Things I would blog about, if I weren’t on blogging vacation.

• A short piece I wrote for Seed about the arrow of time is now on the web. It’s basically a summary of the scenario that Jennie Chen and I are suggesting for spontaneous inflation. On a related note, Karmen at Chaotic Utopia has a series on complexity and time, starting here.
• Cocktail Party Physics advertises a call for proposals from Feminist Press.
  

  Girls and Science: Call for Proposals

  The Feminist Press, in collaboration with The National Science Foundation, is exploring new ways to get girls and young women interested in science. While there are many library resources featuring biographies of women scientists that are suitable for school reports, these are rarely the books that girls seek out themselves to read for pleasure. What would a book, or series of books, about science that girls really want to read look like? That is the question we want to answer.

  I don’t know; seems to me, if we start encouraging girls to become scientists, pretty soon they’ll be replacing equations with hugs and instead of performing experiments we’ll just talk about our feelings or some such thing. That can’t be right.

• Janna Levin, author of the uniquely compelling How the Universe Got Its Spots and the brand-new A Madman Dreams of Turing Machines, appeared on the Colbert Report! I can’t actually get the video to play, but maybe you can.
• Chris Mooney’s The Republican War on Science is now out in paperback. So all you poor liberals who couldn’t afford the hardcover edition now have no excuse.
• Speaking of books, Alex Vilenkin has come out with Many Worlds in One, about eternal inflation and the multiverse. Alex was the one who first realized that inflation could be eternal, and is a world-class cosmologist; whatever you may think of the issues, he’s worth listening to. (And don’t tell me that we cosmologists can’t have a little fun.)
• And Michael Bérubé also has a book out, What’s Liberal About the Liberal Arts?. So many books. Don’t these people know they’re wasting valuable time that could be spent blogging?
• George W. Bush has decided to close EPA regional libraries, to protect the public from information they don’t need.
  

  What has been termed, “positively Orwellian”, by PEER Executive Director Jeff Ruch, is indeed frightening. It seems that the self-appointed “Decider”, George W. Bush, has decided to “end public access to research materials” at EPA Regional libraries without Congressional consent. In an all out effort to impede research and public access, Bush has implemented a loosely covert operation to close down 26 technical libraries under the guise of a budgetary constraint move. Scientists are protesting, but at least 15 of the libraries will be closed by Sept. 30, 2006.

• On the other hand, John Kerry draws support from unseemly quarters, at least according to Yousuf al-Qaradawi.
  

  Kerry, who ran against Bush, was supported by homosexuals and nudists. But it was Bush who won [the elections], because he is Christian, right-wing, tenacious, and unyielding. In other words, the religious overcame the perverted. So we cannot blame all Americans and Westerners.

  So we really shouldn’t complain about the President.

• Weak lensing, uploaded to flickr by darkmatter. Amazing photos.

Last week’s dramatic evidence in favor of particulate dark matter, and weighing against modifications to gravity, as an explanation for the dynamics of galaxy clusters is another terrific result of observational cosmology. Equally important however, are the implications of these observations, at some of the largest scales in the universe, for the physics of the unimaginably small - particle physics.

The Bullet cluster result, building on earlier measurements, adds a crucial discriminating data point to the already overwhelming evidence that the universe contains matter of a type other than that which we see forming galaxies, stars, planets and us (called baryons). In fact, the evidence shows that there is five times more of this so-called dark matter in the universe than there are baryons. It is observed indirectly through many different cosmological methods and, indeed, is the reason that galaxies are able to form the way they do. This is confirmed not only through observations, but by comparing those to the results of increasingly accurate and beautiful numerical simulations of how cosmic structure crystallizes out of a soup of dark and baryonic matter.

That we are now more certain than ever that a critical component of cosmic dynamics is due to an entirely new type of matter, sharpens the associated particle physics question - how do these particles fit into our greater structure of fundamental physics - what is the dark matter?

There is a good reason that the answer is not yet known. The reason the dark matter is not seen glowing along with much of the rest of the material in galaxies is that it does not experience electromagnetism, the force of nature that leads to light. We think that dark matter particles must be only weakly interacting (electromagnetism is quite a strong force) and a consequence of this is that it is hard to get them to do anything measurable to material on Earth in order to betray their presence.

There are two ways to get around this. One is to build very sensitive detectors to measure even the smallest effects of dark matter on normal matter. After all, if there is five times more dark matter than baryons around, there should be lots passing through the Earth all the time as our solar system orbits the galaxy. There are many people devoted to these efforts and there are reasons to think that success is lurking in the not too distant future. The second way is, rather than waiting for cosmological dark matter to hit something in your detector, to smash particles together hard enough to create some of it all for yourself. If one can do this, then one would be able to measure its properties (its mass and the strengths of its interactions) and study how it fits into the overall structure of particle physics. This is where our colliders are indispensable.

