Smithsonian.com

President Barack Obama presents the Medal of Freedom to Stephen Hawking in the East Room of the White House. (Official White House Photo by Chuck Kennedy)

Stephen Hawking, the renowned theoretical physicist from Great Britain, was one of two scientists among yesterday’s recipients of the Presidential Medal of Freedom. Here’s what President Obama had to say about Hawking:

Professor Stephen Hawking was a brilliant man and a mediocre student when he lost his balance and tumbled down a flight of stairs. Diagnosed with a rare disease and told he had just a few years to live, he chose to live with new purpose and happily in the four decades since he has become one of the world’s leading scientists. His work in theoretical physics, which I will not attempt to explain further here, has advanced our understanding of the universe. His popular books have advanced the cause of science itself. From his wheelchair, he’s led us on a journey to the farthest and strangest regions of the cosmos. In so doing, he has stirred our imagination and shown us the power of the human spirit here on Earth.

Scientists don’t often receive the Medal of Freedom, the highest civilian honor in the United States, and it’s far rarer to find a British scientist on the list. But Hawking is special. He has not only made significant advances in fields like theoretical cosmology and quantum gravity, but he has also been a successful writer of popular science books, both while dealing with a form of amyotrophic lateral sclerosis (ALS) that has put him into a wheelchair and made him dependent on a computer for speech.

The British Embassy here in Washington, D.C., hosted a small party for Hawking last night, and I had the privilege to attend with some of the city’s science elite: John Holdren, the president’s science advisor; Arden Bement, director of the National Science Foundation; Ralph Cicerone, president of the National Academy of Sciences. (Odd moment: meeting Jim Guy Tucker, former governor of Arkansas and self-described Hawking fan.)

Hawking gave a small speech in which he emphasized the importance of freedom in science. Galileo Galilei (who, in an odd coincidence, died exactly 300 years before Hawking was born) had been imprisoned in his home by the Catholic Church for the crime of saying the Earth moved around the Sun. Hawking said that, had he lived in Galileo’s time, he might have been put in jail for his own scientific work, but that would not have stopped him from thinking about the universe.

Extreme Ultraviolet Imaging Telescope (EIT) image taken on September 14, 1999. The hottest areas appear almost white, while the darker red areas indicate cooler temperatures. (Courtesy of SOHO/Extreme Ultraviolet Imaging Telescope (EIT) consortium.)

I bet that most of you don’t know that the sunspots are missing. That’s okay. I’m sure many people don’t realize that the sun is more than just a ball of fire: it has a complex internal structure, features that vary based on multi-year cycles, and it can create solar storms that knock out power and communication here on Earth. And sometimes it behaves in ways that scientists still don’t understand well.

Sunspots are areas of intense magnetic activity on the surface of the sun. They look like dark spots to us because they are around a thousand degrees cooler than the area around them. At 4,000 to 4,500 degrees Kelvin (about 7,000 degrees Fahrenheit), though, they’re still incredibly hot. Sunspot activity cycles about every 11 years, and scientists had expected the sun to start the next cycle of heightened activity, Cycle 24, in late 2007 or 2008. Some early forecasts predicted that Cycle 24 would be especially active.

But then the sun stayed quiet—in the solar cycle’s minimum phase—for one to two years longer than expected. There hasn’t been a significant solar flare in the last two years. There had even been talk about whether we might be entering another “Maunder Minimum,” the period in the late 17th- to early 18th-century when there were only a few sunspots, compared to thousands normally, and that coincided with the Little Ice Age. That worry, at least, seems to be unfounded, as NOAA has now seen indications that Cycle 24 is nearly ready to begin, though it will likely be less active than average.

And now we have some clues about why the sun was quiet for so long. Solar scientists led by Frank Hill of the National Solar Observatory announced yesterday at a meeting in Boulder, Colorado, that the delay in the cycle start is associated with a solar jet stream deep below the sun’s surface.

