Tyler Trent Talks Astrophysics: Humble, Social, Creative

If you’re like me, upon meeting an astrophysicist, you might have a sense of admiration and some small element of awe, akin to meeting a rocket scientist, or an astronaut who has taken walkabouts in space. Perhaps it’s because it seems such people are in touch with something bigger than life, something outside the realm of the average mortal.

Tyler Trent’s story brings astrophysics down to earth with the humble point that scientists aren’t inherently smarter than anyone else. “Everyone chooses to spend their time doing certain things and learning about certain things, and I just chose to spend my time learning about [astrophysics]. But it doesn’t make me any smarter or any more capable of navigating the world than someone who decided to be a surfer.”

His Choice of Astrophysics

As discussed in an earlier talk story, Tyler was already interested in physics and mathematics in high school, subjects he continued studying at the University of Hawai‘i at Mānoa. Currently, in graduate school at the University of Arizona, he pursues research in astronomy with a theoretical/computational perspective that, in the profession, is described as the field of astrophysics (as opposed to other areas of astronomy like instrument science or observational astronomy).

An early indicator that Tyler would favor the astrophysical route occurred at the end of his undergraduate years, when he took a course called “electronics for physicists.” It covered the kinds of things someone building or fixing a telescope would need to know, like working with sensors and signal amplifiers. He enjoyed the experience of building tangible and physical things that would get results, but after taking a class on computational physics the next semester, his course was set.

“There just was something empowering about when I realized the capabilities of a computer. Because there are all of these equations that are impossible to solve by hand, but you can program your computer to do it. And not just that: your computer can make these amazing graphics and plots, you can make these very visible. It was at that point I knew I really enjoy programming. I truly believe that the computer is the most powerful tool to man. It amplifies our productivity and me being able to master the computer was one of my goals.”

Another attraction astrophysics held for Tyler was the way computational work is performed. In engineering, one needs to be in a lab, a space that struck Tyler as being a bit cluttered. Computational physics, on the other hand, can occur in a more spartan workspace that can be wherever a person wants. “I could just take my laptop and I could work in a library, I could work in a coffee shop, I could work at home. That was much more appealing to me. I still really enjoy it. One of the sad things during the pandemic was that usually on the weekends while I was in Tucson, I would pick a coffee shop, I’d go and spend all day there doing programming and whatnot. And that all came to a stop.”

2 versions of imaging the event horizon around the black hole Pōwehi
(right) An image from March 24, 2021 of the event horizon around the black hole Pōwehi at the center of galaxy M87. The image is courtesy of the Event Horizon Telescope, two elements of which are telescopes on Mauna Kea. For comparison, see (left) the 2019 image from the EHT.

Tyler’s research specializes on the area surrounding black holes. Black holes, he points out, are more akin to regions of space (like a valley) than discrete objects (like a planet), and that space is so extremely curved that light, and any information it could carry, cannot get out. In order to learn what a black hole is like, a person needs to understand the behavior of things around it, like electrons.

Around the outsides of black holes, electrons move very rapidly and emit photons that telescopes can detect. Additionally, these charged particles create magnetic fields. “Currently what I’m doing is simulating those electrons that are around the black hole just outside of the event horizon. If a black hole is, say, 2 units big, I’m sampling things that are anywhere from 2 to 15 units from the center of a black hole.”

Astrophysics: A Social Science

Tyler writes programs (or, models) that calculate and display how electrons behave around a black hole. Man, computer, coffee shop. Is this endeavor a little solitary? It certainly holds attraction for some who prefer working alone, but Tyler doesn’t classify himself as a hermit. “It depends on the person. Myself, I go out of my way—wandering into other people’s offices, working in the library, being in these public spaces—so that I have interactions with other people. For me, personally, it allows for more social interaction than I thought there was going to be. I do know others who can completely disappear for a week or even longer, and then come back with something.

“It’s really funny, because among my physics and math friends I’m known as the social one. But among some of my local friends who are surfers and stuff, I’m the socially awkward one. I’m the social recluse compared to them, because they’re every day spending with friends and they’re constantly around people. I don’t constantly talk around people, but I’m not in constant isolation, either.”

many people working on a blackboard together
This is probably a little larger than the board in the University of Arizona’s astronomy library.