The mere possibility that we may be able to probe the nature of most of the matter in the universe, hitherto undiscovered, using terrestrial machines is, to my mind, breathtaking science that is crying out to be done. However, in the case of dark matter, and the possibility that is made up of weakly interacting massive particles, there is also a relatively general and quite compelling argument, arising purely from particle physics, that there should be candidate particles within extensions of the standard model of particle physics.

The relevant particle physics/cosmology connection has its roots in the hierarchy problem - the problem of reconciling two wildly disparate mass scales; the weak scale (10² GeV) and the Planck scale (10¹⁹ GeV). This hierarchy is technically unnatural in particle physics, since, in general, the effect of quantum mechanics (here known as renormalization) is to make the observable values of such scales much closer in size.

One approach to this problem is to introduce a mechanism that cancels many of the quantum corrections, allowing the scales to remain widely separated even after quantum mechanics is taken into account. An example of such a mechanism (and the most popular one, for sure) is supersymmetry (SUSY). Supersymmetry is a beautiful idea that relates seemingly unrelated types of particles - fermions (such as the electron), and bosons (such as the photon) - to each other, and also to the underlying symmetries of space and time. A remarkable property of supersymmetric theories is that subtle cancellations between the effects of all the particles mean that the quantum effects I referred to above are rendered harmless. Even though supersymmetry is not an exact symmetry of our world, if it is exact just above the energy scales of the standard model and broken below, the structure of the standard model remains stable, since quantum corrections can only be effective up to the scale at which SUSY becomes exact (much lower than 10¹⁹ GeV in this case).

Another perspective is to view the hierarchy problem no longer as a disparity between mass scales, but rather as an issue of length scales, or volumes. The general hypothesis is that the universe as a whole is 3+1+d dimensional (so that there are d extra spatial dimensions), with gravity propagating in all dimensions, but the standard model fields confined to a 3+1 dimensional submanifold that comprises our observable universe. This submanifold is called the brane (as in membrane).

This is really a superstring-inspired modification of the Kaluza-Klein idea that the universe may have more spatial dimensions than the three that we observe. As in traditional Kaluza-Klein theories, it is necessary that all dimensions other than those we observe be compactified (wrapped up nice and small), so that their existence does not conflict with experimental data. The difference in the new scenarios is that, since standard model fields do not propagate in the extra dimensions, it is only necessary to evade constraints on higher-dimensional gravity, and not, for example, on higher-dimensional electromagnetism. This is important, since electromagnetism is tested to great precision down to extremely small scales, whereas microscopic tests of gravity are far less precise (although remarkable advances have been made in recent years, prompted in part by these theoretical ideas).

Since constraints on the new scenarios are less stringent than those on ordinary Kaluza-Klein theories, the corresponding extra dimensions can be significantly larger, which translates into a much larger allowed volume for the extra dimensions. This extra volume is a big deal, because the spreading of gravitational flux into the large volume of the extra dimensions allows gravity measured on our brane to be so weak, parameterized by the Planck mass M_P, while the fundamental scale of physics M^* is parameterized by the weak scale, M_W, say.

The problem of understanding the hierarchy between the Planck and weak scales now becomes that of understanding why extra dimensions are stabilized at a linear size (~0.1 mm, for example) that is large with respect to the fundamental length scale (1/M^*). This is the rephrasing of the hierarchy problem in these large extra dimension models.

I give the two approaches above as examples, and there certainly exist other approaches to the hierarchy problem. However, an important point is that the connection between dark matter candidates and new particle physics, just above the weak scale, with the power to address the hierarchy problem, is very general one, which is independent of the particular approach one might find most compelling. Here’s the brief argument.

1. In the absence of extreme fine-tuning, the stability of the standard model demands that there be new physics not far above the weak scale - usually referred to as the TeV scale.
2. This new particle physics will inevitably involve new particles and symmetries relating them to the standard model particles (otherwise, how are their interactions to help us with the hierarchy problem).
3. A danger with introducing such new particles is that their interactions may ruin the spectacularly precise and tested predictions of the standard model. To avoid this, one usually needs to introduce a new discrete symmetry - basically saying that all standard model particles have one charge, and all new particles the opposite - to suppress unwanted interactions.
4. There will inevitably be a lightest one of the new particles and it will be stable because it can’t decay into other new particles because they are heavier than it, and it can’t decay into SM particles, because that wouldn’t conserve the new discrete symmetry.
5. In large ranges of parameter space, this lightest particle can be electrically neutral.
6. So now we have a new, weakly interacting, stable particle at the TeV scale (a WIMP), demanded purely from particle physics considerations, that makes an excellent dark matter candidate.

This basic structure applies to the popular ideas for addressing the hierarchy problem that I discussed above. In SUSY, the lightest superpartner of the SM particles (the LSP) can be neutral and rendered stable by the R-Parity symmetry. In extra dimensional models, the lightest Kaluza-Klein particle (the LKP) may be dark matter, and is stable by virtue of KK-Parity, and in little Higgs models, which address the hierarchy problem in a different way, and which I have not discussed, a similar situation holds, with T-Parity playing the relevant stabilizing role.

