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StarTalk Radio

Cosmic Queries - Proving Einstein Right

with Jim Gates

Published November 21, 2025
View Show Notes

About This Episode

Neil deGrasse Tyson and co-host Chuck Nice speak with theoretical physicist Jim Gates about Albert Einstein's special and general relativity, why general relativity required experimental verification, and the 20th‑century efforts to test it via starlight deflection during a solar eclipse. They then field listener questions on topics including the incompatibility between general relativity and quantum mechanics, gravitons and quantum gravity, string theory signatures in the cosmic microwave background, gravitational lensing, and the possibility of a cosmic gravitational-wave background. Throughout, Gates also reflects on the "magic" of mathematics in describing reality and the collaborative, human side of doing physics.

Topics Covered

General relativity Special relativity Black holes Gravitational waves String theory Quantum gravity Cosmic microwave background Observational astronomy Mathematics and physics Einstein

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Quick Takeaways

  • Einstein's general relativity emerged from his 1907 "happiest thought" about a falling worker feeling weightless, but it took nearly a decade of learning new mathematics and collaboration with astronomers to design tests of the theory.
  • General relativity and quantum mechanics clash because gravity is formulated with classical particles embedded in it, while quantum mechanics replaces those with probabilistic wave-like entities, making straightforward combination mathematically inconsistent.
  • A key future milestone would be detecting the quantization of gravitational waves-gravitons-analogous to photons for light, which would deeply reshape our understanding of gravity.
  • String theory may leave observable imprints in the cosmic microwave background that astrophysicists could search for, potentially providing empirical clues to an otherwise highly theoretical framework.
  • Gravitational lensing can create multiple images and arcs of the same distant object, allowing astronomers to test relativity and even see certain transient events, like quasar flares, more than once.
  • Mathematics functions as a kind of "human-created magic" and a universal language that lets scientists perceive and predict aspects of nature that are otherwise inaccessible.
  • Physicists increasingly suspect that resolving black hole information puzzles and uniting gravity with quantum mechanics may require new frameworks, possibly involving string theory and a rethinking of gravity beyond pure spacetime geometry.
  • Scientific breakthroughs, even those attributed to lone geniuses like Einstein, are deeply social processes that depend on constant dialogue and collaboration with colleagues.

Podcast Notes

Episode introduction and archival context

Neil frames the episode as an archival selection

Neil explains that the episode is drawn from StarTalk's archives to address "cosmic curiosities"[1:40]
He notes the archives are extensive and encourages listeners to explore the full catalog on their podcast platform of choice[1:49]

Show start, host and topic introduction

StarTalk branding and host introduction

Standard StarTalk tagline: "your place in the universe where science and pop culture collide"[2:00]
Neil deGrasse Tyson introduces himself as host and as a personal astrophysicist[2:18]

Episode topic and co-host

Neil states that today's topic is "proving Einstein right"[2:18]
Neil brings in co-host Chuck Nice and says he "needed" Chuck for this one[2:27]
Chuck jokes that he never knew Einstein was wrong, questioning where the controversy is[2:31]

Guest introduction and professional background

Introducing theoretical physicist Jim Gates

Neil introduces "friend and longtime colleague" Jim Gates and welcomes him to StarTalk[2:42]
Jim responds that it's good to be back "in the presence of a star" and jokes about calling Neil "James"[2:51]

Current role at Brown University

Neil describes Jim as a theoretical physicist and director of the Center for Theoretical Physics at Brown University in Providence, Rhode Island[3:15]
Jim says he was recruited to Brown at age 66 from the University of Maryland[3:25]
• He told friends he didn't know why Brown wanted an "old car"; a friend replied that he was an "antique car"
• Chuck upgrades the joke by calling Jim "vintage", which he says is more valuable than antique
Jim notes he spent 33 years at his previous institution before moving[3:59]

Relationship with University of Maryland and teaching public policy

Jim confirms his previous university was the University of Maryland, College Park[4:08]
He says they parted on good terms, and he is now an emeritus professor there[4:33]
As an emeritus professor, he has taught two consecutive years of evening courses on public policy[4:37]

