Across the World for ~80 Days

by Calen Henderson

The plan was two weeks. But two became three and weeks stretched to months as I toiled to tailor my application to the requirements of the NSF Graduate Research Opportunities Worldwide (GROW) fellowship. Then in April of this year, several months after submitting the final version, I received the congratulatory email informing me that I’d been awarded the fellowship and would be spending the summer working with a team of my collaborators in Cheongju, South Korea. My name is Calen Henderson, I’m a senior-level PhD student who studies exoplanets, or planets that orbit other stars, and below I’m going to describe an extraordinary summer in the life of an astrophysicist.

First, some background. Prior to 1989, humans knew about the existence of nine planets. They all resided in our Solar System, and Pluto had not yet been demoted. Then, in 1989, our knowledge of other worlds, and with it our own worldview, began to change. To date, astronomers have discovered over one thousand exoplanets that collectively provide insight into how planets form, how common it is for a star to have one or more planets orbiting it (extremely common, it turns out, with our Milky Way Galaxy alone estimated to harbor over 100 billion planets, or one planet per star, on average), and specifically what kinds of planets and planetary architectures are out there. Such findings are the result of using a variety of exoplanet discovery techniques, including transit, radial velocity, and pulsar timing. I specialize in one known as gravitational microlensing, and this method forms the backbone of my PhD research.

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The number of known exoplanets has increased dramatically, especially over the past few years due to the launch of the Kepler satellite. These are indeed exciting times to be an astronomer and to study exoplanets!

Normally when you look at a star, whether with your naked eyes or through a telescope, its brightness remains relatively constant as time marches forward. But, all objects in space are moving, with stars passing in front of and behind other stars, and every so often the alignment of the Earth and two distant stars will be so nearly collinear (all three in a straight line) that the gravity of the middle star will bend some of the light rays emitted from the background star so that they reach Earth rather than continuing to traverse through empty space. We see the manifestation of this alignment as a brightening of the background star, and if the intervening star has a planet in orbit around it, it is possible to see additional amplification of the light of the background star due to the gravity of the planet.

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The brightness as a function of time for the first microlensing event in which a planet was discovered. The circle in the upper panel shows the star being microlensed, though you can’t see the intervening star whose gravity is actually bending the light. When the circle turns red it denotes the anomaly caused by the additional gravity of planet orbiting the intervening star. This animation was created by Dr. Andrzej Udalski of the OGLE collaboration and was borrowed from Dr. David Bennett’s webpage.

Such an occurrence is rare and unpredictable, and so requires monitoring tens of millions of stars to detect a few thousand microlensing events per year. A single microlensing event refers to a star that has been magnified by the gravity of an intervening star that may or may not host one or more planets. Ultimately this process leads to the discovery of just a handful of planets each year. But wait! There’s less! Not only is detecting a possible planetary signature in a microlensing event an unlikely situation, but sifting through the mountains of data taken by the dozens of telescopes around the world to accurately and precisely determine the physical parameters of the planetary system—how massive the planet is, how far away it is from its host star, et cetera—can often take years. Furthermore, only a small number of people have both the knowledge and the access to the vast amounts of computing power necessary to do so.

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Astronomers overcome the extreme rarity of detecting a microlensing event by pointing their telescopes where the density of stars is the highest—toward the central Bulge of our Milky Way Galaxy, marked by the red line.

So far we’ve learned that microlensing is infrequent, difficult, and not very popular. These factors, coupled with the fact that microlensing has not yet discovered as many planets as certain other techniques, often leads to other astronomers viewing microlensing as the “Whose Line Is It Anyway” of exoplanets—the science is made up and the planets don’t really matter. In fact, such an assessment couldn’t be further from the truth. Microlensing is unique in that is has unparalleled sensitivity to low-mass planets orbiting their host stars at large distances. Whereas other discovery techniques can easily find a Jupiter-mass planet orbiting a star at the distance at which Mercury orbits the Sun, only microlensing can easily find planets with the mass of Earth at the distance of Earth. This is integral for our understanding of how common architectures like our own Solar System are as well as how planets are formed.

Re-enter our hero. One of the premier teams of astronomers in the world with the expertise and ability to analyze microlensing events and look for planets is based at Chungbuk National University in Cheongju, South Korea. They are led by Dr. Cheongho Han, who obtained his PhD in astronomy from OSU and with whom I have closely collaborated for the past two years. Through the NSF GROW fellowship, I was able to spend the summer working with Dr. Han and his group to learn how to analyze microlensing events.

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Many consider the entire Korean peninsula to resemble a rabbit. Others, a tiger. I fall in the latter group, and so spent my summer nestled, ferociously, in Korea’s hindquarters.

The primary office in which Dr. Han, his graduate students, and I worked is probably the closest thing to Hollywood’s portrayal of science that I’ve ever witnessed. In this “War Room” there are computers lining two of the walls, with a third hosting a bank of clocks to help keep track of the current time for telescopes at a variety of longitudes. The center of the room is dominated by four huge monitors—the kind measured in feet, not inches—each connected to a different computing cluster, all of which are housed in a separate building due to the loud whirring of the fans that cool them as they radiate extreme amounts of heat while performing billions and billions of calculations.

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Several of Dr. Han’s graduate students and I in the “War Room.”

What makes his group’s approach so unique and powerful is its comprehensiveness. Every day we would analyze all ongoing microlensing events in search of anomalies in the magnified brightness of the microlensed star due to the existence of a planet orbiting the intervening star. We would subsequently circulate our findings to the teams of astronomers in charge of the telescopes to encourage more or fewer observations, depending on our estimation of the likelihood of the existence of a planet. Any spare time was spent reanalyzing older microlensing events—perhaps there were additional or improved data, or maybe someone had insight into a different solution that would better describe the data.