Thus, although it is important to remember that there are other well-motivated dark matter candidates, such as the axion, discovering what new physics exists at the TeV scale may play a central role in uncovering the nature of the particulate dark matter that the Bullet cluster observations have so clearly revealed. This is one reason that cosmologists, as well as particle physicists, await with bated breath the upcoming operation of the Large Hadron Collider (LHC) at CERN. The world’s largest machine is designed to take us one level deeper into the mysteries of subatomic physics, and to help answer some of the most pressing questions in particle physics, such as the origin of electroweak symmetry breaking and the nature of the solution to the hierarchy problem. But these days, particle physics and cosmology walk hand in hand, and every new discovery at the LHC will help us to sharpen and expand our understanding of cosmic evolution. The Bullet cluster observations have provided a yet clearer hint that we are on the right path.

If it’s in The Onion, it must be true.

Remember the 2000 “election”? Remember the debacle in Florida? I know we’re often told that it is old news and that we should forget the travesty that led to the last 6 years and move on. But do you remember who ran the whole show before the final decision was handed off to the mystic dwarves?

Well, Katherine Harris, former Florida Secretary of State, is now a congresswoman for Florida’s 13th district and a candidate in the Republican primary for the U.S. senate. From The Orlando Sentinel, via The Washington Post

Rep. Katherine Harris (R-Fla.) said this week that God did not intend for the United States to be a “nation of secular laws” and that the separation of church and state is a “lie we have been told” to keep religious people out of politics.

“If you’re not electing Christians, then in essence you are going to legislate sin,” Harris told interviewers from the Florida Baptist Witness, the weekly journal of the Florida Baptist State Convention. She cited abortion and same-sex marriage as examples of that sin.

Isn’t this illuminating? Just to be extra clear, how might her view of reality affect other difficult decisions she might be, or have been, called on to make?

Harris, a candidate in the Sept. 5 Republican primary for U.S. Senate, said her religious beliefs “animate” everything she does, including her votes in Congress.

Ah! I see. By the way, this gem also sits on the Homeland Security Committee and the International Relations Committee. And we wonder why the country is in a mess.

Friday afternoon I’ll be on NPR’s Science Friday to talk about the recent dark matter results. Nothing that regular readers haven’t heard already, I suspect.

(Update: the audio files are on the right-hand side of this page. At least the mp3 file seems to be working. It was a short-but-sweet segment.)

We’ll share the show with an update on Pluto’s status. A quick query of Google News reveals that there have been about ten times more stories about Pluto than about dark matter. This despite the fact that the Bullet Cluster data have taught us something profound about the constituents and forces of our universe, while the “planet” business has taught us about the vote of a committee on what to call stuff. Why is that?

(Motivational poster generator found via La Blonde Parisienne.)

This is about a week old, but nonetheless worth promoting to the limelight over and over and over again. From the 11 August issue of Science (sorry, you gotta be registered):

In surveys conducted in 2005, people in the United States and 32 European countries were asked whether to respond “true,” “false” or “not sure” to this statement: “Human beings, as we know them, developed from earlier species of animals.” Here are the results:

Well, at least we beat Turkey. (Actually I would have expected Turkey to do better.)

The study also collected a bunch of other related data. Science reported from the study:

The total effect of fundamentalist religious beliefs on attitude toward evolution (using a standardized metric) was nearly twice as much in the United States as in the nine European countries, which indicates that individuals who hold a strong belief in a personal God and who pray frequently were significantly less likely to view evolution as probably or definitely true than adults with less conservative religious views.

and

The evolution issue has been politicized and incorporated into the current partisan division in the United States in a manner never seen in Europe or Japan. In the second half of the 20th century, the conservative wing of the Republican Party has adopted creationism as a part of a platform designed to consolidate their support in southern and Midwestern states. In the 1990s, the state Republican platforms in seven states included explicit demands for the teaching of “creation science”.

To all people who are Republican because they are fiscally conservative (a point I can understand), can you please take back control of your party away from these religious zealots! And, if only we could have more science education in our schools….perhaps then we could aim to do better than Cyprus next year.

(Picture me dressed as Dr. Evil, with my pinky in the corner of my mouth.) I’ve been watching our visitor meter over the last week or so, waiting to post and thank our readers when Cosmic Variance’s one millionth visitor (to the main page only) arrived.

However, since slashdot linked to Sean’s excellent post about the discovery of dark matter our traffic jumped by a factor of 7-10 over the last day, and some time during the night we just blew straight through the millionth visitor mark and right out the other side by quite a long way.

So my plans for a big fanfare, alarms, flashing lights, a banner and some lucky reader’s chance to grab a shopping cart and tear around the site picking up as many posts as possible in one minute will have to wait for the two million milestone.

Seriously though, to hit a million visitors in a little over our first year is wonderful. Thanks to all of you who drop by, whether it is to lurk or to leave thoughtful and interesting comments. Cheers!

