You are currently browsing the category archive for the ‘history of science’ category.

We’re better now.

Yes, we’re far from perfect.

And in some parts of the world we’re even worse.

But the progress we’ve made since the Enlightenment is remarkable.

In my effort to broaden myself beyond just science and Shakespeare, I read Thomas Hardy’s Tess of the d’Urbervilles, a book that drives home for me just how far we’ve come, how far we still have to go, and how writers like Hardy, in fits and starts, and maybe despite what they think they’re doing, help us get there.

Briefly, Tess Durbeyfield is a young peasant girl in late 19th century England. Her parents are poor, as are her prospects. Through some convoluted storytelling Tess finds herself involved with one Alec d’Urberville, who proceeds to harrass, bully, and finally rape our heroine.

OK, there’s some controversy, purposely engendered by Hardy, about whether Tess was truly raped. Hardy’s Victorian prose is so fastidiously non-sexual that you’re never quite sure what happened between Tess and her assailant – only that Tess got away from Alec as quickly as she could afterwards, and that their time together resulted in a pregnancy.

Tess never communicates her news to Alec, and soon after the baby is born he dies. Yet that isn’t close to the most tragic event of the book.

All the later tragedy spews forth from one Angel Clare, a non-believing son of a minister. Angel falls in love with Tess and, despite her protestations that she’s not good enough for him, essentially browbeats her into finally marrying him. Then, on their wedding night (after Angel divulges his own checkered sexual past) in a fit of conscience Tess reveals all. Angel is repulsed, declaring that Tess isn’t who he thought she was, and immediately runs off to Brazil. Really.

The rest of the story doesn’t bear repeating, though I have to say the final chapters surprised me as much as if our protagonists had been abducted by space aliens and whisked across the Milky Way (that’s not what happens, but almost as crazy).


Here’s Tess, with that pathetic excuse for an athiest Angel behind her. And yes, that’s Stonehenge. You have to read to find out. (Actually that’s Gemma Arterton in the BBC miniseries. Another gift of the Enlightment – the BBC!

Here’s my point. Tess of the d’Urbervilles is a book about an immoral society. I’m not talking about a society that allows rape. In fact, for my argument it doesn’t even matter if Tess was actually raped or not (by the way, she was. So stop arguing).

No, I’m talking about a society that condemns Tess for losing her virginity and giving birth to a baby out of wedlock. Of course, many people through history, and sadly even some today, remain confused about what morality is. They think morality is all about controlling behavior based on some ancient book or set of norms. That’s not morality. As Steven Pinker points out in The Better Angels of Our Nature:

The universality of reason is a momentous realization, because it defines a place for morality. If I appeal to you to do something that affects me . . . I have to state my case in a way that would force me to treat you in kind. I can’t act as if my interests are special because I’m me and you’re not.

Morality, then, is not a set of arbitrary regulations dictated by a vengeful deity and written down in a book; nor is it the custom of a particular culture or tribe. It is a consequence of the interchangeability of perspectives . . .

If all this sounds banal and obvious, then you are a child of the Enlightenment and have absorbed its humanist philosophy. As a matter of historical fact, there is nothing banal or obvious about it.

TBAoON, pp 230-231

Through the skill of the storyteller, we can all see ourselves as Tess. We can see how we can be thrust by circumstances into unhappy situations, how we can struggle with conflicting pressures, emotions, loyalties, and desires. We can develop empathy. And we can, via this empathy and via our own ability to reason, see that a society that punishes young women so harshly and so unfairly is by its very nature immoral.

Well, any lunkhead can see that. (Though, as Pinker points out, plenty of lunkheads in the past didn’t see it. And as my links above show, plenty of lunkheads who are not children of the Enlightenment still don’t see it today.)

What I find more interesting are the contradictions we see in Hardy’s book – contradictions that bring us closer to the question I’m most interested in – how did we get better?

First, let’s consider Angel Clare. It’s saying something that most readers of Tess of the d’Urbervilles hate Angel, mild-mannered and (mostly) peaceful suitor of Tess, at least as much as they hate the rapist Alec. Angel, the child of a preacher and his devout and devoted wife, is probably about as close to an atheist as Hardy could get away with writing in late 19th century Victorian England. While it’s never clear that Angel’s lack of belief is the cause of his immoral treatment of Tess, Hardy makes the point that Angel’s parents, because of their faith-based willingness to forgive sinners, would have advocated for Tess if only they’d known the truth.

I don’t know much about Hardy’s views on religion, though his references to pagan and natural spirituality throughout Tess are suggestive. But I think here Hardy is falling back on old fear and superstition. As religion gradually fell out of favor (a fall that continues to this day), many feared the consequences. I think Hardy is writing Angel’s character as a cautionary tale – without our religious mercy, we are in danger of becoming cold to the messiness of real life. Angel’s lack of belief doesn’t free him – rather, it traps him in a worldview devoid of forgiveness.

(Not that Tess needed forgiven; she was raped! Also, even if she wasn’t, Angel, you just admitted his own infidelity, you hypocrite – so get over yourself! OK, rant over.)

This is hogwash. One of the primary tenets of Enlightenment humanism is that people are fallible. No knowledge is absolute, and therefore no person’s actions are perfect. We all need to forgive one another because we’re all capable of error (again, not that Tess made an error!) If Angel didn’t absorb this lesson, it’s in spite of Enlightenment values, not because of them.

Second, consider the world Tess inhabited. It’s pretty clear that Hardy has strong views about the “old” ways and the “new” ones. Reading about Tess’s experience as a humble milkmaid on a simple dairy farm, one hears the word “bucolic” echoing around as if a thesaurus threw up all over the page. It’s ideal. It’s simple. It’s non-mechanistic. It’s human.

