Of Particular Significance

Science Down, Up, and Inside-Out

POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON 05/25/2012

First, a couple of things you might like to read:

  • There was a long-overdue article from the New York Times as to how, after eight years of cuts from the Bush administration during good economic times, followed by additional inevitable cuts during the Great Recession, formerly world-leading scientific research efforts in the United States are on the verge of collapse, risking far more than the scientific research itself.  The situation is far more dire, in my opinion, than the tone of the article implies; the brain drain of talent leaving the US is frightening and well underway, and the problems are by no means limited to particle physics and astrophysics.
  • The article that I described last month by Moni Bidin et al. that claimed (loudly, in the press) that there was little evidence for dark matter in the Sun’s interstellar neighborhood (but far from the center of the Milky Way galaxy) has been discredited by one of the world’s leading astrophysicists, working with a younger collaborator. The claim (made without a big press release) of Jo Bovy and Scott Tremaine, from the Institute for Advanced Study in Princeton, is that one of the assumptions on which the Moni Bidin et al. argument was based is inconsistent with data and therefore wrong, ruining the argument. Bovy and Tremaine have replaced this assumption with a different one that is consistent with data, and they conclude, in contradiction to Moni Bidin et al., that the corrected argument leads to the conclusion that there is indeed dark matter in the vicinity — roughly the amount one would expect from other considerations. In short, the Moni Bidin argument, once corrected, actually leads to more evidence in favor of the existence of dark matter! A short description of the situation is given on the Resonaances blog.

Second: I’m starting to think about a new section for this website.

Particle physics, quantum mechanics, and all the strange-sounding stuff that many physicists study are often thought of as esoteric, abstract, and irrelevant to ordinary life. But in fact our world is directly impacted, in many different ways, by quarks and photons and quantum uncertainty and the like; these things are not abstract at all. To make this point more accessible, a website like this one needs a good introductory section to help beginners make their way into the world of particle physics. So I’m going to be constructing this section over the coming months. Feedback from readers as to whether the material is readable and sufficiently introductory will be very valuable, so please feel free to offer your comments.

One of my first tasks is to talk about the architecture of the universe — how its parts are formed from smaller parts, on down to the smallest objects we know about so far. Of course there are many other introductions to this subject already on the web (and a few of them are even correct!) What I hope will make my presentation a little different is the inclusion of some insights into not only what we know about the structure of the universe but also how we know it, and additionally some comments on how our lives are impacted by each level of detail in the architectural hierarchy.

The first phase of this process will be to look at how ordinary matter that we are made from and surrounded by is constructed from the basic ingredients of electrons, quarks (and anti-quarks and gluons), and the strong nuclear, electromagnetic and gravitational forces. The figure below gives a preview of what’s coming (and you can click the figure for a larger version.)

The hierarchical architecture of ordinary matter. At the lowest known level are found electrons (e), quarks (u,d,s) and anti-quarks, along with force particles such as gluons. Up and down quarks, gluons and pairs of quarks and antiquarks make up the proton and neutron (the “nucleons”), and are held together by the strong nuclear force; a residual effect of that force holds the protons and neutrons together in atomic nuclei, of which there are a few hundred. The electromagnetic force allows electrons to attach themselves to nuclei, forming a hundred or so chemically distinct types of atoms. A residual effect of the electromagnetic force then binds the atoms together into a gigantic zoo of molecules, out of which the vast complexity of ordinary materials — the air, the sea, the rocks underfoot, and the immense diversity of life — are formed. Meanwhile gravity crushes the earth’s rock into a rough sphere and keeps the air, water, and living things from floating off into outer space.  The rough sizes of the objects appearing at each level of structure are indicated at right.

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25 Responses

  1. Hi would you mind letting me know which webhost
    you’re working with? I’ve loaded your blog in 3 different
    browsers and I must say this blog loads a lot faster then most.

    Can you suggest a good hosting provider at a fair price?

    Kudos, I appreciate it!

  2. Samuels (Eminem) “Nothin’ On You” — Philip Lawrence,
    Ari Levine, Bruno Mars & Bobby Simmons Jr. –LINK REMOVED –>Grammy Nominations 2011<. Neighbours were quite few, high were only three other women living inside neighbourhood – all lived in both bark huts or tents with their young children.