The great accomplishment of late-twentieth-century cosmology was putting together a complete inventory of the universe. We can tell a story that fits all the known data, in which ordinary matter (every particle ever detected in any experiment) constitutes only about 5% of the energy of the universe, with 25% being dark matter and 70% being dark energy. The challenge for early-twenty-first-century cosmology will actually be to understand the nature of these mysterious dark components. A beautiful new result illuminating (if you will) the dark matter in galaxy cluster 1E 0657-56 is an important step in this direction. (Here’s the press release, and an article in the Chandra Chronicles.)

A prerequisite to understanding the dark sector is to make sure we are on the right track. Can we be sure that we haven’t been fooled into believing in dark matter and dark energy? After all, we only infer their existence from detecting their gravitational fields; stronger-than-expected gravity in galaxies and clusters leads us to posit dark matter, while the acceleration of the universe (and the overall geometry of space) leads us to posit dark energy. Could it perhaps be that gravity is modified on the enormous distance scales characteristic of these phenomena? Einstein’s general theory of relativity does a great job of accounting for the behavior of gravity in the Solar System and astrophysical systems like the binary pulsar, but might it be breaking down over larger distances?

A departure from general relativity on very large scales isn’t what one would expect on general principles. In most physical theories that we know and love, modifications are expected to arise on small scales (higher energies), while larger scales should behave themselves. But, we have to keep an open mind — in principle, it’s absolutely possible that gravity could be modified, and it’s worth taking seriously.

Furthermore, it would be really cool. Personally, I would prefer to explain cosmological dynamics using modified gravity instead of dark matter and dark energy, just because it would tell us something qualitatively different about how physics works. (And Vera Rubin agrees.) We would all love to out-Einstein Einstein by coming up with a better theory of gravity. But our job isn’t to express preferences, it’s to suggest hypotheses and then go out and test them.

The problem is, how do you test an idea as vague as “modifying general relativity”? You can imagine testing specific proposals for how gravity should be modified, like Milgrom’s MOND, but in more general terms we might worry that any observations could be explained by some modification of gravity.

But it’s not quite so bad — there are reasonable features that any respectable modification of general relativity ought to have. Specifically, we expect that the gravitational force should point in the direction of its source, not off at some bizarrely skewed angle. So if we imagine doing away with dark matter, we can safely predict that gravity always be pointing in the direction of the ordinary matter. That’s interesting but not immediately helpful, since it’s natural to expect that the ordinary matter and dark matter cluster in the same locations; even if there is dark matter, it’s no surprise to find the gravitational field pointing toward the visible matter as well.

What we really want is to take a big cluster of galaxies and simply sweep away all of the ordinary matter. Dark matter, by hypothesis, doesn’t interact directly with ordinary matter, so we can imagine moving the ordinary stuff while leaving the dark stuff behind. If we then check back and determine where the gravity is, it should be pointing either at the left-behind dark matter (if there is such a thing) or still at the ordinary matter (if not).

Happily, the universe has done exactly this for us. In the Bullet Cluster, more formally known as 1E 0657-56, we actually find two clusters of galaxies that have (relatively) recently passed right through each other. It turns out that the large majority (about 90%) of ordinary matter in a cluster is not in the galaxies themselves, but in hot X-ray emitting intergalactic gas. As the two clusters passed through each other, the hot gas in each smacked into the gas in the other, while the individual galaxies and the dark matter (presumed to be collisionless) passed right through. Here’s an mpeg animation of what we think happened. As hinted at in last week’s NASA media advisory, astrophysicists led by Doug Clowe (Arizona) and Maxim Markevitch (CfA) have now compared images of the gas obtained by the Chandra X-ray telescope to “maps” of the gravitational field deduced from weak lensing observations. Their short paper is astro-ph/0608407, and a longer one on lensing is astro-ph/0608408. And the answer is: there’s definitely dark matter there!

Despite the super-secret embargoed nature of this result, enough hints were given in the media advisory and elsewhere on the web that certain scientific sleuths were basically able to figure out what was going on. But they didn’t have access to the best part: pictures!

Here is 1E 0657-56 in all its glory, or at least some of it’s glory — this is the optical image, in which you can see the actual galaxies.

With some imagination it shouldn’t be too hard to make out the two separate concentrations of galaxies, a larger one on the left and a smaller one on the right. These are pretty clearly clusters, but you can take redshifts to verify that they’re all really at the same location in the universe, not just a random superposition of galaxies at very different distances. Even better, you can map out the gravitational fields of the clusters, using weak gravitational lensing. That is, you take very precise pictures of galaxies that are in the background of these clusters. The images of the background galaxies are gently distorted by the gravitational field of the clusters. The distortion is so gentle that you could never tell it was there if you only looked at one galaxy; but with more than a hundred galaxies, you begin to notice that the images are systematically aligned, characteristic of passing through a coherent gravitational lens. From these distortions it’s possible to work backwards and ask “what kind of mass concentration could have created such a gravitational lens?” Here’s the answer, superimposed on the optical image.

It’s about what you would expect: the dark matter is concentrated in the same regions as the galaxies themselves. But we can separately make X-ray observations to map out the hot gas, which constitutes most of the ordinary (baryonic) matter in the cluster. Here’s what we see.