Service on presidential science advisory council

Neil recalls that Jim served on President Obama's Council of Advisors on Science and Technology (PCAST)[4:56]
Jim confirms he served seven years on PCAST[4:56]
Neil asks whether Jim was invited to serve in the current administration; Jim deflects and they drop the political line of questioning[5:20]

Academic titles at Brown University

Neil distinguishes Jim's director role as a job title and asks his academic title[5:29]
Jim says he is an endowed Ford Professor of Physics at Brown University[5:38]
He is also an affiliate professor in mathematics[5:46]
Additionally, Jim is a faculty fellow at Brown's Watson Institute for Public Affairs and International Affairs[5:49]
Neil notes Jim could be brought back on the show for policy topics, not just theoretical physics[6:04]

Explaining the episode structure and Jim's Einstein book

Planned structure of the discussion

Neil outlines that the first segment will address why Einstein needed to be "proved right"[6:11]
Later segments will be devoted to Cosmic Queries where they take listener questions[6:22]

Jim's book "Proving Einstein Right"

Neil cites Jim's 2019 book titled "Proving Einstein Right: The Daring Expeditions That Changed How We Look at the Universe"[6:56]
Jim confirms he has a co-author, Kathy Pelletier, who lives in Allagash, Maine near the Canadian border[7:06]
Jim says the book is not what people expect; it is not primarily autobiographical or a standard physics book[7:13]
He wanted to write about the "interior lives" of the scientists-their feelings and struggles over nearly a decade-long effort to test Einstein's ideas[7:42]
The book focuses on eight astronomers plus Einstein, telling both the scientific story and the human story[7:50]
Neil notes the 2019 publication was roughly the centennial of the famous experiment that supported Einstein's theory[8:09]

Einstein's 1905 work and the road to general relativity

Special relativity in 1905 and delayed recognition

Neil says physicists know Einstein for special and general relativity, and that people often associate him with effects like time dilation from his 1905 work[8:18]
He asks why, if 1905 relativity worked so well, Einstein still needed to be "proved right" a decade later[8:13]
Jim notes that 2005 was the "Einstein Year of Physics" and he gave 37 talks on six continents that year[9:08]
He explains that in 1905 Einstein published groundbreaking work on space and time, yet by 1907 he was still working at the patent office[9:38]
• There was about a two‑year delay before the physics community recognized the significance of Einstein's 1905 contributions

The 1907 "happiest thought" and birth of general relativity

Jim recounts that in Bern in 1907, Einstein looked out a window, saw workmen on a roof, and imagined one falling[10:25]
Einstein realized that during the fall the worker would not feel his weight; he later called this realization the "happiest thought" of his life[9:04]
Neil compares this to Newton's famous apple insight connecting falling apples to the orbiting Moon[9:30]
Jim emphasizes that Einstein did not yet possess the necessary mathematics and had to learn more to formulate general relativity[10:34]
Einstein did not arrive at the correct mathematical formulation of general relativity until around 1915 or 1916[10:34]
Jim says general relativity is the mathematical framework that gives us the concepts of the Big Bang and a universe about 13.8 billion years old[12:10]

Need for experimental confirmation of a mathematical theory

Jim underscores that at first general relativity was "all math" and the crucial question was how to know whether the math describes objective reality[12:42]
He describes Einstein beginning to think about how to test the theory observationally even before he had the final form of the equations[12:47]

Einstein's collaboration with astronomers and eclipse tests

Early conversations with astronomer Freundlich

Jim introduces German astronomer Erwin (Irving) Freundlich as the first astronomer Einstein seriously consulted about testing his ideas[13:12]
Einstein initially suggested looking for bending of starlight near Jupiter; astronomers responded that this would not work observationally[13:46]
He then proposed observing starlight near Venus at dawn or dusk, but astronomers again said it would not be feasible[14:00]
Through this dialogue, Einstein and the astronomers converged on the idea of observing starlight near the Sun during a total solar eclipse[14:11]
• During an eclipse, the Sun's light is blocked, allowing stars near the Sun on the sky to become visible, so their apparent positions could reveal light bending by solar gravity
Jim notes that these discussions took place around 1912, before the theory was fully finalized[14:43]
He reiterates that the book focuses on the astronomers and their expeditions to test Einstein's predictions, rather than on Einstein himself[14:57]