The structure with the sun. The blue line in the northern and southern hemispheres is the jet stream, which runs about 1000 to 7000 km below the sun’s surface. (AAS/SPD)

These jet streams (one in the northern hemisphere, one in the south) originate at the sun’s poles, a new one every 11 years. Over the next 17 years, the jet streams migrate towards the equator, and when they reach a critical latitude of 22 degrees, they are associated with the production of sunspots. Scientists here on Earth can track these jet streams through the ripples on the sun created by the sound within, Hill said.

However, the jet streams that would be associated with Cycle 24 are a bit sluggish, taking three years to cover 10 degrees in latitude instead of the normal two years. “The flow for this cycle is taking much more time to move down to the critical latitude,” Hill said. But now that the jet streams have reached that latitude, the cycle should start right up.

Hill doesn’t know if the jet streams are a cause of the sunspot cycle or a consequence of it, though he leans towards cause. And though he says that the sluggishness was the result of other things going on under the surface of the sun, he can’t name what those things would be. “We do not fully understand the interplay of the dynamics under the surface of the sun,” he said.

I guess there’s plenty of mystery left, then, to keep the solar scientists busy.

I hadn’t intended on writing about my Saturday excursion to the theater, even though the play, Legacy of Light, was about two female scientists; the play’s run ended on Sunday. However, I’m so disappointed, and I have to tell you why.

“Mme du Châtelet, detail of a portrait by an unknown French artist; in a private collection,” via Wikimedia Commons

The play follows two women: French mathematician and physicist Émilie du Châtelet in the last year of her life, 1749, and Olivia, a present-day astrophysicist in New Jersey. Émilie is 42, pregnant, scared she will die in childbirth (having had two difficult pregnancies) and desperate to accomplish as much as she can in what she expects, correctly, are her last months. We follow Olivia, meanwhile, as she has just made the biggest discovery of her scientific career—a new planet being formed—and decides, at the age of 40, that she wants to become a mother.

Émilie is brilliantly alive in this play. She and her long-term lover Voltaire spar over philosophy and science. She has an affair with a much younger man, the poet Jean François de Saint-Lambert. She plans a future with her 15-year-old daughter Pauline in which they will go to Paris together and demand entry to the Sorbonne. She is vibrant, and her death, even though I knew it was inevitable, was tragic.

Olivia is 40, an astrophysicist, likes the song “She Blinded Me With Science” and gets into a car accident one day and decides she wants to have a child with her elementary-schoolteacher husband. But ovarian cancer leads them to look for a surrogate.

Unlike Émilie, though, Olivia is one-dimensional, a caricature of a female scientist. For her, there is nothing more than an obsession with her scientific discovery and this spur-of-the-moment decision to become a mother. She dresses badly and wears sensible shoes, as if to emphasize the stereotype that a female scientist must look as boring as Olivia sounds.

If I gave the little girls in the audience the choice of becoming Émilie or Olivia, I think they would have chosen Émilie. I would. This in spite of her struggles for recognition for her work, the dangers of childbirth in that age and Émilie’s need to marry off young Pauline for her daughter’s own protection, a sad example of a woman’s only option in the 1700s. Émilie was obviously enjoying life much more than Olivia.

Who wouldn’t choose the vivacious women in red silk who could talk about the nature of light while managing two lovers and a husband instead of the dull modern woman who would bore her listeners with jargon? Somehow the playwright made being a female scientist today less attractive than being one in the 1700s. It really is better to be one now (and a lot easier, too).

It’s not as if there aren’t plenty of models for amazing modern women in science. We’ve featured plenty of them in the pages of Smithsonian. They are more than just females who do science. There are details behind the label, and those details are important to understanding who that person is, why they act as they do.

To present a modern female scientist in such a stereotypical way does a disservice to all women in science. They are so much more interesting that that. They are more than Olivia.

Fingerprint. (Image by Kevin Dooley under Creative Commons license.)

Why do humans, other primates and koalas have fingerprints? All are, or have ancestors who were, tree dwellers, and it has been generally accepted that fingerprints help individuals grab onto things like tree limbs by increasing the friction between the skin and the object.

Maybe not.