On the other hand, when Tess is forced by Angel’s rejection to take work on a mechanized farm, the images Hardy paints are straight from Hell – fiery furnaces, dangerous, dehumanizing, and exhausting tasks that seem never to end, a heartless supervisor who cares only for profits.

Well, fine. While I suspect that pre-industrial farm life was hardly a walk in the park (the word bucolic always makes me think of catching horrible diseases from animal poop, so maybe I’m biased), there’s no doubt that modernization pressed many workers into harsh and dangerous employment. But what else did it bring?

Pinker again:

One technology that did show a precocious increase in productivity before the Industrial Revolution was book production.

-TBAoON, page 219

Pinker then goes on to describe how increased availability of books, due to mechanical and industrial methods of production, let to greater literacy, which in turn led to greater demand for books, which led to more and more reading. And what were we reading? Novels! Novels that put us in the minds of people different from us. Aristocrats read about the lives of the peasants they’d never known. Whites read about the experiences of black slaves. And men found out what it might be like to be a teenage girl in a society that would shame her for being raped and condemn her for bearing the child of her rapist.

Hardy seems to be saying that our modern world, dehumanizing and merciless, is making us less and less moral. I say he’s got it exactly backwards. We were always immoral – judgmental, short on empathy, more interested in codes and obedience than in rights and freedom. It was the values of the Enlightenment, and the advances in wealth and prosperity that it brought, that allowed us our first tentative escapes from the immoral world of our ancestors. No, that world is not perfect. Yes, modernization can feel dehumanizing. But we can make that better. We can reason with our bosses, and with the government, that better working conditions make for more efficient workers. We can argue that, because you = me, we all deserve safe factories, safe food, better health care, universal education, and free public libraries full of books that expand our reason and our empathy. We are getting better, and it’s because of the Enlightenment and the values it engendered, not in spite of them.

I also say that Tess of the d’Urbervilles would have been better with some space aliens.

Next I’ll be reading Shakespeare’s Othello, another tale about the complications of female purity. That will lead me on to a re-visiting of Milton’s Paradise Lost, a poem I faked my way through some 30 years ago. This time, for real.


I read a book not too long ago called The Science of Shakespeare by Dan Falk. It was a lot of fun, delving into both Hamlet and some of Shakespeare’s lesser-known plays, as well as the accelerating pace of science before, during, and after Shakespeare’s time. Truth be told, however, the actual links between Shakespeare and the science of his time are pretty thin. While Shakespeare of course had an amazing intellect and a deep curiosity, I think the most reasonable assessment has to be that Shakespeare wasn’t particularly interested in science.

But the beauty of Symphony is that I’m not limited to only one kind of music. I can love Shakespeare and science – and I do. Today I’m going to tell a story – certainly not worthy of the Bard, but I hope you like it, anyway – about how we got to now.

Now, in case you haven’t been watching, is the time when we humans will complete the initial reconnaissance of our Solar System by visiting tiny Pluto. Planet or not, Pluto is among the last of the major objects in the Sun’s family to receive a visitor from Earth.

As we watch these close-up pictures of Pluto fill our computer screens, let’s think about how we got here.

Long ago, people noticed the stars. No one knew what the stars could be, but that didn’t prevent us from making up stories. The stars were holes in a blanket, revealing a fire behind. They were milk, squirted from the breast of Hera. They (according to Jim and Huck) were eggs, laid by the Moon across the sky just as a frog might lay her own eggs in the river. Clever as they were, none of the stories came anywhere near the massive truth that stars were enormous nuclear furnaces in whose chaotic centers the elements of our very own bodies are forged. Science got us that story, and lots more besides.

Before science, people noticed that the stars moved across the sky in familiar patterns. Certain stars always returned to the same spot in the sky at the same time each season. The bright stars of Orion always appeared in the Autumn in the Northern Hemisphere for instance


But there were other objects, too. They looked something like stars, although they seemed not to twinkle the way stars did. More unusually, though, these objects wandered across the sky separate from the unchanging stars. They were named “planets” a word that meant “wanderers.”

People named the planets after their gods. The lovely morning and evening stars were, once they were found to be the same object, named after the goddess of love. The bright and stately planet that moved over the full sky was the king of the gods. The reddish world was the god of war.

But what were they, really? In 1609 Galileo pointed a new device toward the heavens and saw that the planets were more than just lights in the sky. Venus, not just the goddess of love, was also a world that, like our own Moon, passed through phases of light and dark. Warlike Mars didn’t show phases, but unlike the stars it formed a disk in Galileo’s telescope. And Jupiter, the god king, was not a single world but five, with the four smaller ones circling round and round the central disk (this, incidentally, was a discovery so momentous that even Shakespeare may have referenced it in his play Cymbeline – a work I look forward to reading soon).

Next came the discoveries of Kepler, who found that the orbits of the planets followed strict mathematical rules, and Newton, who explained those rules with an elegantly simple law. Every time an apple falls from a tree it follows the same law that keeps all the worlds of the Solar System in orbit around the Sun.

Later we were able to use those same laws of motion to discover planets and other worlds we couldn’t even see with our eyes! Uranus was revealed due to its invisible influence on Saturn. Neptune showed up when it pulled on Uranus (ok, stop giggling).

The story would be perfect if only Pluto had also shown up due to its gravitational tug on Neptune. Sadly, Pluto’s discovery was actually an accident. Mathematical errors in the calculations of Uranus’ and Neptune’s orbits led scientists to expect another large planet in Pluto’s place. Instead, and mostly by accident, tiny Pluto happened to be in the right place at the right time, showing that even scientists need a little bit of good luck sometimes.