In order to competently perform these tasks, there were several skills I needed to learn. To efficaciously utilize the computing clusters, Dr. Han’s team helped me become proficient in what is called parallel computation. Rather than using a single computer to solve a problem you use several in concert, farming out different tasks to each machine to most efficiently complete the computational task. I also brushed up on my complex analysis background. It turns out that microlensing equations can be more readily solved if you use imaginary numbers, a formalism that is the foundation of the best analysis codes in the world. Most importantly, however, was being able to analyze a multitude of microlensing events and the experience gained from it. When a star becomes microlensed by another, intervening star, there is a myriad of ways that the resulting magnification the light of that background star experiences can change as a function of time. In many cases, knowing a lot of math and having a lot of computers at your disposal can only get you so far—being able to intuit a good guess at the solution right off the bat is your most valuable skill.

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I was able to do some exploring as well! Here is a view near the peak of Daecheongbong, the tallest peak in Seoraksan National Park.

While Dr. Han and his graduate students imparted a wealth of astrophysics, computer science, and higher-level math to me, some of the most meaningful things I took away had nothing to do with microlensing. They were unremitting in their hospitality and eagerness to help me explore Korean cuisine and culture. Their patience was admirable, particularly since I was the visitor who was able to speak only a few phrases of Korean here and there. And their desire to teach was paralleled only by the vast trove of knowledge, both within and external to science, upon which they were able to draw. I find it appropriate and comforting that my search for other worlds comes hand in hand with learning more about my own.

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About Calen Henderson

calen_oryeon_falls_lowresHey! I enjoy playing classical piano music, running, and traveling. I spend my spare time working on a PhD in astronomy at The Ohio State University, trying to discover and characterize exoplanets and gain insight into planet formation. As an Eagle Scout, outreach is also a big component of my life, and I love giving shows at our newly-renovated digital planetarium!

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Fire a laser at it!

by Howard Yu

If you’ve ever seen a Star Wars or Star Trek movie, you’re familiar with the concept of a laser, a word that conjures images of fantastic sci-fi space battles. But lasers are no fantasy – they’ve thoroughly infiltrated everyday life, and are used in everything from barcode scanners and DVD drives to industrial cutting, surgery, and of course, scientific research. How do lasers work, and how do we use them in research? I’ll try to address those questions here.

1 laser show

Truly we live in the future.

Before I talk about lasers, I need to talk a little about light. Physicists use the term “light” to refer to all electromagnetic radiation, which includes the visible light that we see as color, but also things like radio waves, microwaves, and x-rays. Light behaves both like a wave and like a particle, and the individual light particles are called photons (the idea of light as particles originated with Einstein, and is actually the work for which he won the Nobel Prize).

The word “laser” originated as an acronym, standing for light amplification by stimulated emission of radiation. Essentially, lasers consist of an energy source, a gain medium, and an optical resonator. The gain medium is what makes it possible to generate the laser beam and determines the color of the light produced; this is what people are referring to when they say, for example, “HeNe laser” (say hee-knee). In that case, the gain medium is a mixture of helium (He) and neon (Ne) gas, which produces a red beam. Lasers can be made with many different gain mediums, including dyes, gasses, and solids. First, the energy source generates the first few photons to get the laser started. The photons pass through the gain medium, and each photon interacts with the medium and has a chance to produce another photon traveling in the same direction as the original. This is why the word “gain” is used, because you start with one photon and end up with two. Finally, the optical resonator – at its simplest a pair of mirrors at either end of the laser – passes the photons back and forth through the gain medium, so that each photon produces many additional photons before escaping the resonator. This process results in a steady stream of highly coherent photons.

2 Lasercons

Basic design of a laser – in this case, the flashlamp provides the energy source, the Nd:YAG crystal is the gain medium, and the two mirrors form the optical resonator.

The feature that distinguishes a laser from other light sources is the laser’s coherence. Unlike, say, a light bulb, a laser produces light that is almost completely the same color.  (The color of light is determined by its wavelength. Wavelengths of visible light range from about 400 nm to 750 nm – see Andy Berger’s post for an idea of how small that is.) Lasers can be made with a wide variety of wavelengths, ranging from 150 nm to over 1 mm. Different applications have different wavelength requirements – for example, optical disc drives use lasers to read information off of CDs, DVDs, and now Blu-ray discs. The reason Blu-rays can store more data than CDs or DVDs is because the laser used to read the disc is blue, hence the name.  Specifically, Blu-rays use 405 nm light, while CDs and DVDs use 780 and 650 nm respectively.

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Spectrum produced by a fluorescent lamp (left) and by a HeNe laser (right).

Lasers also produce spatially coherent light, by which I mean a laser generally sends photons only in the direction it is pointing. The light from any source will spread out, and lasers are no different (and different lasers will spread at different rates). However, the beam from a flashlight or spotlight will spread out much more quickly than a laser, and we can use various optics to make a laser beam spread very little over long distances (a process called collimation), something that’s only possible because of the laser’s coherence. Even a spotlight is only visible from up to a few miles away, while you could aim an ordinary, well-collimated laser in San Francisco at the Empire State Building and the spot would be maybe a single story tall, so still easily visible (assuming you didn’t hit any mountains along the way). A side effect of this is that you should not be able to see a laser beam if you are not looking right down the beam path, as there simply isn’t any light for your eye to see. When you can see the beam, it’s because some of the light is scattering off particles in the air.

There are a wide variety of measurements you can do with a laser. In our lab, we have a titanium-sapphire laser (Ti:Sapph) that can output about 2 watts of power. We use our laser to investigate different materials properties – one of the basic measurements we do is to just hit a sample with the laser and see what light comes back out. Another measurement that I do is to reflect the beam off of a sample to do a sensitive measurement of its magnetic behavior.

4 Optical table

The inside of our laser (left) and the optical table in our lab (right).

You can see the table has a grid of holes that we use for a variety of equipment, most commonly lenses and mirrors to focus and steer the laser beam. Something we have to keep in mind is that the absolute power of the laser is often not as relevant as the power density. We can focus a laser down to very small spots (about 100 microns in our lab), so the amount of power the laser delivers is also focused into a small area. It’s like using a magnifying glass to start a fire, a staple of survival movies. A typical incandescent light bulb consumes 60 watts of power, which it converts into light and heat (an incandescent bulb is actually much better at producing heat than light). If a laser output that much power and was focused to a 100 micron spot, the power density would be high enough to cut through steel (I have a couple of shirts with holes in them from laser damage).

