A Night on the Mountain

by Kate Grier

My name is Kate Grier and I’m part postdoc and part Planetarium Director in the Department of Astronomy at OSU. That means I get to play two different roles in the department: In my role as a postdoctoral researcher, I spend my time measuring the masses of black holes at the centers of galaxies, and in my role as the planetarium director, I oversee all of the activity of our awesome, newly-renovated planetarium on campus. This week, I am putting on my research hat and escaping the cold Columbus weather with OSU graduate student Jamie Tayar to the sunny desert mountains of Arizona to collect data.

Desert mountains, like those found in Arizona, are perfect places for astronomers to put telescopes for a number of reasons: First, there aren’t many people around, so the skies are very dark. Second, deserts are known for being very dry, and we like dry climates because water molecules in the air interfere with our observations. Third, desert mountains are at high elevations, which means there is less atmosphere between us and outer space, which also helps us to get more accurate information about the stars and galaxies we’re looking at!

MDM Observatory at sunset.

This brings me to the top of Kitt Peak, a mountain in Arizona that has a large number of telescopes at its top. OSU co-owns two telescopes on Kitt Peak at an observatory called MDM, which stands for “Michigan-Dartmouth-MIT” — the original owners of the observatory. One of these telescopes has a mirror that is 1.3m in diameter, and the other has a mirror that is 2.4m in diameter. Even the 1.3m, which is fairly small when compared with the largest telescopes in the world, weighs over 1000 pounds, and the entire telescope structure dwarfs us humans!

The 1.3m McGraw-Hill telescope, with OSU Graduate student Jamie Tayar standing below

Now, follow me as I take you through a night of observing at the 1.3m telescope at MDM in March, on a beautiful, clear (but cold), early-spring night.

The Night Begins

5:oo PM — Before it even gets dark out, we must start taking “calibration data” in the afternoon. Astronomers don’t look through telescopes by eye anymore—we use CCD cameras (basically really expensive digital cameras) to take pictures of galaxies and stars and then save the pictures to analyze later. Because these CCD cameras are not perfect, we take many calibration images before the observing even starts so that we can account for any imperfections in the cameras.

6:oo PM — The first thing we have to do is to make sure the CCD camera that we’re using stays cool. Warm cameras radiate their own light that interferes with the light coming down from the sky, so we cool the cameras down to about -165°F with liquid nitrogen (using liquid nitrogen as a coolant is also a really, really fun way to make ice cream). The liquid nitrogen itself is actually much colder than this—liquid nitrogen is about -321°F, but the insulation of the camera isn’t perfect, so it’s generally warmer than the liquid nitrogen itself. We have to make sure the camera never warms up much more than this, or we could have problems with our observations.

Jamie filling up the instrument with liquid nitrogen to cool down the camera.

6:45 PM — It’s sunset time! Watching the sun set from a beautiful desert mountain in Arizona is one of my favorite parts of observing. Sunsets in Arizona are spectacular, and sunsets at MDM observatory never disappoint.

Me watching the sunset on a clear evening from MDM Observatory in March.

It takes nearly an hour after sunset before it is dark enough for us to take data, but after watching the sunset, we start getting the telescope ready to observe. We call this period after the sun sets “evening twilight,” when there’s still some ambient light in the sky.

7:45 PM — It is now dark enough for us to observe! We start with a star to use for calibrations—we use a star that has had very detailed brightness measurements taken previously. Since we know how bright it should be, we can see how bright it looks to us, and use that to calibrate the brightness of all of our data.

Me hard at work in the telescope control room

8:15 PM — It’s time to observe our first galaxy! Tonight, we are looking at galaxies that are hundreds of millions of light-years away—specifically, we are looking at the centers of these galaxies. Each galaxy has a supermassive black hole that is millions or billions of times as massive as our sun. We watch the gas and other material falling into the black holes in these galaxies to learn about the black holes—specifically, by watching the gas move around the black hole, we can calculate how strong the gravity of the black hole is, which gives us a measurement of the black hole’s mass. Because these galaxies are so far away, they are faint and we have to take really long exposures to collect enough light, so we take three 20-minute-long exposures on each target. Throughout the night, we move to a new galaxy every hour.