This is why it’s the “Bullet” cluster — the bullet-shaped region on the right is a shock front. These two clusters have passed right through each other, creating an incredibly energetic collision between the gas in each of them. The fact that the “bullet” is so sharply defined indicates that the clusters are moving essentially perpendicular to our line of sight.

This collision has done exactly what we want — it’s swept out the ordinary matter from the clusters, displacing it with respect to the dark matter (and the galaxies, which act as collisionless particles for these purposes). You can see it directly by superimposing the weak-lensing map and the Chandra X-ray image.

Clicking on each of these images leads to a higher-resolution version. If you have a tabbed browser, the real fun is opening each of the images in a separate tab and clicking back and forth. The gravitational field, as reconstructed from lensing observations, is not pointing toward the ordinary matter. That’s exactly what you’d expect if you believed in dark matter, but makes no sense from the perspective of modified gravity. If these pictures don’t convince you that dark matter exists, I don’t know what will.

So is this the long-anticipated (in certain circles) end of MOND? What need do we have for modified gravity if there clearly is dark matter? Truth is, it was already very difficult to explain the dynamics of clusters (as opposed to individual galaxies) in terms of MOND without invoking anything but ordinary matter. Even MOND partisans generally agree that some form of dark matter is necessary to account for cluster dynamics and cosmology. It’s certainly conceivable that we are faced with both modified gravity and dark matter. If the dark matter is sufficiently “warm,” it might fail to accumulate in galaxies, but still be important for clusters. Needless to say, the picture begins to become somewhat baroque and unattractive. But the point is not whether or not MOND remains interesting; after all, someone else might come up with a different theory of modified gravity tomorrow that can fit both galaxies and clusters. The point is that, independently of any specific model of modified gravity, we now know that there definitely is dark matter out there. It will always be possible that some sort of modification of gravity lurks just below our threshold of detection; but now we have established beyond reasonable doubt that we need a substantial amount of dark matter to explain cosmological dynamics.

That’s huge news for physicists. Theorists now know what to think about (particle-physics models of dark matter) and experimentalists know what to look for (direct and indirect detection of dark matter particles, production of dark matter candidates at accelerators). The dark matter isn’t just ordinary matter that’s not shining; limits from primordial nucleosynthesis and the cosmic microwave background imply a strict upper bound on the amount of ordinary matter, and it’s not nearly enough to account for all the matter we need. This new result doesn’t tell us which particle the new dark matter is, but it confirms that there is such a particle. We’re definitely making progress on the crucial project of understanding the inventory of the universe.

What about dark energy? The characteristic features of dark energy are that it is smooth (spread evenly throughout space) and persistent (evolving slowly, if at all, with time). In particular, dark energy doesn’t accumulate in dense regions such as galaxies or clusters — it’s the same everywhere. So these observations don’t tell us anything directly about the nature of the 70% of the universe that is purportedly in this ultra-exotic component. In fact we know rather less about dark energy than we do about dark matter, so we have more freedom to speculate. It’s still quite possible that the acceleration of the universe can be explained by modifying gravity rather than invoking a mysterious new dark component. One of our next tasks, then, is obviously to come up with experiments that might distinguish between dark energy and modified gravity — and some of us are doing our best. Stay tuned, as darkness gradually encroaches upon our universe, and Einstein continues to have the last laugh.

Having arrived back about a week ago from my extended weekend in GoogleLand, I am finally ready to spill the beans about the mysterious and stimulating Science Foo Camp.

I arrived at my hotel on Friday afternoon and, after a brief rest, joined some other attendees in the lobby and waited for our ride to show up. I felt a bit like Charlie, waiting with Grandpa Joe for Willy Wonka to turn up and open the gates to the chocolate factory.

Our bus dropped us at the fabled Googleplex, and throngs of “camp counselors” (young Google employees) escorted us to the registration desk, after which we had our photos taken, and wrote lists of topics and words that described our interests below. These were then taped to a large board in the main hall.

While we were restricted to a small part of the complex, which itself is huge, I saw enough of the place for it to become clear that Google must be a terrific place to work. I recall the mid 90’s, when dot-com workplaces took care of every possible employee need, without charge. Although that bubble burst violently, at Google at least the culture seems to have retained that spirit. It isn’t just the walls of snack selections and beverage choices that are dotted around the place, or the outstanding cafeteria and catering staff, or the on-staff nutritionist. It is also the clear thought that has gone into constructing a collaborative environment that must make it particularly fertile for innovation. For our meeting, the “foo bar” helped also

Our first and only scheduled meeting was an introductory session in the largest meeting room. Here, after welcoming words from Tim O’Reilly (of, well, O’Reilly Media), and Timo Hannay (of Nature), we spent a half hour or so introducing ourselves, one-by-one, to the 150-200 other participants. And it turns out that my co-campers were a truly eclectic bunch; scientists, technologists, engineers, computer scientists, publishers, and science fiction writers.