  3. “Down, Up, and Inside-Out” looks like the incantation Cugel the Clever used to escape from the cave in the forest, where he was lured into and kept by the rat people. 🙂 (Jack Vance, The Cave in the Forest)

  4. The Bragg peak in the stopping cross section involves an outstandingly ugly cutoff in the impact parameter, yet has been flogged out to fourth order in the Born series. This is no matter of mere aesthetics: carefully tuned sums of these peaks (`Spread Out Bragg Peaks’) are used to disintegrate tiny cysts deep inside folks’ brains. Maybe the hep community might wish to use its formidable expertise in renormalization etc to devise a less clunky SOBP formula. Such a contribution would be unlikely to go unappreciated.

    1. Hmm. You may be right. Maybe you could write a more complete and concise comment stating the problem, with a couple of references to the state of the art? I can try to draw attention to the problem.

  5. Me again: it’s the Mott cross-section, on BJ-Dr v1 p106, that gives the Bragg peak. One day there’ll be Delta++ beam therapy. But, the budget for the proposed ILC would pay for a lot of proton beam clinics, which cost $100m each. They’d employ of a lot of hep fans who would be doing good by the minute.

    Just a thought.

  6. Proton beam therapy (egads, there’s even talk of `hadron’ therapy) was pioneered in the US, and is even covered under Medicare. What’s not to like? On the subject of which, do you know a modern treatment of the Bragg peak, more modern than Livingston and Bethe, Rev Mod Phys 1937 v9 (3)?
    Or should I be able to dig it out of Bjorken and Drell vol 1 ? (now THAT’s a book and a half). It’s only Coulomb scattering after all, proton off shell electrons.

    I’d still be grateful for a recommendation for Nuclear Physics in general. The texts in the local library are all of an age.

    Thanks for a great website.


  7. “Empires decay by losing track of what is important to their past success.” AARGGH!!!!

  8. This is a fight that we cannot afford to lose. There is no choice but to constantly remind our politicians of what they often forget.

    The reason the United States is still a leading world power has to do with things like radar. Radar helped win World War II. And it has to do with things like transistors, which provided the key ingredient for the computer revolution, and the trillion dollar industry which plays a big role, directly and indirectly, in the economies of the free world. Without the commitment of the United States to science, both through universities like MIT and through companies like Bell Labs, the US would not be a superpower.

    Empires decay by losing track of what is most important to their past success. If we lose track of how scientific research made the United States what it is, and pull the plug on that research, we will watch in dismay as the Chinese (who are putting huge amounts of money into scientific research) outdistance us in technology, putting first our economy and then our national defense at serious risk.

    1. You won’t find many who agree with you more than I do, but we’re stuck at a confluence of forces.

      Shortsighted politicians (which is all or almost all of them) will always go for the immediate stuff that can get them re-elected. At the extreme of that you have the braying naysayers like Proxmire, but the tendency is always there. Add to that the people who agree about causes but consider the result undesirable, from environmental zealots who consider humans a plague on the planet that should be fought (with the US as exemplar) to elites from other countries who resent that the American system throws of wealth and theirs does not, and can find no solution except to impoverish the United States; on top of that are the people who consider any concentration of resources, be it a baby-food factory or an SSC, to be inegalitarian abuse requiring dismantling and “redistribution”. Taken together, they’re going to be hard to stop — and rational arguments are not and have never been a way to stop them because they didn’t arrive at their conclusions by rational thought.

      Science is and has always been an activity of the elite and privileged. The Greek philosophers had slaves, and the class they belonged to used up a huge fraction of the society’s resources — because they had to, else they wouldn’t have had the time and energy to think. A wealthy industrial society like ours produces enough wealth that the amount taken from any individual to support science (or the arts) is minuscule, where many people had to give up their whole lives to support a Plato; but that’s recent, and our feelings derive from earlier times. It isn’t at all hard to make an individual citizen feel that a space program or a multimillion-dollar science project like a collider uses up resources that could make their lives better, and demagogues of all stripes know that and use it with verve. At the moment they’re in the ascendant.

      This is why American college students become lawyers, “educators”, or Government factotums instead of engineers or scientists. That’s where the money, and more importantly the prestige, is. I personally think the process has gone too far to reverse, but I’m happy there are people like yourself still willing to strive. Who knows, it might just work.