Einstein's wife and the nature of scientific creativity

Question about Einstein's wife and credit

Neil asks about claims that Einstein's wife played a major role in his work, referencing a book titled "Einstein's Wife"[15:09]
Jim says some have posited that theory, but his reading of over a dozen historical accounts suggests she was certainly a partner during the Bern years[15:29]
He states that the preponderance of evidence is that Einstein worked out special relativity himself, reportedly thinking about the Bern clock tower while on a tram[15:55]

Importance of intellectual environment and colleagues

Neil suggests that if Einstein had been a complete loner who never traveled, he might not have developed his ideas[16:05]
Jim replies that being a scientist means "swimming in a sea of information" that comes from colleagues[16:29]
• He argues that the stereotype of a solitary genius in a corner is inaccurate; in reality, scientists constantly converse with peers to refine and curate their ideas
Neil distinguishes between swimming in influences versus drowning in them, highlighting the need to manage input[17:02]
Jim says his book with Pelletier aims to show how other scientists "swam" in the ideas Einstein sparked to test his theory against nature[17:25]

Einstein's confidence, views on God, and the "magic" of mathematics

Einstein's confidence in general relativity

Neil asks whether Einstein harbored doubts about his theory[17:25]
Jim says his reading suggests Einstein did not doubt it and cites Einstein's remark that if general relativity were disproven, he would "feel sorry for the good Lord" because the theory was such a brilliant idea[17:44]
They joke about that sounding like Einstein claiming to be "smarter than God", but Jim clarifies that Einstein also wrote about an "illimitable spirit", suggesting he did not place himself above such an entity[18:30]

Why mathematics works so well in physics

Neil asks Jim to comment on the philosophical puzzle that mathematics is a human invention yet accurately describes the universe[19:15]
Jim calls this the only "magic" he has ever experienced that is part of reality[19:29]
• He describes mathematics as human-created magic that not only describes reality but allows prediction, understanding, and extension, acting as a "third eye" for scientists
Jim references an hour-long New York Academy of Sciences discussion he did with Margaret Wertheim about this topic[20:07]
He concludes that mathematics is the only human language that accurately describes nature, and that any conscious being capable of mathematics could access the same knowledge[20:40]
Neil notes this underpins the idea that mathematics could serve as a universal language with aliens and even a way to avoid being harmed by them[20:56]

Start of Cosmic Queries segment: overview of relativity

Reintroduction of topic and guest for Q&A

Neil reopens the show, reiterating the theme "Proving Einstein Right" and reintroduces Chuck and Jim[25:07]
Neil says he has only about three percent overlap with Jim's expertise on this subject[25:46]
Chuck jokes that he has zero percent overlap, which is why he will read the questions[26:01]

Special vs general relativity explanation

Chuck asks Jim to briefly explain the difference between special and general relativity for listeners[25:56]
Jim illustrates special relativity using a car horn approaching and receding, demonstrating the Doppler effect where the frequency (and pitch) changes with motion[26:21]
• He notes that the horn sounds higher-pitched as it approaches and lower-pitched as it moves away
Jim explains that light shows an analogous effect: when a light source moves toward you, it appears bluer; when it moves away, it appears redder[27:32]
He characterizes special relativity as the study of how observers in relative motion perceive events and signals, especially involving light[27:44]
On general relativity, Jim says it tackles the deeper question of what gravity actually is, something Newton did not answer[28:08]
He summarizes Einstein's answer: space and time combine into spacetime, and gravity is the bending of this spacetime[29:00]