10:00 PM — Time for some star gazing. It’s important that we go outside and look at the sky often to make sure there are no clouds interfering with our observations, and on a beautiful, clear night like this, I am happy to go out and check out the sky! Out here, we can see the Milky Way up in the sky, and so many stars! It’s a beautiful night.

The Milky Way galaxy, as seen from MDM. Photo taken by Matthias Dietrich.

12:30 AM — Dinnertime! Since we’re on an observing schedule, our mealtimes are a bit mixed up. I woke up and had breakfast at about 3:00PM and had lunch right after sunset, so now it’s time for dinner! The dorm at the telescope has a mini kitchen that we use to cook food in, so we bring groceries up with us when we come up the mountain. We have to eat quickly, though—we can go eat food while the telescope is taking a 20-minute long exposure, but we can’t leave it for longer than that.

3:00 AM — It’s time for a 3AM dance party! This time of night, even after I’ve been observing for a few days, I tend to get pretty tired—it’s hard work staying up all night long. What better way to wake myself back up then by staging my own dance party inside the control room?

5:15 AM — It’s about an hour before the sun rises this morning, which means it will start getting light out soon. Sunlight will start interfering with our observations, so it’s about time for us to stop observing and pack up for the night. We return the telescope to its home position (pointing straight up), close the dome, cover up the mirrors, and once again, refill the container of liquid nitrogen so the camera doesn’t warm up during the day. Time to head in and go to sleep – successful night of observing!

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About Kate Grier

My name is Kate Grier and I am a recent PhD graduate from The Ohio State University (OSU). I grew up in the suburbs of Chicago and received my undergraduate degrees in both physics and astronomy from the University of Illinois at Urbana-Champaign. Having completed my PhD in Astronomy last summer, I am currently serving as the Director of the OSU Planetarium as well as carrying out postdoctoral research on supermassive black holes. I also love teaching and public outreach, and in my spare time I like to read, hike, and travel the world!

Science Stuck in the Middle: Lasers, Diamonds, and DNA, Oh My!

by Richelle Teeling-Smith

What does it mean to do ‘interdisciplinary’ research? Sometimes in research, you might find that your path to solving a specific problem leads you outside the traditional boundaries of the field you set out to study. That’s how my graduate school experience has gone and I’m not the only one!

I’m a fifth year graduate student at the Ohio State University and I am studying physics. However, unlike most graduate students, I work for three different advisors with three different specialties. All of us are technically in physics, but our work takes us outside of physics on a daily basis. I study the dynamics of single biomolecules, like DNA. I look at how DNA moves using a tool called nitrogen-vacancy (or NV) diamond. My work involves lasers, DNA, diamonds, gold, and magnetic resonance. I use physics, biology, chemistry, and engineering on a daily basis. Yes, it is as cool as it sounds!

Why are scientists so interested in studying the dynamics of single biomolecules? Who cares how a single molecule (like DNA) moves? Single-molecule measurements are becoming more and more popular in biophysics, biology, and biochemical and biomedical engineering because they allow us to clarify and better understand important biochemical processes such as protein-DNA interactions (transcription and translation), protein folding, and the functions of membrane proteins – and much more!

It’s important to look at a single molecule because so much information can be lost in measuring a large number of molecules together. If you take a pipette and suck up some small volume of your sample, you have moles of molecules! We’re talking 10²³ molecules. That’s 23 zeros! When you measure a large ensemble you are averaging over the whole group and you lose important information. Imagine you are an alien studying the planet Earth. You want to understand the life forms that live on Earth and you take one snapshot that averages over all humans on Earth. What do you see? First off, this human is half male and half female. Weird right? Now what do they look like on the outside? Do they have hair? What color?  How tall are they? You get my point? One averaged human does not do a great job of representing us accurately.  Single-molecule measurements of these complex biological systems have allowed us to get a much more accurate and detailed view of what is going on in our bodies!