It quickly became apparent that the intention was to throw this group together for a couple of days of barely-structured mayhem. Our host turned around a large board, with open hour-long slots in about ten rooms of differing capacities listed on it. We were instructed to “swarm the board” - rush up and enter discussion/debate/demonstration/educational sessions on any topic we thought interesting, with the resulting tapestry of ideas then forming the basis from which one could plan one’s own schedule, much as one does when picking through parallel session talks at a regular conference. Here’s a selection of the topics:

• Sending Stuff to Mars
• Mysteries of the human Genome
• A Cool Mathematical Idea from your Field in 15 Minutes
• Education in “Second Life” and the Future of Collaborative Learning
• The World Wide Telescope
• Coping with Politicized Science and “Scientized” Politics
• Open Science Discussion: Open Peer Review, Science Blogs, Science Wikis
• The Nascent WEBMIND
• Science and Spirituality
• How Anti-Copying Technology is Bad for: Science, Competition, Art, Expression, Innovation, …, Humanity
• Bioethics
• A.I. in Planetary Exploration (Titan)
• Self-organization in Evolution

I could go on and on - these are just a somewhat random picks from one of the wikis that I still have access to. I certainly didn’t attend all of these sessions, but I think it is fair to say that I learned something from almost all of those that I did participate in.

I tried to choose a spread of topics to sample the different kinds of thinking that were represented by the range of participants. Some of my sessions were rather close to what I do, such as the discussion of various mathematical properties of images, initiated by a well-known physicist, or the rapid-fire summary of interesting mathematical techniques from different fields. But some others were wildly different (if you haven’t heard of Project Orion, you should take a look at it - it is a hilarious and terrifying example of what one could get money for in the fifties).

One session I attended concerned technology that is designed to prevent the free distribution of legally purchased digital entertainment. The discussion leader was a science fiction writer and technology expert who has been extremely active in this area. It was fascinating to hear his perspective. This wasn’t about stealing music instead of legally downloading it. Rather, the discussion centered on the restrictions that are placed on you after you have purchased it. The canonical example was Apple’s iTunes and iPod (both of which I use frequently), their constraints on the number of devices one can listen to the music on, and the deliberate decision to use a format that means that your downloaded music won’t play on any other player that you might want to buy.

I went to a demonstration of the immersive, interactive online “game”, Second Life, which some participants felt had tremendous educational possibilities. Second Life has to be seen to be believed. One the one hand, it really feels like a game, and those of us who grew up with some of the earlier incarnations of role-playing games will recognize many of the features. However, in Second Life one is not trying to achieve some pre-specified goal, but instead you are supposed to live out an extension of your physical life. While this clearly isn’t for everyone, and I’m not sure I see myself using it any time soon, I did see that there were a number of ways in which one could use this technology for innovative educational purposes. Keep your eye on it, because the numbers of people participating is growing and, interestingly for educational issues, the age and gender mix of participants is much more reflective of that in real society than is true of regular computer games.

As a final example of the kinds of activities I took part in, I went to a session that was billed on the board as “Science and Religion”, but which the moderator actually wanted to be more broadly about Science and Spirituality. I don’t think my views on such things are a secret to any regular Cosmic Variance reader. However, I did want to attend, because I am fascinated by the thought processes that, in clearly highly intelligent and accomplished people, can lead to, in my view, a gaping hole in their intellectual rigor.

The session was fine but somewhat frustrating. There was much discussion of spiritual experience, but I tried and tried to get a clean definition of this and was unsuccessful. In particular, I wanted a definition that would make it clear whether “spiritual” was supposed to mean a type of feeling that was mysterious and enjoyable, but could in principle be due to complex biochemical and neurological processes, or whether “spiritual” was intended to imply something outside of the physical view of reality. I think there were people from both camps in the room, but I did have a hard time getting a clear answer anyway and felt a little frustrated by how some technically educated people can view certain aspects of the world so uncritically.

The meeting ended on Sunday afternoon and, after the closeout session I went for a couple of beers with some people I’d met there, before heading up to JoAnne’s place, where she had invited me to dinner. We had a lovely time - it’s always great to see JoAnne - and enjoyed fine food and wine, and I was even lucky enough to see the famous tomato plants just a few days before their problems developed.

When I got to the airport for my redeye flight I felt tired, but happy and satisfied; and that’s where the fun ended and a small personal nightmare began. For as I waited to board the plane, a rumbling of the belly began which, by the time I had taken my seat, had reached an unignorable crescendo. The accompanying symptoms were unmistakable - I had a pretty nasty case of food poisoning. Since the door was still open, I asked to get off the plane and, between rushing off to deal with symptoms that we need not go into here, was able to reschedule a flight for the next morning and book into a hotel at the airport. I spent the rest of the night extremely unhappy, and managed to fly out the next morning, dealing with a few delays and finally getting home late on Monday. Not a fun way to end a great weekend. I can’t think of what might have given me the food poisoning. Certainly it was far too soon for it to have been any of the wonderful treats that JoAnne served me, and the Google food was so fresh and good that I think I will settle on blaming it on a bad pint in the mid-afternoon.

