Now, new observations by an international team, including University of Vermont astrophysicist Joanna Rankin, make these bizarre stars even more puzzling.

The scientists identified a pulsar that is able to dramatically change the way in which it shines. In just a few seconds, the star can quiet its radio waves while at the same time it makes its X-ray emissions much brighter.

The research “challenges all proposed pulsar emission theories,” the team writes in the Jan. 25 edition of the journal Science and reopens a decades-old debate about how these stars work.

Unexpected X-rays

Like the universe’s most powerful lighthouses, pulsars shine beams of radio waves and other radiation for trillions of miles. As these highly magnetized neutron stars rapidly rotate, a pair of beams sweeps by, appearing as flashes or pulses in telescopes on Earth.

Using a satellite X-ray telescope, coordinated with two radio telescopes on the ground, the team observed a pulsar that was previously known to flip on and off every few hours between strong (or “bright”) radio emissions and weak (or “quiet”) radio emissions.

Monitoring simultaneously in X-rays and radio waves, the team revealed that this pulsar exhibits the same behaviour, but in reverse, when observed at X-ray wavelengths.

This is the first time that a switching X-ray emission has been detected from a pulsar.

Flipping between these two extreme states — one dominated by X-ray pulses, the other by a highly organized pattern of radio pulses — “was very surprising,” says Rankin.

“As well as brightening in the X-rays we discovered that the X-ray emission also shows pulses, something not seen when the radio emission is bright,” said Rankin, who spearheaded the radio observations. “This was completely unexpected.”

No current model of pulsars is able to explain this switching behavior. All theories to date suggest that X-ray emissions would follow radio emissions. Instead, the new observations show the opposite. “The basic physics of a pulsar have never been solved,” Rankin says.

Looking for the switch

The research was conceived by a small team then working at the University of Amsterdam, including UVM’s Rankin, who has studied this pulsar, known as PSR B0943+10, for more than a decade; Wim Hermsen from SRON, the Netherlands Institute for Space Research in Utrecht, and the lead author on the new paper; Ben Stappers from the University of Manchester, UK; and Geoff Wright from Sussex University, UK.

These researchers were joined by colleagues from institutions around the world to conduct simultaneous observations with the European Space Agency’s X-ray satellite, XMM-Newton, and two radio telescopes, the Giant Meter Wave Telescope (GMRT) in India and the Low Frequency Array (LOFAR) in the Netherlands, to reveal this pulsar’s so-far unique behavior.

“There is a general agreement about the origin of the radio emission from pulsars: it is caused by highly energetic electrons, positrons and ions moving along the field lines of the pulsar's magnetic field,” explains Wim Hermsen.

“How exactly the particles are stripped off the neutron star's surface and accelerated to such high energy, however, is still largely unclear,” he adds.

By studying the emission from the pulsar at different wavelengths, the team’s study had been designed to discover which of various possible physical processes take place in the vicinity of the magnetic poles of pulsars.

Instead of narrowing down the possible mechanisms suggested by theory, however, the results of the team’s observing campaign challenge all existing models for pulsar emission. Few astronomical objects are as baffling as pulsars, and despite nearly fifty years of study, they continue to defy theorists’ best efforts.

Of the more than 2,000 pulsars discovered to date, a number of them have erratic behavior, with emissions that can become weak or disappear in a matter of seconds but then suddenly return minutes or hours later.

B0943+10 is one of these erratic stars. Discovered at Pushchino Radio Astronomical Observatory near Moscow, “this star has two very different personalities,” that were uncovered by Svetlana Suleymanova in the 1980s, says Rankin.

“But we’re still in the dark about what causes this, and other pulsars, to switch modes,” Rankin says. “We just don’t know.”

“But the fact that the pulsar keeps memory of its previous state and goes back to it,” says Hermsen, “suggests that it must be something fundamental."

Recent studies indicate that the switch between “radio-bright” and “radio-quiet” states is correlated to the pulsar's dynamics. As pulsars rotate, their spinning period slows down gradually, and in some cases the slow-down process has been observed to accelerate and slow down again, in conjunction with the pulsar switching between bright and quiet states.

This correlation between a pulsar’s rotation and its emission has led astronomers to wonder about a connection between the star’s surface and the much-larger surrounding magnetosphere, which may extend up for 30,000 miles.

These new observations “strongly suggest that a temporary ‘hotspot’ appears close to the pulsar’s magnetic pole which switches on and off with the change of state,” says Geoff Wright, one of the team’s astronomers from the University of Sussex.

But the new results also suggest that something in the whole magnetosphere is changing suddenly and not just at the poles or other hotspots. “Something is happening globally,” Rankin says, across the whole star.

In order for the radio emission to vary so radically on the short timescales observed, the pulsar's global environment must undergo a very rapid – and reversible – transformation.

“If that is true, it means the entire magnetosphere is alive and connected in very important ways,” Rankin says, allowing a change in the pulsar’s basic mode of shining in about one second, less time than it takes it to spin once on its axis.

“Since the switch between a pulsar's bright and quiet states links phenomena that occur on local and global scales, a thorough understanding of this process could clarify several aspects of pulsar physics,” says Hermsen. “Unfortunately, we have not yet been able to explain it.”

No model works

The team planned to search for the same pattern in X-rays that has been observed in radio waves – to investigate what causes this switching behavior. They chose as their subject PSR B0943+10, a pulsar that is well known for its switching behavior at radio wavelengths and for its X-ray emission, which is brighter than might be expected for its age.

“Young pulsars shine brightly in X-rays because the surface of the neutron star is still very hot. But PSR B0943+10 is five million years old, which is relatively old for a pulsar: the neutron star's surface has cooled down by then,” explains Hermsen.

Astronomers know of only a handful of old pulsars that shine in X-rays and believe that this emission comes from the magnetic poles – the sites on the neutron star's surface where the acceleration of charged particles is triggered. “We think that, from the polar caps, accelerated particles either move outwards to the magnetosphere, where they produce radio emission, or inwards, bombarding the polar caps and creating X-ray-emitting hot-spots,” Hermsen adds.

There are two main models that describe these processes, depending on whether the electric and magnetic fields at play allow charged particles to escape freely from the neutron star's surface. In both cases, it has been argued that the emission of X-rays follows that of radio waves.

Monitoring the pulsar in X-rays and radio waves at the same time, the astronomers hoped to be able to discern between the two models.