On an average day, at least before the pandemic, mornings would find Tyler working in the office he shares with other graduate students. When his program was ready to run a simulation, which could take up to 45 minutes or an hour to complete, it was time for lunch. Afterward, if his program crashed, or if he was looking for other help with his work, he would walk the halls in his department and find a professor to talk it out with.

Or go to the department’s library. “The astronomy department has its own little private library, which is really comfortable; it has couches and stuff.” There he could read papers or other textbooks for other things he needed to learn, or try and work out some calculations on the white board.

“Usually the people I’d work with already had their PhDs, usually doing their postdoctoral research. It would either be me at the board, writing things and sitting down, and they’d be like “OK, that looks right, but try this.’ And I’d try that out at the board and they would watch. Or it would be the both of us up there and I’d be like, ‘OK, so is it like this?’ and I’d write something, and they’d say, ‘Oh, I think it’s like this’ and they’d write something, and we’d be erasing each other’s work, and slowly arrive at an answer.”

An answer that would enable his computer program to run. “So when people think, ‘Oh, you work on black holes,’ they probably think you do crazy kinds of things. But 99% of what I work on usually is coordinate transformation.”

We may remember being taught in school about the Cartesian coordinate system that can be used to map 3-dimensionsal space with x, y, and z coordinates. Another way to map space is with a spherical coordinate system which tracks locations with the coordinates r (or rho), theta, and phi.

Tyler’s programs often need to switch between equations using Cartesian coordinates, and others using spherical coordinates. It is critical that those two descriptions are equal to one another. But making that happen, and making sure it is correct, is difficult, time-consuming and sometimes needs a little group effort.

Being outside and away from the computer is also important; Tyler says, “Getting in the water is my favorite hobby to do in Hawai‘i and hiking is my favorite to do here in Arizona!” Left, Tyler comes up for air after bodysurfing a wave in O‘ahu last winter. Right, he takes a yoga break in April 2021 while hiking at Tanque Verde falls in Tucson. Photos courtesy of Tyler Trent

Additionally, the research done by astrophysicists like Tyler is not isolated from what happens elsewhere in astronomy. Astrophysicists’ models, for instance, can help explain what is detected by telescopes. Tyler explains with an example concerning observations of the black hole at the center of the Milky Way galaxy:

“At the center of our galaxy there is a supermassive black hole, Sagittarius A* (Sgr A*). We have been observing this black hole for decades in various wavelengths from radio waves all the way up to X-rays. In the X-ray wavelength the brightness of Sgr A* “flickers” i.e., the X-ray intensity/brightness of Sgr A* goes from being really dim to really bright for a moment. This is believed to be from flaring in the accretion flow around Sgr A*, kind of like how our sun has flares. Flares are these extremely energetic events where strong magnetic fields undergo a quick change in direction and launch electrons out in various directions. I like to think of it as an explosion of electrons. Current simulations are unable to include flaring and my PhD project is to build a simulation that does include them. When we include the flaring in these accretion simulations we will be able to reproduce the X-ray flickering seen in observations, in our models. Also, in 2019 the Event Horizon Telescope (EHT) collaboration published the first ever image of a black hole and is currently working on an image of Sgr A*. The model that I am building will help with interpreting these images.”

Astrophysical Curiosity and Creativity

It might surprise some to hear that an astrophysicist’s work is also creative. “Building programs, I find that very creative: you have a start point which is nothing. You have a desired goal somewhere. And in programming, there’s an infinite number of ways to achieve your goal. And that process of building your programming to get to that goal is really creative and I really enjoy that aspect of it.” In this sense, programming sounds very much like painting, drawing, or writing!

Let’s consider as a base level, that being creative means having a knowledge or understanding of the subject matter (like ingredients, or specific subjects or information), of knowing how to find and use tools needed in the creative process (like knives or the oven, paint or a drawing tablet, a computer or a pencil and paper). And the process is geared toward finding something new, or a new understanding of something one is already aware of, like a new way of preparing eggs altogether, or a new representation of something already considered beautiful in a painting or sculpture.