But my overriding memories will be of Science Foo Camp as a wonderful experience. It was well conceived and well organized, and Google was a splendid host. They provided us with a wonderful space, great food and drink, and a group of smart, knowledgeable and helpful counselors who made the whole thing run so smoothly. I can’t thank the Nature, O’Reilly and Google folks enough for their invitation, their hospitality and their vision in putting together such a wacky and fun weekend. I would definitely go back; although their plan is to try to get mostly new people each year they do this.

The next Categorically Not! is Thursday 31st August. You may recall my post on the Categorically Not! series of events, started by K. C. Cole, and held at the Santa Monica Art Studios. They’re fantastic, and I strongly encourage you to come to them. Have a look at the last two descriptions here and here.

It is important to note that this one is a USC event, and not a Santa Monica event! It is on a Thursday and not a Sunday! You might wonder - why these changes? Ah! I promised to reveal what was going on behind that photo shoot I told you about a long time ago (with K.C., Tara McPherson, and myself - recall the fun we had with that picture?), and now realize that I did not get around to it.

This is it. There is a series of wonderful events going on throughout the year on the USC campus - the embodiment of our new Provost’s “Arts and Humanities Initiative”. It is called “Visions and Voices”, and I’ll tell you more about it on Asymptotia. Our program within that larger program is not called Categorically Not! but “Science and Serendipity”. Anyway more on that elsewhere.

So will the old Categorically Not! series stop? No. The Santa Monica series will continue, but there will be some gaps to accommodate the USC events. We hope that the regular Santa Monica crowd will make the short trip across the city to USC on those nights. For more information, visit the Categorically Not! website. More about the relation to the Categorically Not! events can be found in this post on Asymptotia.

Anyway, here is the blurb for the upcoming event on the 31st August:

Continue reading ‘Categorically Not! - Uncertainty (Revisited)’

Now I finally have an idea what might have happened!

I woke up this morning to find this:

and it triggered my instinct to kill. I mean, some varmint is eating my food! Can’t get more instinctual than that. Not to mention all the time and investment I have put into nurturing this crop. Not to mention that my very first BIG juicy tomato was just about ripe enough to pick…

After a thorough debate and inspection of the photos, the concensus of the SLAC theory group is squirrels, rats, or birds. Keeping in mind that my tomatoes are in container pots, on my deck, about 30-40 feet off the ground, rabbits were immediately excluded. I have ruled out birds after a detailed investigation of the crime scene this evening. Burton Richter himself (Nobel prize winner and co-discoverer of charm and former director of SLAC) made a point of calling his wife - an expert on such things - in order to determine the origin of the varmit. Mrs. Richter suggested roof rats. Egads!! I certainly hope not - that sounds rather disgusting and I’d rather have squirrels…

Meanwhile, I have put up every defense possible, short of building a cage for the plants. I might do that this weekend, but since the plants are 6 feet tall, it will be a job. I did some web research and devised a fortified multi-strategy defense. I have purchased Shake-Away Critter-Repellent, it is composed mainly of garlic and fox urine so it is organic, and sprinkled it about. I put out boxes of rat poison and traps, as well as one of those ultra-sonic/EM-wave rodent repellent thingies I had in my garage. I also put out 2 bowls of water (several websites said squirrles eat tomatoes for H2O during a drought - which adequately describes summer in California) and a bowl containing the 7 partially eaten tomatoes from the night before, hoping it might be easier for the varmint to finish them off first. I have also left the lights on, on my deck.

Short of building a cage (or sleeping on the deck with a BB gun) it’s the best I can do….we shall see what has transpired in the morning. If my tomatoes are further eaten by the morning, hell will hath no fury….

Update: It is now Friday. Last night around 1 AM I went out to check on the plants. Sure enough a large juicy (but green) tomato was sitting at the base of the pots. Then there was a rustling noise and a reasonably large RAT (Eeuw!) scurried out of the container pots and ran away. I caught the varmint red-handed! I involuntarily jumped back and screamed (wonder what my neighbors think now), but had no weapon on me so just watched the critter scurry away. (Actually, I don’t have weapons save for a baseball bat or two.) So much for the ultra-sound thingie. I unplugged it and turned on a radio instead for the rest of the night. LaRose Richter gets the prize for the correct hypothesis. Today I took action - the rat control people are coming first thing tomorrow morning, the container with my best plants is now sitting in the middle of my kitchen for the night, and I have about 10 zillion traps surrounding the plants left outdoors….

Update^2: 1:30 AM Saturday. No rat like a dead rat. Yep, my tom-cat snapper trap got’em! Gotta have the right tools for the job.

Jacques is advertising the launch of a new physics group blog - The n-Category Café. Run by John Baez, David Corfield and Urs Schreiber ( of the String Coffee Table), with technical support from Jacques himself, their self-described brief is the interface between Physics, Mathematics and Philosophy.