“The X-ray emission of pulsar PSR B0943+10 beautifully mirrors the switches that are seen at radio wavelengths but, to our surprise, the correlation between these two emissions appears to be inverse: when the source is at its brightest in radio waves, it reaches its faintest in X-rays, and vice versa,” says Hermsen.

The new data also show that the source pulsates in X-rays only during the X-ray-bright phase – which corresponds to the quiet state at radio wavelengths. During this phase, the X-ray emission appears to be the sum of two components: a pulsating component consisting of thermal X-rays, which is seen to switch off during the X-ray-quiet phase, and a persistent one consisting of non-thermal X-rays.

Neither of the leading models for pulsar emission predicts such behavior.

In the second half of 2013, the team plans to repeat the same study for another pulsar, PSR B1822-09, which exhibits similar radio emission properties but with a different geometry.

In the meantime, these observations will keep theoretical astrophysicists busy investigating possible physical mechanisms that could cause the sudden and drastic changes to the pulsar's entire magnetosphere and result in such a curious flip in how they shine.

Max's poster, entitled "Path Integral Monte Carlo Study of Proximity Effects in Confined Helium-4" displays his recent numerical work on how the thermodynamic properties of Helium-4 atoms confined to localized regions of space are affected by coupling to neighboring regions at low temperatures. This study was motivated by recent experiments performed by the Gasparini group at SUNY Buffalo that showed that Helium-4 under these conditions exhibits an enhanced superfluid response as well as an excess specific heat. 

Max and Prof. Del Maestro believe that these strange phenomena are due to the intrinsic indistinguishability of the bosonic Helium-4 atoms, and they plan to test their hypothesis by studying both quantum and classical atoms.  For the classical distinguishable atoms, they conjecture that this exotic behavior should be absent, and that the phenomena is a macroscopic manifestion of quantum mechanics.

Unfortunately, these ships also often unload invasive species — unwanted hitchhikers, like zebra mussel larvae and purple loosestrife seeds — travelling in the ship’s ballast water. This, too, can come from any port on the planet.

In the U.S., dumped ballast water may be the leading source of invasive species found in freshwater and marine ecosystems, according the Environmental Protection Agency. From the Caspian Sea to Lake Champlain, communities have suffered profound damage — like collapsed fisheries and clogged pipes — due to invaders that arrived in ballast water.

Efforts to remove species from ballast water have proven very difficult, often toxic, and expensive.

But Junru Wu, a physicist at the University of Vermont, has invented a promising new approach: blast them to death with sound.

He and Meiyin Wu (no relation), an ecologist at Montclair State University in New Jersey, have been collaborating for nearly a decade to create a device — they call it BallastSolution. The machine will treat ballast water, as ships take it in and dump it out, with a lethal dose of ultrasound. (Lethal, that is, to wee beasties; it’s harmless to people.)

In recent tests, “we thought we’d be happy if we could kill close to ninety percent” of the small clams, water fleas, and e. coli bacteria sent into the machine, said Junru Wu, “but the results were over ninety-nine percent.”

Stricter rules

Ballast water is essential to cargo ships (as well as cruise-liners and sailboats) allowing them to stay at the proper depth, steer correctly, and not tip over. But as ships take on and unload cargo, they also pump and dump enormous quantities of water. Globally, twelve billion tons of the stuff is dumped each year — with some ten thousand species being carried across the oceans each day in the ballast water of cargo ships, according to expert testimony before the U.S. Senate.

“These species introductions are one of the leading causes of losing biodiversity around the globe,” says Meiyin Wu, “so we’re trying to plug the hole.”

So are new tougher global regulations of ballast water. The U.S. Coast Guard rolled out rules in March requiring ocean-going ships to have an onboard ballast treatment system and limiting how many organisms they can release in coastal waters. And the U.N.’s International Maritime Organization will require all ships to have a treatment system by the end of 2016.

“There will be a lot of market demand for ballast treatment systems,” says Meiyin Wu. “There are millions of ships out there that will have to comply with these new regulations.”

Bubble solution

The scientists anticipate that their machine, once commercialized, could be mounted inside the engine room of ships and available for use whenever needed, either in dock or as ships change their ballast at sea.

The device relies on what physicists call “cavitation,” the formation and implosion of tiny bubbles within the organisms. These bubbles in liquid, created by mechanical waves from the ultrasound, “basically rip them apart,” says Junru Wu.

The ultrasound has advantages over other treatments, like ultraviolet light that has a hard time penetrating murky water, or chemical treatments, like chlorine, which have environmental problems. “Our goal is to produce a system that doesn’t produce secondary pollution,” says Meiyin Wu.

The patented BallastSolution device, funded by a $673,000 grant from the U.S. Department of the Interior, is made from twenty ultrasound transducers, arranged in a spiral, that protrude into a pipe about ten inches wide on the interior. As the ballast water pumps through, the transducers oscillate at frequencies above the range of human hearing.

In goes a load of potential bad guys at one end -- and out comes nearly sterile water at the other.

At least that’s what the first tests have shown. The machine, built at UVM by Junru Wu and post-doctoral researcher Di Chen, was delivered to Meiyin Wu at the beginning of 2012 for testing in her laboratory in New Jersey.

“The results are fantastic,” says Junru Wu, “much better than expected.”

More demand than supply

This fall, the BallastSolution machine will be shipped to Wisconsin for a next round of testing by an independent laboratory under guidelines approved by the International Maritime Organization and the U.S. Coast Guard. If it passes these tests, it can be submitted to the IMO for approval and international use.

Current treatment technologies can cost millions of dollars to install on a medium-sized ship, Meiyin Wu says — which is why there is a global hunt to find new systems that work and are affordable.

“There are a lot of people and companies working on ballast treatments,” she says. “But there is simply no way that that the supply will be enough for the demand by 2016."

Three companies have shown interest in licensing the BallastSolutions technology, Meiyin Wu says. “We’re hoping it will be ready before 2016,” she says, noting that the cost of a commercial version of their machine is very hard to predict at this early stage -- and will depend on the size of the ship and the complexity of retrofitting it.

“We’re researchers. We’re not in the place or business to commercialize this,” she says. Which is why she and Junru Wu are looking for investors. And considering new research applications for ultrasound.

 “We’re looking at ways it could be used to treat invasive jellyfish,” she says, “or clean swimming pools.”