So why diamond?  And what do lasers have to do with this?

NV diamond is really a great tool. Have you ever heard of colored diamonds? Diamonds can be blue, yellow, or pink. These colors are caused by impurities in the diamond crystal. Normally, diamond is composed of carbon atoms arranged in a tetrahedral lattice structure. However, if you replace or remove some of these carbon atoms in a specific way, you can change the optical and electrical properties of diamond.

Pink Nitrogen-Vacancy Diamond (image by Young Woo Jung)

NV diamond involves just that. One carbon atom is replaced by a nitrogen atom. Adjacent to that, one carbon atom is removed altogether to leave a gap in the lattice. These atoms form the NV center. This is what makes the NV diamond pink!

Nitrogen-vacancy centers in the carbon diamond lattice. Nitrogen atoms are yellow, the vacancies are transparent, and the bond between the N-V is highlighted in pink. (Image by Young Woo Jung)

NV diamond has the unique electrical property that if you shine a laser on it, it will fluoresce. This means that it emits red photons. It glows red. No really… And NV diamond is a good measurement tool because this fluorescence can be controlled by external magnetic fields and microwaves. This is called magnetic resonance. We apply energy (in the form of microwaves) to the NV diamond sample. I use gold waveguides to do this.

Gold waveguide (fabricated on a glass slide) and soldered to a copper mount to create a microwave circuit. 8 flow channels are placed across the microwave channel. This is where the DNA experiment is housed. (Design and image by Richelle Teeling-Smith)

I design a very intricate pattern in gold that controls the path and intensity of the traveling microwaves. At very specific frequencies, the diamond absorbs the microwave energy. This causes the electrons in the diamond to change their quantum state and ‘go dark’. You control the ‘dark’ frequencies of the diamond by applying magnetic fields to the sample. People have used this to measure small magnetic fields, or even measure a single electron and nuclear spin. This is the tool that allows us to track the dynamics of a single biomolecule in a magnetic field.

In the process of conducting this interdisciplinary experiment, I have had to become a jack-of-all-trades. I engineered and built my own microscope for imaging this diamond-DNA sample. This required learning how to design and utilize both the hardware and software needed to take this measurement. I’ve learned electrical engineering, mechanical engineering, and coding through trial and error.   I also design and fabricate my own waveguides (to supply the microwaves to the sample).   I’ve even become a bit of a biologist and a chemist. Biophysics is an inherently interdisciplinary field, as Morgan Bernier pointed out in her post.  To create my sample, I had to learn the chemistry and biology necessary to attach a single molecule of DNA to a piece of glass on the microscope objective, and also to attach a single nanometer-sized diamond to the other end of the DNA molecule.

Schematic of the NV-nanodiamond attached to the end of a single DNA molecule. This experiment is conducted in a ‘flow channel’ where we house the DNA in solution and apply magnetic and microwave fields. (Design and image by Richelle Teeling-Smith)

This project is highly interdisciplinary. I regularly pull from the expertise of each of my three advisors (magnetic resonance measurements, optics and lasers, and biophysics) and I have had to teach myself a wide array of new skills to conduct this experiment. But as scientists move forward and push the boundaries of the incredibly small, incredibly large, and imperceptibly fast, research is by necessity becoming more and more interdisciplinary. More and more often, the solutions to our problems are beyond the scope of a single discipline and require specialized knowledge from multiple fields. Thinking across boundaries, and a willingness to take on any new challenge to solve a problem, are two important skills that will allow us to develop innovative solutions to our research problems.

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About Richelle Teeling-Smith

I grew up in Akron, Ohio.  I am the first woman in my family to earn a bachelor’s degree in any field.  I went to college at Kent State University in Kent, OH, and didn’t decide to go into physics until my sophomore year.  I graduated in 2009 with my B.S. and now attend The Ohio State University.  In 2011 I earned my M.S. in physics and I am now working on finishing my Ph.D.  I do research in experimental condensed matter physics and biophysics.  I study the dynamics of bio-molecules, like DNA, using impurity centers in diamonds. I am also a mother to a beautiful little girl.