For thousands of years, people wondered about the planets. But the discoveries of Galileo, Kepler, Newton and their followers let us not only learn what the planets are, but actually travel there. In less than 24 hours, New Horizons will zip along its Newtonian trajectory, flying past a world that Newton’s genius (and a few math errors) helped us know.


Now that I no longer work at COSI, I suppose there’s nothing stopping me making this story public.

For as long as I can remember, the wearing and displaying of crucifixes has bothered me. Whatever your feelings about the historicity of religions, make no mistake: crucifixion was real, as was a horrible method of not just killing someone but delivering a tortuous, humiliating public death (and is the origin of our word excruciating).

I always wondered what people would think if some group began wearing electric chairs or guillotines as ornament.

In the mid-90’s, in perhaps my second year as the first floor volunteer coordinator at COSI, I convinced the powers-that-be that we needed an area-specific award for volunteers who had gone above and beyond the call of duty. I suggested calling it the Hypatia award, explaining only that Hypatia had been a female scientist who had given her life to science. The PCness of an award named for a woman was irresistible, and the Hypatia Award was born.

Of course, those of you who know the story of Hypatia know what i left out.

Carl Sagan’s Cosmos had an enormous influence on me, and I always remembered his story of Hypatia:


Whether the details of Hypatia’s story are historically accurate, and there is controversy about that, it is certainly a lovely story, and Sagan told it with a passion and intensity that burned into my 12-year-old brain.

A decade and a half later, I still remembered the story. I was allowed to select the symbol for the Hypatia Award, and I of course chose a seashell, the symbol of Hypatia’s martyrdom at the hands of Saint Cyril’s murderous mob.


The funny thing was, the Hypatia Award became wildly popular with COSI volunteers. They prized it, and worked hard to impress me and the rest of the team in order to earn it. The recipients wore their seashells proudly on their hour ribbons. Eventually, the other areas at COSI adopted similar awards for their volunteers.

It always gave me great pleasure (yes, I admit it) to see volunteers, some of them homeschoolers from rather fundamentalist religious backgrounds, proudly sporting this symbol of Hypatia’s martyrdom. Of course I generally kept this part of the story to myself. Until now.

I know, I know, I’m a terrible person, tricking people into wearing a pagan crucifix. I feel bad about it every day.

tee hee

My new book is now available as an ebook at Barnes and Noble. From the website:

Atoms and Eve is a story of discovery. Born in 19th century America, Eve Dalrymple wants to know everything. She struggles to find her way in the male-dominated field of nuclear physics, but thrills to the amazing discoveries she and her colleagues make about the nature of the atom. Those discoveries will ultimately lead Eve, her heroes, and her colleagues to the most difficult and dangerous moral dilemmas the world has ever faced. Through Eve, we experience the wonders of the hidden, beautiful, and perilous world of the atom.

The cost of the ebook is $1.00. After the ringing success of The Turtle and the Universe (whose title was swiftly changed to “half off” I think), no publisher wanted to commit paper and ink to another effort. After much thought, I decided to go the self-publishing route.

If you don’t have a nook reader, no worries, you can download the free nook reader app for use on your computer or mobile device:

For my COSI friends out there, you’ll recognize that Eve’s story is inspired by the Electric Workshop in Progress. Yes, I changed the spelling of “Dalyrimple” and I changed Eliza to Eve so as to make a weak joke. But I think you’ll enjoy the story behind all those crazy electric machines.

I’d love to know what you think of Atoms and Eve.

The Hubble Space Telescope is in many ways one of humanity’s supreme achievements.


I remember as a child reading about the wonders that will open for us when we are able to put a telescope in orbit. The Hubble has certainly lived up to this billing. Among other accomplishments, it was part of the network of telescopes that helped scientists discover dark energy and the accelerating expansion of the universe, probably the most exciting cosmological discovery in my lifetime.

I was recently building a paper model of the Hubble (Yes, I do that sort of thing. Hot, huh?) when I came across an interesting piece of equipment attached to the telescope. It’s called a “magnetic torquer” and it helps the Hubble to move about in an ingenious way.

Consider the problem: you’ve got a telescope in orbit around the Earth. You can’t very well leave the telescope pointed in a single direction all the time. It needs to scan the entire sky. You also can’t move it around with any sort of propellant, as some of the fuel would inevitably end up on the telescope’s mirrors or other sensitive equipment. So how do you move?

Electric motors can make the telescope move one direction, as long as a counterbalance moves the other direction at the same time. But eventually you’ll want to cancel some of that extra motion. It certainly would be nice to have something to push against, something with which to exchange some of that excess momentum.

But there is something: the Earth itself! No, the Hubble can’t reach the surface of the Earth, or even the atmosphere. But it can reach something: the Earth’s magnetic field. It turns out that the magnetic torquers on the Hubble allow it to create a magnetic field that reacts with the weak but steady (at least on short time frames) magnetic field of the Earth. Engineers on Earth send a carefully controlled electric current into one or more of the three torquers to create the desired magnetic field. This field pushes on the Earth’s magnetic field, exchanging some momentum with the Earth, and moving the Hubble in just the desired manner. Amazing!

I am constantly in awe not just of the universe around us, but of humankind’s ability to use ingenuity and creativity to discover the deepest secrets. Go Hubble!