In the latest edition of UVM in the News, The Atlantic, The Wall Street Journal, Fast Company and The Boston Globe are among numerous national outlets focusing on scholarship and other accomplishments at the University of Vermont. From Rubenstein professor Carol Adair’s research published in Nature, demonstrating the potentially devastating consequences of biodiversity loss, to the Daily Beast’s commencement video (UVM was among their picks for best speech in the country), the publication highlights the broad range of expertise and activity that attracts media attention.

Following is a small sampling of recent stories in the national – and local – spotlight:

An Ultrasound 'Ballast Blaster'

The Wall Street Journal blog "Ideas Market" features an invention co-created by physics professor Junru Wu that, through the use of ultrasound, has been shown to kill virtually all E. coli and other bacteria in ballast water, as well as creatures that elude filters, including water fleas, plankton and zebra mussels. It works by causing gas bubbles within the organisms to violently vibrate, rupturing key structures. Ballast water from international cargo ships has been introducing invasive species into the Great Lakes and elsewhere, which the new method could manage without the use of chemicals. Read the post at WSJ.com...

Ingredients for Success in Vermont Wine

The Boston Globe profiles alumna Christina Castegren '01 and her Vermont winery, Fresh Tracks. Read the story at TheBostonGlobe.com...

The Real Wealth of Nations

The Economist cites the work of Taylor Ricketts, professor and director of the Gund Institute for Ecological Economics, in its argument supporting a recent United Nations report that attempts to calculate physical, human and natural capital as part of a nation's wealth rather than settling for GDP alone. Rickets, by example, has been calculating the value of bee pollination, determining that one Costa Rican coffee grower benefited by $62,000 a year from feral honey bees in two nearby patches of forest. Read the story at Economist.com...

UVM Students Put Wetland Restoration Study to the Test

The Burlington Free Press follows Bill Keeton, associate professor in the Rubenstein School, and his Restoration Ecology service-learning class out to Charlotte where, with hoes, shovels, saws and axes they worked to return a low-lying meadow back to the wetland habitat it once was, planting along the way some 900 native trees and shrubs. Read the story at BurlingtonFreePress.com...

On the other side of the door, Furis, an assistant professor of physics, and her students, run a powerful magnet that could wreak havoc on such devices. “Sorry, but if you get a pacemaker you cannot be a high-magnetic-field researcher,” she says, with a cheerful laugh in her rich Romanian accent.

But her magnet research may help bring to life a whole new generation of devices, like computer screens that could roll up like a piece of paper.

“Making cheap, flexible electronics — that’s the ultimate goal of this work,” she says.

Electron behaviors

Furis’ research is several steps removed from manufacturing or even from materials engineering. Instead, she seeks to peek deep inside the molecular structure of strange organic compounds -- called metal phthalocyanines -- and, with a combination of light and extreme magnetic fields, catch a glimpse of certain spinning electrons.

“What we do here is probe electrons in materials,” she says. “Our field of research is to look at how electrons behave in different materials, because electrons are what makes your computer work, what makes your solid-state lighting.”

And how the electrons are arranged and flow in phthalocyanines give these materials their gorgeous blue colors (they were originally used as dyes in the early twentieth century) but also the rare property of being organic compounds that are, sometimes, magnetic.

And materials like these raise the possibility of creating semiconductors — the basis of modern electronics, from hard drives to telephones — that are made from inexpensive, flexible organic molecules. The hope is that these could be precisely engineered — “tuned,” as physicists say — to have particular combinations of magnetism and conductivity, for applications like switches and data storage.

But in order to do this, the specific families of electrons that control the degree of magnetism need to be pinpointed. Which is where very big magnets and lasers come in handy.

Magnetism has been observed since ancient times, but only in the last century have physicists exposed the underlying cause. “It’s actually the quantum mechanical properties of the electron — called spin — that is the origin of magnetization,” explains Furis.

Typically, measurements of magnetization are done in the realm of classical physics. This is the familiar, macro-scale world where, for some spooky reason, chunks of metal will stick to your refrigerator. This magnetism is measured by taking an indirect reading of an ensemble of many of these quantum-scale effects.

But that macro effect in no way points to its micro cause. “If electrons are involved in mediating this interaction, in arranging the spins, which ones of them are doing that?” asks Furis. “That’s a very big question. And that cannot be answered with a classical measurement of the net magnetization.”

Polarized probe

Getting a view of these electrons is not easy. But it turns out that photons of light — of carefully selected wavelengths and with a special twist called circular polarization — shining onto these organic materials lets Furis and her team identify and select certain electrons — some are free and some are bound to the nucleus of atoms; some are at higher energy states and others at lower ones; some line up parallel to the magnetic field, others antiparallel. And how the photons are absorbed and bounced back allows the researchers to find out which electrons are the underlying engine of that material’s magnetism.

But this probing with polarized light — for materials of relatively low magnetic power like phthalocyanines — only works in the presence of a magnetic field. A very strong magnetic field.

Which is why Furis and her students place samples in the magnet here in her laboratory. Rated to five tesla (a tesla is a unit of magnetic field strength), and purchased with support from the National Science Foundation, this machine is far stronger than a typical hospital MRI machine, thousands of times stronger than the Earth’s magnetic field.

“See this?” says Lane Manning ’08, now a doctoral student in Furis’ lab. He holds up a small threaded disc with a tiny wafer of blue-green material affixed at center. It’s a sample of phthalocyanine.

“This sample is mounted on this probe here, and we’ll put the sample right in the center,” he says, screwing the disc into a large blue ring with tubes and wires sticking out in many directions. This is the UVM team’s magnet. “Now we have the sample in the magnet,” he says, “then we can bring in light to probe it.”

“And see this?” he says pointing to the opening through the middle of the magnet. “We can see through this magnet, and that is key,” he says. Instead of having to use fiber optics, this direct path “allows us to have an incredibly precise control of the polarization of the light going to the sample.” And that precision is what lets them detect the relatively weak magnetic interactions in these organic materials.

To 25 tesla

But this magnet is really just a pre-testing site, and stepping stone, to a much more powerful one that Furis and her students helped inaugurate this past summer. The new twenty-five telsa magnet at the National High Magnetic Field Laboratory at Florida State University in Tallahassee is the strongest so-called “split-magnet” in the world.

It’s hard to create a powerful magnet, but ever so much more difficult to make a window into it. But that is what this new machine does; it’s split into two halves, with a direct sightline in, which allows Furis’ team to shine polarized light at samples within, unlike other magnets of similar strength.

“Optics in high-magnetic fields were always the Cinderella of high-magnetic fields despite the huge amount of information one can get out of this,” says Furis, “because they are so hard to do.” But this machine may be ushering in a new era, she thinks.