Biomechanist Roland Ennos of the University of Manchester teamed up with undergraduate student Peter Warman to test the idea that fingerprints improve grip friction. They produced a system for measuring the friction between a fingertip and a piece of acrylic glass. Using a weighted apparatus, they could vary the force between Warman’s finger and the acrylic and carry out the experiment with different fingers and at different angles. (The diagram in their paper in the Journal of Experimental Biology is hilarious—it looks like they had to cut off Warman’s fingers to do the test. I doubt that the university would have allowed this, though, even with an undergrad as a test subject.)

With normal solids, friction increases in proportion to the force between two objects. In the fingertip experiment, however, the friction increased less than expected. The fingertip behaved more like a rubbery surface. Friction was determined less by force than by how flat the fingers were; that is, flatter fingers increased the contact area between the finger and the acrylic and created more friction. But the ridges and valleys, Ennos and Warman found, actually work to reduce the contact area between the finger and the flat surface, which reduces the friction between the two. “These results force us to re-evaluate the role of fingerprints,” they wrote.

With increased friction ruled out, scientists are left with having to again hypothesize why we have them. Possible functions for fingerprints include:

• Increased friction on rougher surfaces, like tree branches, compared with flat skin. The ridges might “project into the depressions of such surfaces and provide a higher contact area.”
• Improved grip on wet surfaces by helping water to run off, like a car tire’s tread.
• Increased contact area and friction as gripping force is increased.
• Increased touch sensitivity.

A lituus being played (courtesy of EPSRC)

In 1737-8, Johann Sebastian Bach composed and performed a cantata, “O Jesu Christ, meins lebens licht” (”O Jesus Christ, light of my life”). Among the instruments called for in the score are “two Litui.” However, the Lituus is a forgotten instrument. No one has played or heard the instrument in modern times; there aren’t even illustrations of one.

Musicians at a Swiss conservatory, the Schola Cantorum Basiliensis (SCB), had heard of a computer program developed by a University of Edinburgh Ph.D. student to help in the design of modern brass instruments. The SCB provided a group of Edinburgh scientists with design requirements, such as notes that would have been played with the Lituus, how it sounded and how it might have been played. (Though likely made of wood, the Lituus qualifies as a brass instrument.) The result: a two-and-a-half-meter-long horn made of pine with a flared bell at one end and a mouthpiece made of cow horn at the other. And they built two.

SCB musicians played the Litui in a performance of the Bach cantata earlier this year. (Excerpts can be heard in the video below.) The instruments are not likely to be used in too many performances, though, since the Bach piece is the only known surviving work that calls for them. And I doubt many modern musicians will begin composing new works for an instrument that is so rare, awkward to transport and is reportedly difficult to play.

But the computer program could get a lot more use. If you’ve never met a professional brass musician, you probably don’t know that they spend thousands of dollars tweaking their instruments. Not only are they trying to get an instrument perfect for the type of music they play (jazz and classical have different sound requirements), they are also trying to balance two characteristics: an instrument that sounds the best to the player (an esoteric quality, unique to every musician) and one that is the easiest for him or her to use. “Sound hard but play easy,” says my brother, a bass trombone player. The Edinburgh scientists claim that the software will help the manufacturers of brass instruments fine-tune their designs to meet the needs of picky players.

My brother, though, a classical musician, isn’t so sure about this claim. “The computer can help a little,” he wrote to me, “but this is not the best thing since sliced bread. In fact, I know that the best instrument-repair professionals can tell you what specific areas of your instrument will affect this note or that note. Think of it this way, in cooking, we can take every ingredient in a recipe and analyze it down to its molecular level. But you still go to where there’s a great chef. Nobody goes out to eat at Dell.”

Just as well, then, that the scientists see another use for their computer program, or at least a similar version: pinpointing leaks in hard-to-access pipes and ducts in buildings.

Not Schrödinger's cat

You may have heard the phrase “Schrödinger’s cat,” but like me, you may not have entirely understood what it meant. But I get it now, having watched the video below. It’s from scientists at the University of Nottingham in England, and in their Sixty Symbols project (a companion to the Periodic Table of Videos) they are producing videos explaining various symbols used in physics and astronomy. Schrödinger’s cat isn’t a symbol in the traditional sense, such as the Greek letters that often pop up in physics equations, but it definitely could benefit from some explanation.

