Author: thegreenalgae

About thegreenalgae

I am currently a staff scientist at Caltech/IPAC. Before that I worked at Draper Lab for two years preceded by a postdoc at the University of Michigan. I am most interested in high contrast imaging & interferometry of young stars, wavefront sensing, and star & planet formation. I'm originally from the Bronx, NY, I spent my PhD years in Baltimore, and have hopped around between Ann Arbor, Boston, and now Pasadena. I care a lot about STEM education on all levels and showcasing the human side of scientific research.

Falling back in love with the night sky, or, how Octavia Butler saved my love for space

“All that you touch You Change. 

All that you Change Changes you. 

The only lasting truth Is Change.”

― Octavia E. Butler, Parable of the Sower

Parable of the Sower very quickly became my favorite book in 2021, when I was working through what some professionals described to me as an “adjustment anxiety disorder.” Despite being published almost 30 years prior, Butler presciently imagined the natural culmination of corporate cruelty, political manipulation, and economic devastation. But as dark as the story gets, she also imagined a hopeful future, a different way of existing through action and cultivation, even when the surrounding world was burning itself to the ground. 

Lauren Olamina grows up in a United States that has deteriorated in every sense, politically, economically, environmentally. There’s something special about Lauren (and several folks she meets along the way). She has a form of hyper-empathy, an ability that allows her to feel what she perceives others to be feeling. At first, in a ruthless apocalyptic setting, this is seen as a severe weakness, to be hidden lest she be taken advantage of. As Lauren plants the seeds of a new philosophy and accumulates her community, it is clear that her empathy is rather a superpower. 

Amid this collapse of society, the news reports on a crewed mission to Mars. A typical sentiment is shared among those around her, Why are we sending people to space while we have so many problems at home? The incontrovertible contrast between space travel and deteriorating conditions on earth certainly evokes this question. And yet, Lauren dreams of a future in space. Lauren dreams of a new collective that will eventually seed the heavens. A heaven that is there for us all, and not just for the ultra rich or politically powerful. 

When I read this novel I recently finished working on a lunar lander project, part of the team run by Blue Origin (Jeff Bezos’s fun side project); moreover, I was stuck on a defense project that I felt morally compromised by. I love space, but it was hard to hold two concepts together, the excitement of space exploration, and the political, economic, and cultural violence at home, some of which I felt complicit in due to my job. The more I learned, the more I saw an obvious connection between military development and space technology. Butler’s Parable of the Sower showed me how, even in a corrupt system, even when some of the progress is made for the wrong reasons, we can still dream of the stars, and damn it, if I didn’t need to hear that. It wasn’t long after that I quit my job and went back to astronomy.

Twilight has always been my favorite time of the day; a gradient from light to deep blue stretches across the sky, a faint touch of pink and orange paints the horizon, and, if I’m lucky, Venus shines blazingly bright, welcoming the night. For a little while I could not look at the sky without a sinking feeling in my stomach, feeling that I had ruined this beautiful natural resource. It is such a relief to be back in a work environment where I don’t feel like I am constantly hiding who I am. I still feel guilt, but I am working on that. Thank you Octavia E. Butler, thank you behavioral therapy, and thank you to all the people who are just trying to make it work day to day and be their true selves. It’s damn hard work. I am so excited to be excited about astronomy again, to feel joy for space telescope milestones instead of guilt and regret, to feel energized by my future instead of trapped by it. At the same time, I have a greater appreciation for what technology enables the study I love, and a renewed responsibility to approach that study with thoughtfulness and empathy. Nothing is pure, but that doesn’t mean we can’t still dream of the stars. 

Appreciating the early night sky through a canopy of Palm Trees

Big Glass

At the end of March I got to travel to Tuscon for the first time for a project in collaboration with the University of Arizona. Being an astronomer it’s a bit surprising I had never been to Tucson before since U of A is involved in many observatories and countless astronomical instrumentation projects (not limited to JWST-NIRCam, and Magellan-AO). Between the huge astronomy presence and the legendary tamales, I was excited for the visit. I was also looking forward to some warm weather and a change of scenery.