In a first-of-its-kind experiment, with support from the National Science Foundation, Furis and several of her students, including doctoral student Zhenwen Pan and undergraduate Cody Lamarche, tested a copper-based phthalocyanine on the new Florida magnet — to see if they could identify which electrons were responsible for its magnetism.

It worked. Though the whole experiment won’t be complete until the team can return to the magnet this spring to do additional tests at extremely low temperatures, the initial results at room and fairly low temperatures were promising.

“We basically identified which electronic states are responsible for mediating this interaction,” says Furis.

Spintronics

And this kind of knowledge opens the possibility for chemists and materials engineers to “reverse engineer” desired properties into different forms of these organic semiconductors. For example, by changing the metal atom at the heart of the organic ring that forms phthalocyanines — perhaps changing it from copper to manganese — produces different numbers and densities of free electrons in the material, which, in turn, creates different magnetic strengths. Or arranging the molecules like plates in a dishrack, instead of like a vertical stack of plates, creates different patterns of electrons too.

“Almost every single device we have works because we understand the quantum mechanic properties of electrons,” says Furis.

Furis is helping lead an emerging field of physics called “spintronics” which is looking at the potential of using spin —  the quantum mechanical property of electrons — instead of traditional electric charge, as means of moving and storing information.

“This work is of interest not only for organic semiconductors; there has been an effort in the world of silicon for almost twenty years to make a device where we control electron spin in the same way we control charge in transistors,” says Furis, “and having an all-organic version of that, where you could have control of charge as well as spin, would be very attractive.”

story & photography by Joshua Brown

It is almost night on the island of Puerto Rico. Astronomer Joanna Rankin raises her head toward the sky. A few of the brightest stars shine through blue cracks in a ragged dome of gray clouds. To her back, a jungle throbs with the insistent call of frogs. In front of her, a giant bowl made of perforated metal dips steeply and rises on the other side of the valley, a thousand feet away. It looks like a colossal contact lens dropped from outer space.

This is the reflecting dish of the Arecibo Observatory: the largest radio telescope in the world, located in Puerto Rico due to ideal natural conditions, a sinkhole in the limestone hills over which to suspend the dish. Rankin has been coming here to study stars since she was a graduate student in the 1960s. Now she brings her own students here to, as she says, “get their hands on the wheel.” Tonight, she stands next to one of the three concrete towers that surround the dish, chatting amiably in the fading pink light with her partner, Mary Fillmore, and three undergraduates from the UVM physics department: Isabel Kloumann ’10, Mateus Teixeira ’11, and Stephanie Young ’11.

Above them, 450 feet over the center of the reflecting dish, floats an impossible-looking metal lattice triangle. Suspended by cables from the three towers, it looks like some child’s fantasy airship made from an erector set—except it weighs nine-hundred tons. From the underbelly of this contraption dangles a huge antenna and a flattened silver ball sixty feet across, the telescope’s Gregorian dome.

 “I’ve never lost sight of my privilege in using this instrument,” Rankin says, again turning her head skyward, “to come here and have a kind of one-way conversation with nature that almost no one else can.”

What Rankin listens for in this conversation are the sounds of pulsars—one of nature’s strangest objects. And what she hears from these unlikely stars may help to prove one of Albert Einstein’s most outlandish theories: the existence of waves in the fabric of space itself. But even if the sky were perfectly clear tonight, the pulsars Rankin has come here to study would not be visible. Instead, she relies on the staggering sensitivity of this telescope to gather infinitesimal drops of radio-wave energy from them, which she then teases apart looking for sidereal meaning, the language of stars.

At first, astronomers thought pulsars might be aliens. In 1967, an enterprising graduate student at Cambridge University named Jocelyn Bell was baffled by the extreme regularity of highly focused radio wave bursts she accidentally discovered coming in from one point in the Milky Way. On then off—every 1.3 seconds. Nothing like this had ever been observed in the heavens; nothing like it had even been imagined. She dubbed the source LGM-1, for “little green men.” Had she made contact? The extraterrestrial messages turned out to be radio bursts from a pulsar.

No bright glowing ball of gas like our home-star, pulsars are the burned-out core of a moderately large star that has consumed all its fuel. With no more outward pressure from the burning hydrogen, the star suddenly collapses on itself and then rebounds, blowing off its outer layer in a spectacularly violent explosion. Compressed by the explosion and gravity, what remains is a sphere so dense that its atoms degenerate into naked neutrons and exotic particles smashed on top of each other in unearthly layers that contain about a billion tons per square centimeter.

“Pulsars are about the size of a small city, like Burlington—maybe ten miles across,” Rankin says, “with mass comparable to or somewhat greater than the sun.” Compared to a black hole, a pulsar is a kind of scrawny cousin not quite massive enough to fall into complete light-sucking density. Still, a sugar cube of this star-stuff would weigh more than all the people on Earth.

And, like a twirling figure skater who suddenly pulls her arms in and starts spinning much faster, this tremendous compression of mass during the formation of a pulsar sets it spinning so fast it challenges our Earth-bound conception of speed. A “regular” pulsar will spin several times per second, but another family of pulsars gathers additional speed by pulling in gas from another star nearby. These so-called millisecond pulsars can spin as fast as seven hundred times a second, nearly one-quarter the speed of light.

“Pulsar” is a contraction for “pulsating star”—but they’re actually more like a lighthouse. As a pulsar spins—or more accurately because a pulsar spins, like the universe’s most powerful electrical generator—it shoots out two cones of radio emissions from several hundred miles above its bogglingly powerful magnetic poles. Then this dual beam sweeps across the cosmos for hundreds or thousands of years, until it happens to shine on Earth, and a few of its photons chance to fall on a reflector in a limestone sinkhole in a Puerto Rican forest—where this radio energy appears as a methodical flash in a telescope tuned to the right frequencies.

Two days later, Rankin and one of her students, Isabel Kloumann, are in the Arecibo Observatory’s control room, tuning in pulsars. They’ve been allotted about three hours to run the telescope. The place looks like a cross between the bridge from Star Trek and the nurse’s station in an intensive care unit. Behind a curving bank of double-stacked computer screens—filled with pulsing graphs and long rows of numbers—a two-story window looks out on the telescope. From speakers on the wall, a soft repetitive beeping fills the air, sounding a bit like Arecibo’s nighttime frogs. It’s the noise of motors and gears on the telescope’s platform, moving overhead to follow a star.