Scientific discovery is inherently creative. It’s a bit hard to see it that way sometimes, because the creation is slower than we might like. It’s slower, for instance, than the creation inherent in new movies, a new baseball season, or some new trend on Twitter (OK, I know nothing  of Twitter, but I think they have trends, right?)

Today is one of those glorious days when the creativity of science becomes apparent. Today the Planck telescope released the best picture of our universe’s earliest visible moment that (as far as we know right now) we’ll ever have. Here it is:

Planck_CMB_565x318So what’s the big deal?

Here’s the big deal.

Stars don’t come with labels. When we look up into the sky, we see lots of little points of light. Some might be brighter or dimmer, and a few even have visibly different colors. But they don’t tell us what they are. One of the amazing accomplishments of humanity is that we can look up at the stars and know that they aren’t little lights in the sky. They are suns, seen from very, very far away.

How far away? By a handful of connected methods, we’ve learned how to measure the distance to the stars. The first of those methods starts like this:

Hold your finger up in front of your nose. Look at it with your left eye. Notice what part of the far wall your finger blocks. Now close that eye and open the other. Your finger blocks out another part of the wall. With a little bit of trigonometry, you can find out how much closer your finger is than the back wall.

Stars are a lot further away than your finger, but that same idea helped us discover the distance to some of the nearest stars. More distant stars required other methods, including one discovered by an astronomer named Henrietta Swan Leavitt.

Leavitt began her astronomy career as a computer, hired to perform boring mathematical calculations in the days before such calculations were automated. Leavitt stuck with it, and became a trusted member of the Harvard College Observatory. Well, trusted may be a bit of an overstatement. As a woman, Leavitt was never allowed to use the observatory telescope. But she was given access to photographic plates, from Harvard and elsewhere. Leavitt noticed something strange on these plates. Most stars looked exactly the same on the plates, night after night after night. But other stars changed their brightness over a period of days or weeks. That wasn’t the exciting discovery. Variable stars had been known for a long time.

The exciting part was this: Leavitt noticed that the variable stars in the Large Magellanic Cloud, a cluster of stars visible only from Earth’s Southern Hemisphere, had an interesting relationship. The brighter the star, the longer its period of bright and dark. In fact, the relationship was so strong that Leavitt could turn the data into a straight line graph.

Why was that so exciting? The Large Magellanic Cloud was suspected to be very, very far from Earth. Suppose you live in Baltimore and have two friends living in Seattle. Those two friends are just about the same distance from you, even if they live a few miles apart. The same is true of stars in the Large Magellanic Cloud as seen from Earth. They are all so far away that any difference in their distances from us are unimportant. To a good approximation, these stars are all the same distance from us.

That means that the bright stars really are bright, the dim stars really dim. This relationship (with a few details omitted) let us humans find the distance not just to stars but to to galaxies containing those stars.

Where are we in our tale? We’ve got not just stars, but galaxies, collections of perhaps 100 billion stars or more, whose distances we can know through nothing but our ability to build instruments, make observations, and formulate and then test bold ideas about what’s out there.

Time for another down-to-earth phenomenon with cosmic significance. Watch a NASCAR race on television. As the 200 mph billboards fly past, you’ll hear a distinctive sound. The sound starts high, then suddenly switches to a lower pitch as the car goes past you. This is the Doppler effect, the result of sound waves bunched up in front of the approaching car, stretched out by the receding speeder.

An analogous effect occurs with light. Instead of pitch, the change is in color. As objects move away from us, the light they emit is shifted toward red. As they move toward us, light is shifted toward blue. In 1929, Edwin Hubble (and as it turns out two years earlier Georges Lemaître) discovered an odd relationship. Almost every observable galaxy wasredshifted; the were almost all rushing away from us. Not only that, but the further away the galaxy, the faster it was receding.

It was soon realized that this could be explained not by postulating our galaxy as the center of the universe, but instead by seeing that the view would be just the same from any galaxy if space itself were expanding. In that case, sort of a raisin bread view of the universe, all the galaxies would be raisins and space would be the expanding bread. From any raisin, it looks as if all the other raisins are running away.

Further, if we run the tape backward, we see that the universe as not expanding into the future, but contracting into the past. There must have been, in this scenario, a time when the universe was incredibly small, incredibly dense, and incredibly hot.

George Gamow and many others realized that such a small, dense, hot universe would have left behind a fossil. In 1965 two scientists named Arno Penzias and Robert Wilson accidentally discovered this fossil. It was an invisible kind of light, so stretched out over time and space that it was now in the microwave region of the spectrum. (Penzias and Wilson at first mistook this radiation as a residue reflection caused by pigeon poop in their radio antenna.) This radiation formed less than a million years after the Big Bang, at the moment when the universe had expanded and cooled just enough to let the first atoms form. Why then? Because before the formation of atoms, the universe was filled with a sea of charged particles such as electrons and protons. These charged particles absorb light, so that when they were freely roaming space no bit of light could last long before being absorbed. When protons and electrons formed atoms, the light could for the first time roam free.

When it first formed, the background radiation was at a temperature of around 4000 Kelvin (where 0 Kelvin is absolute zero and 273 Kelvin is the freezing point of water). Today, this background radiation is so stretched out it gives empty space a temperature everywhere of around 3 Kelvin, extremely cold but not absolute zero.

This radiation is amazingly uniform through space. But it isn’t perfectly uniform. Ever since Penzias and Wilson stumbled upon the world’s oldest fossil, scientists have been devising ways to study it in more and more detail. Today, the Planck telescope

planck telescope

released the finest-ever picture of the “bumpiness” in that radiation.