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I was not disappointed.

As a part of my trip, my collaborator Jared Males was nice enough to give me a tour of the mirror lab, where the Giant Magellan Telescope mirrors are being built. GMT is part of a set of next generation “extremely large telescopes” (ELTs) that will be a few times larger in diameter than any ground-based optical telescope in use now (8-10m currently). GMT will have a 24.5m diameter. All of the ELTs will be made up of smaller mirror segments that form the full telescope surface. Each segment of GMT is 8.4m across.

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And here they make the solid glass surfaces, braced from behind with a honeycomb structure to reduce the total weight. They assemble chunks of special glass over the ceramic honeycomb molding and melt it in a giant spinning furnace. The glass is cooled rapidly first, and then very slowly over months. After the mirror has been set it is polished to the correct specifications (the step shown above).

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Needless to say, I was grateful for the tour. I am definitely on team big glass. My trip to Tucson was fun and productive. I even got to see some nearby nature at the Sonora Desert Museum. Driving out to the museum was breath-taking, where cacti characteristic of the Sonora Desert fill the landscape.

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And of course every trip is better with cute animals…

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It’s taken me a long time to make a trip out to Tucson, but I hope I’ll be back soon!

Astro demos

A friend asked me to come to her daughter’s 3rd grade class to talk about astronomy and my research in exoplanets. So I teamed up with two other women in my department who are finishing up their PhDs, to bring a range of perspectives to the kids. For this kind of class we wanted to do a few simple but engaging demos related to the kinds of things astronomers measure. Between the three of us we had 2 observers, a theorist, and some instrumentation experience.

For my part I picked up one of my favorite teaching tools, a package of pocket diffraction gratings made by rainbowsymphony.com. These are pretty cheap so you can give them away to a full class of kids. Along with this, I wanted to bring a non-white light source, but I didn’t have access to any sort of gas tube lamps and for some reason had trouble finding LED flashlights that were true “single color” LEDs (as opposed to a white light with a colorful cap. It is however easy to purchase a large number of individual diodes of different colors, resistors, and a small breadboard for less than $15.

So as long as you remember how a breadboard works (give me a break, it’s been almost a decade since I used one), this is a pretty simple and cheap solution.

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Above are red and blue LEDs with the appropriate resistors and 9V battery sources. Please don’t mind the shoddy wiring to the batteries (yes that is scotch tape), like I said, it’s been a while, and I don’t have all the nice tools.

With the diffraction gratings, this was a pretty easy way to show 3rd and 4th graders two main ideas:

  1. Different light sources produce different parts of the “rainbow” seen from the white lights in the room.
  2. Even a seemingly “blue” or “red” LED contains other colors in the spectrum. We can use this tool to study what wavelengths (or colors) of light are present.

My best try taking a picture through the grating of my LED setup.

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For the second half of the time, we showed a demonstration on gravity and how the movement of objects is affected by massive bodies. This was done with a lycra sheet wrapped around a hula hoop, with balls and marbles of different sizes and masses. Using this demo we were able to talk about how we can detect and characterize very massive objects like supermassive black holes. These two demonstrations were a great way to start the conversation of how and what astronomers measure.

I still have about 200 LEDs of different colors so I’m definitely using them again!

Another one for the books

Last year I swam the longest race I’ve ever swam, a 10km out-and-back swim in out out of a few connecting Michigan lakes. (You can read about that, and going to see the total eclipse right afterwards in an old post from last year). Last year I finished with a time of 2:49:21.

STTMRacePath

This year I had two major goals for the repeat swim. I wanted it to be less painful, and I wanted to finish in under 2:45:00.