Rankin and Kloumann have almost finished a forty-minute run of having the telescope track a faint pulsar named, without even a whiff of poetry, B2044+15. “So, we should make a move to a new star,” Rankin says, and then looks through the top of her glasses with a smile. “Do you want to drive?”

“I’d love to, yes,” says Kloumann and Rankin pushes back her chair so that her student can get to the keyboard.

Rankin points to one of the flat-screen monitors glowing blue in the strange half-light. “If you go over to the left-most panel you can bring up pointing control,” Rankin instructs. “And let’s go to pulsar 2110+27,” she says.

Kloumann begins to enter instructions into the computer and soon the massive telescope outside starts moving to her commands, the Gregorian dome ponderously sliding along its curving track as the whole circular base rotates. Soon radio waves from B2110+27 will begin bouncing off the reflecting dish up to helium-cooled receivers in the Gregorian dome. Then, as improbably as picking out a mosquito’s heartbeat in a roaring stadium, the star’s pulses begin thump, thump, thumping across the screen.

In these pulses is the raw material for months of future analysis by Rankin and her students. And much of what has been learned about pulsars in the last four decades has been from radio data gathered, just like what Rankin and Kloumann are doing, here at the Arecibo Observatory, a facility of the National Science Foundation.

“But there is much that remains mysterious,” Rankin says. “We have a very good cartoon,” she says, “we know that pulsars tap their rotational energy—somehow—and turn it into radio waves.”

“But we don’t exactly understand the emissions processes,” she says, “is it more like a laser or clouds of particles?”

To even get to the cartoon stage of understanding, astrophysicists like Rankin have tried to decipher the language of emissions that different kinds of pulsars produce. And her students do the same.

“The flash is not just a flash,” Kloumann says, “it has structure to it.”

When you shine a flashlight on the wall, some parts are bright, some are dim. Ditto for pulsar emissions. The radio beam surges and shifts like a rotating carousel of lights. “The devil is in those details of the pulse’s variations and geometry,” says Rankin.

Or consider pulsar B1944+17 that Kloumann has been studying on her own for several years. She will be presenting a scientific paper on this star here at the observatory in a few days—in a conference dubbed the “Fab Five Fest,” to honor five astronomers, including Rankin, who have been the leading pulsar scientists at Arecibo over the years. Kloumann will tell them how B1944+17 sometimes just turns off. And no one is exactly sure why.

“All of us in Joanna’s group, we’re looking at these really unusual stars that don’t fit the perfect model,” Kloumann says. “They test the bounds of the theory—which is what you always should do in science: push the limits of the theory.”

Night has fallen again and Joanna Rankin, Mary Fillmore, and Isabel Kloumann are sitting on the porch of one of the small plywood huts that dot the steep hillside about the telescope, mixing drinks with pineapple juice. Again the darkness is laced with the sound of frogs, a hint of salt air from the nearby ocean, and thin bands of stars through the thick vegetation.

Over the years, with funding from the National Science Foundation, Rankin has brought many crews of students to Arecibo. “They’re my pulsar mafia,” she says with a deadpan look and then laughs, “watch out for astronomers.” Some of the students do go on in astronomy. Isaac Backus ’11 came back for a summer internship at the observatory and then onto another post at a telescope in India. He’s about to begin a doctorate in physics at the University of Washington. Megan Force ’09 G’11 came to Arecibo with Rankin and is now enrolled in a doctoral program in astrophysics at Dartmouth. And this is Kloumann’s second trip to the telescope. She has leveraged her training in astronomy and applied mathematics into a slot as a doctoral student at Cornell.

Rankin, and several of Kloumann’s other professors, describe her as one of the finest students they’ve taught. Winner of a Goldwater Scholarship and other awards, she’s first author on a publication in the Monthly Notices of the Royal Astronomical Society and is a co-author on a forthcoming article in the journal PLoS One.

In her turn, Kloumann raves about Rankin. “Joanna is a pulsar goddess,” Kloumann and the other physics students say several times during the Arecibo visit. “She’s a fantastic mentor who is there when you need her and leaves you alone when you don’t.”

Tonight, Rankin and Kloumann are tutoring a somewhat more plodding student of physics. They’re explaining to me, for a second time, how a better theory of pulsars may, in turn, help confirm one of Albert Einstein’s most intriguing predictions: the existence of gravitational waves.

In 1916, Einstein put forth his general theory of relativity and that was the end of Western science’s two-hundred-year trip on Isaac Newton’s leaking boat. In the first great scientific revolution of the twentieth century,
Einstein demonstrated that space and time flow together—that they are, really, as physicists now say, “spacetime.” Equally strange, Einstein demonstrated that this spacetime, “like a vast sheet of rubber,” says Kloumann, can be bent by matter and energy.

And it’s this bending, these dimples and depressions in this substanceless sheet, that are responsible for gravity. In Isaac Newton’s universe, the moon and Earth simply attract each other. In Albert Einstein’s universe, the moon falls into the depression the Earth has made in the fabric of spacetime. And the flow of time, too, slows down as spacetime is warped near massive objects, like Earth, or, far more so, stars.

From this general theory, Einstein conjectured that when two massive objects, say two black holes, “go spinning around each other like a whirling dumbbell,” says Kloumann, they should make waves in the fabric of spacetime. “A bit like ripples from a pebble tossed into a pond,” she says.

These waves, physicists now are confident, travel through the universe, passing through Earth, you, this magazine—at the speed of light.

“To detect gravitational waves is in some sense the missing link of Einstein’s theory of general relativity,” says Rankin. Problem is, gravitational waves are small. “Exceedingly tiny, tiny, tiny,” says Kloumann. So small that a passing gravitational wave would stretch this magazine by only a fraction of the width of an atom. Which is why, though they were indirectly confirmed in 1993, they have never been directly observed.

Here’s where pulsars may help. To understand how, consider another freakish aspect of these stars: they are the universe’s best clocks. In 1967, Jocelyn Bell discovered that her little green men didn’t flash every 1.3 seconds, they flashed exactly every 1.337 seconds. No, every 1.33728 seconds…and when she and her professor were done calculating they realized that the finest human-made clocks of the day were not accurate enough to time this strange signal.

Because of their extreme density and enormous speed, pulsars turn out to be a nearly perfect flywheel—and this stability makes the arrival of each pulse so regular that some pulsars rival or exceed the precision of human-made atomic clocks. Scientists can now show that, about five hundred light-years away, the pulsar J0437-4715 spins on its axis every 5.7574451831072007 milliseconds—give or take a pinch.