  9. Are Bovy and Tremaine better astrophysicists than Kroupa and McGaugh? Consider Milgrom’s ideas on dark matter:
    “To think, as dark-matter advocates say they do, that the universal MOND regularities exhibited by galaxies will one day be shown to somehow follow from complex formation processes, is, to my mind, a delusion.” — Mordehai Milgrom, “DM or MD?”, p. 1
    arxiv.org/pdf/1101.5122v1 “MD or DM? Modified dynamics at low accelerations versus dark matter” by M. Milgrom, 2010, Proceedings of Science
    “I think few people appreciate that the main difficulty for DM is that the host of regularities pointed out by MOND, if taken as just a summary of how DM behaves and interacts with normal matter, suggests that these two matter components are coupled and correlated very strongly in many ways. … if MOND does turn out to have some truth to it, the fact that it has encountered so much opposition will just show how nontrivial a thought it was.” — Mordehai Milgrom, interview entitled “Dark-matter heretic”, American Scientist, Jan.-Feb. 2003, Vol. 91, #1, p. 1

    1. “Are Bovy and Tremaine better astrophysicists than Kroupa and McGaugh?”

      Tremaine is clearly one of the world’s best. Bovy is young and unknown to me personally, but the postdoctoral researchers in astrophysics whom I knew when I was a postdoc at the Institute for Advanced Study are now among the world’s leading astrophysics faculty. I would view this as a blue-ribbon team.

  10. I don’t think there’s a need to add another section, since your current “technical zone” at the top can house this section in addition to its current purpose. It would be great if you could put your articles on energy, momentum etc there also since these great articles are currently hidden from the potential newbies visiting this site over the coming years of the LHC run.

  11. Isn’t power point great?! 🙂

    A curious observation is as the structures, atoms and molecules, become more complex the outcome, evolution of the universe, tends to life and beyond to consciousness, (we are very high up in the overall scheme of existence).

    We have a consciousness which is very difficult to define and formulate with the same math we use to formulate physical phenomena. Below is a very interesting video of a 3D formulation of what the known universe looks like. As you can see it has a striking resemblance to the structure of our brain, the structure that gives us consciousness.

    1. Do you believe that a universal consciousness can exist given this data?

    2. This maybe a bit over reaching but here goes … Like our own consciousness can control our brain functions and hence our body functions, could the universal consciousness (once it “turned on”) create the more complex of fields from the fundamental field (gravity or something else) and hence drive the primordial chaotic universe to one of order and expanding, … order and expanding … order and expanding. i.e. the expansion of the universe is not related to the initial conditions at the big bang but rather the universal consciousness is reinforcing and evolving to a higher and higher state. A principle of conscious advancement as the driving for everything. No conservation laws need to be violated or invalidated.


  12. So many decisions and public-sphere arguments have left me jumping up and down and screaming in frustration. The argument over the fate of the SSC (anybody remember?) was particularly maddening. I had to stand there and watch, helpless, as scientists explained the costs to people in “billions of dollars” instead of simply stating that the cost per taxpayer was something on the order of $20 per year during construction. Why some scientists and politicians don’t understand the necessity of bringing numbers and decisions down to the scale of a single individual human being to talk publicly about them is one of the great mysteries of the universe, and likely the #1 reason my blood pressure is going to kill me one of these days.

    1. Hi Xezlec,

      your suggestion of saying what funding “big science” would actually mean for each citizen rather than throwing around large numbers seems very reasonable and it probably could have saved some now dead nice projects … :-/

  13. I do feel for our American cousins across the pond. The politician’s there have been steadily and systematically throwing away their leading contributions to science, and by extension humanity, for too long and I feel a recovery is becoming increasingly less likely as time goes by. What a waste.

    I welcome your new plans to the blog. It sounds like a great idea and I look forward to reading, and commenting upon, your ideas.

  14. Firstly – thanks for a wonderful website.
    For an introductory diagram why show 3 types of quark – would it not be less confusing to show just the U and D types on this diagram.
    Also think many readers would be confused by showing 2/4/6 ‘types’ of quark underneath the box for the strong nuclear force (which mentions 8 gluons).
    Handling the range of scales is going to be difficult – could use Km for the ‘Earth’ level, 0.001mm to 100Km for the next level (Diversity of Structures), and mm for the lower levels.

  15. Scale in decimals of a meter on right side of figure is just about unreadable. Suggest adding commas and scientific notation in parentheses.

    1. At the very least, please consider some “1000x smaller” notes between adjacent labels so that we can easily tell how big the jumps are.

  16. Observing how the US governement systematically destroys fundamental physics since a long time ago now is very sad 🙁

    1. … I mean, we probably have now the knowledge and the technology (or could develop it fast enough) to answer some interesting fundamental questions scientifically but if governements of large and powerful enough countries decide to destroy these possibilities it is all in vain 🙁

      The new section of this site Prof. Strassler wants to develop will certainly be beautiful and I hope it will help and serve its purpose …

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