Cosmic Query: incompatibility of general relativity and quantum mechanics

Question from young listener Violetta

Violetta from Birmingham, Alabama asks why scientists say general relativity and quantum mechanics are incompatible and "don't work together" mathematically[29:17]

Jim's explanation of the conflict

Jim notes he must phrase his answer without using full mathematics, joking that his first language is mathematics and English is his second[30:09]
He explains that in quantum mechanics you must give up the classical picture of electrons as tiny balls and instead treat them as wave-like entities, except when they behave like particles[31:27]
The Schrödinger equation is the mathematical tool that tells you how these quantum states evolve and how to calculate probabilities[31:41]
Jim says that when you try to apply this quantum formalism directly to gravity, the calculations become a mess and you cannot get sensible answers[32:21]
• He notes that the way Einstein and Newton formulated gravity embeds the idea of particles in a classical way, which clashes with the quantum requirement to abandon that picture

Who "gives" in the clash: gravity or quantum mechanics?

Neil asks whether gravity will have to "bend" to quantum mechanics, or whether a third, larger idea will subsume both[33:04]
Jim says some researchers believe gravity will have to "lose" in the clash and be reformulated[33:23]
Others pursue a third-idea approach, for example focusing on information and black holes and whether information is conserved like energy[33:44]
He mentions the long-running debate over whether black holes destroy information and thus violate a conservation principle[33:44]
Jim notes that resolving black hole information issues has been a major topic in theoretical physics for over a decade[34:06]
He adds that many, including himself, think string theory will play a role in the ultimate resolution[35:11]

Cosmic Query: next predictions of general relativity and gravitons

Question about future tests of general relativity

Listener Paul notes that gravitational waves and a black hole event-horizon image have confirmed GR predictions and asks what is the next big prediction to be tested[35:40]

Einstein, quantization, and gravitons

Jim recalls that one of Einstein's 1905 papers on the photoelectric effect showed that energy must be quantized[36:20]
He notes that even though Einstein disliked quantum theory's probabilistic nature and preferred determinism, he was nonetheless a father of quantum theory[36:31]
Jim says that after detecting gravitational waves, the next major step is to detect the quantization of the energy in those waves[37:38]
• Detecting discrete energy packets in gravitational waves would amount to observing gravitons, analogous to photons for light
He notes that in Star Trek, "graviton" waves are fictional; detecting them would move the concept from science fiction to actual science[37:22]
Neil reiterates the analogy: a photon is a particle of light even though light is also waves; similarly, gravitons would be particles of gravitational waves[37:38]
Jim says he is not aware of any current experiments capable of detecting gravitons, emphasizing that existing detectors are only just able to see gravitational waves[37:58]
He speculates that it may take 50 or 100 years before technology allows graviton detection[39:38]

Impact of gravitons on our view of gravity

Neil asks whether finding gravitons would undermine the interpretation of gravity as curved spacetime[39:34]
Jim says many expect graviton detection would force a rethinking of gravity; he personally already tends to think about gravity in terms of field theory rather than geometry[41:28]
He characterizes Einstein's curved spacetime picture as a useful way to get correct answers in certain regimes but likely not the total story[40:49]

Start of third segment: social media, family, and research background

Chuck and Jim's social media and other work

Neil mentions Chuck's social media handle @ChuckNiceComic[42:56]
He notes he discovered Chuck has a TED Talk about technology and human interaction, which Chuck confirms[43:01]
Neil asks Jim if he has social media; Jim says he uses @DrJimGates on Twitter and Facebook[43:30]

Background image of artificial neurons and Jim's children

Neil notices Jim's spacey-looking background and asks about it[44:07]
Jim explains that he has twin children who both seem headed toward physics careers[44:08]
His daughter, Delilah, works on black holes and has begun publishing; he recently watched her give a talk[44:21]
His son is working in biophysics, growing artificial neurons in the lab[44:37]
• The green splotches in Jim's background image are real neurons from his son's cell lines, which show ganglia-like brain cell development