So what does it mean? It means, for one, that our best theories about the beginning of the universe are doing remarkably well when they might have failed. This is an enormous accomplishment. First of all, scientists accomplished something wonderful by creating theories that could fail. Secondly, when given the chance to fail, the theories held up. They made predictions about reality, and those predictions were borne out by observations, some of which were released today. The Big Bang, as envisioned by modern cosmology, really did happen. The picture at the beginning of this (already very long) blog entry is the best evidence yet. This is a triumph of human creativity.

But though we should celebrate our accomplishments today, we should also look ahead. Not every detail of Planck’s fantastic photograph can be explained by our best current theories. There are interesting patches in this image, strange irregularities, and no one yet knows what they mean. They might signal new physics. They might give us our first evidence for parallel universes. They might give us details about not just how the Big Bang happened, but why it occurred in the first place. In other words, the details of this image might bring us closer to ultimate question: How did we get here? And where is “here” anyway? The best discoveries answer some questions, but raise even bigger ones. Today’s discovery is a fine example.

I started this blog with a couple of everyday experiments that lead to our discovery of the distances to stars and galaxies, and eventually the birth of the universe itself. Now I’d like to finish with one more experiment you can try. All you need is a television not connected to a cable box or, if you don’t have that, you can just use this video


Now reach out and put your hand on the screen.

Around one out of every one hundred of those little bursts impacting your hand is caused by a bit of light left over from the Big Bang. When you touch that screen, you are touching the Big Bang itself.

We humans are creators. We created the knowledge that today lets us not only touch the Big Bang, but more importantly know what it is we are touching.

Now for something more interesting. A while back I wrote twelve pieces on the surprising ways helium has impacted our view of the universe. I thought I was finished, but recently, as I was researching a possible article on an astronomer named Henrietta Leavitt, I stumbled upon helium tale number thirteen.

Let’s start with something completely unrelated to helium, but which, I promise, will get us back to this amazing idea.

Imagine a pot of water boiling on a stove. Were you to insert a thermometer into that pot of water, you would discover something odd. The temperature of the water is (more or less) 100 degrees C (or 212 degrees F, if you prefer such things). Even though the stove is pumping lots of heat into this boiling water, the temperature does not change. It stays right at the boiling point of water until all the water is converted to vapor.

Now consider just the opposite. I’ll use the liquid-to-solid transition because it’s easier to deal with, but the vapor-to-liquid transition works, too. Imagine a pot of water in a freezer. Again, there’s a thermometer in the water. The temperature drops, drops, and drops until the thermometer reads 0 degrees C (32 degrees F). And then the thermometer stays there until every bit of the water is converted to ice. Even though the freezer is pulling heat away from the water, the temperature of the water does not change.

OK, familiar enough. This phenomenon (known as latent heat) is what drives thunderstorms and hurricanes, protects water-covered fruit during rare Floridian freezes, and makes steam burns so dangerous. It’s caused, by the way, by hydrogen bonds, amazing and important in the own right for many, many reasons. Maybe a future blog subject.

The important point for now is that the phase change provides a sort of reservoir for energy at a particular temperature. If you look at a graph of temperature change versus heat added for water, you get these plateaus where the phase change is occurring.

Notice that the water-vapor phase change plateau is enormous! It takes much, much more heat to boil a gallon of hot water into steam than it does to heat that same gallon from the freezing point to the boiling point. Hydrogen bonds are tough little boogers, and it’s hard work to get water molecules apart.

OK, enough with water. What about stars?

Stars are balancing acts, kinda like this:

Gravity is forever trying to squash the star down. Pressure, provided by the nuclear reactions in the star’s core, is trying to blow it apart. The balance between these two forces is the star we see. What if, for whatever reason, the star were a little too squashed? Were that ever to happen, increased pressure would drive the temperature up. Then the star would swell (and cool) until it was the right size (and right temperature) again. What if the star were too swollen? In that case, reduced pressure would cause the temperature to drop, and the star would contract back to where it belonged, all the while heating back up to its appropriate temperature. In fact, all stars go through these cycles a little bit all the time. Because most never go much beyond their equilibrium point, we never notice.

However, some stars, called Cepheid variables, get caught in large, days-long cycles that keep oscillating for many years. What causes this oscillation? Here it comes: helium!

Henrietta Leavitt was an astronomer in the early 1900s. She became an expert in recognizing and measuring Cepheid variables. Noticing that the Cepheids in the small magellanic cloud had a regular period-to-brightness relationship, Leavitt was able to build a crucial early piece of what would become our cosmic yardstick. Her story is both triumphant and tragic, and I’ll save it for my article if I ever write it. For now I’ll tell just the helium part of the story.

It turns out that the reason Cepheid variables are, well, variable, is that helium near the surface of these stars is undergoing a phase change. No, not from liquid to gas. Stars are much too hot for anything like liquid helium to exist. Instead, the phase change is from one type of ionized helium to another.

OK, so what is ionized helium?

Helium may be number one in our hearts, but on the periodic table it’s always number two. Every helium atom has two protons in its nucleus – otherwise it isn’t helium. Normally, helium also has two electrons buzzing about outside the nucleus. Normally.

But stars aren’t normal. As Laura Dern once said, they’re “hotter’n Georgia asphalt.”

Inside a hot star (stop it, this is a family blog!), there’s lots of energy. Deep in the interior, no atoms have electrons. As you move out toward the edge of the star, however, atoms start to recapture some or all of their lost electrons.