To reach the first goal, this probably meant I needed to train more and stretch more leading up to race day. But then around February I started having some serious problems with my shoulders cramping up with greater frequency than ever before. I enrolled in physical therapy with Probility to work on the right stretching and strengthening routines to relieve the muscle imbalance I had developed after many years of distance swimming and probably a lot of poor posture at work. I still have a lot of work to do but they fixed me up well enough to complete the swim. I also switched to an adjustable sit/stand desk at work which has helped a lot with back and hip stiffness. This year’s swim was indeed a lot less painful than last year, even with my new shoulder stress. It was still a lot to put my body through, and I think I can do more to prepare next time around.

Towards the second goal, I increased my training this summer. Compared to last year, I started swimming mornings, where the water is cooler and practices tend to reach higher distances with more freestyle (same stroke I swim for the 10k). I swam about 4 days per week almost all summer. Even when I was out of town for work I found some masters groups to drop in on and put at least 3 days of swimming. Travel can make it hard to keep up with exercise and I was lucky to find some temporary solutions. Unfortunately, because of the travel (almost all of July) I barely got in any open water training (just once)! While not ideal, at least it means I have a way to push my goals even farther next year! And here’s the punchline, I finished my swim this year with a time of 2:38:31!

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So here’s a picture of me, barely standing and very happy to be done:

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I think with a combination of weight training (with new exercises I have from PT), cross training with a lot of training, and more lake swimming, I can push my finish time closer to 2:30:00. Hope to see you next year with an update!

 

Women of NASA Legos

A little while back the Women of NASA Lego set came out. This set featured some pretty awesome ladies, Margaret Hamilton (Apollo software scientist/engineer), Mae Jemison (Astronaut, MD, all-around amazing person), Sally Ride (Astronaut), and Nancy Roman (NASA Astronomer who played a large role in the Hubble Space Telescope Program).  Nearly all the women in STEM I know got the set for the holidays. I had not. I was not jealous. (I was a little jealous). But I surely didn’t need to have this set, I didn’t need to buy it for myself, I wasn’t that excited about it. I was lying to myself.

Well a good friend of mine sent me the set recently, because she is awesome and a very nice person. When the package arrived and I figured out what was inside, I thought, I’ll have to find time to put this together… later. And before I knew it I was unboxing it.

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… And before I knew it I was putting pieces together (hey Mae)…

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… And then I was still putting together pieces…

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…. Until the sun was setting and there was nothing left to do “later.” It made for a very dramatic “finished” photo:

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Thanks Catie Royko (who is another awesome woman in STEM!) for the very thoughtful gift that made me feel like both a kid and a cool adult for an afternoon. Catie is a Nuclear Engineer for the Susquehanna Nuclear Power Plant and we were college roommates our freshman year! I am lucky to have both awesome role models and peers.

MagAO observing 2018

I’m excited to be back at Magellan to observe for the second time with MagAO. Even better, this year I am observing for my own project that I hope leads to many more MagAO nights! (And many more burros)

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I have two major goals for this run, one technical, one science. On the technical side I want to test the image quality for “interferometric” analysis ala kernel phase (Martinache 2010). I will look at a range of sources at varying brightness (varying AO correction & integration times) and be able to get a good idea of when this method works. And I am really hoping it works especially for the faintest targets in my program because then I can exercise MagAO’s superpower — observing “faint” stars (I~12-15). For science, I am looking at young binaries (or suspected binaries). This is a great test for kernel phase!

In order to process the data we need to have a good model of the pupil so I am also running a test to figure out the orientation of the secondary mirror obstructions relative to the detector.

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The bright cross features are from the secondary spiders, the single dark lane going across the images is from the cold stop. An example pupil model looks like this, where the thicker obstruction is from the cold stop in the instrument and the thinner obstructions are from the secondary mirror:

clio-pup

What I need to figure out is how the secondary mirror supports move with the telescope between slews so I can build the appropriate model for each new set of images. Looking forward to tomorrow night!

 

Important update: turns out it doesn’t move! Now we know for sure.

