I’ve always been fascinated by very old human artifacts. I don’t mean LPs from the sixties or paintings from the Renaissance, although they certainly are interesting. No, I mean really old things; things that are old enough to have a thick air of mystery about them. Things so old that sometimes their purposes and creators have been forgotten. Like many matters of taste, it’s hard to explain why—even to myself. I have a few theories. Here they are, in alphabetical order:

  • The Admiration Theory: nothing today is built to last for millennia; in fact, many things are built to purposely fail after a set amount of time. I can really admire the skill of ancient craftsmen who created buildings and art that outlived not only themselves, but sometimes also their entire civilizations.
  • The Extreme Theory: am I big or small? Fast or slow? Important or insignificant? I can’t answer these questions with absolute certainty, but I can place myself on a continuum. To do so requires knowledge of extremes. Learning about the oldest human creations can help me to understand where I stand in the universe.
  • The Limitless Theory: people are stuck to the Earth, can only move one direction in time, and eventually die. Knowledge and imagination are the only ways for us to extend beyond these limits. By learning about the distant past, I can pretend as if I had experienced it; my lifespan artificially increases by thousands of years.
  • The Nostalgia Theory: technologies like computers, medicine, and plumbing ensure that life is better today than it has ever been in the past. But at the same time, the simplicity of our ancestors’ lives calls to me. I have an inkling that the people of the past were more in tune with themselves and with nature than I am right now—and therefore more satisfied, in a way. I can’t return to this time for a visit, so the next best thing is to study whatever remnants are left.
  • The Significance Theory: ancient people had to spend most of their time finding food and protecting their families. They had even less free time than we do today—but they still somehow made time to build impressive monuments. Even if we don’t always understand why they were built, these things still deserve our attention and reverence. They have the power to fill us with a sense of mystical wonder.

The reason I bring this up is that I was recently able to visit Newgrange—one of the best very old things on the planet. Newgrange is an ancient Irish passage tomb. Carbon-14 dating places its construction around 3200 BCE, making it over five thousand years old—older than Stonehenge, the Pyramid of Djoser, Mohenjo-Daro, the Easter Island statues, and nearly anything else famous for being old and mysterious.

I first learned about Newgrange in high school, either by finding it on the internet or by studying it in art class. (I’m not sure which came first.) I always thought it was amazing, but it never occurred to me that I might be able to visit it some day. It turns out that Newgrange is less than an hour-long bus ride from Dublin. So when Heidi and I planned our trip to Ireland, I made sure that we would visit this ancient site. While Skellig Michael was probably the most dramatic and awe-inspiring thing I saw in Ireland, Newgrange was the most exciting to me, since I had known and wondered about it for so long.

We happened to visit on a beautiful, cloudless day. Even though I had been drinking awake until 4:30 AM the night before and was running on about two hours of sleep, the combination of the perfect weather and the excitement of being at Newgrange made my mind crystal clear. Colors even seemed brighter than usual—I’m not kidding!

You can read all about Newgrange elsewhere. I’m just going to mention a few things related to my trip and my pictures. (Otherwise I think I’ll end up writing a book instead of a blog post, and no one will want to read it.)

Here’s a picture of the whole thing:

Newgrange is essentially a stone chamber buried under a huge mound of earth. A passageway leads to the outside, a stone wall surrounds it, and there are a few standing stones near its entrance. It was sealed and abandoned a few hundred years after its construction, and it remained hidden until 1699. People know a lot about its physical presence, but essentially nothing about its builders or its purpose.

The current wall is a reconstruction—and a controversial one at that. It is held up by concrete because it won’t stay up on its own. Many people believe that if the wall requires concrete to stand, there is no way the ancient Irish could have built it. A popular alternative theory is that the stones of the wall were originally arranged on the ground as a kind of skirt.

Most of the wall is made of white stones, but there are a few areas with gray stones. I liked the contrast in this shot:

The entrance is perhaps the most famous part of Newgrange. One striking feature is the large carved stone, which features a three-spiral pattern. This is a rare symbol in ancient art, and Newgrange is one of its earliest expressions. The other important item is the small window above the door. The interior chamber is pitch black for most of the year, but the small window is built to let in the sun’s light during dawn and dusk on the winter solstice.