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Kind of like this. (Goldfinger, 1964)

It’s hard to believe that when they were invented, lasers didn’t have any obvious purpose – they were a solution in search of a problem, a toy for scientists to play with. Today, they’re widely used in both commercial and research applications, from more mundane uses like laser pointers to out-of-this-world uses like igniting nuclear fusion. It just goes to show that as a scientist, you never know when the experiment you’re slaving over could someday affect the lives of millions of people around the world.

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About Howard Yu

ahowardI’m a senior graduate student in Professor Zeke Johnston-Halperin’s lab at OSU. I was born and raised in California, but chose to come to Ohio anyway. In my free time, I read a lot of books, watch a lot of movies, and play soccer and basketball. After graduating, I hope to work in public policy.

Aren’t You Just a Biologist?

by Morgan Bernier

Biophysics is one of the fastest growing occupations according to the Bureau of Labor Statistics, though most physicists often hesitate to call it “real” physics.  “Aren’t you just a biologist?” my friends ask, “How is mixing one clear liquid into another clear liquid physics?”

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Mixing samples for my experiment.

It’s true that I’ve spent 90% of my graduate school career using biochemical techniques to prepare my biological samples (more on these later) but, like other physicists, I am ultimately trying to measure physical quantities: energies, forces, and motion of matter.

I am a physics graduate student at The Ohio State University with an undergraduate degree in physics (from Miami University in Oxford, Ohio).  I have not taken any biology or chemistry classes since high school.  I spent the first few years of graduate school teaching myself all of the biology and chemistry I need for my experiments, and I’m still learning new things today.  Mastering completely new lab techniques that most physicists will never do is actually a lot of fun.

At Ohio State, I work in Dr. Michael Poirier’s biophysics lab.  We study how DNA is organized and compacted by proteins inside the cell nucleus.  DNA contains all of the information for how our bodies look and function, and we have nearly 2 meters (about 6 feet) of DNA in each of our cells.  Organization and compaction of the DNA is necessary for all of it to fit inside our tiny cells, so our cells wrap the DNA around protein molecules called histones into what look like little spools of thread.  These DNA/protein spools are called nucleosomes.

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An image of a small section of DNA wrapped into nucleosomes taken using an atomic force microscope by a former graduate student in our lab, Marek Simon. This type of microscope allows us to see things that are too small to see under a regular light microscope.

By wrapping the DNA into nucleosomes, the DNA becomes more compact and is protected from damage.  My samples usually consist of a single nucleosome, so that I can observe the physical interaction between the DNA and the proteins.

Our lab is broken up into two physical areas: the biochemistry lab and the physics lab.  I spend most of my days in the biochemistry lab making my DNA/protein samples.  Thankfully, I have helpers, millions of them actually.  We program E. Coli bacteria to make our DNA and proteins, so part of my job involves carefully growing E. Coli bacteria.  Sometimes this means that I have to come into the lab in the middle of the night to check on them.  I can’t be sure, but I think singing to them helps.

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The biochemistry lab (left) and the physics lab (right).

E. Coli bacteria are typically associated with food poisoning from contaminated meat, but they are also found in your intestines and help you digest your food.  We use E. Coli because they reproduce very quickly (about once every 20 minutes), and we can easily program them to produce DNA and proteins that are usually found in other organisms like frogs and mice.  By using E. Coli, we don’t have to sacrifice frogs and mice for our science.

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Agar plates growing E. Coli bacteria. These particular ones were used to produce DNA. These plates are about the size of the palm of your hand. The streaks you see are colonies of E. Coli bacteria growing. Each streak contains thousands of individual E. Coli bacteria.

So where does the physics come in?  Once I have my nucleosome sample, we use a microscope equipped with lasers to look at them.  The lasers are used to excite dyes on our samples, so that we can see them and observe dynamics of our DNA-protein structures.  I think the coolest part of this experiment is that because the dye molecules are so bright, we can see individual DNA molecules with proteins fluctuating on our slides.  The down side is that I end up spending hours in a dark room watching little blinking dots on a screen.  That is how research is though. Some days can be pretty boring, but other days, when your experiment is working, you are observing something no one has ever seen before.

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Microscope slide containing our sample on the stage of our microscope where we do our experiments. The green light is from a laser that we shine onto our samples to illuminate the dye molecules attached to our bio-molecules.

One of the best parts of biophysics is that it is highly interdisciplinary.  In my research I work with biochemists, mechanical engineers, chemists, materials scientists and occasionally other physicists.  I get to meet graduate students from other departments at Ohio State, but also from other universities and sometimes other countries.  Sometimes I work in their labs and sometimes they work in ours.  There are some days that our lab is busier than the cafeteria at lunch time.  I am a very social person, so I love having someone to talk to while I work.  With so many people in the lab, it’s hard not to have a little fun.

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We have a freezer in our lab that is at -80 degrees Celsius (-112 degrees Fahrenheit) to store protein, DNA and E. Coli cells for long periods of time. The freezer accumulates a lot of snow and ice, so one day while we were cleaning it, we decided to make a snowman.

Scientific research isn’t all fun and games, but it isn’t boring all of the time either.  We work pretty hard most days, but being able to observe single molecules is really cool.  I am very happy that I decided to become a biophysicist whether it’s ‘real’ physics or not.

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Poirier Lab at our yearly summer picnic. I am in the front row, third person from the right.

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About Morgan Bernier

MorganpicI am a 5th year graduate student doing experimental biophysics at The Ohio State University.  In my spare time, I enjoy running, hiking and camping with my husband, Dan, and our dog, Indiana.  Our cat doesn’t really behave that well on a leash.  When I graduate, I hope to conduct research in the biotech industry and someday start my own company.