UM Science Communication Fellows Program

I totally should have written sooner about the Science Communication Fellows program hosted by the U of M Museum of Natural History. This is a really great opportunity for grad students, postdocs, and faculty to design a demo for the public that will kick-start a discussion about their research. The program included an “orientation” day where museum curators teach volunteers some best practices of science communication through activities. Then volunteers get a day to try out a model of their demo to see what does or doesn’t work. After this, the newly oriented scientists set up during open days at the Museum to showcase their demos and engage the public about their research.

I had the pleasure of participating last Fall (2017) with a demo I called “Resolving the Universe.” I learned a lot from the museum, especially how to let the audience guide the conversation by asking questions, rather than assuming I know what is the most interesting. My demo showed what happens to light when it passes through an aperture, by shining a laser through 1) a small hole pierced into aluminum foil 2) two adjacent small holes in aluminum foil. The first nicely shows the classic “Airy” pattern, the point-spread function of a circular aperture. The second shows interference fringes. I would ask the audience what they expected the light pattern to look like through each aperture. We made predictions and tested it out. I also showed PSFs of other more complex apertures that I generated on the computer, including the James Webb Space Telescope PSF which is an important part of my research.

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The museum does a really good job of trying to accommodate as many people that are interested as they can. I definitely recommend doing this once the museum is open again next year! In the future I will try to think of a demo that is more accessible to a younger audience. Feel free to let me know if you have any good ideas!

Astronomy is for everyone.

Short update: As I’ve completed a year in the Michigan Astronomy department, it’s a good opportunity to reflect on the community I’ve joined. I’m really grateful that I’ve been able to find a place here and that there is a network of kind and supportive people that make up this department. Earlier in the year I helped put together a department poster that would capture, at least partially our collective values of inclusivity. We had a range of ideas and strategies that we debated. And then an idea emerged that we all, for the most part, agreed on! “One Planet, One people. Astronomy is for Everyone.” While a simple statement cannot capture all the values of our department, this is a start for expressing to everyone who comes through that they belong here.

astronomyisforeveryone

The poster is now displayed prominently in front of the department office. I consider this a constant reminder to myself to check my biases, to be supportive of my colleagues, and to foster a positive climate wherever I am doing astronomy. Astronomy is for everyone.

Workshop on the origin of volatiles in habitable planets

I had the opportunity to help organize a workshop held here at University of Michigan earlier this week. The workshop was sponsored by the Michigan Institute for Research in Astrophysics, which aims to foster interdisciplinary collaborations. The meeting was organized by both Astronomy and Earth & Environmental Sciences faculty to put together a diverse set of speakers. We heard talks from cosmo-chemists,  geo-physicists, exoplanet demographers, planetary scientists, and everything in between.

This was a great learning experience for me and I felt the workshop did a great job bringing out the big picture — what questions each sub-field is trying to answer. Of course the *right* answer has to agree between all disciplines. I’ll share some of my favorite highlights from the meeting, in no particular order.

