Student Research | Searching for the universe’s most elusive objects

Fifth-year Haynes Stephens with the UC Berkeley Astronomy department telescope. Stephens uses microlensing to search for black holes.
Joshua Jordan/Senior Staff

Editor’s note: This is one of a continuing series highlighting the research being carries out by undergraduates at UC Berkeley across a variety of disciplines. You can find all the stories in the series here.

Black holes have fascinated astronomers and the public alike since their earliest theoretical beginnings — often, the mysterious objects are synonymous with names such as Stephen Hawking or Kip Thorne. But given their unique, nearly invisible nature, scientists are still working on how to actually observe them and measure their properties.

Haynes Stephens studies gravitational microlensing events with professor Jessica Lu to glimpse invisible black holes in our galaxy. Stephens, a fifth-year student, combines skills from computer science with astrophysical theory to analyze the complex and tantalizing data that can teach us about the nature of black holes.

Stephens credits Carl Sagan and Neil deGrasse Tyson as two of the multiple inspirations that led him to astrophysics. “They make astronomy interesting for everyone,” Stephens said. “They describe it in a way that is compelling and gives it full color and flavor.”

Ironically, this description of Sagan and deGrasse Tyson is embodied in Stephens himself — he likewise does justice to the depth and complexity of space, while communicating the intricate concepts he studies in a comprehensible manner.

Stephens was not initially invested in astronomy as a field of interest, and started his undergraduate studies at the University of Miami. But one summer, he enrolled in Astronomy C10 — “Introduction to General Astronomy,” taught by Steven Stahler at UC Berkeley. Stephens said that taking this course was “very much the moment I decided I wanted to go fully into this field and try to pursue a degree in it.” A short time later he became a junior transfer student at UC Berkeley intending to major in astrophysics and complete a minor in physics. Now, his career plans include graduate school in astrobiology or astrophysics.

Stephens quickly came to realize the importance of getting involved with research as an undergraduate student. “I soon found out that in order to look good for a graduate application and in order to be in the physics field, you need to do research as soon as you feel able,” he explained.

He asserted that it is crucial for a student interested in research as a career to explore their options as an undergraduate. After working for a summer with Breakthrough Listen — a research project geared towards detecting signals of extraterrestrial life — Stephens connected with Lu and became a student researcher in her group.

Working with Lu, Stephens studies gravitational microlensing events, leveraging Albert Einstein’s theory of relativity to predict the existence of objects that do not emit light, such as black holes. “Anything with mass can act as a magnifying glass to light,” Stephens explained. “So when a very massive object passes between our line of sight and a star, the object can magnify the brightness of that star as it moves in front of it.”

Using enhanced imaging and the measurements between when the star’s brightness is magnified and when it returns to its normal level, researches can get an idea of the mass of the unknown object.

Stephens specifically uses the occurrence of gravitational microlensing events to study black holes. “There is no way to look up at the sky and see a black hole or take a picture of one,” Stephens explained, alluding to the fact that because no light can escape a black hole once it’s fallen in, these objects can typically only be found via their effects on their surroundings.

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In Lu’s group, Stephens is studying two specific instances where a star’s brightness spiked and then returned to normal. If the team can prove that isolated stellar mass black holes are the cause of the microlensing event, it will be the first discovery of its kind.  

Black holes have long been the subject of science fiction fascination — seen as potential wormholes or time travel portals a la the blockbuster “Interstellar.” Stephens takes that fascination with a grain of salt, asserting both alignment and disjointment between the sci-fi presentation and reality. “When I try to understand a lot of my research it boils down to physics and fundamental concepts, which can make it seem a lot less crazy than it actually is,” he explained. “At the same time, in some ways, science fiction actually undersells what is real.”

Stephens is not sure if he will continue research in microlensing events in his professional career — recently he has branched out, taking classes in biology and chemistry to explore the possibility of life on other worlds. But he still maintains that his overall student research experience has been a positive one.

“When I try to understand a lot of my research it boils down to physics and fundamental concepts.”

— Haynes Stephens

Being involved in research as an undergraduate has not only enhanced his ability to problem solve, Stephens said, but has also increased his feelings of independence. He also emphasized the ways in which the experience has opened his eyes to the vastness and mysteriousness of space. “The more I learn about my research, the more I realize how much left there is to figure out — from little details to big ideas,” he said. “Even our best scientists don’t understand black holes as well as we’d like to understand them.”

Pursuing that understanding, both of black holes and of space in general, is something Stephens contends can serve as the bridge between scientists and the public. “To a lot of people, (astrophysics) is something that comes from a science fiction movie,” he said. “It’s important to confront these things, to keep society interested, and to continue contesting and expanding our imagination.”

Whether astronomers or not, we can all endeavor to that.

Contact Sydney Schoonover at [email protected].