Blogs / Cosmic Variance

Today has been a good day for smackdowns! First up, Simon White in New Scientist, punching up his previous argument:

We need to apply a hard-nosed cost-benefit analysis to dark energy projects. We must recognise the cultural differences between high-energy physics and astronomy, and be willing to argue that astronomical discoveries – that the universe expands, chemical elements were built in stars, black holes exist, planets orbit other stars – are no less significant for humanity than clarifying the underlying nature of forces and particles.

Any large new astronomical project should be designed to push back frontiers in several areas of astronomy…

If we don’t do these things, we may lose both the creative brains and the instruments that our field needs to remain vibrant. Dark energy is a Pied Piper, luring astronomers away from their home territory to follow high-energy physicists down the path to professional extinction.

Next, Pope Benedict (via Atrios and Cynical-C), putting the hurt on those nefarious splitters:

The Vatican reiterated Tuesday that the Catholic Church is the one true church established by Jesus Christ and that other Christian denominations are defective, although they have elements of truth and sanctity.

In a brief document, “Responses to Some Questions Regarding Certain Aspects of the Doctrine of the Church,” the Vatican’s doctrinal office, with Pope Benedict XVI’s approval, reiterated controversial assertions made in its 2000 document, “Dominus Iesus,” that Christian denominations that do not have apostolic succession — the ability to trace their bishops back to Christ’s original apostles — can’t properly be called churches.

And finally, Senator Patrick Leahy, via Matthew Yglesias and a dozen other blogs:

A powerful elixir of sarcasm and high dudgeon mixed into a few sort sentences! Awesome.

Vote for your favorite.

So, I’ve been in the throes of grant proposal writing, which as far as I can tell is the worst part of becoming a professor. As such, I’ve been ignoring as much of my email as humanly possible for the past week. Until I got an email from David Weinberg this afternoon, announcing to the SDSS (Sloan Digital Sky Survey) mailing list the arrival of a new web-based galaxy classification project, Galaxy Zoo. The project was started by some scientists with SDSS, including Alex Szalay and Bob Nichol, and others. They had a press release today, and it’s already been covered by the BBC and was picked up by AP, so I think the website has gotten a bit hammered in the first day.

The basic idea here is to harness the collective eyes and brains of the internet to visually classify galaxies by morphology. It turns out that galaxy mophologies are in some ways a lot easier to classify by eye than by computer, just like faces and other complex images. This is one reason that now that surveys include millions of galaxies, morphology studies have not been as popular as other classification schemes based on colors or spectral types. Apparently, galaxy zoo to the rescue!

Here’s the first thing I learned: looking at pictures of galaxies is a lot more fun than writing proposals to the NSF to get funding to think about galaxies.
(Dear Galaxy Zoo: if I don’t get a CAREER grant this year, I blame you!)

There were tools to do this before, and I actually have managed to (finally) look
at a bunch of these Sloan galaxies over the past few years (I’m a theorist who’s never been observing, and normally I only look at fake galaxies in my computer — or real galaxies labeled by just a couple of variables like luminosity and color instead of their infinite structural variety). But the fact that galaxyzoo gives you a goal for looking at each galaxy makes it totally addictive. Plus galaxies are just pretty awesome looking! Even better, each galaxy has a link directly back to the SDSS Sky Server, which has tons of other info about the galaxy, like a spectrum where available, 5 band magnitudes, etc.
Personally, I found myself compelled to look at this information when perplexed about how to classify something. What’s it’s color? Is it star forming? What’s is redshift? All there. (Really, it was all there in the Sky Server before, but this is a pretty cool interface to it because you start by wondering.)

It turns out there’s a lot of cool stuff in the Universe. In just a bit of classifying, I found a couple of cool galaxy interactions (click for more info):

A galaxy that to me looks like the cartwheel galaxy with bad seeing:

My main gripe about the site is that they’ve made the classification pretty simple,
just allowing for 3 types of spirals, counterclockwise, clockwise, and edge on
(none of which are really different types in the classical sense), elliptical galaxies, and mergers.
What was I supposed to do with the cartwheel?
And what about this bloby guy, which has whopping H-alpha and OII emission and the mysterious zwarning “NOT_GAL”? Clearly has no structure but I just couldn’t bring myself to call it an elliptical.

