Overview of #312 Sabrina Pasterski - Theoretical Physicist on the Hidden Code of the Universe
In this Shawn Ryan interview, theoretical physicist Sabrina Gonzalez Pasterski discusses her unusual path from a childhood built around flight and engineering to high-energy theory, black holes, and holography. The conversation centers on her current research at the Perimeter Institute, especially gravitational memory effects and celestial holography—an attempt to describe gravity and quantum mechanics using boundary data. Along the way, she reflects on MIT, Harvard, CERN, public recognition, AI’s growing usefulness, the sociology of physics, and her views on space, black holes, UFOs, religion, and what it would actually mean to “solve physics.”
Sabrina Pasterski’s Background and Path Into Physics
Early life and education
- Born in Chicago to Cuban-American parents.
- Grew up in a family with no physics background:
- Father was a public defender with an engineering undergrad degree.
- Mother worked for the EPA.
- She credits her upbringing for fostering:
- hands-on problem solving,
- encouragement from parents,
- and a strong “build things” mentality.
Flight and building an airplane
- Her interest in aviation started with a first flight lesson at age 9.
- Between ages 12 and 14, she helped build a Zenith CH601XL single-engine airplane.
- That project became a key part of her identity and later helped her network into MIT.
- She sees the airplane build less as a direct physics lesson and more as an early lesson in:
- systematic work,
- engineering mindset,
- and making something real from a complex goal.
Schooling and admissions
- Attended a selective public magnet program in Chicago, then the Illinois Math and Science Academy boarding school.
- Rejected from Harvard, wait-listed at MIT, then admitted off the waitlist.
- She describes her MIT admission as the result of a lot of persistence, networking, and the airplane story.
Core Scientific Ideas Discussed
What she studies
- Pasterski works in high-energy theoretical physics.
- Her current work is tied to:
- gravitational waves,
- black holes,
- soft theorems,
- asymptotic symmetries,
- and holography.
- She’s leading work associated with the Celestial Holography Initiative, which seeks a boundary-based description of spacetime physics.
Gravitational memory effect
- She explains gravitational memory as a lasting shift left behind after a gravitational-wave event.
- In simple terms:
- when massive objects like black holes collide,
- ripples in spacetime pass by distant detectors,
- and the detectors’ relative positions can change in a way that “remembers” the event.
- She also discusses a related result:
- spin memory or angular momentum memory,
- which is a subleading version tied to rotation/angular momentum loss.
Why it matters
- The memory effect gives a way to connect:
- abstract symmetry principles,
- to observable consequences in gravitational-wave physics.
- Her work is partly about showing how mathematical structures can generate measurable predictions.
Holography and celestial holography
- Pasterski explains holography as the idea that a theory in the bulk of spacetime may be equivalent to a lower-dimensional theory on a boundary.
- In her area, this becomes celestial holography:
- rewriting scattering data in terms of variables on the celestial sphere.
- She emphasizes that she is not claiming “everything is literally a hologram” in the sci-fi sense.
- Instead, she’s working on whether:
- spacetime physics,
- especially scattering and gravity,
- can be encoded consistently in boundary observables.
Quantum gravity and string theory
- She describes the larger goal of theoretical physics as finding a framework that unifies:
- quantum mechanics,
- and general relativity.
- String theory is discussed as one route toward that goal.
- Her tone is careful and pragmatic:
- she sees the field as using consistency and mathematics to infer laws of nature when direct experiments are limited.
Academic Journey and Research Culture
MIT, Harvard, and CERN
- She loved MIT for its rigor, structure, and merit-based environment.
- Harvard was where she earned her PhD in 2019.
- She did summer work at CERN and was there during the Higgs boson discovery.
- She explains CERN as a massive engineering and physics machine where detectors infer events indirectly from particle tracks and energy deposits.
Her PhD work and early recognition
- She discusses her dissertation-related work on:
- soft physics,
- spin memory,
- and gravitational radiation.
- She mentions being cited by Stephen Hawking, which she treats as exciting but not as proof that her work is earth-shattering.
- She is notably modest about the “next Einstein” label, saying it’s inaccurate and often driven by hype.
Hype, labels, and the politics of physics
- She repeatedly pushes back against oversimplified media narratives.
- Her view:
- public labels can be flattering but misleading,
- and they can distort how people think about science and scientists.
