Moore ( 538166 ) on Saturday January 28, 2006 @02:02PM (#14588832) Journal
      The problem is, there isn't a lot of reason to believe that these scenarios ought to be true; they are highly speculative (even relative to string theory as a whole!).

      Actually there is a good, theoretical, reason to think that these "Large Extra Dimension" (LED) scenarios might be correct (though I'll only believe it if we get data to back it up). If LEDs do exist they can solve the problem that the Standard Model of particle physics has explaining the huge difference in energy scales between the Planck scale (10^16 GeV) and the electroweak scale (10^2 GeV).

      If LEDs exist then gravity might become a lot stronger above the ~TeV energy scale i.e. the Planck scale is actually ~10^3-4 GeV and not 10^16 GeV and a lower energy scales we are fooled into thinking gravity is a lot weaker simply because we can't see these extra dimensions where it spends a lot of its time.

      The problem that LEDs have is in explaining proton decay. It is very likely that protons do in fact decay (this is linked to the fact that we only see protons and no anti-protons in the Universe) but with an incredibly long lifetime caused by the very high energy of the Planck scale. If you lower this energy to a few TeV you either end up with rapidly decaying protons (bad!) or having to put a conserved symmetry in which prevents all proton decay (also bad!).

      So LEDs are an interesting theory which could solve some real problems with existing theory at the cost of introducing some new problems of their own. As a result I think Supersymmetry (which solves the problem which LEDs answer as well as the missing dark matter problem) is a better bet but I'll only believe it if we see it! Unfortunately from an experimentalists point of view LEDs would be a far more interesting discovery since it would mean we could start doing quantum gravity experimentally before the theorists have figured it all out....but not knowing exactly what you'll find is part of the fun of physics!

    • We SHOULD get our hopes up. The only other neutrino detectors I know of are the Sudbudy N Observatory and the super Kamiokande which is out of commission for the while. I dont know how much is SNO producing data and thesis papers, but one detector on the whole earth is underdoing it. And the southpole project is simply more fun while being in a cleaner environment (except possibly nearly nuclear submarines polluting the radiation space.

  • Who needs evidence? (Score:5, Insightful)

    by ScentCone ( 795499 ) on Saturday January 28, 2006 @09:51AM (#14587792)
    "Strings" are just another way of describing devine, Noodly Appendages [venganza.org].

    Actually, this is really cool. Looking forward to what the use of the new detector shows, or doesn't, as the case may be. String theory is such a mind bender for most people (including me), that anything making it more directly tangible will really help focus the conversation. Or end it. Either way is good.

  • This sounds familiar (Score:3, Funny)

    by Rude Turnip ( 49495 ) <valuationNO@SPAMgmail.com> on Saturday January 28, 2006 @09:57AM (#14587818)
    I remember what happened the last time some scientists were doing experimental research in the South Pole. Let's just nip this one in the bud, shall we? Launch Eva!

  • You may know him from (Score:5, Funny)

    by Dachannien ( 617929 ) on Saturday January 28, 2006 @09:58AM (#14587820)
    AMANDA's larger successor, called IceCube,

    Also seen in such blockbuster hits as Boyz n the Nucleus, Three Quarks, and xXx: State of the Quantum.

  • That's nice, but. . . (Score:5, Insightful)

    by petra13 ( 785564 ) on Saturday January 28, 2006 @09:58AM (#14587822) Journal
    It's cool that there's a testable prediction coming out of string theory, but I would take this with a grain of salt for the next few decades. For one thing, I don't think neutrinos themselves are well enough understood yet that string theory would provide the only (or even the best) possible explanation for discrepencies in their 'up' and 'down' neutrino rates. A multitude of experiments are being done now just to try to pin down the parameters governing neutrnio behavior. So if AMANDA sees the discrepency predicted by string theory, it would take a lot more work and many more years to demonstrate that there isn't a better explanation for it.
    • Generaly speaking, if a hypothesis makes a prediction, and the predition turns out to be true, then the hypothesis is reasonable at least for the domaain probed by that experiment, and represent at least a small part of reality.

      We can take three cases. First, the flat earth. On a small scale, the earth seems flat, and in every day life we treat it so. The success of this theory is shown by out upstanding building and bridges. The problem occurs when we try to assume that local flatness is universal.

  • Conversation at the South Pole (Score:5, Funny)

    by Ancient_Hacker ( 751168 ) on Saturday January 28, 2006 @10:00AM (#14587830)
    Top Scientist: How's the measurements going?