Cosmic Query: other disciplines in string theory evidence

Question about cross-disciplinary work in string theory

Lisa Hansen from the Bay Area says she loves thinking about string theories and asks which other scientific disciplines are involved in searching for evidence or proof, and what such clues might be[45:45]

SUSY Reels and cosmic microwave background signatures

Jim points to a paper he co-authored the previous summer with colleagues Stefan Alexander, Evan McDonough, Constantinos Koutsoulis, and grad student Leah Jenks[46:38]
In that work they proposed that strings might create specific structures, which they call "SUSY Reels", that could appear in the cosmic microwave background (CMB)[46:57]
He briefly defines the CMB as microwave radiation detectable when looking out at the universe[47:11]
Jim says if string theory is correct, it could leave a kind of signature written into the CMB's structure[47:20]
He concludes that astrophysicists-people capable of observing the universe in microwaves-are the scientists needed to test such string-theory predictions[47:20]
Neil draws a parallel: Einstein needed astronomers, and string theory may similarly depend on astrophysicists for empirical tests[47:40]
Jim confirms that co-author Stefan Alexander is both a physicist at Brown and a professional-level jazz musician, author of "The Jazz of Physics"[48:15]

Cosmic Query: what are strings made of?

Question from Samantha about string composition

Samantha (Sam O'Neill) asks what the strings in superstring theory are made of[49:16]

Jim's answer on fundamental objects and mathematical foundations

Jim answers that strings are not made of anything; if string theory is correct, strings are the fundamental entities out of which everything else is made[50:31]
Chuck remarks that this sounds circular, prompting Jim to note that mathematics requires some unprovable starting points[50:44]
Jim references a mathematical result (a Gödel theorem) that shows some truths cannot be proven from within a system, implying some axioms must be accepted[50:59]
Neil distinguishes between taking something on faith and asserting it as an axiom that yields a consistent structure, while acknowledging you cannot prove the axiom itself[51:29]

Cosmic Query: possibility of a cosmic gravitational background

Question about gravitational-wave background

Listener Woody asks for Jim's thoughts on a cosmic gravitational background analogous to the CMB[52:22]

Feasibility and required technology

Jim says he has not heard rigorous scientific discussions of a cosmic gravitational background but sees no reason in principle why it could not exist[52:54]
Neil explains that the CMB is useful not just because it exists but because astronomers have made highly detailed all-sky maps of its structure[53:41]
He notes that current gravitational-wave detections provide only rough directional information, not full-sky precision[54:06]
Jim estimates that achieving a detailed gravitational-wave map will require more detectors; he says there are currently about four major detectors (one in Europe, one in Australia, two in the U.S.)[53:45]
He suggests it might take 20 to 30 years to build a sufficient network and capability to map a gravitational-wave background[54:06]
Neil adds that beyond more detectors, scientists would want sensitivity to different gravitational-wave wavelengths to obtain a spectrum, further enriching the information[54:56]
They agree that such data would provide insights into the earliest moments of the universe once technology matures[55:40]

Cosmic Query: gravitational lensing and multiple images of stars

Question about duplicated star images

Listener Roman Prekop asks whether some stars in the night sky might be duplicated due to light bending by massive objects like supermassive black holes[56:02]

Neil's explanation of Einstein rings and multiple images

Neil answers yes, explaining that gravitational lensing can create multiple images of the same background object[56:02]
He recounts Einstein's prediction of an "Einstein ring" where perfect alignment would cause a circular image of a background source[56:11]
Neil notes that exact alignments are rare, so astronomers more commonly observe arcs and partial rings rather than full Einstein rings[57:09]
He states that a single background object can produce at least three images: one direct line-of-sight and two bent around the lensing mass, with possibilities for three, five, or seven images[57:11]
Neil describes lensed quasars whose light takes different paths around galaxy clusters, with differing path lengths[56:49]
• Because quasars vary in brightness, astronomers can see a flare in one image and then see the same variation appear later in another image, effectively observing the same event twice
• These time delays let scientists test the curvature of space, the mass in the cluster, and the distances to the quasar and lens