First Job’s the Charm

by Alexander Speirs

“Choose a job you love, and you will never have to work a day in your life.” This is one of the few Confucius sayings with which I can fully identify. Although I suppose I’m not actually the best judge on that front, as I have only had jobs in academia throughout my life. The closest I’ve had to a “regular” work is tutoring during high school along with some volunteering and extracurricular organizational work. Straight out of high school I began an internship funded by the National Science Foundation with Dr. Roland Kawakami’s group at the University of California, Riverside (UCR), and I have simply never stopped working in research.

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The Kawakami Group at Mt. Rubidoux in Riverside, California. Dr. Roland Kawakami is in the middle of the top row and I am to the far right in the bottom row.

To clarify, the positions I’ve held, both at The Ohio State University and at UCR, fall into the category of experimental condensed matter physics research, which is a fancy way of saying we study materials, ranging from your standard metals (iron, copper, nickel, etc) to the novel two-dimensional sheet of carbon called graphene. Now, “What’s so great about this gig?” you might ask. Physics, and other more math-centric scientific concentrations (engineering, computer science, etc) depend more on application and evolution of knowledge, as opposed to memorization and technique. I prefer it this way, it makes being bored a rare occurrence. When you are working on a specific project, it is normal that the methods and even the goals change as you go, and the results are often quite beautiful.

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Part of my summer project at OSU, acid-etched silicon wafers resulting in a vibrant rainbow pattern.

One of the main factors keeping me interested in this profession is the constant evolution that other jobs seem to lack. I often feel slightly left out when I hear friends and colleagues discussing past jobs and experiences, however I can’t imagine myself enjoying any other job. My understanding is that most “normal” jobs, such as clerical, retail or restaurant positions, involve extremely repetitive tasks or routines. In my 2 years working at UCR’s Nanoscale Spintronics Laboratory, the closest I came to having a routine was regularly producing graphene samples, and even then there were constant changes from problems cropping up, improvements being made and needs evolving. This constant adaptation is the way of things when you are working on scientific research, as our work generally does not extend beyond a fundamental understanding. I (and most scientists) are like children in this way, we tend to be distracted by shiny new things, almost never being involved in application phases. I would like to be able to give a run-through of what an average day of work is for me, but the truth is that I never have an average day. As an undergraduate in research, I often shadow graduate students in their efforts, learning and contributing where I can, but their days rarely go as planned either. This is another aspect that makes this path desirable for me: everyone is constantly learning. Even our “boss” (the Professor or Principal Investigator) constantly adapts to new information. For instance, when our vacuum chamber was disabled by a procedure involving reactive gasses, many members of the group, including the Principal Investigator and myself, quickly decided to shift the study and procedure to the furnace system which I was currently working with.

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The proposed electronic device for a collaborative project of which my graphene production focused on.

In my spare time, I enjoy building things, from circuits and models to more radical projects such as a ten foot tall trebuchet. This is likely another reason I enjoy my job so much, because it’s similar to my hobbies, but on a much more fundamental level. I like to call many of my projects “big boy Legos”, such as designing and building an extruded aluminum and steel frame to protect us from potential explosions in the lab. Even my graphene production essentially involves stacking carbon and other materials such as metals or semiconductors, but on the atomic scale. One of the main differences is that now I get to play with much more expensive and potent toys. For instance: when moving lab locations at UCR, I was handed one small piece of equipment from our extremely large and complicated vacuum chamber; I was then told that it was worth over twenty thousand dollars. Needless to say, I am very careful around even the most basic looking items in the lab. I also get to work with ultra-high vacuum systems, flammable gases, reactive substances, high voltages and corrosive liquids on a daily basis. I believe that if I were to switch careers, anything else would just seem boring by contrast.

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Big Boy Legos: An extruded aluminum frame to enclose the lab’s furnace (upper left).

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An example of the expensive component: an atomic hydrogen source. Source: SVT Associates, Inc.

I doubt that I will ever leave the sciences, for a reason told best by Richard Feynman: “You say you are a nameless man.** You are not to your wife and to your child. You will not long remain so to your immediate colleagues if you can answer their simple questions when they come into your office.” There is a definite joy and meaning in simply being able to answer questions and expand knowledge. Despite a certain arrogance that comes from physics being the “purest” science, it is certainly impossible to say that any one person is more knowledgeable than another. In most meetings that I’ve attended, everyone in the room is the resident expert on some aspect, facet or procedure. That sort of identity and importance is very endearing, and leads us to be more productive, more invested in ourselves, the group, and the research. With all of this in mind, I hope to always have a career in this field, it is always interesting and exciting.

**Remember, women are physicists too!

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About Alexander Speirs

BioPicBorn and raised in the desert valley of Riverside, California, I was inclined to stay indoors to escape the relentless heat and sun. I read lots of books, played lots of video games, and watched lots of Discovery Channel. I still do all of these things, but currently my focus is on my undergraduate studies at the University of California, Riverside, and on my research projects as well as my officer position in the student chapter of the Materials Research Society at UCR. I play bass guitar, enjoy cooking, programming, building and blowing things up, and the occasional physical activity (football, frisbee, rock climbing) or beach trip.

Imperceptibly Fast

by Andy Berger

If the width of a human hair is the smallest thing visible to the naked eye, what is the shortest amount of time that we can distinguish? The phrase “in the blink of an eye” suggests an answer.  And it’s a decent suggestion.  Go ahead and blink.  Back already?  That was fast.  The average length of a blink is 0.1 seconds.  Compared to some physical processes – as shown below – that is actually a really long time.

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TOP: Time interval for some fast events.
BOTTOM: Frequency of various waves, shown directly below the amount of time for 1 period of oscillation.

I’ve always enjoyed music, as I’m sure many of you do.  In fact, one of my favorite hobbies is to play the guitar.  There is a lot of physics behind the workings of a guitar, but one of the most fascinating aspects is the speed of sound-producing processes.  Consider the simple case of playing a middle C (for those guitar players out there – this is the first fret on the B-string of the guitar, or for piano players – the key in the exact middle of a standard keyboard).  When this note is played, the string vibrates 261 times per second (or 261 Hz).