Or these very nebulous beauties:

I kept wishing for a button that said “This one’s interesting” or allowed me to choose from a menu, including things like “close pair“, “blobby star forming thing“,
“scoop of neopolitan ice cream” or “i’ve got a green crayon“.
In all seriousness, I understand the simple scheme, but it does seem like there’s a lot of potential here from a lot of eyes that won’t be realized with it. I wonder whether a lot of this won’t come from the classification statistics, though, i.e., probably many of the interested objects will have less consistent classifications than normal ellipticals or spirals.

To be honest, I think I have exactly the wrong amount of knowledge to do this task effectively as designed — I overanalyze it and think I must know what’s going on, but am clearly just a clueless theorist. Turns out we’re still trying to explain the two most basic parameters.

Anyways, go check it out. A Universe of galaxies awaits at your fingertips!

According to the Argus Leader, via the Science Journalism Tracker. The National Science Foundation has finally decided on a location for its Deep Underground Science and Engineering Laboratory, which has been up in the air for years now. The winner is the place that had a head start on its various competitors: the Homestake Mine in the Black Hills.

The underground lab will be the site for a diverse array of experiments, from searches for dark matter and proton decay to investigations into biology and geology under extreme conditions. The Homestake site is already famous, of course, as the home of Ray Davis’s neutrino experiment, where the solar neutrino problem was first identified. The mine itself, the deepest and (until recently) oldest operating mine in the Western Hemisphere, was operational until 2001. The NSF immediately wanted to take it over to use as a lab, but the Barrick Mining Corporation demanded that the government also assume any future liability for problems arising the mine (not a stance that fills one with confidence), and if not, they would flood it. While negotiations dragged on, others jumped into the game, and eventually a competition was launched that ended up choosing Homestake anyway. I’m not expert enough to judge whether the effort expended on the competition was all just a waste of time, or whether the ultimate scientific capabilities of the facility were really improved by the process.

Brynn at Shakesville points to a study by Kristine Nowak and Christian Rauh of the Human-Computer Interaction Lab at the University of Connecticut. The authors investigated the impact of the appearance of digital avatars on people’s perceptions of trustworthiness. (Here’s what appears to be an earlier version of the study.) They did a blind test, with participants chatting online via various sorts of avatars. Some looked recognizably human and gender-specific, others were cats or lizards or apples. They then asked the participants to rate the credibility of the people they had been talking to.

Everyone is talking about the fact that the participants rated androgynous avatars as less trustworthy. Images that were recognizably male or female were thought of as more credible than those sneaky in-between ones.

To me, the more important finding was that the ketchup bottle finished near the very bottom of the trustworthiness scale, only beating out a menacing-looking lizard beast. Even the cat was judged more trustworthy than the ketchup bottle; if you’ve ever met a cat, you’ll understand that that’s saying something. I’m happy to see that my long-standing distrust of ketchup has been scientifically vindicated.

(Others have suggested that the study’s authors are just dumb bitches. Happily, sexism has been eradicated, so that web page must be at least fifty years old.)

Now that I’ve been back from hunting dinosaurs with Project Exploration for a few days, I owe you all the report. I’m not going to go into all of the background, as that was covered pretty well in my blog posts about the 2004 trip, Dinosaur Report I and Dinosaur Report II. So this will just be a little photo-essay about the heavy lifting that was specific to this trip.

During the previous two trips I had been on with Project Exploration, the focus was on prospecting and the early stages of bringing fossils out of the ground. Clearing away the dirt, exposing bone, determining what we found, estimating the physical extent of the fossils. The eventual goal, of course, is to clear away everything but the bones and enough rock (called “matrix” in paleo-speak) to hold it together, wrap up the pieces snugly in wood and plaster (”jacketing”), and bring it all back home — in this case, Paul Sereno’s lab at the University of Chicago. But the process as a whole takes time, and three days of work by a crew of enthusiastic but untutored amateurs generally isn’t going to make it happen. But on this trip we were working on a site where most of the work had been done, and our task was to finish the job. In fact, we were back to the site I had gone to in 2005. In the meantime the locations of the various bones had been ascertained, many of them had been fully jacketed, and our task was primarily to finish off the biggest pieces. “Finishing off” means completing the jacketing process and transporting the jackets to Billings, Montana, where a freight company would carry them to Chicago.

