A little while back we advertised that Eugene Lim had volunteered to visit Haiti to teach in a university there over the summer, and would be reporting back about the experience. Here’s Eugene’s write-up — a powerful and affecting look into conditions there, and the spirit of the students.

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I noticed a puzzled look on Vicky’s face — she was squinting at the blackboard filled with equations describing how the subtitution rule in integral calculus works. She is one of my better students whom I know to be following my lectures well. I took it as a cue that I have not made a point clear, and I knew I must fallen back into speaking as though as my students are native English speakers. They are not — they speak Haitian Creole, and I was trying to teach them basic intro to mathematics in English and and a smattering of Creole.

Hello from Fondwa, Haiti, elevation 850m, Population 8000. For the past twenty days, I have been teaching a group of enthusiastic Haitian university students at the University of Fondwa. As I mentioned in my previous post, the university lost all its buildings during the Jan 12 quake. At the moment, we are using an abandoned warehouse as a temporary campus. It has no roof, so we put a tin roof over to keep the rain out. We use tarps (thank you USAID) for our windows to keep the rain out. There are 3 classrooms and an office. Some of the students have lost their homes in the Jan 12 earthquake, so the university allowed them to stay inside the warehouse.

We have no running water and a few solar panels for power. Water is obtained from wells, from a spring (about 15 minutes walk up hill), and from the regular rain showers we have been getting — hurricane season is upon us after all. This often led to me wondering whether I should be wishing for rain so we can fill up our water tank, or for the sun so we can charge up our batteries.

Many of the students are extremely enthusiastic. In my first full day, when I was just waiting for a teaching assignment, Deb, Vicky and Everest approached me and asked me in halting English what I would be teaching. I told them I would probably be teaching them math, and they said they have not had a math professor for the entire semester, and oh would you help us with some of these problems. So I ended up working with them right there and then. Turns out that these vanguard of students have been trying to teach themselves math from some books. They have had some confusion with concepts that one would expect from being self-taught, but they were sharp and intelligent. I found it a joy to work with them. Deb in particular, is especially strong and spoke some English, so I hired him as my Teaching Assistant who can also translate for me. Given his mathematical acumen, I started teaching him more advanced topics in a special class.

I was assigned to teach two classes in four weeks — an Intro to mathematics (for first years) and the vaguely titled “Business Mathematics” class to the 4th years. After a quick evaluation of the students’ ability, I ended up deciding that I am going to teach the first years differential and integral calculus — useful things to know whether you are going to be an agronomist or a manager. For the “business math” class, I chose to teach them some basic statistics — with the goal that they should be able to deal with frequency and probability distribution functions when completed.

English is not a widely spoken language in Haiti, so it was a challenge to teach the classes. However, I find that we can make a lot of headway with a mixture of my rudimentary Creole and the combined English knowledge of my students, assisted by a dictionary. The classes understandably proceed slower than usual, but that is not always a bad thing in pedagogy. After a hesitant start, we settled on a good system where some of the more capable English speakers would translate for the other students in real time. Sometimes, some of the more advanced students would volunteer to teach a difficult concept which they have grasped to the class in Creole. The students are generally attentive, and eager — I am often asked to teach extra classes.

When classes are not in session, I am kept busy with students who wanted to learn more, or have questions about math or English. I find these impromptu discussion sessions the most rewarding — I can teach the students at the pace at which they are learning. As a personal bonus, I have the luxury of having the students teach *me* Creole. Although I am assigned a very good Creole teacher, I learned most of my Creole from such constant interaction with the students.

Living conditions in Fondwa are rough. I am staying in a semi-collapsed building with a couple of volunteers from the US (Rohan Mahy and Reuben Grandon), and a rotating roster of Haitian teachers, most who live outside Fondwa : unfortunately qualified teachers and lecturers are extremely scarce in Haiti. Our quake damaged building has no running water, no power, and red “X” marks on parts of the buildings that are unstable — a non-trivial indicator since we are still experiencing aftershocks (I personally felt three so far). On the other hand, we have a great view — on a clear day, we can see distant Leogane northward and the Gulf of Mexico, 80 km away.

Nevertheless, our humble abode is a palace compared to the conditions that most Haitians live in. Many of them have lost homes in the quake; some of hem are still living in tents. Ironically, many of the stone buildings collapsed, while the wooden ones survived. I visited one of the tent cities of Port-au-Prince — they are hot, dusty, crowded and so incredibly unsanitary that they seems like epidemic timebombs waiting to go off. Every single building left standing suffered some form of damage from the quake — sometimes looking past the intact facade will reveal a completely collapsed back portion of the house. This does not stop Haitians from living in them. There is a strong sense of communal spirit among rural Haitians, more than once, I was told by the tenants that their house was “kraze” (destroyed) in the gudu-gudu (quake) and they are living in that “kind madame’s” house. Our neighbouring house, a wooden structure no bigger than the size of a school bus, is home to thirty men, women and children.