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TOP: Middle C as played on guitar.
BOTTOM: Position of the blue dot versus time.

This plot shows the position of the blue dot on the string versus time.  Note that, because it’s vibrating at 261 Hz, it takes less than .004 seconds to vibrate back and forth once.  In the time it takes you to blink, the string has gone back and forth 25 times.  While it’s vibrating, the string pushes around air molecules.  Eventually, these air molecules bump into your eardrum causing it to vibrate just like the string, and voila – you hear a middle C.

Of course, music isn’t terribly interesting if you just hear a single note at a time.  Often a guitarist might be playing a chord with six different notes, while the singer and bassist are each holding a note, all during a symbol crash and bass drum thump.  The speakers that we use to listen to recorded music have to vibrate accordingly to imitate all these different sounds (see a vibrating speaker in action).

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Signal responsible for vibrating the left and right speaker cones at 56.5 seconds into Metallica’s “No Leaf Clover.”

This is the actual signal sent to the speakers 56.5 seconds into (my favorite song) Metallica’s “No Leaf Clover.”    I chose this part of the song, because not only are there two guitars, a bassist, and a drummer playing, but they are supported by an entire orchestra.  It’s amazing to me that two tiny earbuds can accurately replicate the sound of nearly 100 instruments.  Sports fans: the amount of time depicted in this graph – .01 seconds – is the margin by which Michael Phelps won the 100m butterfly (and 7th gold) at the 2008 Olympics.

Our eardrums are not the only aspect of biology that are capable of high speed dynamics.  In my first blog post, I discussed the nanoscale machinery of DNA.  This machinery isn’t just small – it also operates very quickly.  Check out this real-time animation: DNA Transcription.  The enzyme zipping along the DNA is reading and copying the genetic code at a rate of about 30 nucleotides per second.  Try to count to 30 in one second.  In the time it takes you to blink an eye, 3 nucleotides have been transcribed simultaneously throughout the nuclei of most of the cells in your body.  I wish I had seen visualizations like this while I was studying biology, chemistry, and physics in high school.  The static illustrations in a textbook just can’t compete.

As impressive as the machinery of our cells is, they move at a snail’s pace when compared with the information processing speed of our electronic devices.  We have all come to expect a lot of our computers and cell phones.  But let’s stop and consider what has to happen to open a saved picture.  A typical image is a couple of megabytes in size.  Your computer has to individually read each of those million bytes in order to reassemble the image from the 1s and 0s that currently encode it.  If it took “the blink of an eye” (0.1s) to read each bit, it would take more than a day to load a single image!  Forget watching a video.  Luckily, a computer can shuttle information around blazingly fast.  The bits are zipping by at billions of bytes per second – and so as far as we are concerned, an image opens instantly.  To draw an analogy, when a hard drive is reading the bits that encode an image, the bit sensor is like a “jet plane flying at [18,600 miles per hour] one meter above the ground recording each blade of grass.

Technology has enabled us to do a lot in the time that passes in the blink of an eye.  It took the invention of high speed photography (1 frame every .04 seconds) to prove that all four hooves of a galloping horse are simultaneously in the air, tucked underneath its body.  Prior to these photographs, artists would incorrectly depict the position of the legs of galloping horses.  Time simply moves too fast for human perception to accurately keep up.

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TOP: Painting of galloping horses from 1821.
BOTTOM: High-speed photograph from 1878.

Today, scientists use “cameras” ten trillion times faster – taking snapshots once every femtosecond (10-15 seconds) – and can actually monitor the progress of chemical reactions.  There are 10,000 times more femtoseconds in the blink of an eye than there are years in the age of the universe.  Take a moment to pause and appreciate how quickly everything is buzzing around us, shaping our world and how we interact with and experience it.

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About Andy Berger

Picture1I grew up in Mansfield, Ohio, received my undergraduate degree from Kenyon College in Gambier, Ohio, and am now finishing my fifth year of the physics PhD program at Ohio State.  I am a condensed matter experimentalist with a focus on scanning probe microscopy, magnetism, and graphene.  I never would’ve guessed that would be my “job description” when I was in high school.  Away from the lab, I enjoy staying active – mostly through swimming, running, cycling, and soccer.

What is Clean?

by Megan Harberts

Have you ever heard of a cleanroom before? You probably think that is what your parents want your room to be, but what does it mean for a laboratory to be in a cleanroom?  Have you ever seen a picture of someone wearing a white suit in a yellow room with a bunch of equipment?

http://www.ensl.osu.edu/

Nanosystems Laboratory (NSL) cleanroom at The Ohio State University

That is one type of cleanroom used for scientific research, as well as manufacturing of circuits and solar cells and I am a graduate student at OSU who does research in one of these rooms.

So what does it mean for the room to be clean and why do you have to wear a special suit?  Cleanrooms provide an environment where there are very few particles in the air. More and more technology is being done at the nanoscale, this means a lot of the components are on the order of nanometers.  There are 109 nanometers in one meter.  Typical dust particles are on the order of microns, there are 106 microns in one meter.  Therefore, a single dust particle landing on a device can ruin it by bridging connections or introducing unwanted impurities.

How can you keep a room free of dust particles? Well, where do the particles come from?  Some are from dirt and other things outside, others are from dead skin cells and fibers. One way to keep from adding new particles to the room is to wear a suit to keep particles from coming off your body and to keep things out of the room like fabric and paper which tend to shed fibers.

Before the 1960’s, the best practice was to wear a suit, and keep the room sealed as best as they could. Like you do when you clean your room, they tried to remove particles that got into the room by vacuuming, using a special vacuum that sucks up and traps small particles with a filter to prevent them from getting out of the vacuum, but when particles got into the room they still caused problems.  This all changed when physicist Willis Whitfield invented the laminar flow cleanroom, which revolutionized the way cleanroom processes worked.  The idea is to constantly cycle filtered air into the room.  Air coming into the room is passed through HEPA (high-efficiency particulate air) filters in the ceiling and then is passed out through vents on or near the floor so that gravity can help pull out any particles in the air.  50 years later this is still the standard for cleanrooms for research, manufacturing, and even in hospitals.