Austrian physicist Erwin Schrödinger used the cat in a thought experiment to demonstrate that it was ridiculous to apply a feature of quantum mechanics to everyday objects like a cat. That feature is that an object can be in two different states simultaneously. And while this may be possible at the quantum mechanical level, it is not with a cat, for example, which cannot be both dead and alive.

Princeton University held an “Art of Science” competition, challenging students, staff and alumni to submit “found art,” that is, extraordinary images produced in the course of scientific research. Three winners were announced last week, and voting is now underway for a People’s Choice award. And the image above?

Organic electronics is an emerging field that holds promise for low-cost photovoltaic applications. This image of annealed organic solar cells was taken using an optical microscope with cross-polarizers and a Nomarski filter. The two moon-like circles are metal cathodes which define the active area of the device. Thermal annealing of these thin-film devices often leads to improved power conversion efficiency. In this case, however, annealing at a temperature near the melting point of one of the constituent components led to the formation of device-ruining ridges and valleys.

Credit: R. R. Lunt, Princeton Art of Science, 2009

The American Association of Physics Teachers placed signs, like this one explaining torque, throughout the park.

After mentioning the Six Flags America Roller Coaster Design Contest earlier this month, I received an invitation to Physics Day at the amusement park. I had to convince my boss I didn’t intend to ride roller coasters all day (unlikely, since I get queasy riding backwards on the Metro), but then I was off to the park on a sunny, warm Friday morning last week.

A couple thousand high school (and a few middle school) students were at the park that day. Their teachers had been provided with an extensive workbook of activities for the kids—such as calculating the acceleration of the bus on their way to the park, determining angles of flight on the Flying Carousel and calculating the power used to take students to the top of the Tower of Doom. Of course, there were plenty of roller-coaster related activities as well. And there were even instructions on how to make a force meter (and, importantly, how to understand it).

In the park, college students from the Society of Physics Students and employees of the American Physical Society were on hand for demonstrations of physics concepts, such as wave motion, conservation of energy and gravity. I learned how to make a simple motor with a battery, nail, neodymium magnet and wire.

Two students in blue vests housing accelerometers ride in the front of Superman: Ride of Steel.

But the seven roller coasters and other rides were the real fun. Students could wear a vest with an accelerometer that would track how fast they were moving in three axes (x, y and z; side-to-side, up and down, and forwards and backwards). Once they got off the ride, the data would be downloaded onto laptops and a program called Data Studio that would graph their ride. I had seen similar graphs before (they’re a staple when designing rides in Roller Coaster Tycoon, once one of my favorite computer games), but I was a little surprised that the graphs were messier than the ones from the computer game. I shouldn’t have been though; reality is always more complicated than a simulation.

Joker’s Jinx, the only induction coaster at Six Flags America.

My favorite geeky moment of the morning, though, was the explanation I received of the Joker’s Jinx roller coaster, the only induction coaster at Six Flags America. I was enjoying the coaster from a purely aesthetic viewpoint—the green and purple coloring was striking, and the cars made a lovely wooshing sound unlike any of the others. Becky Thompson-Flagg, of the American Physical Society, explained to me that the other roller coasters slowly take the cars to the top of a large hill and then rely on gravity for the acceleration that will move the cars through the remaining hills and loops. An induction coaster, however, uses magnets and electricity for acceleration. (An in-depth explanation of linear motors as used in roller coasters can be found here.) Gravity obviously still plays a role, but the main advantage, as I see it, is that there is no long waiting period at the beginning of the ride. Shortly after you move away from the entrance, you’re propelled upward at high speed by the linear motor.

Six Flags America will host a Math and Science Day in May. And while some students will get nothing more out of these days than a bit of fun on the rides, I hope that at least a few will take advantage of the fun to be had in the acts of doing science and maybe get inspired to continue this as they grow up.