They’re just getting going, but I expect we’ll see plenty of fascinating stuff from them, and I hope you drop by to welcome this new venture to the physics blogosphere.

Can’t … stop … blogging … must … resist …

So you may have heard that Pluto is still a planet, and indeed we have a few new ones as well! Phil Plait, Rob Knop, Clifford, and Steinn have all weighed in. Hey, it’s on the front page of the New York Times, above the fold!

The problem is that Pluto is kind of small, and far away. Those aren’t problems by themselves, but there are lots of similar-sized objects that are also out beyond Neptune, in the Kuiper Belt. As we discover more and more, should they all count as planets? And if not, shouldn’t Pluto be demoted? Nobody wants to lose Pluto among the family of planets — rumors to that effect were previously enough to inspire classrooms around the globe to write pleading letters to the astronomical powers that be, begging them not to discard the plucky ninth planet. But it’s really hard to come up with some objective criteria of planet-ness that would include the canonical nine but not open the doors to all sorts of unwanted interlopers. Now the Planet Definition Committee of the International Astronomical Union has proposed a new definition:

1) A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet.

It turns out that, by this proposed definition, there are twelve planets — not just the usual nine, but also Ceres (the largest asteroid, between Mars and Jupiter), and also Charon (Pluto’s moon, but far enough away that apparently it doesn’t count as a “satellite,” but as a double-planet), and UB313, a faraway rock that is even bigger than Pluto. I’m not sure why anyone thinks this is an improvement.

The thing is, it doesn’t matter. Most everyone who writes about it admits that it doesn’t matter, before launching into a passionate defense of what they think the real definition should be. But, seriously: it really doesn’t matter. We are not doing science, or learning anything about the universe here. We’re just making up a definition, and we’re doing so solely for our own convenience. There is no pre-existing Platonic nature of “planet-ness” located out there in the world, which we are trying to discover so that we may bring our nomenclature in line with it. We are not discovering anything new about nature, nor even bringing any reality into existence by our choices.

The Pragmatists figured this out long ago: we get to choose the definition to be whatever we want, and the best criterion by which to make that choice is whatever is most useful and convenient for our purposes. But people have some deep-seated desire to believe that our words should be brought in line with objective criteria, even if it’s dramatically inconvenient. (These are the same people, presumably, who think that spelling reform would be really cool.) But as Rob says, there is no physically reasonable definition that would let us stick with nine planets. That’s okay! We have every right to define “planet” to mean “Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto, plus whatever other large rocky bodies we find orbiting other stars.” Or whatever else we want. It’s completely up to us.

So we really shouldn’t have to tear up a century’s worth of textbooks and illustrations, and start trying to figure out when the shape of some particular body is governed by hydrostatic equilibrium, just to pat ourselves on the back for obeying “physically reasonable” definitions. But it looks like that’s what the IAU Planet Definition Committee wants us to do. Of course that’s what you’d expect a Planet Definition Committee to suggest; otherwise why would we need a Planet Definition Committee?

Now if you’ll excuse me, I have change-of-address forms to fill out.

[And don't even contemplate accusing me of hypocrisy for dragging myself away from a much-deserved blog-vacation to carry on about something that I claim doesn't matter. The definition of "planet" doesn't matter; but appreciating that the choice of definition is a matter of our own convenience, not a matter of necessarily conforming to some objective criteria about the physical world, matters a lot.]

Update: Chris Clarke for the opposition.

The team behind the popular science magazine Symmetry is having a workshop at SLAC this week with the purpose of designing a good graphical presentation of the Higgs mechanism and Supersymmetry. People have tried this for years and it’s a tall order. Believe me, I know. But if anyone can pull it off, the Symmetry folks can!

I’ve been enlisted as a technical expert - one not only has to design a good graphic, it also has to bring home a technical point - and be technically correct. I consider this a fun challenge and am asking for you - our CV readers - for help! When designing a graphic to entice the interest of the scientifically interested public (not to mention policy makers), what better than to actually ask that audience what they like? So here we are….

To define a place for us all to get started, I asked David Harris, editor-in-chief of Symmetry, to give the top 4 graphics, each, for Higgs and Supersymmetry that are on the market today. And here they are (note these are a collage of the 4 different graphics):

For Higgs,

and for Supersymmetry,

They can be found at the links higgshere, higgshere, higgshere, higgshere, susyhere, susyhere, susyhere, and susyhere.

Let’s all take a few minutes to look critically at these pictures. Gosh - they are actually pretty bad, aren’t they! To be honest, I was shocked (although I have a slight fondness for the SUSY shadow dancing). The Higgs graphics hit me the hardest - I don’t even get the point in some of them, at least not by just looking at the picture without reading the accompanying commentary. I think we, the collective CV readership, can do much better than this! Don’t you!?!? So this is your challenge: please, spout forth your opinions - what do you like about these graphics? what turns you off? what confuses you? what better ideas do you have?

After the workshop, I’ll post the drafts of the new and improved graphics for further comments… And, don’t be shy now, this is your chance to speak up!