The Haitians are very friendly. After getting past the initial bemusement (and amusement) of being called “blan” (white man) in the first few days, I find the Haitians incredibly hospitable, and resilient in the face of such hardship. Wherever I go, it is easy to smile and call out a “bonjou” or “bonswa”, or “komen ou ye” (how are you?) to people passing me or just doing chores in front of their houses. I have a special love for the Haitian children — they are the most energetic and playful bunch of kids I have ever met. A group of them would show up at our house from time to time, screaming the names of us *blan* volunteers, and we would end up playing with them until we are exhausted. It is poignant for me to know that some of them have lost siblings and parents in the quake.

I will be leaving Haiti in a few days. Personally, I found the teaching experience and my interactions with the Haitians incredibly fulfilling and rewarding. But it was also very sobering to see the damage, destruction and human misery caused by the quake. There is a lingering sense of not having done enough, and that there is so much more left to be done. I do plan to come back again, and perhaps learn enough Creole to teach in it next time.

Eugene Lim was one of my first graduate students at the University of Chicago. We violated Lorentz invariance together (it’s not as dirty as it sounds), and he’s since gone on to think about bubble collisions and eternal inflation at prestigious places like Yale, Columbia, and Cambridge.

But Eugene always cared about other things in addition to physics, and today he’s bringing us a guest post about a heart-wrenching topic: education in Haiti in the aftermath of their devastating earthquake. Not content to agitate for support from the comfort of his computer, Eugene is actually hopping on a plane this weekend to spend a month teaching math at a poor rural university. Here’s his introduction, and we hope to have a follow-up post after he returns from his travels.

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On Tuesday, January 12, 2010 at 4:53pm, a massive quake hit Haiti, killing an approximate quarter of a million people, injuring another quarter of a million, and causing massive infrastructure damage. Today, more than five months later, as the news cycle has moved on, Haitians are still pulling themselves out of the disaster, with 1.5 million people still homeless.

Fondwa is the 10th Communal Section of Leogane situated about 60 km south of the Haitian capital, Port-au-Prince, near the epicenter of the quake. It is a rural community with big dreams, the peasants banded together in 1988 to form the APF (Association of Peasants of Fondwa) to create a model community, not just with the aim of providing basic services but to empower the people of Haiti by providing them with the education and knowledge to improve their own lives.

One of their amazing achievement is the founding of a university, the University of Fondwa (UNIF) in 2004 in the mountains of Haiti, offering majors in Management, Agricultural Engineering and Veterinary Science — skills necessary for a rural community to survive and thrive — with about 40 students from all over Haiti. They graduated their first class last year.

The quake destroyed all the buildings of UNIF : the main building, the dorms and the lecture halls. Remarkably, classes continued after the quake, first in tents, and hopefully soon in temporary shelters. Final exams were given and graded, and the new semester began on schedule, May 5.

I met the founder of the University, Fr. Joseph Phillipe in New York a few weeks ago (he also founded Haiti’s biggest microfinance bank, FONKOZE, but that’s another story) — a series of hopeful email inquiries inspired by the watching a documentary about Fondwa led to having coffee with him in uptown New York City. Despite the challenges that his community is facing, he was full of energy, focusing on what to do for the future. I was impressed. I told him I want to help out.

I told him I wanted to volunteer to teach in UNIF, but I was not sure what I need to do. He said “We are waiting for you in Fondwa.”

This week, I am headed down to Fondwa to teach math for a month. I was told to be prepared to be caught unprepared. Internet permitting, I hope to post a follow-up to this when I get to Fondwa with more pictures from the ground.

A month is not exactly a long time. But I hope that any help is better than no help at all — they are short on teaching staff after the quake. Personally, I have been inspired by humanitarian groups like Doctors without Borders and Paul Farmer’s Partners in Health. I can’t save lives as a doctor, but I can teach! A long term hope is to be able to build ties in Fondwa, and perhaps do this on a yearly basis. I believe that academics have a lot to contribute in making this world a better place beyond hanging out in our ivory towers.

I asked Fr. Joseph what else I can do to help, he said “Tell your friends about us, and ask your friends to come too”.

Sean has kindly allowed me to use this blog to publicize the plight of the community at Fondwa. They are still trying to get basic services in. Their main needs are monetary donations, temporary housing, clean water and volunteers! They are especially looking for long term volunteers for six months of longer. They are also looking for a President for UNIF — I am serious — if you are interested or know anybody who might be interested, email APF below.

If you like want to volunteer, the best way is to contact APF directly at apf222@aol.com or go to the APF homepage. If you like to donate directly to APF click on the link to my blog for the bank information. If you want help out Haitians to help themselves : support Fonkoze’s microfinancing efforts by helping out here.

We’ve been talking about life quite a bit here recently at Cosmic Variance, and it’s always fun to talk about areas in which one has absolutely no professional expertise. But it’s also fun to bring in experts, which is why we’re happy to welcome Caleb Scharf as a guest blogger. Caleb is Director of Astrobiology at Columbia University, author of a textbook on the subject, an recently jumped into blogging. In this post he reminds us that we’re still learning a lot about the forms of life right here on Earth — knowledge that will be invaluable as we search for it elsewhere.