A Cepheid variable is a star nearing the end of its short life. For most of its life cycle, the star is no more variable than our own Sun is. But Cepheids are bigger than the Sun, and so they burn through their hydrogen fuel much more quickly than the Sun does, in just millions instead of billions of years. At some point, the mixture of chemicals in the star is just right to cause the star to start blinking brighter and dimmer. By the time such a star starts to blink, it has burned its hydrogen fuel and has started in on its helium. In the core, helium fuses into carbon, oxygen, and heavier elements. Away from the core, helium isn’t fusing, but it is hot enough to have lost one, but not both, of its electrons. We say that the helium is singly ionized. This ionized helium near the star’s surface is the key to its blinking behavior. How? Read on!

The funny thing about ions is that they interact strongly with light. This makes sense if you think about it; light is nothing more (and nothing less!) than waves of electromagnetism. Ions have an electric charge. When electromagnetic waves reach ions, they interact. This means the ions are somewhat opaque – they absorb the energy of the light and heat up.

When singly ionized helium ions heat up, they tend to lose their one remaining electron. This makes them – you guessed it – doubly ionized. Doubly ionized helium is even more opaque than singly ionized helium, so heating the helium results in the outer layer absorbing even more energy.

Now comes the key point. Think back to the water on the stove. Remember how it stayed at the boiling point as it boiled, not getting any hotter until all the liquid was changed to gas. A very similar thing happens to helium in a Cepheid variable star. Instead of driving the temperature up, much of that extra absorbed light drives the helium from its singly ionized state to its doubly ionized state. The temperature doesn’t go up (much) until essentially all the singly ionized helium has changed into doubly ionized helium. The star has found a helium plateau! In effect, the star is storing energy in this altered helium. So what happens next?

Once the helium is doubly ionized, there’s nothing to stop the star’s temperature from going up. The increasing temperature causes the star to swell, and this swelling causes the temperature to drop. But wait! Now there’s all this doubly ionized helium. As the temperature drops, we hit the helium plateau again, this time moving the other direction. The doubly ionized helium gains an electron and becomes singly ionized, releasing energy in the process and stopping the temperature drop, in the same way that steam turning to water or water turning to ice prevents temperature drops.

Why helium? With electrons in the very bottom shell, completely unshielded by the positive charge of the nucleus, and with two units of positive charge instead of just the single unit of hydrogen, helium is (like water’s hydrogen bonds, only on a much higher-energy scale) a tough booger. It takes a lot of energy to ionize helium, and this makes it perfect for a phase-change plateau inside stars. Once again, the deceptive simplicity of the helium atom makes the world a much more interesting place.

All this heating, cooling, ionizing, and deionizing causes the Cepheid to, again and again, overshoot its equilibrium. Each heating and swelling causes a cooling and collapse, and each collapse causes the next round of heating and swelling. That helium plateau stuck in the middle keeps the star from ever settling down (that is, until in its evolution it leaves the Cepheid variable stage). The star gets brighter, then dimmer, then brighter, then dimmer again, in a very regular and predictable pattern. And it gives us exactly the tool we need to discover just where we are in this vast and surprising universe. Once again, helium is the key.

I read Leonard Susskind’s book about the Anthropic Principle both before and after reading The Beginning of Infinity. In fact, it was one of the driving forces behind my choice of Deutsch’s book. Susskind’s description of the problems associated with an infinite multiverse (Susskind calls it a megaverse instead) was another reason for me to doubt that infinity could exist. Deutsch convinced me, though, that if infinity appears in our best explanations, then it must be real. And the reality of infinity is a big problem for Susskind’s Anthropic idea.

Susskind bases his main argument on four ideas. Two are from theoretical physics, two are from observational cosmology.

1) Eternal inflation demands that the world be a megaverse, with pocket universes that bubble up out of inflating space.

2) String theory defines not just one unique set of universal laws, but rather an enormous 10500 such sets of laws (maybe more). Such a huge landscape virtually ensures that one (or more than one) will have the right set of laws and constants to make our existence possible.

Combine these two and you see that if each of the universes in the megaverse has a randomly-selected set of laws and constants, then one of those pocket universes will be ours.

3) Measurements on the cosmic microwave background indicates that inflation really did happen, making the megaverse much more probable.

4) Most crucially for Susskind’s argument is the discovery of the non-zero cosmological constant (dark energy). According to Susskind, the only “explanation” for this incredibly small yet non-zero quantity is the Anthropic Principle.

I found it all to be a compelling argument before I read Deutsch. I still find it compelling after reading Deutsch, with the caveat (that Susskind himself covers fully in his book) that the measure problem is a big one.

First, there is excellent evidence that inflation actually occurred. The cosmic background radiation is still under active study, but the idea of inflation has survived all the CMB tests so far, when it could easily have failed any one of them. That’s impressive.

Second, no one seems to see a way for cosmic inflation to produce anything but a huge number, in fact an infinite number, of pocket universes.

Third, string theory is pointing toward a reality in which our laws of physics are arbitrary, the result of a contingent accident that happened in our particular pocket universe. In any other pocket universe, the compactification of extra dimensions and the collection of stuff found in those dimensions would almost certainly lead to a very different universe, almost certainly one with laws of physics completely hostile to life.

Fourth, while we don’t yet know what combination of canceling particles leads to such a tiny but non-zero cosmological constant, it seems pretty certain that it is a result of this contingent accident – because the contant is to high precision exactly what it would need to be for us to be here.

The problem is the not just large number, but infinitely large number of universes that seem to come from inflation. With a very large number of universes, we’re still in good shape in applying the Anthropic Principle as a guide. But with an infinite number of universes, probabilities become meaningless. What does it mean to say that our universe is rare if there are an infinite number just like it? And another infinite number just like it except for one tiny difference? And another . . . you get the point.