- She also talks about the social side of academia:
- popular science,
- funding pressures,
- and how research fields can become siloed.
Views on AI, Technology, and Research
AI as a practical tool
- Pasterski’s stance on AI has shifted from skepticism to excitement.
- She now sees AI tools as genuinely useful for theoretical physics, especially for:
- coding,
- exploring datasets of papers,
- doing brute-force or repetitive computations,
- and helping individual researchers prototype tools without full dev teams.
- She likes that AI can democratize some work that was previously blocked by coding or staffing limitations.
Concern about hype
- She is wary of overpromising:
- especially around quantum computing,
- quantum gravity claims,
- and “AI will solve everything” narratives.
- But she acknowledges that hype can still produce valuable tools and infrastructure.
Science funding and institutions
- She is interested in new models for funding theoretical research:
- better collaboration with industry,
- private-public partnerships,
- and supporting research that isn’t immediately profitable.
- She praises institutions like Perimeter Institute and contrasts them with traditional universities.
- She argues that valuable science shouldn’t have to justify itself only through short-term commercial returns.
Space, Black Holes, Aliens, and the Big Questions
Mars and space exploration
- She is interested in space, but not romantically attached to Mars colonization.
- Her view is pragmatic:
- space missions can be cool,
- but the real question is what the goal is and whether it’s worth the risk.
- She says she would personally care more about infrastructure like trains than more aerospace if resources were equal.
Black holes
- She explains black holes as solutions to Einstein’s equations with a horizon from which light cannot escape.
- Key points:
- black holes are not “magic objects” so much as geometrical solutions,
- the paradoxes around them reveal where current assumptions break down,
- and they are central to questions about quantum gravity.
- She discusses:
- information loss,
- firewalls/fuzzballs,
- and the tension between classical GR and quantum field theory.
Gravitational waves and observation
- She notes that gravitational-wave detectors don’t “see” the wave directly in a simple visual sense.
- Instead, they infer it from the motion of mirrors and the resulting signal pattern.
- She repeatedly emphasizes the difference between:
- direct observation,
- and inference from measurement.
Aliens and UFOs
- She believes alien life probably exists statistically.
- She does not believe there is good evidence that aliens have contacted Earth.
- On UAP/UFO claims, she is skeptical and prefers prosaic explanations unless the evidence is overwhelming.
- Her general posture is:
- “I wish it were real, because it would be cooler,”
- but skepticism should remain high.
Flat Earth, Religion, and Philosophy
Flat Earth
- When asked about flat Earth claims, she points to basic physical and observational evidence:
- satellite imagery,
- GPS,
- communication systems,
- and the overall consistency of modern technology with a round Earth.
- She frames flat Earth thinking as a failure to properly extend intuition beyond everyday experience.
Religion and her mother
- Her mother is Catholic, and Sabrina treats that respectfully.
- She says her mom views physics almost like a substitute belief system in some ways.
- Sabrina’s own view is more agnostic:
- she values scientific humility,
- dislikes dogmatism,
- and believes both science and religion deal with origin questions, but in very different ways.
What happens after death
- She does not claim certainty.
- Her answer is essentially that physics doesn’t tell us enough to know.
- She frames this as a boundary of scientific knowledge, not as a personal declaration of belief.
Main Takeaways
- Sabrina Pasterski is not presenting herself as a messianic genius; she’s a rigorous physicist who cares about precision, structure, and useful frameworks.
- Her work is focused on turning deep mathematical ideas into physical observables, especially through:
- gravitational memory,
- asymptotic symmetries,
- and celestial holography.
- She is enthusiastic about AI when it helps researchers do real work faster.
- She’s skeptical of hype in science, UFOs, and media narratives.
- More broadly, she sees physics as a search for compact, elegant rules that describe nature across scales.
Notable Themes
Science as compression
- Pasterski repeatedly returns to the idea that physics is about finding a highly compressed description of reality.
Usefulness of structure
- She prefers:
- systematic work,
- modular ideas,
- and tools that help researchers move faster.
Hype vs. reality
- A major thread of the interview is her irritation with overblown claims—whether about Einstein comparisons, quantum tech, or pop-science framing.
Curiosity with discipline
- She is clearly imaginative, but insists that imagination has to be anchored in:
- equations,
- observables,
- and physical constraints.