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It’s a real privilege to be able to write a guest blog for Cosmic Variance and to take a little side trip from my regular postings to Life, Unbounded – the science of origins.

The modern search for life in the universe encompasses everything from exoplanets and astrochemistry to geophysics and paleontology. Underlying and motivating the investigations in these fields – collectively labeled astrobiology – there are some fundamental assumptions, but do they make sense?

In recent weeks one might be forgiven for thinking that a shadowy biosphere surrounds us, aliens are poised to dismantle civilization, and that time traveling species are flitting in and out of view like barflies on a Saturday night. It’s a little disconcerting, does the Kool Aid have something special in it this Spring?

Unfortunately I think that all of these headline grabbing items miss the real story of what life is, here on Earth and potentially further afield. The idea of ‘shadow biospheres’ or multiple origins of terrestrial life sounds intriguing, and certainly helps bring focus to the fact that we can be very blinkered in our outlook. It also steers attention away from a more interesting and demonstrably real point.

In the past couple of decades we have found a shadow biosphere, except that far from lurking in the cracks it turns out to be the biggest, most critical, biosphere on the planet. An astonishing 99.9% of life on Earth cannot be coerced to grow in a lab, and so we have overlooked it. Microbial life – single-celled bacteria and our ancient cousins the Archaea – is not just the stuff under your fingernails, it is what makes multi-cellular life like us function, and it helps govern the grand chemical cycles of our planet, from the continents to the oceans to the atmosphere. Such organisms have, over three to four billion years, evolved into an eye popping array of microscopic machines, the ultimate nano-bots. They can extract energy and raw materials from, it seems, almost any environment. A particularly good example is Desulforudis audaxviator – discovered 2.8 km down in a South African gold mine in a pocket of isolated water. Little audaxviator lives all alone when the vast majority of microbial life is utterly reliant on colonial symbiosis. It earns a living by mopping up the molecular detritus left after radioactive decay in the uranium rich rocks dissociates water and bicarbonates. That’s a very, very neat trick.

Twenty or thirty years ago we barely understood that such life existed on this planet. Now we are beginning to see that the longevity of our biosphere owes itself to precisely this crowd of ‘shadowy’ organisms. A truly wonderful paper was published a couple of years ago in which Falkowski, Fenchel and Delong laid out the big picture for life on Earth. In essence, they argue that single-celled microbial life is the manifestation of an even deeper truth; the core planetary gene set. This is the set of recipes for metabolism, or how to harvest a planet for energy, and we all rely on them. The result of billions of years of natural selection, these genes are widely dispersed across the microbial biosphere. This is true to such an extent that should 99% of life be wiped out by an asteroid collision, supervolcano, or dirty telephone receiver, the information for the molecular machinery that drives all organisms will be safely preserved in the surviving 1%. The living world does not end, it just reboots. Because of this, carbon-based life is a far more robust phenomenon than we could have ever imagined. It is the ultimate, Google-like, cloud computer.

Still though, isn’t this also a blinkered view of what might constitute life? Well, sure, but there’s another fact to consider. When we look out into the universe we find that the chemistry of our life – carbon based molecular structures – is not just occasional, it’s ubiquitous. Carbon is a fabulous player; simple molecules, rings, chains, polymers, sheets, crystals, and great clumps of sooty particles abound. Some is produced directly from the huge outflows of cooling gas from old stars, much forms in the thick nebulae and proto-stellar cocoons that eventually give rise to planets. Thousands of recognizable organic molecules, including amino acids, are found in the treacly mix of some meteorites – the remains of our own ancient solar system. This is a chemical bonanza that must have played a role in setting the stage on the young planet Earth. If this is blinkered then stick a blindfold on me.

So life on Earth is tough and tenacious, and the building blocks are everywhere. Is this enough reason to think that a similar blueprint exists in other places across the universe? Well, it’s definitely motivation to go looking, and to go looking for the kind of exotica that we already know, rather than inventing new ones. Is this reason enough to think that ‘intelligent’ life exists somewhere else? That’s a tough call. Life on Earth did remarkably well for the past 3.5 billion years without us around, I don’t think there is anything that indicates we are more than an evolutionary oddity (albeit an incredible one). It’s a big universe though, with plenty of room for oddities, even if they turn out to be extremely familiar.

We’re very happy to have a guest post from Malcolm MacIver. See if you can keep this straight: Malcolm is a professor in the departments of Mechanical Engineering and Biomedical Engineering at Northwestern, with undergraduate degrees in philosophy and computer science, and a Ph.D. in neuroscience. He’s also one of the only people I know who has a doctorate but no high school diploma.