Although the passageway and exterior wall have been restored, the inner chamber is completely original. Visitors can go inside, and can even touch the walls. What an electric experience! Cameras are not allowed inside, so you’ll just have to imagine what it’s like in there. I think it’s better this way. No camera could ever begin to capture the feeling of being inside a hill’s womb; no camera could capture the feeling of meeting a five-thousand-year-old ancestor through a stone medium. A camera would only weaken the magic by adding an extra veil between visitor and reality.

Now, for my last picture: since I can’t show you the inside, I thought I’d show you the back of Newgrange. It’s certainly beautiful, but it never shows up in Newgrange photo galleries. The absence of the white wall makes it more authentic in a sense.

I left Newgrange feeling fuzzy and happy. I hope this post has at least partially explained why, and I hope you’ve picked up a little bit of the awesomeness of Newgrange.

Further Reading


Skellig Michael

Fourteen hundred years ago, an unnamed Irish monk decided to head out into the wilds. He was a rugged survivor, and his goal was to grow closer to God by living a simple life. Inspired by Saint Anthony of the Desert, he went to the literal end of the world—a tiny, inhospitable island seven miles off the coast of western Ireland.

Clinging to the island’s steep rocky cliffs, the first monk eked out a humble existence by fishing and hunting for puffins. Bad weather often isolated him from the mainland for days or weeks at a time. He spent hours each day praying and meditating, and almost no time at all sleeping. Slowly but surely, he gathered rocks—sometimes he had to smash them loose with a crowbar—and began constructing a stone staircase from his usual landing point.

Eventually, more monks joined him. They took their crowbars to the highest point on the island, broke the rock down, and built a flat terrace out of it. On top of the terrace, they built walls and stone beehive huts. Through sheer perseverance, they transformed the place into a home—not a fancy or comfortable one, but one that suited their desires. The island, now known as Skellig Michael, became the site of a small monastery that endured for over six hundred years.

Even today, getting to Skellig Michael presents a challenge. Boats are only able to land during the summer, and usually only three days out of a week have suitable conditions. Even when it is possible to land, the island is often a dark and rainy place.

I was fortunate enough to recently visit the Skellig Islands (Skellig Michael and the nearby Little Skellig) on a rare sunny day. Words and pictures can’t really describe the trip—but I’ll try to use them anyway.

Heidi and I arrived in Portmagee the day before our trip. It was a fitting place to begin an expedition to the Skelligs—small and quiet, surrounded by natural beauty—it encouraged stillness and prepared our minds for the journey to come. Skellig experts checked the sea conditions in the morning, and everything seemed fine. We got on a small motorboat—practically the only modern convenience of the whole trip—and started the choppy ninety minute trip to Skellig Michael.

From far off, the islands looked featureless and gray. Skellig Michael appeared on the right and Little Skellig on the left.

But as we got closer—passing Little Skellig and approaching the pier on Skellig Michael—they became alive with color.

We landed, jumped off the boat, and started the climb to the top. The monks did this all without engines or a pier—what was it like for them? Partway up the path, we encountered our first puffins—a source of beauty for us, a source of food for the monks.

We paused to rest at a place called Christ’s Saddle, where the staircase—the original, thousand-plus-year-old staircase—looms upwards at an ever-increasing angle. Part of the thrill of Skellig Michael is that even in this modern age, it remains a remote and untamed place. Two tourists died in 2009 after falling from this particular portion of the path.

Closer to the top, we were treated to a glimpse of Little Skellig sitting like an uncut jewel in the great blue expanse of sea and sky.

Out of breath, we finally reached the monastery at the top. The monks had built a chapel, a kitchen, a graveyard, a toilet, and several houses. There are even rumors of a secret underground tunnel somewhere in the complex. All of these structures were built entirely out of stone; not even mortar was used. Each stone piece was carefully placed to fit tightly with its neighbors and angled outwards to deflect rainwater.

A closer view of the kitchen reveals that the monks even gave it vents to allow smoke to escape. I wish I could meet one of these monks: fisherman, hunter, engineer, laborer, ascetic, scholar, and meditator, all rolled into one person.