  • From exoplanet observations, we see that planets of a given mass have a range of bulk densities, even within the same system. This implies widely varying envelope size, that can’t just be explained by the initial composition of a disk. This is especially notable in Kepler multi-planet systems that show a range of bulk densities. A popular theme during the talks was that impacts throughout the solar system evolution tune the atmospheres of planets post-formation.
  • When it comes to super-earths we really want to know if they have water. The range of bulk densities could means there is a degeneracy between rocky worlds and water worlds. Knowing the mass is very important. But even on top of this, we can come up with a range of Hydrogen-Helium-Rock mixtures that mimc the density of water, so bulk density doesn’t tell the whole story.
  • In our own solar systems, we can look at the abundance of volatiles and noble gases and how these vary between the sun, terrestrial planets, solar system moons, and various classes of chondrites. These abundances also seem to vary among the terrestrial planets, which could support a similar scenario that post-formation events lead to the eventual atmospheres. This also highlights that we should proceed with caution assuming solar abundance for exoplanets.
  • The presence of giant planets could be very important for getting the volatile elements to the inner terrestrial planets, by scattering small bodies as they grow and/or migrate.
  • It is unclear how the volatile delivery/transport scenario trends with the host star mass. More massive stars tend to have more massive disks, but less massive stars have disks that live longer. The demographics also change with stellar type. These different variables could all affect transport of materials.
  • Impacts are very likely a big part of the story, but giant impacts don’t necessary deplete all the volatiles! Hilke Schlichting showed us that small impacts are more efficient at removing atmospheres. And Sarah Stewart convinced us through many awesome videos that a hot, even turbulent, rotating liquid body does not mix well. Volatiles can remain trapped even after a large impact event.
  • I also learned the origin of the term “synestia” — Syn: co-, Hestia: Goddess of architecture — which describes an object whose outer material is not co-rotating with its core, what could result after a giant impact.
  • Laboratory and modeling suggest that tiny particles could efficiently stick together and grow to about ~mm-cm size pebbles before collisions and fragmentation start to be a problem, which is a problem for having the larger planetary embryos form through this same mechanism. Instead the larger planetesimals could form from some kind of gravitational instability. The observation of binary asteroids in the Kuiper Belt supports this. Once we have both planetesimals and pebbles, numerical models show we can have pebble accretion to form the cores of giant planets.
  • Solar system chemistry starts in the ISM, where we see different kind of chemistry in different states of material (gases, ices, etc). Gas-grain interaction is the core of interstellar chemistry that leads to more complex molecules that could not form in the gas alone. Photolysis of ices can also lead to complex species. Protoplanetary disks process ISM material into the building blocks of planets. Measuring molecules in disks  is key to learn about the processes that differentiate disk composition from ISM composition.
  • The solids in meteorites reflect integrated effects of every environment they saw in solar nebula/ protoplanetary disk. Rather than a simple model of disk chemistry with fixed zones, we must think of the disk as dynamic. The former cannot explain meteorite content — a mixture of things that had to form in different environments.
  • “Choose your geochemist friends wisely.” Without being in the field it’s hard to understand the agreement/controversy surround reported composition values for Earth. There is often a lot of disagreement.

Experiencing Totality

I had never seen even a partial solar eclipse. My first experience with solar viewing glasses was just over 4 years ago when I got to see Venus transit the sun. This August was a great opportunity for folks in the US to see an eclipse — partial or total. Living in Michigan now, I was not that far from the path of totality, and I had some grad school friends traveling to Kentucky. We all converged in Lexington by Sunday night and hit the road by 6am Monday morning.

As an aside, the whole weekend was pretty special for me. I started it off with my first 10k-distance open water swim on Sunday morning, just as the sun was beginning to rise in Eastern Michigan. Ok, so Michigan is pretty far west in EST so sunrise was not that early (~6:30am). After the grueling race, I was glad to sit back for the 5+ hour drive to Lexington.

swimtothemoon2017-ANIMATION

Our drive down to Carriage House Vineyards in Auburn, KY on Monday morning went very smoothly. We set up our blankets on the lawn that the Vineyard kindly opened up for the event. As the eclipse began we got our our prepared “equipment.”

Some solar-viewing glasses…

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Despite not being able to see anything except the sun with the glasses on I manage to take a decent selfie.

A last-minute pinhole projector constructed from an old shoebox…

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Outside view of the projector. The aluminum foil has a tiny hole at the front of the shoebox.

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View of the screen in the back of the shoebox as the eclipse begins. The sun appears nearly full here.

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Not long after, we see the partial eclipse, the projection appears as a crescent.

And even a colander!

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I even tried to take a snapshot of the partial eclipse from my cellphone camera through the eclipse glasses. Here is my best try:

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There are plenty of professional photos all over the web now that do a pretty good job of capturing totality, but I’ve got to say that experiencing it in person was a truly amazing and weird and surreal experience. And now I have this great direct analogy to make when explaining coronagraphs! I’m so thankful that the moon is the perfect angular size that we can see these dazzling eclipses every so often, and I’m ready to catch the next nearby one in 2024!

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Totality through a cell phone camera.