With this varied background, Malcolm studies connections between biomechanics and neuroscience — how do brains and bodies interact? This unique expertise helped land him a gig as the science advisor on Caprica, the SyFy Channel’s prequel show to Battlestar Galactica. He also blogs at Northwestern’s Science and Society blog. It’s a pleasure to welcome him to Cosmic Variance, where he’ll tell us about robots, artificial intelligence, and war.

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It’s a pleasure to guest blog for CV and Sean Carroll, a friend of some years now. In my last posting back at Northwestern University’s Science and Society Blog, I introduced some issues at the intersection of robotics, artificial intelligence (AI), and morality. While I’ve long been interested in this nexus, the most immediate impetus for the posting was meeting Peter Singer, author of the excellent book ‘Wired for War’ about the rise of unmanned warfare, while simultaneously working for the TV show Caprica and a U.S. military research agency that funds some of the work in my laboratory on bio-inspired robotics. Caprica, for those who don’t know it, is a show about a time when humans invent sentient robotic warriors. Caprica is a prequel to Battlestar Galactica, and as we know from that show, these warriors rise up against humans and nearly drive them to extinction.

Here, I’d like to push the idea that as interesting as the technical challenges in making sentient robots like those on Caprica are, an equally interesting area is the moral challenges of making such machines. But “interesting” is too dispassionate—I believe that we need to begin the conversation on these moral challenges. Roboticist Ron Arkin has been making this point for some time, and has written a book on how we may integrate ethical decision making into autonomous robots.

Given that we are hardly at the threshold of building sentient robots, it may seem overly dramatic to characterize this as an urgent concern, but new developments in the way we wage war should make you think otherwise. I heard a telling sign of how things are changing when I recently tuned in to the live feed of the most popular radio station in Washington DC, WTOP. The station had commercial after commercial from iRobot (of Roomba fame), a leading builder of unmanned military robots, clearly targeting military listeners. These commercials reflect how the use of unmanned robots in the military has gone from close to zero in 2001 to over ten thousand now, with the pace of acquisition still accelerating. For more details on this, see Peter Singer’s ‘Wired for War’, or the March 23 2010 congressional hearing on The Rise of the Drones here.

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Over the last few months I have had the pleasure of discussing science and science journalism with Faye Flam, who covers science for The Philadelphia Inquirer. Faye reports on all kinds of science, and a number of other topics, as you can read about on her web site. But most recently she has put a great deal of work into covering climate change; even interviewing Michael Mann, who will be visiting us at Penn for a physics colloquium in just a couple of weeks. And she has found it enough of a challenge that she has chosen to write about it as a (first of several, I hope) guest post.

This is a hot topic, as we all know, and I’m hoping we get a thoughtful and respectful discussion in the comments. Nevertheless, this might be a good place to remind people that we’ll generally delete comments that are off topic or offensive.

Now, here’s Faye.

There must be some redeeming lesson to come from covering the so-called climate gate scandal that’s dragged on over the last two months. Member of the public actually care about science. They’re even passionate about it. But when that happens it’s not always pretty.

Never in my 14 years as a newspaper science writer have I found myself on the receiving end of such a powerful stream of hate mail – searing bombs of name-calling that get fired into my personal and work inboxes, as well as screaming, profanity-laced screeds landing in my voice mail. There’s much gloating about the downfall of newspapers and speculation that soon I’ll perish on the streets, begging for pennies.

I even got my first death threat following this story. It was the first of three stories I wrote on this topic for the Philadelphia Inquirer after a cache of e-mail messages were stolen from some prominent climate scientists and picked over by their worst enemies for signs of malfeasance.

Many member of the public are raging at me for failing to point out what they see as an inexcusable case of scientific fraud. For them, there’s no distinction between committing fraud and being wrong. That might worry some members of the scientific community.

I wasn’t ordered to write anything on this issue. During the same period I also wrote a nice story about the Hubble Telescope, and one about heroic cancer researchers. I could easily have skipped this whole mess and written other nice stories – on Kepler, or maybe LHC. People always like stories about planets and particles.

But instead, I returned from Thanksgiving vacation to write this quick overview, followed by the more offbeat Q and A story linked above.

Then, in a fit of masochism, I decided to profile one of the scientists involved – Michael Mann – because he works nearby at Penn State University. That gave the whole thing a local angle.

Mann’s work has been scrutinized for years, after a researcher in Canada pointed out a possible statistical flaw in some climate reconstructions done in the 1990s. That eventually led to an investigation by a National Academy panel. They concluded that Mann’s initial papers weren’t perfect but the general conclusions held up, and there was no evidence of fraud.

In other areas of science, the public can be more tolerant. Back in the 1990s, people were in some disagreement about the age of the universe. When new information came in, some were shown to be off be a few billions years, give or take, but they didn’t get carted off to Siberia.

Others had wrong ideas about the shape and fate of the universe, since nobody back then thought it was accelerating. That’s the beauty of science. It’s self-correcting – though sometimes the corrections can take a while.

The other lesson here is that many people don’t understand the role of uncertainty in science. There is uncertainty over the way water vapor changes the situation, for example, with most experts saying it will create a positive feedback but a few arguing for a negative one.