Our pilgrimage complete, we walked back to the bottom and began our journey back home. On the return trip, we made a close pass by Little Skellig. Little Skellig is even less hospitable than Skellig Michael, and it is nearly impossible to land on. People are actually forbidden to go there. It is a haven for gannets; tens of thousands of gannets make their nests on Little Skellig each year. The whole island is white with them.

I think I could have spent weeks on Skellig Michael in a state of constant amazement, and I was sad to leave after just two hours. At the same time, I’m extremely grateful that I was able to experience such a rare and interesting place—even if it was only for a short while.

Further Reading

  • Official UNESCO World Heritage Site webpage
  • Wikipedia and Wikitravel articles about Skellig Michael
  • Boat operator’s website with info and pictures
  • Article about the recent deaths on Skellig Michael
  • A free online book about the South peak of Skellig Michael. The main monastic settlement was on the North peak, but a few extremely dedicated monks led even more solitary lives on the steeper South peak.
  • A book about all aspects of the Skelligs.

Why Does a Small Aperture Increase Depth of Field?

Photographers know that decreasing the aperture size on their camera will produce an image with a larger depth of field. Although it’s possible to take a great picture without understanding why this is true, it doesn’t hurt to know! All we need to figure it out is a little bit of geometry and physics, plus a little knowledge about how a camera works. This is a really fascinating topic for me; it shows how a single topic can have many different levels of understanding.

Click here to learn about aperture size and depth of field

The Two Cultures and a Call for Discussion

When I was a sophomore in college, I took a class about thermodynamics and statistical mechanics. Each chapter of the textbook (An Introduction to Thermal Physics by Daniel V. Schroeder) was preceded by an “amusing” quote about the subject material. One in particular caught my attention; it appeared before the chapter about entropy and the second law of thermodynamics:

“A good many times I have been present at gatherings of people who, by the standards of the traditional culture, are thought highly educated and who have with considerable gusto been expressing their incredulity at the illiteracy of scientists. Once or twice I have been provoked and have asked the company how many of them could describe the Second Law of Thermodynamics. The response was cold: it was also negative. Yet I was asking something which is about the scientific equivalent of Have you read a work of Shakespeare’s?”

This idea fit nicely with some things my friends and I had been talking about, such as the strange fact that many schools offer “science for humanities majors” classes but no corresponding “humanities for science majors” classes. We weren’t interested in taking watered-down humanities courses; we just thought that English majors should have to learn real science. It seemed like a dangerous double standard that could produce one-sided people unable to completely understand the world around them. So naturally, I wanted to read the book that this quote came from: The Two Cultures and the Scientific Revolution, by the British novelist C. P. Snow.

However, the library didn’t have it and my desire to read it quickly got buried under all the other things happening in my life. It’s always been floating around in the back of my head though, and I finally got a chance to read it last month. I can’t say that it quite lived up to my expectations. The book is full of vague generalizations (“If the scientists have the future in their bones, then the traditional culture responds by wishing the future did not exist.”), opinions stated as facts (“The only writer of world class who seems to have had an understanding of the industrial revolution was Ibsen in his old age”), and irrelevant stories about famous people. One of its most serious defects is that Snow never actually explains why a lack of communication between scientists and ‘literary intellectuals’ is bad—he says: “There seems then to be no place where the cultures meet. I am not going to waste time saying that this is a pity. It is much worse than that. Soon I shall come to some practical consequences,” but the consequences never come.

It seems that I am not the only person who was bothered by Snow’s argument (or lack thereof). His book (which was actually the printed version of a public lecture he gave at Cambridge in 1959) set off a huge controversy in the British press. His most famous opponent was F. R. Leavis, a literary critic who in 1962 made a scathing attack (also in the form of a lecture at Cambridge) against Snow and his ideas. Roger Kimball has described Leavis’s talk as “a devastating rhetorical fusillade. It’s not just that no two stones of Snow’s argument are left standing: each and every pebble is pulverized, the fields are salted, and the entire population is sold into slavery.” Leavis’s talk was published as The Two Cultures? The Significance of C. P. Snow, and I read this book too. It’s great—Leavis’s style is unlike anything I’ve ever read, and the cultural issues he brings up seem as relevant today as they did in the sixties.