A picture of the airflow in a laminar flow cleanroom coming in through filters.

A picture of the airflow in a laminar flow cleanroom coming in through filters.

This is the basis for all cleanrooms, but they come in different classifications.  These classifications are based on the number of particles that are 0.5 microns or larger measured with an instrument called a particle counter. They range from class 1 to class 100,000.

For rooms that are the cleanest, class 1, the users have to wear a full suit and a respirator so that they don’t introduce particles from inside their bodies.  I work in a class 10,000 cleanroom, meaning we expect there to be no more than 10,000 particles in a square meter, so I only have wear a hair net, gown, booties, and gloves.

This me in my cleanroom outfit.

This is me in my cleanroom outfit.

Other ways we keep the dust level down include sticky mats that we step on when we enter the lab and vacuuming every week.  The doors to our lab are not sealed so our lab is kept at positive pressure so air always flows out of the room around the doors and the only air that flows in passes through filters.

Sticky mat at the entrance to the cleanroom.

Sticky mat at the entrance to the cleanroom.

As I mentioned earlier, a lot of cleanrooms have yellow light and I always wondered why before I started working in one.  It turns out that the yellow lights and window covering are not necessary for keeping the room clean, but they are necessary for doing photolithography which is common process done in cleanrooms. As I said before, a lot of new devices have components on the scale of nanometers and one of the ways to make small circuits and devices is with photolithography.

Photolithography is similar to how pictures are developed. During device processing, a sample is covered with a light sensitive material called photoresist, which does not react to yellow light. The photoresist covered sample is then exposed to ultra violet light under a patterned mask.  Only parts of the photoresist on the sample will be removed when it is placed in a developer solution. The photoresist that remains protects the sample to allow somebody to now either remove material from the exposed parts, called etching, or cover them with an additional material like a metal for contact pads. Later the photoresist can be removed and you can end up with something like my sample with a specific pattern.  In my research, we have to have small contacts on the sample because the materials are can be hard to process on a larger scale and the tools we have for measuring do not leave much room.

Here is a one of my samples which is about 1 cm long on each side with a very small circuit on it. The mask covered the clear parts during the processing.

Here is a one of my samples, which is about 1 cm long on each side, with a very small circuit on it. The mask covered the clear parts during the processing.

Photolithography is just one of many types of processes that are done in cleanrooms.  While it can be cumbersome to have to put on all those extra layers every time you go to work, doing work in a dust free environment ensures that very small devices can be made consistently, which is important for both research and manufacturing. This tells you a little bit about what clean means for my research, but the question, “What is Clean?” can mean very different things if you work in a biology lab or even when it comes to your room.

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About Megan Harberts

picture of me

I am one of the founders of “A Day in the Life” and a current graduate student at Ohio State University working on my PhD in condensed matter physics.  Outside of school and working on the blog, I play water polo for the OSU club team. Leave a comment or find me on Twitter @meganharberts if you want to know more!

Contributing to an International Collaboration as an Undergraduate

by Paul Schellin

The evening before the physics GRE (a test required for my graduate school applications) I received an email from my advisor asking if I was interested in a project involving hardware work. I have been working on the hardware for two different ultra-high energy neutrino detectors (ANITA and ARA) for about two years now, so this was not unusual. The difference with this request was that the work would be in Taiwan, and that a colleague of mine, Eugene (a PhD student), and I would be traveling there for two weeks!

I can’t say that I when I began my undergraduate research I thought that I would have the opportunity to travel overseas to work on a project, and as such I was extremely excited about this request from my advisor. I got very little sleep thinking about it that night, but still I went in to take the GRE feeling pretty confident. The rest of the summer I spent preparing myself for the work by learning as much as possible about the systems that we would be working with and the measurements we would want to make.

Soon enough though, I found myself having taken the ~24 hour journey to Taiwan. During our first hour on the campus of National Taiwan University (NTU) we were already lost, but luckily a couple capable of understanding English were able to point us to the hotel where we would be staying.

The next day was full of introductions and acclimation, but it was made very easy for Eugene and I. We felt right at home in their laboratory and everyone was friendly to us and always offering to help. The communication in the lab was already in English on a day-to-day basis, as their research group is advised by a professor from South Korea (who does not speak much Chinese). During our stay there were also two visiting researchers from Japan, all working alongside us toward the same goal.

What I did in Taiwan is probably best explained by the flow of the average day:

We woke up in the early morning, having slept on these bamboo-ish mattresses. Showered, headed to Taiwan’s cafe-style version of 7-Eleven for breakfast. For breakfast there I generally had these triangles of rice and fish wrapped in seaweed, which were really pretty tasty.

After breakfast we walked through the early morning heat to the physics building. Every time I walked somewhere in Taipei, I was seriously dumbfounded by the amount of litter in this city. There isn’t any. None. This makes me reflect upon the respect individuals in East Asia seem to have toward their city, and I can’t help but compare this to Americans and Europeans.

Upon arriving to the physics building, we would swipe a card to enter. There are at least three security cameras to every room and hallway on the ground floor. We’d take the elevator (which normally tried to have some sort of conversation with me, but I could never understand exactly what the elevator was trying to convey…) up to the ninth floor, where the lab is.  Just like at American universities, the grad students tend to arrive a good amount after 9am.

The view from the lab’s windows is gorgeous. I can see the Taipei traffic come and go as well as the mountains around this side of the city.  You can actually see a good amount of the surrounding area too, since most buildings in that direction aren’t too tall.  Eventually, I have to stop staring out the window and actually do work.

The view from the lab in Taipei.