Susskind gets it, too, and spends some time reflecting on the past. The ultraviolet catastrophe was a case in which theory predicted an infinity. Planck developed the idea of the quantum to get around it. Later, on, quantum electrodynamics was plagued by infinities until Feynman and others developed renormalization techniques that made the infinities go away. So perhaps, Susskind postulates, the idea of infinite numbers of pocket universes will go away, too, with further research.

The other point I recognize from Deutsch is that of course the Anthropic Principle is really just a guide. It might well play a part in the final explanation, but it cannot be the whole explanation. Something makes the cosmological constant so incredibly tiny and yet non-zero. That something, to have so much possible variability, must be enormously complex. It reminds me a little bit of the discovery of the periodic table. The fact that the elements had such diversity should have been a clue that there was structure in there. The discovery that the diversity had patterns seems to be about where we are now in string theory. What do the patterns mean? That comes next.

The most exciting thing about this whole subject is that even the top scientists in the field recognize how utterly far away we are from knowing the answer. And yet, as I learned from Deutsch, the answer is out there. Problems are soluble. I can’t wait to learn more.

Flying from Dallas to San Francisco on Monday, I looked out the window of the airplane and saw a rainbow.

OK, this isn’t my picture. I took some pictures of what I saw, but I don’t think they came out. My knowledge of cameras is purely theoretical – in other words, I can’t take a good picture to save my life. Besides that, I’m in San Francisco and don’t have a way of transferring pictures from the camera to my computer.

Anyway, what I saw, and what you see in the image above, is called a glory. What a great name! It’s essentially a rainbow seen from above. The Sun was on the opposite side of the plane from me, and the light of the Sun, bouncing back to my eye after its 93 million mile journey, was divided into its spectrum by the cloud.

Clouds are made of tiny drops of liquid water. They’re usually white because light that goes into a cloud normally bounces around inside like a pinball before returning to our eyes. As a result, all colors of light are on average scattered the same amount.  But at the very top of a cloud, where drops are not so packed in, light beams can enter a single drop, bounce off the back, and enter right into my (or your) eye. Because different colors of light bend different amounts in passing from air to water (and water to air), the colors normally hidden in sunlight enter my eye at different angles. The result? Glory!

(By the way, this image shows what I saw, a double glory. This results from an extra reflection from some of the light, so that the colors in the second, outer, glory, are the reverse of the colors in the primary, inner glory. Glorious!)

But, in one of those wonderful, beautiful connections that make my heart sing, there’s more to the story. In 1911, a meteorologist named C.T.R. Wilson was at the Ben Nevis weather station on the Scottish mountain of the same name. He looked down onto the low-lying fog below him and saw what I saw, a glory at the top of the clouds. Wilson wondered if he could create a glory in the laboratory.

To create a glory, first Wilson needed a cloud. How to make a cloud in a laboratory? Wilson’s answer was to create a cloud chamber. He did so, and quickly forgot all about glories, because his cloud chamber revealed something even more amazing – pieces of atoms! Cloud chambers became the tool of choice for atomic physicists to study all manner of sub-atomic particles, and Wilson won the 1927 Nobel Prize in physics.

The curving tracks of charged particles in a magnetic field cloud chamber

Today, physicists have moved beyond cloud chambers to more sophisticated detectors. The most advanced of these detectors – in many ways the most sophisticated scientific instruments ever constructed – are now to be found at the Large Hadron Collider in Europe. And this very day, scientists at the LHC are set to announce their first significant findings – discoveries that will forever change the way we see the world. If you follow the news out of the LHC (and I hope you do – you can bet I will), remember that it all started with glory.

Sometimes I worry that I’ve given a blog entry a title that someone else has used before. This time I think I’m safe.

I saw Black Swan over the weekend and loved it. For me this movie was about losing yourself in your art, and in that way finding that experience of being alive, what Joseph Campbell called “following your bliss.” I think this movie is metaphor. I could argue that all the horrible things Nina the ballerina does or experiences in this film are in her imagination, and I actually think a strong case can be made for it. But I don’t have to, because real or not the events are all just metaphor. The film is about art, and Nina’s discovery of the artist within her. The rest is incidental (yes, even THAT scene!)

Most reviews I’ve read describe the movie as a descent into madness, but they miss the point. Creating art is like madness, but that doesn’t make it madness itself. Art is by its nature the creation of something that wasn’t there before, and is therefore unreal. What you see in your mind, what you imagine, what you are driven to create doesn’t exist until you create it. So of course that act of creation feels crazy. It’s believing in something that doesn’t exist – yet.

Emily Dickinson wrote a poem about what it feels like to give birth to a poem – how painful, tortuous, maddening, and finally liberating it can be. The creative power! The power to give life to something that never existed until it somehow grew within your own mind, sprang from your own soul. Here’s the poem: 

I felt a Funeral, in my Brain,
And Mourners to and fro
Kept treading – treading – till it seemed
That Sense was breaking through – 

And when they all were seated,
A Service, like a Drum – 
Kept beating – beating – till I thought
My Mind was going numb – 

And then I heard them lift a Box
And creak across my Soul
With those same Boots of Lead, again,
Then Space – began to toll,

As all the Heavens were a Bell,
And Being, but an Ear,
And I, and Silence, some strange Race
Wrecked, solitary, here – 

And then a Plank in Reason, broke,
And I dropped down, and down – 
And hit a World, at every plunge,
And Finished knowing – then – 

OK, now you’re convinced. I’m out of my mind. This isn’t a poem about writing poetry, it’s a poem about going crazy. That’s what all the critics and all the web sites say. And THEY’RE ALL WRONG! Notice the hints Emily Dickinson leaves us.