The story is conveyed better by words than by pictures. Click to get hi-res versions in a new window.

Here is a view of our vans, as seen from the dig site. Each morning we’d get up bright and early to have breakfast at Dirty Annie’s (the finest dining establishment in all of Shell, Wyoming, featuring chokecherry pancakes the size of garbage-can lids). Afterwards we’d head out to the site in two rented vans, the backs of which were filled with all the paleontological necessities: burlap, plaster, water, picks, awls, hammers, GPS units, shovels, trowels, gloves, 2×4’s, buckets, tarps, brushes, kneepads, and sundry snack foods. The vans would bounce over dirt trails to the foot of the hill where the fossils were, and we would all jump out, eager to get our hands dirty. (On at least one occasion, unanticipated logistics forced the crew into drafting a theoretical physicist into van-driving duty. Thankfully, nobody was seriously injured.)

And here is the dig site, as seen from where we parked the vans. Just to the left of center there you can see the plaster around the main group of fossils — jacketing that bad boy and trucking it to Billings was our primary challenge for this trip.

For some reason (too excited by the goings-on, probably) I neglected to take a close-up photo of the main fossil group before we covered it with plaster. But to get the idea, here is a smaller group, this one a collection of vertebrae. In the field, the main goal is to roughly carve out the bone and get it back to the lab in workable condition. On the other hand, you don’t want to make it heavier than it needs to be, so you try to remove as much matrix as you can without sacrificing the structural integrity of the fossil. Once the bone is exposed, you cover it with tinfoil, then wrap it with burlap strips dipped in plaster. Delicate soul that I am, I resisted participating in the plastering at first, but ultimately I realized that everyone else was right, it really was the most fun part of the whole procedure. To make the jacket a bit stronger you can plaster pieces of wood to the whole collection, as seen in the bottom part of the picture.

Here is Paul on the first day, explaining to our intrepid crew of newcomers what we’ll be doing out here. The part of the process for which I was best suited was the delicate work with an awl and a brush, clearing away bits of matrix right up against the bone. Probably I’d be even better suited for the close-up work performed by the preparators back in the lab, who work under microscopes to remove things at the grain-of-sand level and reconstruct the bones. Actually, come to think of it, I’d be best suited to be sequestered in a room far away from any fossils, left with a pen and paper to think about the universe. So that all worked out for the best.

Paul, eager to get going, burns off nervous energy by doing push-ups. (He was the only one to employ that strategy.)

Here is the main collection of fossils, separated out from the surroundings and covered on the top with plaster. It consisted of vertebrae, ribs, and sundry other bones that I won’t pretend I could identify. Paul figured that it was a sort of Diplodocus, one of those lumbering herbivores with giant necks and tails that roamed North America during the Jurassic. But the structure of the hip bones differed from that of the ordinary Diplodocus, so Paul judged that it was a new species. By the second day he had promoted it to a new genus — apparently the rules for whether a new species is in a distinct genus or an entirely new one are a little fuzzy. In any event, our job was to hack away at the underpinnings of this rock, and eventually to bring it home.

And away we go!

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Today is the last day left in the FDA’s public comment period regarding changes to the labeling rules for irradiated food. Given the other problems in the world, this may or may not have been on your radar screen, but if you eat meat it certainly should.

Imagine if there were a product, say a soft drink, that sickened upwards of 200,000 people every year, and killed thousands. How would the public react? Clearly there would be outrage on a truly massive scale, legislation, regulation, whatever it took to end the scourge. Just look at the outrage ensuing after the spinach crisis last year.

We have such a product in this country: meat. It is produced in conditions such that the main processing challenge in bringing it to market is simply keeping “filth” – the animals’ own excrement – from infecting the final product. The public has simply accepted the sickness and death as collateral damage, not a problem to be solved. Nothing must get in the way of the steady stream of 99 cent burgers!

The meat industry has a “solution” which I put in quotes because it may be worse than the problem itself: food irradiation. The minute most people hear that their hamburger is made from meat that was irradiated, they don’t want it. And if more read the label that is presently required (but proposed by the meat industry to be removed) then they might not buy it.

Food irradiation kills bacteria, but not all of them. The meat industry wants to irradiate food so as not to have to spend more money making meat processing safer at the slaughterhouse, which would raise the cost to consumers.