And still, some people write to inform me that the science is “settled.” These critics are not sure what’s settled but they’ve heard this and seem to think it’s important to repeat.

Others recognize the uncertainty in climate science and find it appalling. That’s particularly true of engineers, who seem pretty well-represented among self-proclaimed global warming skeptics. It’s a level of uncertainty that would never fly in modeling systems for chemical refineries, or so they tell me.

One MIT-trained engineer said his own calculations prove that the climate models can’t work because, in short: “junk in equals junk out”. It would make for a great story if a local guy who worked for a chemical refinery took down the whole climate science establishment on the back of an envelope. Unfortunately, I have to consider the possibility that he hasn’t.

The global warming skeptics also love to use the term “AGW theory”. This proved a great strategy for debating because the scientists don’t really refer to anthropogenic global warming as a theory, and many aren’t sure what AGW theory means. That gives the critics the freedom to say it means that only humans can influence the climate – and that the climate never changed at all before humans hit the scene. Then they can point to this untenable position and say, “ha ha – aren’t these scientists dumb!”

Coming from the more liberal side of things, a reader suggested that even if some fatal flaw crops up in both the climate models and the climate reconstructions, and the world does plunge into a protracted global cold spell, the scientists who had done the original work shouldn’t necessarily be thrown in prison or burned at the stake.

It might seem strange, even insane, for the public to base views of the carbon cycle and water vapor feedbacks on politics. Is it a problem of science illiteracy? I don’t think so. We could all be better educated about basic physics and chemistry and this debate would still play out the same way.

It all makes more sense, though, in light of the way differing political philosophies tolerate uncertainty – whether they’re considering government-funded scientists delivering uncertainty or the prospect of policy changes based on uncertain science. How much should we know before we start conserving energy? Classify CO2 as a pollutant? Submitting to international regulations? The best we can do as scientists and science writers is respect those political differences, state what’s known as clearly as possible, and be honest about what’s not known. People will still hate us, of course. There’s no way to escape that.

Scientists like to argue, contra Walt Whitman, that understanding something increases our appreciation of its beauty, rather than detracting from it. The image below, as Evalyn Gates explains, is a perfect example. Evalyn is an astronomer at the University of Chicago, and the author of a great new book on the science of gravitational lensing, Einstein’s Telescope: The Hunt for Dark Matter and Dark Energy in the Universe (Amazon, Barnes & Noble, Powell’s). This post is an introduction to how gravitational lensing gives us some of the most visually arresting and scientifically informative images in all of astronomy.

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I had the pleasure of meeting up with Sean and some other old friends at the World Science Festival in NYC last month, and over champagne at the opening night reception (science has its benefits) Sean graciously invited me to write a guest post on gravitational lensing. It’s a broad topic, mainly because lensing is proving to be such an incredibly useful tool for many areas of cosmology and astronomy, but I have to admit that the visual beauty of the images produced by lensing is part of the appeal for me.
I’m also enamored of the visceral connection between these images and lensing phenomena that all of us encounter in daily life – and the access into a complex theory that this connection affords. The giant arcs, Einstein Rings, and multiple copies of a single distant galaxy or quasar that have now been observed in hundreds of images are concrete visualizations of otherwise abstract concepts of general relativity – they effectively trace out the warps in spacetime created by massive objects, revealing the outline of the cosmos much as the technique of “rubbing” can reveal the writing on an ancient gravestone.

This image, from a recent paper by Adi Zitrin and Tom Broadhurst is both scientifically and visually irresistible:

First, the image itself is really cool. The bright white/yellow galaxies are members of a cluster known as MACS J1149.5+2223, while the blue amoeba-like objects that appear to be invading the cluster are actually five images of a single distant (z ~ 1) spiral galaxy.

This galaxy has been lensed by the warp in spacetime created by the cluster. Light from the galaxy, which lies almost directly behind the center of the cluster but much farther away from us, travels along several curved paths through the cluster lens, producing multiple magnified images of the galaxy. The inset box shows a computer generated model of the unlensed source galaxy, enlarged by a factor of four so that the details, including the spiral arm structure, are visible. Without the lensing power of the cluster, we would see this galaxy as a single small blue smudge.

In general, lensing will both magnify and distort (shear) images of a background source. This lens is fairly unique in that we see large but relatively intact images of the spiral galaxy, which implies that the mass distribution in the central region of the cluster must be nearly uniform. The images in the upper left (#1) and lower right (#2) are especially striking. #1 is magnified but very minimally distorted, while #2, the largest image with a magnification of over 80, seems to be curling its tentacles about one of the galaxies in the cluster.

A close look also reveals the negative parity (mirror symmetry) of the remaining three images – the spiral arms appear to circle in the opposite direction – as expected from lensing. The total magnification of the distant galaxy (the sum of all five images) is about 200, the largest known to date – supporting the authors’s claim that this is “the more powerful lens yet discovered.”