Four years after his talk, Snow made a response in the form of another book (The Two Cultures: A Second Look, which is usually now included with The Two Cultures and the Scientific Revolution). In it, he expresses his surprise at the controversy he had created. He muses that:

“As the flood of literature mounted, two deductions became self-evident. The first was that if a nerve had been touched almost simultaneously in different intellectual societies, in different parts of the world, the ideas which produced this response couldn’t possibly be original.”

Truer words were never said. The Two Cultures and its surrounding debate are merely the most visible elements in a long string of literature that stretches from the deep past all the way to the present. I have now read quite a bit of it, and it has been a very interesting experience. (See Further Reading for a some of the best/easiest-to-find parts.) All this reading has caused me to think about a number of things that I don’t normally think about, such as:

  • What does it mean to be a scientist?
  • What is and what should be the role of science in society?
  • How does science affect nonscientific beliefs?
  • Is a scientific education sufficient for imparting culture?
  • What would a true synthesis of science and art look like?
  • Is there a “gulf of mutual incomprehension” between the sciences and the humanities? If so, is this bad, and if it is bad, what should be done about it?

And in another sense, I think that all these questions are manifestations of the following deeper questions:

  • How much, and what kinds of things, can humans know?
  • How should one live one’s life?
  • What does it mean to be human?

I think this is the “nerve” that Snow speaks about. I will probably share my thoughts on at least a few of these topics in later blog posts—but I would really like to have a conversation first. So please read some of these things and let me know what you think. If you’re having trouble finding The Two Cultures or The Significance of C. P. Snow, let me know and I may be able to help you out.

Further Reading

The list is virtually endless, so I’ll restrict myself to things available online for free.

  • The Four Ages of Poetry, by Thomas Peacock—a satire of the scientific/anti-poetic attitude the author felt was becoming prevalent. Published 1820. Available here.
  • A Defense of Poetry, by Percy Shelley—a response to Peacock’s satire that explains the virtues of poetry. Written 1821. Available here.
  • Science and Culture, by Thomas Huxley—a lecture given at the opening of a scientific school. His defense of science puts Snow’s to shame. Given 1880. Available here
  • Literature and Science, by Matthew Arnold—a response to Thomas Huxley’s talk. His argument is more effective and less cruel than Leavis’s. It is interesting to note that Arnold and Snow both gave their talks as Rede lectures at Cambridge. Arnold’s is from 1882. Available here.
  • The Value of Science, by Richard Feynman—some philosophy from everyone’s favorite physicist. This is a talk given in 1955. Available here.
  • ‘The Two Cultures’ Today, by Roger Kimball—a look back at the controversy from one of the best social critics around today. Published 1994. Available here.

Overwhelming Oddness

Here’s a short story I wrote for a tenth grade English class assignment. Before you read it, I want to mention a few things:

  1. Back then, everything I knew about quantum mechanics came from second-hand reports of friends who had seen The Elegant Universe.
  2. I had just finished reading Breakfast of Champions when I wrote this.
  3. There’s a painfully obvious reference to a Matthew Arnold poem in here–can you find it?

Click here to read the story!

How to Choose a School

(Updated on 04-03-2012.)

Prospective graduate students came to visit our physics department last weekend. For many of them, this visit marked the beginning of Decision Season. It’s a magical time of year: stressed-out prospectives are trying to figure out where they want to spend the next 5-7 years — older graduate students are trying to give them as much alcohol as possible — and everyone is trying to eat free food.

Since I recently went through this process myself about a year ago, I thought I would throw in my two cents about how to choose a school. (I think this whole post applies to college as well as grad school… so I’m just calling it “school.”) It’s a pretty daunting task to make such a big decision based on so little information, so I think most people love to hear advice about it.