The real problem, though, is how radiation kills bacteria. Often the irradiation is performed using an isotope of cobalt which emits gamma rays – very energetic photons, more energetic than x-rays, which are also used for this purpose. These photons travel a long way through most materials and lose their energy by knocking electrons off the atoms of the material. The emitted electrons have a great deal of energy and knock off other electrons, sometimes resulting in breaking up the molecules of the material. These molecular fragments are called radiolytic byproducts. The radiation does not just kill bacteria, but produces new molecules in the meat itself never encountered in nature, some of which may be harmful. We actually don’t know very much about this possibility.

We do know that for irradiated fats, long-chain carbon based molecules, the radiolytic byproducts include 2-ACB, a chemical shown to cause colon cancer in mice. But that is just one of potentially thousands of different radiolytic byproducts of irradtiation. In effect, we are performing an enormous, uncontrolled experiment on millions of human beings – us – for the sole purpose of saving the already heavily subsidized meat industry a few pennies on the dollar. The effects could be devastating, healthwise, or maybe not. Is it worth the risk?

Even more interesting is a study of the change in flavor of irradiated meat products. The irradiated meat was descibred as tasting like “wet dog” or “singed hair”. Yum.

Food irradiation is banned in Europe, largely due to the above concerns. At a minimum, the labelling requirements should stay in place. The meat industry has lobbied to change the label to say “cold pasteurized” or remove it altogether. But we ought to be considering an outright ban on this very questionable practice.

I am not a vegetarian, but I used to be for about eight years, partly for reasons like this. I buy organic meat now whenever possible, and avoid fast food. I want to know what I am getting, and the meat industry doesn’t want us to know! Why don’t we let an informed market decide this one?

Here is a link to the FDA proposed rule change and public comment info.

I’m writing this from Berlin, in my room at Harnack-Haus, a meeting center and guest house owned by the Max Planck Society. The institute itself has a fascinating history, of which I just found the following spellbinding

Immediately upon opening its doors, the Harnack-House began to feed the “Dahlem Legend.” Nobel Prize winners and their students met here in social exchange and for academic discussion, holding lectures and colloquia. The House served as a club for members of the Kaiser Wilhelm Institute. Here they could lunch, read the international press, drink coffee in the garden, engage in sports, and play music. Foreign scholars were lodged in the guest apartments. The list of guests and lecturers reads like a “Who’s Who of Science”: Albert Einstein, Peter Deybe, Werner Heisenberg, Fritz Haber, Adolf Butenandt, Otto Hahn, Lise Meitner, Otto Meyerhof, Max Planck, Max von Laue and Otto Warburg. One Nobel Prize winner, the biologist Hans Fischer, even received the news of his award during his stay at the Harnack-House.

I’m here on an extremely short visit (arrived in Berlin around 1pm yesterday and fly out early tomorrow morning) for the annual meeting of the editorial board of New Journal of Physics (NJP). While quite a trek, and a not inconsequential amount of work, this is nevertheless a fun meeting (even though I didn’t get to watch World cup games in London, like last year.)

One thing that NJP likes to do is publish a number of focus issues each year. These involve enlisting one or more guest editors and getting them to corral a group of experts to contribute original research to a volume tightly concentrated on a particular topic. Sean and I (and our students) contributed a paper to one last year (for which Sean was the guest editor), but there are many others across all fields (which is what NJP covers). A full list, going back to 2000, when focus issues began is

• Focus on Measurement-Based Quantum Information Processing
• Focus on Complex Networked Systems: Theory and Application
• Focus on Interference in Mesoscopic Systems
• Focus on Dark Energy
• Focus on Accelerator and Beam Physics
• Focus on Casimir Forces
• Focus on Nanophotonics
• Focus on Correlated Electrons, Magnetism and Superconductivity in High Magnetic Fields
• Focus on Cold Atoms in Optical Lattices
• Focus on Gamma-Ray Bursts in the Swift Era
• Focus on Nano-electromechanical Systems
• Focus on Spacetime 100 Years Later
• Focus on Solid State Quantum Information
• Focus on Negative Refraction
• Focus on Photoemission and Electronic Structure
• Focus on Brownian Motion and Diffusion in the 21st Century
• Focus on Ultrafast Optics
• Focus on Orbital Physics
• Focus on Single Photons on Demand
• Focus on Turbulence
• Focus on Neutrino Physics
• Focus on Nanostructured Soft Matter
• Focus on Carbon Nanotubes
• Focus on Pattern Formation
• Focus on Quantum Gases
• Focus on Complex (Dusty) Plasmas
• Focus on Clusters at Surfaces
• Focus on Quantum Cryptography
• Focus on Turbulence in Magnetized Plasmas
• Focus on Supersymmetry in Physics
• Focus on Quark Gluon Plasma Searches in Heavy Ion Collisions
• Focus on Microlaser and Cavity QED
• Focus on Dark Matter