And that accuracy—and more—will be necessary to surf the trough of a gravitational wave. Which is what a consortium of U.S. and international astrophysicists, including Rankin, aims to do. The group, NANOGrav, is assembling a selection of highly precise pulsars in many parts of the sky and is timing the arrival of their pulses for years.

These dozens of pulsars, working as far-off clocks, will allow the team to sift out when a gravitational wave has passed by. They’ll be looking for a distinctive pattern in the arrival time of emissions from pulsars in opposite sides of the sky. And this requires developing enough precision to distinguish the wave’s faint but unmistakable signature from many other disturbances to the incoming radio waves.

“Pulsars are highly precise, but they’re not perfectly precise,” Kloumann says. Sometimes pulsars appear to have starquakes. These kinds of glitches and the variations within single pulses that Rankin studies are one form of noise that need to be accounted for in the NANOGrav models—so the team can pick out the puny voice of gravity from the roaring din of the cosmos.

If gravitational waves can be detected, then the location and strength of their sources can be calculated. And that, Rankin thinks, could be as revolutionary as Galileo’s invention of the optical telescope. “Being able to detect gravitational waves opens up a whole new equivalent spectrum,” she says. “We’ll be able to study gravitational radiation as well as electromagnetic radiation.”

Some astronomers anticipate the invention of gravity telescopes that will be able to look at spinning black holes, cracks in the universe called cosmic strings, and deeper into space than the most-distant quasars now visible. Some speculate about revealing new galaxies of invisible stars made from exotic dark matter. Perhaps some member of Joanna Rankin’s pulsar mafia will, like Jocelyn Bell in 1967, make the next unexpected discovery. “Who knows what we’ll find out there,” says Kloumann. “It’s like never having seen light before.”

He was of the Acoustical Society of America, the American Institute of Ultrasound in Medicine (AIUM), and the American Association for the Advancement of Sciences. He was also an honorary member of National Council on Radiation Protection and Measurements and served as a consultant to the WHO and FDA. He was presented with many honors and awards including the prestigious Silver Medal of Acoustic Society of America, the Joseph H. Homes Pioneer Award, the W. J. Fry Memorial Lecture Award, and the Lauriston S. Taylor Lecture Award.

He was a venerable, gentle man with a fine sweetness of character and humility. He loved the UVM Physics Department, and worked there more than 50 years. He donated generously to the department, making possible the establishment of a physics colloquium, a new faculty startup fund and a students’ summer research scholarship. Wes was also a deeply religious man. He was active in his local Community Lutheran church and the community, and gave freely and generously to many charities. He loved to sing, and was in a barbershop quartet as a young man and in church choirs for many years thereafter.

Wes deeply loved and cherished his wife Beth who died in 1989 after 44 years of marriage. He is survived by his daughter, Elsa Mondou, of Raleigh, North Carolina, four grandchildren, Christine, Michael, Julie, and Martin, and additional family and friends. He was an exceptional man with a profoundly good temperament, whose gift of unconditional love, and qualities of determination and independent spirit will provide inspiration for young scientists for a long time to come.

According to the story, “Happy Words Trump Negativity in the English Language,” the researchers used “overwhelming mathematical force” to analyze 361 billion words used in databases from Google Books, Twitter, the New York Times and lyrics from popular songs. Read the story at Wired.com.

This spring she may get closer to an answer. Rankin has been selected to lead a new international effort to study the strange star using a combination of both radio and x-ray telescopes. She traveled to the Netherlands in February to develop plans with her collaborators there. Other team members came from Britain and India.

The work will proceed with 36 hours of x-ray observation on the European Space Agency’s X-ray Multi-Mirror Mission (XMM-Newton) satellite-based telescopes, “probably in May,” Rankin says. This x-ray data will be correlated to radio observations of the pulsar’s two modes, likely collected at the Giant Metrewave Radio Telescope in Pune, India.

Rankin’s work is supported by the U.S. National Science Foundation.

At the limit of Maxwell’s equations

For more than four decades, astronomers have wondered how pulsars do their pulsing. These bizarre hyper-dense neutron stars send forth beams of radio waves and other radiation like a rotating lighthouse. Pulsars are more massive than our sun, but only the size of Manhattan. A sugar cube of pulsar would weigh more than all the people on Earth and the power of their emissions test the outer limits of our understanding of electromagnetism.

Pulsars, thus, serve as a kind of space-based laboratory of extreme physics.

But some pulsars are stranger than others. Like B0943+10.

“Why should a pulsar do one thing for hours and then another thing for hours? Something really fundamental has got to change,” Rankin says. “And we don’t know what that fundamental something is.”

Hot under the cap

By looking at the combination of x-ray and radio emissions from B0943+10, about three thousand light years distant, Rankin hopes that the cause of the pulsar’s distinct “bright” and “quiescent” modes will become clearer.

“We know that the magnetic polar caps of pulsars are hot because that is what produces the x-ray emissions,” she says, “but it might be that the region has a varying temperature,” she says. And this varying temperature might be the on/off switch for the pulsar’s two modes.

 Under the extreme conditions of a pulsar, particles streaming off the surface are ripped into their constituent atoms and their electrons are peeled away too. In other words, they form a fourth state of matter called a plasma. And it’s this plasma above the star that ultimately sends forth the radio signals that have made pulsars famous as cosmic lighthouses. (When the first pulsar was observed in 1967 there was some speculation that it was aliens signaling and so it was, wryly, labeled LGM-1 for “little green men.”)

But the massive outpouring of radio waves and other radiation must have an effect back on the surface of the pulsar. “If you have electrons going out, you have positrons coming back—and those heat the surface,” Rankin says. “So, part of the star’s radiation energy gets put into surface heating and maybe it’s the surface heating that changes and puts the pulsar in a different state.”

If this is true, then the varied heating should show up in telescope images as a difference in the “brightness” of the x-rays between the two modes. But this can’t be measured on Earth’s surface; it has to be measured in space, outside our atmosphere.

The rare and highly sought opportunity to use the satellite-based x-ray telescopes on XMM-Newton will allow Rankin and her colleagues to put this idea to the test.

“If there really is a difference it will be a major new direction,” she says, “This is something that nobody has ever had occasion to do before.”

Rankin’s primary colleagues in the venture are x-ray astronomer Wim Hermsen from SRON, the Netherlands Institute for Space Research; Dipanjan Mitra with the National Center for Radio Astrophysics in Pune, India; and Joeri van Leeuwen, with the Dutch Radio Astronomy Center, ASTRON.