Sense was breaking through – not through the floor, that comes later in the poem. This sense is the sense of what this newest, latest poem is going to be about. Dickinson, who wrote in the metaphor of death, had a muse. That muse was a funeral.

Those same boots of lead, again. Several times in the poem, Dickinson indicates that this experience was not once in a lifetime. It has happened to her, in her, again and again.

All the heavens were a bell and being but an ear. She couldn’t help but listen to her muse, the sound in her head was so loud that it consumed her existence, turning her into a receiver only, just an ear.

Her race is with silence, in other words, with death. It isn’t clear in this poem if Dickinson fears death, but it is quite clear that she fears losing to silence, not creating this new poem before she dies. She sees herself wrecked, solitary, unable to complete this thing that is her child, her creation, before silence finally wins.

So far, maybe you’re not convinced. All these things could just as easily apply to madness. Fair enough. But in the final stanza, Dickinson reveals the true nature of this act of creation.

A plank in reason breaks. The final wall, the final block between her and this future place where the poem lives, complete and perfect. With this plank broken, Dickinson falls freely. Again we see that she’s made this journey before, hitting a “world” (a poem) each time she’s taken the plunge. What an amazing metaphor! Writing poetry, creating anything really, is taking a plunge, believing that you’ll hit a world, not knowing, yet taking the leap. The leap . . .

And then the last line, where Dickinson reveals that now, finished, she has a knowledge she lacked before. As painful as it was, she has followed her bliss, she has hit a world, she has finished knowing.

But she’s not done, and maybe never will be. The word –then– followed by Dickinson’s favorite punctuation, the pregnant, anticipatory dash, sends us back to the top of the poem, where the entire process begins again. Lather, rinse, repeat.

This act of creation, this birthing and breathing of life into art, is never pretty. It upsets people. It makes one late for dinner. It soils what we think is proper in ballet, or poetry. Or science. Yes, you knew I had to get there eventually.

Niels Bohr was an artist, as much as he was a scientist. Just like Nina in Black Swan, just like Emily Dickinson with her world plunging, Niels Bohr fought and struggled and convulsed in agonized spasms of pure beauty – and out popped the Bohr model of the atom.


It’s 1911. One of my all-time heroes, Ernest Rutherford, that living bowling ball of enthusiasm and intuition, has just discovered something that cannot be. Rutherford has found that the atom consists of an incredibly dense central nucleus surrounded by bits of orbiting electronic fluff, a little like a miniature solar system. But that is, according to all the science Rutherford or anyone else knows, impossible. Electrons have an electric charge, and whenever objects with an electric charge accelerate, they must radiate away energy. If electrons in an atom did that, all atoms in the universe would collapse to nothing in a tiny fraction of a second.

A tall, shy, and brilliant student of Rutherford’s named Niels Bohr determines to find out why the universe still exists. He plays with an impossible idea. Maybe the electrons don’t fall. No reason, they just don’t. Or rather, they fall, all right, but only an exact, specific amount, and never beyond their lowest energy level. There they stay, never to cease. Why? Mystery . . .

But Bohr’s model, illogical, ugly (and yet so, so beautiful), without any reason behind it, worked. A plank in reason broke (not Max Planck, though I’m sure he wasn’t pleased) and Bohr plunged into a new world. And it worked. When Bohr compared his model to the spectral lines produced by hydrogen, the model worked.

What does that mean, worked? Here’s the picture. A Bohr hydrogen atom has a single electron in orbit. Let’s suppose this atom is energized, perhaps heated, jostled, it doesn’t matter. That means the single electron is orbiting higher than its lowest possible orbit, and that makes the electron unstable. Then, suddenly, the electron falls (a plank in reason breaks?) and out flies a photon. The electron reaches its ground state orbit and stops falling.

Here’s the amazing thing, the thing that Rutherford himself pointed out.

“How,” Rutherford wrote to Bohr, “does an electron decide what frequency it is going to vibrate at when it passes from one stationary state to another? It seems to me that you have to assume that the electron knows beforehand where it is going to stop.”

Indeed. Bohr’s answer, that the transition itself is fundamental, not capable of simpler explanation, was so disturbing that many physicists detested it. Paul Ehrenfest, another physicist and one of Bohr’s closest companions, said, “Bohr’s work . . . has driven me to despair. If this is the way to reach the goal, I must give up doing physics.”

But Bohr had shown the way to the goal. Yes, it is true that the Bohr model was soon eclipsed by better models. But this doesn’t change one bit the amazing accomplishment of this artist doing science. Bohr created something that wasn’t there before, an atom in which electrons behaved like nothing else ever conceived. Bohr hit a world, and finished knowing – then –

Just like Black Swan, just like Dickinson’s funeral in her brain, Bohr’s atom was metaphor. It was creation itself, that act that makes us uniquely human. We are pattern-makers, story tellers. We are the creators. Whether a poem that lasts as long as there are readers, a dance that lasts only moments on the stage, or a model of the atom that holds sway until a better model replaces it, all these creations are metaphor.*

*What’s a metaphor? It’s for cows to eat in!

My first book, called The Turtle and the Universe, was published by Prometheus Books in July 2008. You can read about it by clicking on the link above.
My second book, Atoms and Eve, is available as an e-book at Barnes and Noble. Click the link above. You can download the free nook e-reader by clicking the link below.
April 2018
« Nov    
A blog by Stephen Whitt

Enter your email address to follow this blog and receive notifications of new posts by email.

Join 88 other followers