At position a, Neptune gravitationally perturbs the orbit of Uranus, pulling it ahead of the predicted location. The reverse is true at b, where the perturbation retards the orbital motion of Uranus. Image by RJHall (https://en.wikipedia.org/wiki/Discovery_of_Neptune)

With scientific modeling, one starts with a knowledge of the part of the universe one wants to represent, and with the tools like relevant mathematical formulae and other things like pencil, paper, and computers. To take a simplified example from history, after the discovery of the planet Uranus, observers noticed irregularities in its pathway across the sky. With an understanding of planetary motion, plus Newton’s theory of gravity and other equations, predictions were made in 1845 about a yet-undiscovered planet massive enough to account for Uranus’ motion. That led observers to locate what came to be known as Neptune, which was detected telescopically in 1846. This situation should be read as ushering in novel and creative theoretical work: both because it can be read as the theoretical prediction of a completely new planet, and (since the object had been observed before, but wasn’t recognized as a planet) as a way of freshly representing what was already noticed.

The work of astrophysicists such as Tyler, on average, probably won’t be as monumental as discovering an entirely new planet, but it is still similar in kind. A person has knowledge of the part world that one wants to know more about—say, a charged particle moving through space. One has familiarity with the relevant tools—like the relevant field of physics and its equations, a computer’s processing power. And can connect those equations in order that questions about the system—like, “What is the trajectory of an electron with this charge in this sort of gravitational field?”—you can get an answer, meaning: the equation is solvable.

Albert Einstein
Albert Einstein. photo by Doris Ulmann

Tyler was recently working on putting together just such a set of equations, which proved frustrating because at first it was unsolvable. “You can write down a super complex formula that describes [an electron moving around a black hole], but if you can’t solve it, if it’s some super-complex differential equation, then it doesn’t get you anywhere.” Fortunately, Tyler was able to include Einstein’s e=mc2 which linked his unsolvable formula with one that was. “It takes a broad knowledge of the field combined with the creativity of picking the things and putting them together to see what happens.”

Einstein, incidentally, is also Tyler’s favorite physicist. “Einstein seems like he was a brilliant person; he overcame failures and letdowns in his life, and he was super nice. He went out of his way to try and be inclusive; he went out of his way to give lectures at historically black universities. I think Einstein, in my opinion, was a really good guy. And he used his platform, when necessary, to advocate for a more peaceful time.”

Science as Publicly Perceived

If there is anything Tyler would wish for in terms of the public’s perception of science, it would be to be more temperate with questions like “What’s the point of astrophysics?” and “Why would you want to do that, it sounds so impractical?” It can seem, for the questioner, that an astrophysicist’s understanding of, say, a black hole has no relevance at all to their everyday life.

Tyler believes that this kind of perception is misguided. Take, for instance, Einstein’s e=mc2 mentioned before. “When Einstein first presented special relativity that light has a finite speed, when he first said that, there was so much criticism by people saying, ‘That’s so unuseful; no one is ever going to need that, that doesn’t matter.’ But you know what? Today, GPS needs special relativity to work. Without special relativity, there’d be no GPS, we wouldn’t have the internet connections like we do today.”

The theoretical successes of today can take 10 or 15 years to come to practical fruition, and that delayed payoff is worth waiting for. “One day there will be a technology that needs that science, and that is a huge driver, a huge motivation, for a lot of us. It’s like, ‘By making this understanding, we are contributing.’ So, it’s not this impractical thing; I remember an economist putting it: science is a long-term investment, it’s not an immediate pay-out. It’s something for the future.

weather map
Predicting the weather involves the use of chaos theory, a branch of mathematics first developed in the 1960s–1970s, and met with initial skepticism. Chaos theory has come to be useful in a number of fields, such as anthropology and business, where complex systems are studied.

“Another example of that is around 100, 150 years ago, there was research into what was called chaos theory. In weather [forecasting] they use differential equations that are considered chaotic and you need to use chaos theory to solve them, to figure out what the weather is going to do. A hundred or so years ago, people looked down, saying that this field didn’t make any sense, and it was shunned. But now, today, chaos theory is in standard physics textbooks. And the author even makes points about it like, ‘This field was looked down upon and now it’s making a comeback because this really helps with predicting the weather because weather is chaotic systems.’

“Imagine if every painting ever done was by commission. Would we have the Mona Lisa? Would we have all the great expressionists? It wouldn’t have happened. If every piece of art was done was because someone said I want you to paint this or that, or something that symbolizes this, we wouldn’t have the great artworks we do today. And it’s the same in science.”

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