You can find links to all these at the focus issues site, and I hope you’ll take a look if interested, because anyone can read them, since open access is one of NJP’s raisons d’être.

I particularly enjoy the part of our meeting in which we brainstorm about possible future focus issues, and there are a couple coming out relatively soon that I am quite proud to have been either the originator or co-originator of. And, at today’s meeting, I suggested one specific focus issue to be initiated that was well received and which I think, when it comes out, will be of particular interest to many of our readers. It wouldn’t be right to go into details here (and I won’t in the comments), but I really hope it works out, and assuming it does, I’ll link to it here with a covering discussion.

Anyway, time for bed – my taxi will arrive ridiculously early tomorrow.

Against the languor of the Independence Day weekend, a tiny bit of media attention has managed to focus itself on a new paper by Martin Bojowald. (The paper doesn’t seem to be on the arxiv yet, but is apparently closely related to this one.) It’s about the sexy topic of “What happened before the Big Bang?” Bojowald uses some ideas from loop quantum gravity to try to resolve the initial singularity and follow the quantum state of the universe past the Bang back into a pre-existing universe.

You already know what I think about such ideas, but let me just focus in on one big problem with all such approaches (which I’ve already alluded to in a comment at Bad Astronomy, although I kind of garbled it). If you try to invent a cosmology in which you straightforwardly replace the singular Big Bang by a smooth Big Bounce continuation into a previous spacetime, you have one of two choices: either the entropy continues to decrease as we travel backwards in time through the Bang, or it changes direction and begins to increase. Sadly, neither makes any sense.

If you are imagining that the arrow of time is continuous as you travel back through the Bounce, then you are positing a very strange universe indeed on the other side. It’s one in which the infinite past has an extremely tiny entropy, which increases only very slightly as the universe collapses, so that it can come out the other side in our observed low-entropy state. That requires the state at t=-infinity state of the universe to be infinitely finely tuned, for no apparent reason. (The same holds true for the Steinhardt-Turok cyclic universe.)

On the other hand, if you imagine that the arrow of time reverses direction at the Bounce, you’ve moved your extremely-finely-tuned-for-no-good-reason condition to the Bounce itself. In models where the Big Bang is really the beginning of the universe, one could in principle imagine that some unknown law of physics makes the boundary conditions there very special, and explains the low entropy (a possibility that Roger Penrose, for example, has taken seriously). But if it’s not a boundary, why are the conditions there so special?

Someday we’ll understand how the Big Bang singularity is resolved in quantum gravity. But the real world is going to be more complicated (and more interesting) than these simple models.

If you are really lucky, then you may have a great new idea about particle physics. It may be a way to address the hierarchy problem (why is gravity so much weaker then the known particle physics forces), or to generate mass for fermions (after all, we haven’t found the Higgs yet), or to understand the flavor hierarchy (how come there are three repeated families of particles in the standard model with increasing masses), or perhaps to unify all the forces into one (Grand Unification). Obviously, your obligation is to begin systematically computing the consequences of this idea for existing and future particle physics experiments.

Thirty years or so ago, with a few notable exceptions this would have been the end of the story. But it has become increasingly clear to most physicists that there exists a complementary list of consequences that should be figured out; those for cosmology. These days, this approach is basically second nature to any of us who might have new ideas about how the micro-world works, and reflects the modern thinking that particle physics and cosmology are not distinct disciplines, but are two sides of the same set of questions.