We would start off our day assembling the components to be tested. We were testing the radio equipment (coaxial cables, amplifiers, filters, and fiber transceivers) that would be deployed with a new station for ARA. These measurements not only allow us to verify that each component works, but they also enable more accurate simulations of the detector as well as improve analysis of the collected data after the detector is deployed. A lot of care had to be taken during these measurements, documenting which wire went to which component and recording every serial number combination. It was rather tedious, but I could at least talk to the other researchers in the lab during this time (there were a few electrical engineers and grad students who did arrive before 10am), so I was able to learn quite a bit about academic life outside of the West.

After we finished whichever component testing rig we were working on, the fun could begin. We would hop into the elevator with the rig, go down to the second basement, through a dark, abandoned parking garage, and through double doors. Inside, there are working lights and turning them on reveals the door to a large anechoic RF-shielded chamber.

The anechoic chamber.

We would run a bunch of tests on the components, measuring several electrical properties of each component and comparing them to either the expected values or the “ideal” values. For the most part the tests were executed properly, which was quite a rewarding feeling. The Antarctic-bound detector we were working on has a really strict shipping schedule, so it is very important that every component is carefully tested as any major setback has a chance to delay the deployment by an entire year. After finishing the tests, we would retrieve the components and return to the lab. By that time most of the group would have arrived, and we’d discuss things that needed to be done, things which were behind schedule, and results that others had attained. The rest of the day we typically spent compiling all of our data together into plots to be presented to the collaboration members. This was my least favorite part, but without it no one would be able to make heads or tails of what we were doing and what our results actually meant. When we finished the data compilation, it was around dinner time.

Every night (for two weeks!) we would have dinner at a different restaurant. There was a wide variety of food, mainly different East Asian dishes, all of which were excellent. I’ve added quite a few meals to my “to-attempt-to-replicate” list, so it will be a while before I run out of things to try to cook.

Since returning from Taiwan, I’ve resumed my regular class and research schedule. I have found that the work we did has improved my understanding of several concepts which have been useful in the development of detector simulations for my research, but also helpful in my classes, for example in my senior lab class I was able to apply techniques of making data less noisy, allowing me to take on and resolve a tricky data analysis predicament. The most remarkable thing which I’ve taken away from the experience, however, was seeing the results of the work that has been done at Ohio State and at all of the other collaborating universities being pieced together to form a complete, functional system. Seeing this after two years working on the project reminded me of the importance of every individual’s contribution to the finished product, a thought which I will not forget anytime soon.

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About Paul Schellin

I grew up in Port Clinton, Ohio, hoping to study robot engineering, but after spending a year abroad in Germany after high school, my ambition shifted toward studying physics and astronomy, which I am currently doing as a senior at Ohio State. I am currently working on research focusing on detecting ultra-high energy (UHE) neutrinos and cosmic rays using the ANITA and ARA detectors. Next year I plan on continuing my physics education at the graduate level, though I’m not sure where just yet.

My Summer Research Experience

by Jasneet Singh

With the new school year underway, I often think back to the few precious months I spent homework-free.  My summer, however, was very different than that of many of my classmates.  As a high school junior, I was given the opportunity to work in Professor Leonard Brillson’s Surfaces and Interfaces Laboratory at The Ohio State University.  In April of this year, Prof. Brillson came to my school, Columbus School for Girls (CSG), and gave a presentation about the research his lab conducted.  As soon as he introduced his topic of semiconductors I was lost.  I spent the rest of his twenty-minute presentation trying to piece together what I did understand from his PowerPoint (which was not much) and form a picture of his research. The questions running through my mind were endless but the few that bothered me the most were, could I work in a university lab with my one-year knowledge of high school physics?  Was I smart enough?  Pushing my low self-confidence aside, I submitted my resume, thinking it could not hurt.  It was not until Dr. Sweeney, who organized this program from the CSG end, informed me that I had been placed in Prof. Brillson’s lab, did the feelings of nervousness and anxiety return.

My first day of work was a blur of tours, filling out paperwork, and many handshakes.  Having four other CSG girls participating in the program with me made me feel much more comfortable but once we split up to meet our mentors, I was on my own.  After navigating through the Physics Research Building, I finally found my way to the office of post doctoral researcher Dr. Snjezana (Snow) Balaz.  As soon as I met my mentor for the rest of the summer, I felt at ease; she was incredibly friendly and easy to converse with as we toured the different labs.  Even though I did not know some of the terminology she used, and could not have told you the long names of the different machinery after she said them, I still learned an immense amount that first day.  Evan, a graduate student in the group, helped Snow explain to me the concept of radiative recombination when showing the Depth-Resolved Cathodoluminescence Spectroscopy (DRCLS), an instrument I used throughout my internship.

The rest of summer followed the tone of that first day, learning more and more about how the instruments work, and what physics they study.  Not long after, I was also able to learn how to take data on my own.  One of the most rewarding experiences was learning how to use DRCLS and be sent by Dr. Balaz to the lab to take data on a few samples of zinc oxide (ZnO) that were being used for collaboration with the Seebauer Group from University of Illinois.  The purpose of this collaboration is to see if the defects are driven by electrostatic or thermodynamic forces.  After taking data, I learnt how to use a software program called Origin in order to analyze peak intensities and provide Dr. Balaz with graphs to include in a report that was sent to the other group.

I also got over my apprehension towards asking questions, and am grateful for Dr. Balaz’s patience.  She told me it was better to ask questions than to assume an answer, because assumptions can lead to many more mistakes.  I took that advice very seriously and made sure to clarify anything I was unsure about.  I also was able to build my self-confidence and noticed a significant change when explaining what I was doing to my family.  The true test arrived on the day of my final presentation, when I had to explain concepts that were still relatively new to me, to Prof. Brillson, Dr. Sweeney and the other CSG girls.  The nervousness stayed with me up until I took the stage.  Once I started my PowerPoint, I knew what I wanted to say and felt comfortable presenting the data; this was one of my proudest moments.