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One of the big questions for people who believe in extra dimensions is: Why don’t we see them? Sure, we have methods for hiding them, usually by making them really tiny, but then we need to ask: Why are they tiny?

Matt Johnson, Lisa Randall and I just came out with a paper that takes a partial stab at this question: Dynamical Compactification from de Sitter Space. (And a similar-sounding paper came out the same day from Jose Blanco-Pillado, Delia Schwartz-Perlov, and Alex Vilenkin.) It’s an intriguing idea, if I do say so myself: starting with nothing more complicated than a higher-dimensional spacetime with a positive vacuum energy and an electromagnetic field (or a higher-dimensional generalization thereof), you will automatically get quantum fluctuations into lower-dimensional spacetimes! If we really believe in extra dimensions, we need to understand how regions with different effective dimensionalities are cosmologically related, and this is a step in that direction.

Normally I’d blog all about it, but on this occasion we’re outsourcing to a guest blogger. My collaborator Matt Johnson is a postdoc at Caltech, and before that was a grad student at UC Santa Cruz, where he worked with Anthony Aguirre — a previous guest-blogger of ours! We like to keep things in the family.

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Extra dimensions. Sounds preposterous at first. Well, perhaps more accurately, it sounds preposterous to most people who don’t do high-energy theory. But, really I assure you, there are many well-motivated reasons why us wacky theorists like to ponder the existence of extra dimensions.

For one, as shown long ago by Kaluza and Klein, it is possible to get Maxwell’s equations of electromagnetism in four dimensions by taking 5 dimensional General Relativity and wrapping one of the spatial dimensions up in a circle too small to see. The smaller the circle is, the harder it is to move in this “other direction,” and so there is no danger in getting lost on the way home. In this way, Maxwell’s equations have an elegant geometrical origin and gravity and electricity & magnatism are combined into one force (5 dimensional gravity).

Another strong motivation comes from string theory, which is only a consistent quantum theory of gravity if there are 10 or 11 dimensions in total. Again, since we don’t see them, it is necessary to hide the existence of the extra dimensions. Inspired by the fact that it was possible to hide one extra dimension by wrapping it up in a circle, generally the extra 6 or 7 dimensions are thought to be “compactified” into a very small compact geometry like a sphere or a torus.

At this point, the five-year-old in the audience is insistently asking, “If you have all these extra dimensions, and you are telling me that they are wrapped up into this tiny ball, how did they get wrapped up in the first place? Why are the four dimensions we see so large, and the others so small?”

After nearly a century of thinking about the existence of extra dimensions, there are surprisingly few plausible answers to this very simple question. One of the few answers was proposed by Brandenberger and Vafa. They studied the thermodynamics of strings in a torus-shaped hot early-universe, and found that miraculously it is favorable for only four of the dimensions to become large. Pretty nice, if the universe is a torus and all the dimensions started out small and compact. But, it would be nice to have some alternatives in case this turns out not to be viable.

Sean Carroll, Lisa Randall, and I recently wrote a paper that revisits the five-year-old’s question. We wanted to start with the very simplest model that has extra dimensions and solutions in which some of them can be compactified. A minimal set of ingredients needed to accomplish this includes 1) D-dimensional gravity, 2) a positive D-dimensional cosmological constant, and 3) a (D-4)-form gauge field (think E&M, but with more indices). This theory has long been known to have solutions where 4 of the dimensions are non-compact and (D-4) of them correspond to directions on a sphere, whose size is stabilized by the energetics of curvature and a background Electric or Magnetic field.

More interestingly, we showed that some of the spacetimes that are solutions to this theory contain a four-dimensional universe that lives behind the event horizon of an extended object, a “p-brane” or “black brane,” that is embedded in a background D-dimensional spacetime. Moreover, there are mechanisms that dynamically give rise to such objects, thanks to the magic of quantum mechanics, and this leads to an explanation for why some number of extra dimensions became compact!

Sounds complicated, but you can actually go a long way towards understanding what we did by considering plain-old four dimensional black holes. (more…)

Marcelo Gleiser, Appleton Professor of Natural Philosophy at Dartmouth College, is a theoretical physicist who has worked on a diverse set of topics: cosmology, particle physics, phase transitions, condensed matter physics and biophysics. He is also a well-known author and public science communicator. A couple of months ago Marcelo suggested a guest piece for Cosmic Variance, and I’m delighted to be able to post it below. I hope you enjoy it, and I’ll encourage Marcelo to look in on the comments section and contribute there if he’d like.

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Here are some thoughts on something that has been bothering me for a while. How do we know the world is the way it is? Easy, a pragmatic person would say, just look and measure. We see a tree, a chair, a table; we hear the wind, music, people talking. We feel heat and cold against our skin. Once our brains integrate this sensorial information, we have a conception of what is real that allows us to function in the world. We know where to go, what to eat, what not to touch; we enjoy a good meal, a nice hug. But what happens when we go beyond our senses, using tools to extend our conception of reality? We don’t see galaxies with the naked eye (well, maybe Andromeda on a moonless, dry night) and much less a carbon atom. How do we know they are there, that they exist?