The decision-making process can be broken into two steps: one in which you weed out schools that are bad, and another in which you select the best choice out of the ones that remain. There’s tons of advice about how to do the first step, and I’ve given links to some of my favorite advice sites at the end of this post. However, this part can hardly be called a decision; it’s more like a mechanical filtering process. The most frustrating part of choosing a school (to me) is picking between several good schools whose relative pros and cons seem to essentially balance out. Given the relative lack of advice pertaining to this step, I’d like to offer my own. So here’s the main idea:

Don’t Think Too Much

I’d like to now expound upon what I mean. First, here are three things that I believe to be true:

  1. You’re ignorant. There are simply too many things that you cannot/don’t understand/know. The future and your own personality are too unpredictable. Can you really know what is best for you, or that a particular school will provide it? I don’t think so.
  2. You’re making a bet on yourself. Individual people have individual reasons for going to school, but I think I can confidently assume that you are at least after knowledge, experience, and a good time. These things are highly personal endeavors. A teacher can present information to you, but you have to choose to learn. Professors can offer you research opportunities, but you have to take them. You can have fun, but not if you sit around doing nothing all day. In the end, it’s you that determines your success, not your school. Have some faith in yourself.
  3. There’s no bad choice. Many people approach the decision-making process with the assumption that the school they choose will make a major impact on the rest of their lives. This is completely true. Unfortunately, most people also believe a corollary to this assumption — one which makes them think that if they choose the wrong school, it will have a major negative effect. While this can happen in some extreme situations, it’s pretty unlikely. For one piece of evidence, see the previous bullet point. For another, watch this awesome TED talk. I don’t want to profane it with an attempt to sum it up in one sentence. It’s pretty short, and you’ll be glad you watched it. Do it!

With the wrong attitude, the school search can turn into a hellish and stressful situation. While I think it’s totally reasonable to try to pick the school that seems to offer you the best experience, it’s also extremely important to realize that there’s almost no way you can make a mistake. So keep your favorite criteria in mind — reputation, location, aesthetics, stipend, atmosphere, faculty, etc — but don’t fret too much if you’re having a tough time picking a single school.

If you can narrow down your search to just two top schools, then it’s time to really “go with your gut.” If you’re choosing between two, they’re probably both pretty awesome. Your conscious mind is never going to be able to satisfactorily differentiate between the two. But you can turn to your subconscious mind instead. It’s been with you through the whole process, absorbing information and coming to its own conclusions. Here’s a trick to let it share its opinion: flip a coin. Heads is school X, tails is school Y. If you’re fine with the coin’s outcome, just stick with it. If you get a sinking feeling accompanied by a wish that it had landed the other way, then this is your subconscious talking to you. It’s that simple.

So, to repeat: don’t think too much! Think a little, but realize that thinking has limitations. Put your trust in yourself rather than your school. You’ll be fine no matter where you go.

Current grads: How did you pick your schools? Do you agree with my advice?

Further Reading

Of Temples and Table Salt

Have you ever seen a diagram of a substance’s atomic structure (like the one below, for table salt) and wondered where it came from? If you haven’t, I’ll try to quickly explain why the existence of such a picture might be a mystery:

  • Typical atomic sizes are between 30 and 300 picometers. A picometer is one thousandth of a nanometer, which is one millionth of a millimeter. Atoms are really small!
  • Typical interatomic spacings in solids are bigger, but not by much; they are usually between 0.1 and 1 nanometers. So at the very least, we need to be able to detect things that are about 1 nanometer in size to determine the atomic structure of a molecule or material.
  • The physical size of the average pupil prevents human eyes from seeing anything much smaller than a hair, which is about 0.1 millimeters wide– far larger than a nanometer! (Go here for an explanation.)
  • In fact, the large wavelength of visible light prevents any standard optical device (including eyes and microscopes) from seeing anything smaller than a few hundred nanometers.
  • X-rays have wavelengths comparable to interatomic spacings, but it is nearly impossible to build lenses for x-rays. Thus, x-ray microscopes don’t really exist.

So how do we know what anything looks like on such a small scale? Well, people have actually invented a whole bunch of clever methods for seeing very tiny things. I would love to talk about all of them, but for now I am just going to focus on one of the oldest and most widely-used techniques: x-ray diffraction. X-ray diffraction is a tool for determining the structure of a crystal, which is a solid material that has a repeating atomic structure. It’s true that not every material has a repeating structure, but many do. What’s even better is that many molecules can be tricked into growing in a crystalline form; for example, proteins can be stacked into periodic arrays. This allows x-ray diffraction to determine their molecular structures. This information is invaluable to physicists, chemists, biologists, doctors, and pharmaceutical companies. (Here is a big ol’ pile of protein structures.)

Continue reading to learn how x-ray diffraction works!