So, parallel to the cross-section and decay rate calculations, what are the most common cosmological areas in which one currently looks for further constraints on one’s new particle physics idea? What new questions do you need to ask yourself?
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PZ Myers links to a great Ted Rall cartoon on Stupid Design. The point being that the world around us isn’t anything close to being efficiently designed. If it is the reflection of the plans of some supernatural architect, many of us could have offered a few useful pointers. As with most such arguments, David Hume was there first:

In a word, Cleanthes, a man who follows your hypothesis is able perhaps to assert, or conjecture, that the universe, sometime, arose from something like design: but beyond that position he cannot ascertain one single circumstance; and is left afterwards to fix every point of his theology by the utmost license of fancy and hypothesis. This world, for aught he knows, is very faulty and imperfect, compared to a superior standard; and was only the first rude essay of some infant deity, who afterwards abandoned it, ashamed of his lame performance: it is the work only of some dependent, inferior deity; and is the object of derision to his superiors: it is the production of old age and dotage in some superannuated deity; and ever since his death, has run on at adventures, from the first impulse and active force which it received from him.

Hume gets extra bonus points for writing before Darwin demonstrated how complex adaptive organisms can arise even without a designer. (But he loses some points for weaseling at the end of the Dialogues.)

Before Darwin, you couldn’t really fault someone for thinking “Gee, my two choices are between imagining that something as complicated as a human being just sort of came together by accident, or that someone designed it. I think I’ll go for Door Number Two.” But once we figured out that there was a Door Number Three — that such complexity could evolve through descent with random modification and natural selection — it boggles the mind how anyone could look at the natural world and conclude that it shows any signs of being intentionally constructed just this way.

One of the prevalent misconceptions about evolution is that, in response to a certain problem, organisms can (over the course of generations) simply “evolve an appropriate solution.” Of course they don’t always do so; sometimes they just die off. But more importantly, the space of possibilities that organisms explore via descent with minor modifications is most definitely not the space of small variations on bodies (or behaviors); it’s the space of small variations on genomes. Even if a certain physiological feature would be useful, we’re not going to be able to evolve it unless flicking a few switches in the genetic code would lead to an intrinsically useful mutation that would move us along that direction.

Years ago, Stephen Jay Gould and Richard Lewontin borrowed the term spandrel from architecture to illustrate an important consequence of the way evolution works. A spandrel is an aspect of some form (whether from Renaissance arches or paedomorphic morphology) that arises as a side effect of some other trait that is useful, even if it doesn’t itself serve a necessary purpose. Those kinds of non-adaptations and accidents and anachronistic features are found all over the place in real organisms. Any intelligent designer with a shred of self-respect would be embarrassed to exhibit such shoddy workmanship.

The classic argument-from-design question is: What good is half an eye? Even when I was twelve years old, I could guess the answer to that one: it’s a lot of good! Imagine just a few photo-sensitive cells evolving on the skin of a sightless organism; that could be immensely useful, offering a decided advantage to its offspring. Continual reinforcement of that tendency could directly lead to better sensitivity and all the other highly-specialized upgrades that our own eyes come with.

On the other hand: What good is half a wheel? Now you’ve got me. The wheel is an excellent answer to a pretty obvious question, if you’re a person sitting there thinking about how to move heavy loads more quickly or efficiently. And it’s not hard to imagine wheels coming in useful on certain organisms. (Tell me that a snake with wheels wouldn’t be pretty efficient, if a bit scary.) But you just can’t get there from here, by ordinary evolutionary means. It’s hard to think of useful transitional forms.

All of which should teach us a lesson when we sit down to try to understand and reproduce the workings of actual organisms. The idea behind Strong Artificial Intelligence is that the brain is basically a computer — a thesis I’m happy to go along with. But reproducing brainlike behavior in actual computers has turned out to be much harder than many people anticipated. In retrospect it’s not hard to see why; the brain might be a computer, but it’s certainly not the same kind of computer that we are used to programming. Its functioning arose naturally, rather than through top-down planning, and this kind of “organic design” leads to very different structures than “synthetic design.” Rather than relatively straightforward sets of algorithms expressed in neurological lines of code divided into tidy subprograms, our minds are subtle machines with virtual processors distributed holographically and interacting nonlocally throughout the brain. As a result, computers still aren’t very good poets, but they’re definitely better at multiplication and division than we are. (Now you tell me which talent might have been more useful out there on the veldt.)