The learning did not occur solely in the labs or through the whiteboards in the office.  I also had the opportunity to attend group meetings, talks, lectures, tour different labs, and met researchers from the Air Force Research Laboratory.  Dr. Balaz was a great teacher, and also acted as a resource for all of my questions, giving me advice regarding choosing majors in college, undergraduate research, and career options.  Even though I am a high school student, and graduate school seems many years away, it was nice to have someone to talk to about the process.  Dan, a graduate student working in the same office as Dr. Balaz, also became an advisor to me and answered my questions about his undergraduate and graduate school experiences at OSU.   I knew how lucky I was to have so many people willing to talk to me about their experiences, and help me think ahead to my future.

I can confidently say that taking advantage of the opportunity to work in Prof. Brillson’s lab this summer was one of the best decisions I have made.  I am proud of everything that I have learned and accomplished in such a short period of time, and am not sure I would have achieved this level of personal satisfaction from another job.  I’ve opened my eyes and mind to the world of research, and found that I enjoyed every minute I spent in those labs.  Thank you Prof. Brillson, Dr. Sweeney, for organizing this program, and thank you to Dr. Balaz, Dan, Chung-Han, Evan, Mitchell, and Jackie, for welcoming me into the group and taking the time to explain to me the different aspects of your research.  It truly was a memorable summer.

Taking data on the Atomic Force Microscope, measuring forces between the tip and the sample to obtain the topography of the ZnO sample.

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About Jasneet Singh

I was born and raised in Lancaster, Ohio and am currently a senior at Columbus School for Girls.  I am unsure of where I will be attending college next year but I plan to major in either chemical engineering or biomedical engineering.  Wherever I attend college, I hope to become involved in some form of research.  Any advice or comments are welcome!

My Summer Doing Undergraduate Research in Astronomy

by Brittney Curtis

I’m a third-year undergraduate at Ohio State University, with a double major in physics and astronomy and astrophysics. Instead of taking classes or working a boring summer job like a lot of my friends, I got to spend this past summer studying the shapes and colors of beautiful warped disk galaxies in the Department of Astronomy and Astrophysics as a participant of SURP (the Summer Undergraduate Research Program). I was one of four students who was selected to spend ten weeks working with a faculty advisor on an individual research project that will eventually become an undergraduate thesis.One of the best things about SURP was that it fully immersed the four of us into the culture of the research community. Much like the professors and graduate students in the department, I spent about 40 hours per week in the office – just like a full-time job. You get to hear bits and pieces about your professors’ research during lecture a few times a week, but spending a whole summer just down the hall from them as they make breakthroughs and publish papers is entirely different. I could see and hear real science being done all around me, as professors dissected new theories from recently-published scientific papers and students just slightly older than me gave presentations about supernovae or black holes they had just discovered. Just this summer, one of the graduate students that worked right down the hall from me was featured in the New York Times for helping to discover a couple of planets with a very small telescope.One thing was more exciting than watching the expert astrophysicists at work; each of us had our own little slice of science to explore throughout the course of the summer. My project focused on the colors of galaxies that have warped disks. Warped disk galaxies are interesting because the mechanism that causes them to stay warped for such a long time is currently unknown. If the galaxies are more blue, which means they have younger stars, that might mean that something (a nearby galaxy that we can see or else something invisible to us, like dark matter) is actively sustaining the warp and causing new stars to be born. On the other hand, if the galaxies are more yellow and they have older stars, it could mean that the warp is self-sustaining.
I learned that it’s easiest to visually detect warps in galaxies that we see edge-on from Earth. Here you can see the long s-shaped warp in the disk of the galaxy, which you couldn’t see if you were looking at the galaxy from above.  Image Credit: NASA’s Hubble Space Telescope
To investigate this question, I downloaded information about nearly a million galaxies from the Sloan Digital Sky Survey. I analyzed the data to try to find an algorithm that could pick out the warped galaxies from the normal galaxies based on their shapes. Along the way I learned more about computer programming than I ever did in class. I also got to spend hours looking through pictures of galaxies and learning which parameters to use to define their shapes and positions in the sky, and I had many conversations with my wonderful advisor, Dr. Barbara Ryden, about our data and the methods we used. Some of the steps in my project were rather difficult, but I was always able to find someone in the department that was willing to help or give advice. I’m not quite finished with my research project, so I’m going to continue working on it later this year and publish my results next year.The three other students in the program were all classmates of mine (and are now great friends). Adam, Zach, Jacob, and I shared a tiny office with four desks and we ate lunch together almost every day. If any of us were stuck on a section of code or forgot certain syntax, we asked each other for help and worked together to solve the problem. On a typical day, we spent 5 or 6 hours in the office working on code, and we took a few breaks from our computers to attend research lectures by local or visiting professors. These lectures covered diverse topics from the structure of the large-scale universe to neutrino detection in Antarctica and the construction of large telescopes. In addition to these occasional lectures, we attended the “Astronomy Coffee”  meeting that was hosted by our department every morning. At Astronomy Coffee, professors and students gathered to drink coffee and discuss the newest astrophysics research.Between helping each other out on our projects and listening to lectures about hot topics in astrophysics, we learned much more about astronomy than just the facts pertaining to our own project. We quickly learned that real science isn’t at all like what it seems in the classroom, but instead it’s more challenging and much more fun! I feel that participating in SURP has given me the most accurate view of what it’s like to be a scientist, much more than my classes. The most important thing I took away from my experience is that I truly enjoy the challenge of scientific research and I’m more sure than ever that I want to devote my career to it.
This picture was taken on the final day of SURP, just after we had given presentations about our summer research to a group of professors and graduate students. I’m on the far right, standing in front of my advisor.

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About Brittney Curtis

I grew up on the northwest coast of Oregon but I came to Ohio for college to study physics and astronomy. I am the first member of my family to attend college. I’m an honors student at Ohio State University and I intend to graduate in 2014 with two degrees, one B.S. in physics and another in astronomy and astrophysics. After graduation I plan to attend graduate school and work towards my Ph.D, although I haven’t decided yet if I’ll pursue physics or astronomy. Feel free to contact me by leaving a comment on this post!