When Galileo showed his telescope to the Venetian senators in 1609, some refused to accept that what they saw was real. More recently, late in the 19th century, physicist and philosopher Ernst Mach refused to accept the existence of atoms, claiming they would never be seen and hence couldn’t be proven to exist. Mach and the Venetian senators were wrong. What we see through telescopes is, of course, perfectly real; we capture photons—particles of light—that a celestial body emits (or reflects, for planets and moons). If the source doesn’t emit in the visible and is so dim that we can’t capture photons between red and violet, we capture photons from radio or infrared radiation, no less real even though our eyes can’t see them. When atomic electrons jump from orbit to orbit, they also emit (or absorb) photons that can be detected by instruments or, in the case of certain transitions, by our eyes. The instruments we use in the study of natural phenomena are an extension of our senses. This amplification of reality is one of the most spectacular feats of science, allowing us to see beyond the visible. So far, so good.

The situation gets complicated when the complexity of the phenomenon forces us to filter the data, and we select to study only part of what is happening. Our brains, of course, do this all the time, what we call “focus”; otherwise, we would be flooded with such an absurd amount of sounds and images that we wouldn’t be able to do anything. When we look at a star with the naked eye or with an optical telescope, we only see part of it, what it emits in the visible. A complete view of the star would incorporate all of its emissions, in the infrared, ultraviolet, x rays, etc. This fact has a simple but, to my mind, profound consequence: our construction of reality, being necessarily filtered, is incomplete. We only know what we can measure.

In the case of elementary particle physics the situation is even more alarming. The Large Hadron Collider, for example, should start working this coming summer or early fall. In its full capacity, it should produce around 600 million collisions per second. This translates to about 700 megabytes per second of data, more than 10 petabytes (1015) per year. That’s more than a million hard drives, each with a gigabyte. To make sense of this flood of information, physicists have to filter the data, selecting events deemed “interesting.” This selection, in turn, is based on our current theories that speculate on what’s beyond the standard model of particle physics, that is, theories that speculate on stuff we don’t know is there. Although these theories are mostly pretty solid (the Higgs particle as universal giver of mass; extensions of the standard model using more than one Higgs, supersymmetry or/and more than three spatial dimensions…) they can only be confirmed through the very same experiments whose outcome they are trying to predict. Given this mechanism, there is a risk that unexpected phenomena, not predicted by any current theory and hence not included in the subset of collisions deemed interesting, will be eliminated by the data filtering process. In this case, and in a paradoxical way, the theories that we construct to amplify our view of physical reality will actually limit what we can know about nature.

Most physics fans out there have probably heard of Kip Thorne, author of Black Holes and Time Warps and some other books. If you polled physicists to find out who they thought had been the most influential American scientist doing research in general relativity over the past several decades, Thorne would win hands-down. (Here’s a recent interview in Discover.)

And if you dropped the delimiter “American” from the question above, the winner would undoubtedly be Stephen Hawking. So we’re very happy to have a guest post from Kip, announcing an upcoming talk by Hawking.

Left to right: John Preskill, Kip Thorne, and Stephen Hawking.

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Stephen Hawking is coming to town – to Pasadena, that is.

Caltech, in Pasadena, California, is Hawking’s home away from home. Since 1991 he has spent roughly a month a year here as our Sherman Fairchild Distinguished Scholar. This year he flies in from his English home at the end of February, then heads off to Texas in early April.

He arrives with an entourage of five care givers to tend to his physical needs, one or two family members, several graduate students, and a “graduate assistant” who handles logistics and serves as general fixit-person for his computer system and mechanized wheel chair. His current chair is new and sophisticated. At the flick of a switch, its hydraulics can lift him up to a standing person’s eye level or slide him down near ground level for high-speed chases — he has been known to take pleasure from running over the toes of university presidents.

Hawking’s Pasadena sojourns are rather like Einstein’s in the 1930s. Caltech is an intellectual magnet – a crossroad for ideas about the cosmos and the fundamental laws of nature, which are Hawking’s passion. He contributes mightily to the ferment, and partakes. Our California night life (LA, not Caltech!) is also pretty good; and Hawking, like Einstein, is a party animal, only more so. During his annual month here, my own social life intensifies five-fold just from being his closest California friend. He loves opera, theater, jazz clubs, barbecues that he hosts in the patio of his Pasadena home, and dinners with fine wine – especially an Indian Feast prepared for him by Caltech undergraduates. Yes, we geeks can cook up a storm – well, not me, but the younger generation.

Conversation with Stephen is slow, about 3 words a minute, produced by Stephen moving a muscle in his face (imaged by a lens and photodetector) to control a cursor on his computer screen. It’s slow, but rewarding. You never know, until his sentence is complete, whether it will be a pearl of wisdom or an off-the-wall joke. Faster speeds are on the horizon: computer control via brane waves, without drilling a hole in his head (he’s opposed to that). But he resists changing technology, even without drilling, until forced to. “I can’t believe it’s as good as what I have.” (It actually is; my wife has a friend with ALS who proves it so.)