Grad student William DeWitt and Professor Kelvin Chu, Department of Physics, have invented a new way to peer into proteins. Their paper in Physical Review Letters pinpoints which atoms within the protein myoglobin hold and release oxygen to meet the unique needs of different animals. (Photo: Joshua Brown)

A cheetah lies still in the grass. Finally, a gazelle comes into view. The cheetah plunges forward, reaches sixty-five miles per hour in three seconds, and has the hapless gazelle by the jugular in less than a minute. Then it must catch its breath, resting before eating.

A blue whale surfaces, blasting water high from its blowhole. It breathes in great gasps, filling its thousand-gallon lungs with air. Then it descends again to look for krill, staying below for 10, 20, even 30 minutes before taking another breath.

Both animals need oxygen, of course. And both depend on the protein myoglobin to store and then release that oxygen within their working muscles. But how they need oxygen differs. The whale must have enough to last a whole dive. Its muscles have a high concentration of myoglobin that delivers oxygen steadily. In contrast, the cheetah's myoglobin must perform like a fast-shooting cannon. The cheetah needs to suddenly take up and release large doses of oxygen to stoke its explosive speed.

How does myoglobin do all that? For decades, biologists have wondered how -- and with what atomic motions, exactly -- the folded structure of myoglobin allows it to hold and release oxygen.

Now, two physicists at the University of Vermont have an answer. They've developed a new way to peer into the inner workings of proteins and detect which specific atoms are at work. Their work was published in the Aug. 27 issue of the journal Physical Review Letters.

Atomic bondage

Using myoglobin as a test, the scientists were able to home in on the critical functional piece of the protein, separating it from the vast number of other "jigglings and wigglings of atoms" says William DeWitt, a UVM graduate student and the lead author on the paper that describes the finding.

"We've been able to identify the motion of one particular amino acid -- this group of atoms called the distal histidine -- that controls the binding process," he says.

Shaped a bit like a tennis racket over a basket, this tiny arm of the protein moves, through thermal fluctuations, to open or close the binding site near the myoglobin's iron-filled center. "As the atoms move in one direction it becomes easier to bind oxygen," says DeWitt, "and as they move in the reverse direction it becomes less easy."

And how this distal histidine moves should vary between the whale and the cheetah. "I would imagine," says Kelvin Chu, associate professor of physics and DeWitt's co-author, "that there has been evolutionary pressure on every species to adapt this motion in the myoglobin for their particular oxygen-binding needs."

"That's a testable hypothesis," Chu says. "What we would expect to see across species is that the tennis rackets are in different places or move different amounts."

DeWitt and Chu's work extends far beyond myoglobin. The two physicists see broad application of their new method in creating custom-crafted proteins.

"Once you know what these motions are and what the important atoms are," says Chu, "you can make mutants of proteins that have different binding attributes." And these different attributes have promise in developing new biotechnologies "ranging from blood substitutes to organic solar cells," he says.

Function follows form

Proteins are a cell's heavy laborers: hauling water, taking out the trash, carrying in the groceries -- and trillions of other tasks that make life. But how the shape of a protein determines its function remains one of the most vexing and important questions in the physics of biology.

Proteins are not the static, Lego-like objects you might see in an x-ray photograph in a biochemistry textbook. Instead, made from long chains of amino acids scrunched into various blobs and globs, a protein is always jumping between slightly different structural arrangements due to thermal motion of its atoms. Even a modest-sized protein like myoglobin has more possible arrangements of its atoms than there are stars in the universe. And each of these arrangements slightly changes a protein's function.

"But what are the important motions that control its function?" asks Chu.

"Relating the structure of a protein to what it is doing is the holy grail," he says. For myoglobin at least, the two UVM scientists seem to have brought the prize a lot closer to hand.

The power of parsimony

Their method -- called temperature derivative spectroscopy or TDS -- involves cooling myoglobin to as low as -450 degrees Fahrenheit, about 18 degrees above absolute zero, and then measuring its oxygen-binding process. At these chilly temperatures, each protein basically gets stuck in just one arrangement. These individual atomic arrangements can't be observed directly, but, using infrared light, a pack of myoglobin molecules does yield a kind of group portrait -- a summing, called a TDS surface -- of the position of all the proteins as they bind to the oxygen in carbon monoxide.

The Vermont scientists' innovation comes largely from what they have been able to do with this group portrait.

"This scenario is called an inverse problem," DeWitt notes, "we have measured the effect but want to determine the cause." Unfortunately, a bit like asking what two numbers add up to ten, there are many solutions.

But, usually, nature does not build wasteful structures -- and though the universe is undoubtedly complex, it does not seem given to capricious complexity. In other words, the scientific principle of parsimony -- what philosophy students encounter as Occam's Razor -- suggests that the least complex explanation is the most likely.

Applying a mathematical version of this idea from Bayesian statistics, called the principle of maximum entropy, DeWitt and Chu went looking for the simplest solution to the TDS surface created by their group of myoglobin molecules. And the answer: the motion of the distal histidine most simply explains how myoglobin regulates oxygen binding.

They followed this prediction by performing a computer simulation of the molecular dynamics of the distal histidine, which confirmed their interpretation.

"Will did a lot of this on his own," says Chu, "He took the data, and the analysis was done on a MacPro," plus some time on the National Science Foundation's high-performance computer network, the TeraGrid.

"He's a clever guy," says Chu.

Graduate student Lan Zhou and her advisor Randy Headrick made a fundamental discovery in physics that may improve computer chips, solar panels, x-ray lenses, and even your next pair of mirrored sunglasses. (Photo: Sally McCay)

When you tear open a bag of potato chips or pop in a DVD, you're probably putting your hand on sputter deposition. No, don't run for the soap.

Sputter deposition is an industrial process used since the 1970s to spray -- sputter, that is -- thin films onto various backings, like the metallic coating on potato chip bags, the reflective surface on DVDs, or the electronics on computer chips.

Mostly, the process works very well. In a vacuum chamber filled with an inert gas, like argon, high voltage is applied to a magnet. This energizes the argon, which, in turn, bumps particles of, say, tungsten metal from a source near the magnet out into the cloud of gas. Some of these extremely hot, charged tungsten particles zip at high speed through the argon and deposit onto the target, forming a thin film.