    Peon: We've counted 12 possible events out of 789,567,345,754,234,567,876 (est) neutrinos passing thru the detector.

    TS: Hmm, that's as expected, totally useless number of events to draw any inferences from. Keep at it.

    (Next day) South Pole Grant Administrator: Hey, TS, got any news I can tell Washington? Your grant approval comittee meeting for the Big Project is next week!

    TS: Oh, yes, Er, Um, hte data we got from their previous infusion of cash indicates Big Things, the possible proff of String Theory, SuperGravity, The AntiMacassar Postulate, and much more. But better just mention String Theory to the commitee, it was on the cover of Popular Science last month.

    SPGA: Will do!

    • Actually (Score:2, Interesting)

      by Anonymous Coward

      Peon: We've counted 12 possible events out of 789,567,345,754,234,567,876 (est) neutrinos passing thru the detector.

      TS: Hmm, that's as expected, totally useless number of events to draw any inferences from. Keep at it.

      I think you were joking, but astrophysicists extracted a surprising amount of information [arxiv.org] from the 19 neutrinos observed from Supernova 1987A.
      • Yes, they did. But that's only because before that there was near to absolutely NO information about neutrino bursts, and this rare occurrence is just what they needed. Any addition of information to nearly nothing is a big additon.

        In this case there's no convenient source of neutrino burts. Just a huge constant flood. It's much harder to draw conclusions when you can't turn off the source!

  • Heim theory? (Score:4, Interesting)

    by MobyDisk ( 75490 ) on Saturday January 28, 2006 @10:02AM (#14587838) Homepage
    Will this neutrino evidence support or detract from Heim Theory [wikipedia.org], which also predicts multiple dimensions?

    • Sigh (Score:5, Interesting)

      by Anonymous Coward on Saturday January 28, 2006 @10:27AM (#14587918)
      New Scientist sure has created a lot of Heim groupies.

      The fact is, pretty much nobody knows what the hell Heim theory predicts. Most of his theory was never published or reviewed by his peers. We don't even know if his theory is self-consistent, whether the predictions hyped by New Scientist or the Internet "Heim appreciation society" that's pushing it are actually predictions of the theory, etc. For that matter, hardly anybody knows what the definition of the theory is.

      Just because some people have made a bunch of wild claims about what Heim theory can predict, doesn't mean it's something to get excited about. Nor does Heim's reputation. Schroedinger himself thought he had come up with a unified field theory, called a big press conference, privately spoke of winning a second Nobel Prize. Some reporter asked Einstein what he thought, and he responded with a carefully worded response to the effect that one shouldn't get the impression that physics is like unstable Third World dictatorships, always experiencing revolutions. Schroedinger's theory didn't pan out and the two stopped corresponding for over a year.

      • Re:Sigh (Score:5, Interesting)

        by sploxx ( 622853 ) on Saturday January 28, 2006 @06:55PM (#14590576)
        I can only agree with this. The most important finding of this Mr. Heim seems to be a formula to derive the masses of all elementary particles. I n the various (crackpot) sources on the net, it is alleged that this formula has been numerically evaluated with a computer program at CERN, yielding the exact masses.

        Now, there is NO paper or source code available which does this. Hermetism, no thank you, this is the strongest indicator that its simply bunk.
  • There's no need for all this deep theoretical work and all these expensive detectors. I've got plenty of string at home in a jam jar. If they ask nicely, they can have some; it's in this dimension too (I think..).
  • Someone drop me a line when we can use this knowledge to do that Quantum Leap thing and jump around in our own lifetime.

    Then I can go back and warn myself not to:
    Write articles about how Apple is dying
    Buy a DIVX player from Circuit City
    Open the red door in that Choose Your Own Adventure book that ended in me being killed by that vampire that on the cover sort of looks like Boy George.

  • See "Not Even Wrong" Blog (Score:3, Informative)

    by pmjbf ( 950254 ) on Saturday January 28, 2006 @11:23AM (#14588143)
    This is discussed in this blog entry:

    http://www.math.columbia.edu/~woit/wordpress/?p=33 5 [columbia.edu]

    A snippet of which is:

    The half a dozen references to string theory in the short press release might lead the gullible to think that we're about to be provided with evidence for the "exotic predictions of string theory", but that has little relationship to the reality here, one aspect of which of course is that there are no "predictions of string theory" about any of this.