Most of Hawking’s Pasadena time is spent thinking, conversing, and working on projects. Jim Hartle drives down from Santa Barbara to continue their decades-long research collaboration on the birth of the Universe. Leonard Mlodinow, a Pasadena-based free-lance writer, toils with him on a book: in the past, A Briefer History of Time; now, their forthcoming The Grand Design. And there are drives to Hollywood to film for Star Trek or the Simpsons or the forthcoming Stephen Hawking’s Beyond the Horizon.

On each Pasadena visit, Hawking gives a lecture for the general public – always before in Caltech’s limited-seating Beckman Auditorium, but this year in the newly renovated Pasadena Convention Center, at 8PM, Monday March 9. “Why We [the human race] Should Go into Space” is his title. It’s an opportunity to see him in action, be immersed in his mind’s world, and – if last year’s lecture is any indication – participate in a happening. Tickets are available from the Caltech ticket office, (626) 395-4652, at $10 each.

The last time I saw Hawking speak to such a large audience, thousands, was in a converted railway station in Santiago Chile, soon after General Pinochet’s regime gave way to civilian rule. It was quite a show. Hawking made a grand entrance to rock music and charmed the crowd. The President of Chile and other civilian officials sat on one side of the giant stage, the military brass on the other, with enormous tension between them; they were hardly speaking to each other in those days. Only Hawking could bring them into the same room. His aura works magic. The next day the military flew us to Antarctica: a C130 cargo plane filled with TV cameras, journalists and physicists. It was August, the Antarctic winter, the first flight to Antarctica in more than a month due to winter storms. It was a Hawking Adventure, one among many. He lives life to the fullest. He will fly on a rocket into space soon.

One of our guiding principles here at CV has always been that disciplinary barriers are meant to be leapt across. So, to mark the passing of an influential writer of fiction, who better than an influential writer of quantum field theory textbooks? We’re happy to have Michael Peskin contribute a guest post on the passing of John Updike.

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John Updike (1932-2009)

John Updike, one of the great American writers, died on Tuesday. The Cosmic Variance bloggers might seem to write incessantly, but they had nothing on him. Updike produced 26 novels, 9 poetry collections, and, it seemed, a short story in the New Yorker every other week. There was no aspect of culture that he did not know. Yesterday, I saw him celebrated on the sports page of the San Francisco Chronicle for his classic on Ted Williams’ last at bat, “Hub Fans Bid Kid Adieu”. We scientists should also acknowledge our gratitude and send our friends out to read his work.

Every particle physicist knows Updike’s poem “Cosmic Gall,” the number one popularization of neutrinos:

At night, they enter at Nepal
and pierce the lover and his lass
From underneath the bed …

Readers of Cosmic Variance will find much more interesting his 1986 novel Roger’s Version. In Chapter One, the scruffy fundamentalist computer science graduate student Dale Kohler walks into the office of the comfortably middle-aged Harvard professor of divinity Roger Lambert and shatters his worldview by explaining that new discoveries in physics and cosmology require intelligent design. The characters in the story that follows personify all points of view in the science versus religion debate, until — but I shouldn’t ruin the surprise.

People who are serious about literature claim that these works have merely intellectual interest. If you are in that group, there are also Updike novels that will move you with the depth of his empathy. His masterwork is the set of four Rabbit Angstrom novels, a thousand pages in all, one novel every ten years from 1960 to 1990. The greatest moments of Harry “Rabbit” Angstrom’s life came in high school, when he was a star basketball player in his small town in upstate Pennsylvania. When the first novel opens, that part of his life is already over. He has an uninspiring job, a tiny apartment, and a baby who dies in the first few pages. Harry has no introspection. The glow that surrounded him on the basketball court brings him women, and, one after another, they push him into all varieties of trouble. Harry’s wife Janice is tougher and recognizes that the two are stronger together than apart, but she cannot control his whims. In Rabbit, Run, he wanders in and out of his new marriage and an affair with a girl from the town. In Rabbit, Redux, he takes in a runaway teen and her drug habit. In Rabbit is Rich, he inherits his father-in-law’s Toyota dealership and samples the country-club life. In Rabbit at Rest, he tries to retire to Florida, but the bad choices of the past three books — and one astonishing new one — follow him. Harry also seduces his readers. We stay one step ahead of him in anticipating the next catastrophe, but we also watch through his eyes the panorama of America in Updike’s era.

If this is too heavy to carry, you could pick up the short, early novel The Centaur. A father, a high school science teacher, sacrifices himself for his son. It is a brief story, told with great pathos. But also, magically, just under the surface, the story unfolds as a Greek myth, and, in the end, the father, Updike’s father, ascends to the heavens.

It may not be true for those who blog, but those who put pen to paper will always be with us. Enjoy!

John Updike Image (c) Michael Mundy