But sometimes the coatings peel off or the product bends in on itself and cracks, as if the film was stretched tight before it was applied to the surface. Other times, the films are just too rough. For decades, scientists have been baffled -- and manufacturers frustrated -- about why these problems happen.

Particle pile-up

Now researchers at the University of Vermont and the Argonne National Laboratory near Chicago have an explanation: "it's nanoparticles," says Randy Headrick, professor of physics at UVM, "sticking and pulling together."

The discovery, led by Headrick's graduate student, Lan Zhou, was published August 10 in the journal Physical Review B.

Using high-powered x-rays, the team measured the size of tungsten particles depositing on a target and were amazed. Above a critical pressure in the argon gas (eight one-millionths of an atmosphere), the size suddenly jumped. Instead of single atoms or several-atom molecules -- as would be expected in the high-heat, high-velocity environment of a sputter chamber -- they detected relatively gigantic blobs of hundreds of atoms: what the researchers call a "nanoparticle aggregation."

"It's a condensation, like clouds, like mist," says Headrick, "this is something we really didn't expect."

These nanoparticles pull together and fuse, drawing the film tight as tiny "nano-voids" between particles are eliminated. This can create stress in thin films strong enough to pull electronic wafers into a cup shape or roughness that distorts the delicate coatings of optical lenses.

One nanometer, please

"No one realized that in the gas phase you could produce a particle so large," says Al Macrander, a physicist at Argonne National Laboratory and a co-author on the article. "They're highly energized, so it's counter-intuitive that they would stick -- because of their velocity," he says. But stick they do.

In the sputter deposition chamber, "particles start off with temperatures of around ten thousand degrees," UVM's Randy Headrick explains. But even as they are moving in the gas, they cool slightly and "once they cool," he says, "they want to go back to being a solid."

"This has large implications," Macrander says, "for many industries, not only optics." For his part, the new findings are likely to help accelerate the creation of advanced x-ray lenses that he has been helping to develop.

So far, the efforts to make these lenses have not succeeded since the sputter deposition process has produced coatings that are still too rough with too much tension -- despite using state-of-the-art techniques.

"These lenses are intended to focus x-ray beams on smaller dimensions than have ever been achieved," he said, "down to one nanometer." To make these lenses requires more than a thousand layers of thin film. "Stress builds up and becomes a problem," he says.

The team's new insight into the basic physics of sputter deposition points the way toward a solution, but the equation is complex. "If you want to get real smooth surfaces, you have to deposit at lower argon pressures," says UVM’s Lan Zhou. But at this very low pressure, the particles hit with such velocity that the thin films want to expand, creating the opposite problem by pulling films apart.

"Its still an open question: what do you do to make a film with zero stress and as smooth as possible?" says Headrick.

"At least now we understand what is happening," says Zhou, "so people can try to optimize the film deposition conditions, for structure and roughness."

Hard thought

Still, what are problems in one application might be a benefit in others. "There is a lot more to this finding than lens coatings," says Headrick, "there are many kinds of materials where you want to make nanoparticles, like some kinds of catalytic converters or solar cells. This could be a good way to make nanoparticles cheaply."

But the cost of figuring it out was steep. "This took years for us to understand," says Zhou, with the slightly worn smile that PhD students wear best, "it was hard to think of aggregate particles forming in the middle of a flux."

"It's like playing a slow video game," says Kloumann. Far stranger are the objects they are pointing the telescope toward: pulsars many light years away.

Compared to a black hole, a pulsar is a kind of scrawny cousin not quite massive enough to fall into complete light-sucking density. Still, these strange objects are staggeringly dense, holding about a billion tons per cubic centimeter. Imagine a teaspoon of sugar that weighed as much as three thousand Empire State Buildings.

"Pulsars are about the size of Burlington with mass comparable or greater than the sun," says UVM astrophysicist Joanna Rankin, who has employed Kloumann and Backus as independent researchers. "What we're observing this morning are city-sized remnants of medium-massed stars." This observing depends on the Arecibo telescope that Rankin and her students use several times each year through funding from the National Science Foundation. With a reflecting dish a thousand feet across and a colossal cable system to carry the receiver hither and yon overtop, the telescope gathers radio waves pouring in from clouds of cold gas throughout the Milky Way and beyond, like the famed Andromeda galaxy.

But the telescope also records the compact, highly regular, on/off bursts of radio energy that come from pulsars. ("Pulsar" is a contraction of pulsating star.) As these spheres of hyper-dense neutrons spin -- some rotating once every few seconds, some hundreds of times per second -- they shoot out two cones of radio emissions from above their bogglingly powerful magnetic poles.

"It's just like a lighthouse," says Kloumann, "every time it sweeps past, you get a flash." Kloumann has been studying pulsar B1944+17 on her own for the past year. Sometimes it just turns off. And no one is exactly sure why.

"We're looking at these really unusual stars that don't fit the perfect model," she says. "They test the bounds of the theory -- which is what you always should do in science: push the limits of the theory." The students pushed enough to get the attention of professional astronomers. In May 2010, the prestigious astronomy journal, the Monthly Notices of the Royal Astronomical Society published a scientific paper comparing two unusual pulsars -- with Isaac Backus as the lead author; a rare feat for an undergraduate. The journal's referees, "liked it," he says. "The comments were mostly about grammar. Well, with a few other things."

Kloumann -- an Honors College student, Goldwater Scholar, and "one of UVM's stars in physics and mathematics," says Rankin -- also published her study of pulsar B1944+17 in the same journal.

"My freshman year I wanted to be involved in research, so I went and found Joanna," Kloumann says. She found that Joanna Rankin is both a devoted teacher and researcher. Rankin’s work on pulsar “carousels” has helped pioneer a new understanding of how these stars generate radio radiation. This summer, Rankin launched a new project, funded by the National Science Foundation, to see if the hyper-precise timing of pulsar radio bursts can be used to detect one of the most elusive prizes in physics: gravity waves.

"I worked one-on-one with her every week and she would tell me about pulsars for three hours!" Kloumann says. "She's a great mentor. She's given us a lot of freedom and flexibility. And she's there when you need her."

Kloumann, Backus, and graduate student Megan Force have worked closely together, and each has had a chance to travel to Arecibo with Rankin to see the telescope in action. Now, Backus has what he calls the best summer job ever: a three-month stint working at the Arecibo telescope with Rankin's close colleague Dipanjan Mitra, a leading Indian pulsar astronomer.

For her part, Megan Force finds working at Arecibo deeply inspirational. “You feel like Galileo,” she says, “right there next to the machine."