    ...and which might be worth reading if this interests you.

  • Comment removed (Score:5, Interesting)

    by account_deleted ( 4530225 ) on Saturday January 28, 2006 @11:28AM (#14588160)
    Comment removed based on user account deletion

  • So... (Score:2, Funny)

    by Ostien ( 893052 )
    Will Jerry O'Connell [imdb.com] be involved in this one as well?
  • Loop Quantum Gravity: http://www.angryflower.com/dating.gif [angryflower.com]

  • predictions, evidence, and testing hypotheses (Score:3, Insightful)

    by penguin-collective ( 932038 ) on Saturday January 28, 2006 @02:56PM (#14589177)
    A correct prediction is not necessarily evidence for a theory; the prediction might be a tautology or it might be true of many other theories as well.

    For example, my hypothesis might be that Donald Trump's social security number is 666-66-6666. Now, I conduct an experiment in which I test the prediction that his social security number is not 123-45-6789 and the experiment succeeds. I have gotten a tiny bit of evidence for my original hypothesis, but it's so small as to be negligible.

    Well, with scientific theories, it's even worse because there are not just 1 billion of them but an infinite number--unless you do things exactly right, a successful prediction gives you no evidence for a scientific theory at all.

  • Some comments from an Amandroid... (Score:5, Informative)

    by kievit ( 303920 ) on Saturday January 28, 2006 @05:16PM (#14589975) Journal

    I work for AMANDA/IceCube. It's nice to see that our supercool experiment gets media attention, but there are a few statements in that article which need a comment or two. User davidoff404 [slashdot.org] already commented [slashdot.org] on the theoretical aspects of the article, so I will mostly limit myself to the experimental aspects.

    "No more than a dozen high-energy neutrinos have been detected so far."

    Actually, we see about 900 neutrino events per year. Their directions are homogeneously distributed over the sky and the energy spectrum is (still) compatible with the assumption that all these neutrinos were produced in interactions of high energy cosmic rays (protons, nuclei) with the Earth atmosphere (all around the globe). It might be that there are neutrinos among them from extraterrestrial sources, but individual events cannot be identified as such. We continue taking data until neutrino events from single extraterrestrial sources (or with higher energy than expected from atmospheric neutrinos) pile up enough such that they stick out over the atmospheric neutrino background.

    Note: we do not detect those neutrinos directly; they interact with the ice, and may convert into a "muon" (which is like an electron, only about 200 times heavier, and it decays after a little while). That muon still carries most of the neutrino's energy with it, so it flies practically with the speed of light through the ice, sending out Cherenkov light (the electromagnetic equivalent of a sonic boom) along the way. The tracks can be kilometers long. We only see the part of the track in or near our detector, so we can only estimate a lower limit of the energy of an individual muon. When the neutrino does not convert into a muon, then the energy is dissipated in a relatively small volume; which makes it much harder to estimate the direction, but easier to estimate the energy.

    (And of course those atmospheric neutrinos are not only background. We are happy to see them, as they prove that our detector is not blind. And we can use them to test the models of cosmic ray spectra and to study properties of neutrinos themselves.)

    AMANDA, funded by the National Science Foundation, attempts to detect neutrinos raining down from above but also coming "up" through the Earth. Neutrinos are so weakly interacting that some can pass through the entire Earth unscathed. The total number of "down" and "up" neutrinos is uncertain; however, barring exotic effects, the relative detection rates are well known.

    Actually, neutrinos are so weakly interacting that the vast majority of them just flies right through the Earth. It is really tiny fraction of them which happens to bump into an terrestrial atom. And an even tinier fraction which bumps into an ice molecule near our machine. So they come from all directions, up and down, the Earth is not shielding them. However, like everywhere on Earth there is a lot of cosmic rays thundering down on the atmosphere above the South Pole, and some of it results in high energy muons which make it all the way down to our detector. Their rate is about a million times higher than that of the muons originating from the neutrinos. Only when we see a muon track going upwards, or when it has an energy much higher than expected from the cosmic ray spectrum, then we call it a neutrino event.

    When we start talking about really very high energy neutrinos (PeV and more) then the picture gets a little bit different: at those energies the probability that a neutrino interacts with atoms gets so high that the Earth is indeed opaque for neutrinos. If there are such high energy neutrinos flying through the universe, then we expect to see them from above and horizontally. This is already expected with standard model physics, without assumptions about microscopic black holes; so I am curious as to what Goldberg and Feng are after.

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