Jim's daughter's work on black hole rings

Jim connects this to his daughter's research, which studies glowing rings of matter around rotating black holes[58:31]
He notes that gravity bending the light from these rings allows observers to see the backside of the ring, an effect his daughter investigates[58:34]

Cosmic Query: white holes and black hole radiation

Question on the existence of white holes

Listener Glenn asks Jim whether white holes exist and what Einstein might have been observing to think they did[59:04]

Jim's assessment of white holes and black hole properties

Jim first points out that black holes are not perfectly black; due to Stephen Hawking's work, we know they emit faint Hawking radiation[58:34]
He says he is unaware of solid scientific arguments or observational evidence supporting the existence of white holes[59:34]
Neil adds that a white hole would be the time-reverse of a black hole, spewing out matter and energy in a spectacular fashion, and that we see no such phenomena in the universe[59:04]

Closing remarks

Plans to have Jim back and sign-off

Neil says they could invite Jim back for many other topics beyond Einstein[59:40]
He thanks Chuck and Jim and ends with his customary exhortation to "keep looking up"[59:44]

Lessons Learned

Actionable insights and wisdom you can apply to your business, career, and personal life.

1

Breakthroughs that look like solitary genius from the outside almost always depend on immersion in a community, where constant dialogue with colleagues helps refine, test, and sharpen ideas.

Reflection Questions:

  • • Who are the people in your current environment that challenge your thinking and help you refine your ideas, and how often are you actually engaging with them?
  • • How could you create more structured opportunities-like regular discussions or feedback sessions-to "swim" in a richer sea of information rather than thinking in isolation?
  • • What is one project you're working on now that would benefit from bringing in two or three diverse perspectives this month?
2

Mathematics functions as a precise language that can reveal aspects of reality beyond direct sensory experience, effectively serving as a "third eye" for understanding the world.

Reflection Questions:

  • • Where in your work or life could translating a messy situation into numbers, patterns, or models give you clearer insight than intuition alone?
  • • How might learning a bit more formal math or statistics in your field change the kinds of questions you're able to ask and answer?
  • • What is one complex decision you're facing where building even a simple quantitative model this week could clarify your options?
3

A powerful theory is not enough on its own; it must make testable predictions that can be confronted with observations, and designing those tests often requires creativity and collaboration across disciplines.

Reflection Questions:

  • • What beliefs or strategic assumptions are you currently operating under that you have never explicitly tested in the real world?
  • • How could you design a small, low-risk experiment or measurement in the next month that would give you evidence for or against one of your key assumptions?
  • • Who in another discipline or department could you partner with to help you design a better test or metric for an important idea you're pursuing?
4

Conflicts between successful frameworks-like general relativity and quantum mechanics-signal that our understanding is incomplete and that a deeper, unifying perspective may be needed.

Reflection Questions:

  • • Where in your own work or thinking do you notice two approaches that both seem to work locally but contradict each other globally?
  • • How might reframing an apparent either-or conflict in your life as a both-and problem push you to seek a third, more integrative solution?
  • • What is one area this quarter where you could step back from "defending a side" and instead map out what a higher-level framework that contains both sides might look like?
5

Technological progress often unlocks entirely new kinds of questions-like detecting gravitational waves first, and only then contemplating how to measure individual gravitons-which means long-term vision must be paired with patience.

Reflection Questions:

  • • What long-term questions or ambitions do you have that are currently limited by your tools, skills, or resources rather than by imagination?
  • • How can you sequence your efforts over the next few years so that each capability you build enables the next, more ambitious question to become testable?
  • • What is one capability or tool you could start investing time into learning this month that would expand the kinds of problems you can tackle a year from now?
6

Accepting that some foundational assumptions (axioms) must simply be chosen-and then rigorously exploring their implications-can be more productive than endlessly seeking certainty before moving forward.

Reflection Questions:

  • • What are the core assumptions you rely on in your work or personal philosophy that you rarely question but also cannot fully prove?
  • • How might explicitly writing down your top three assumptions change the way you interpret evidence that supports or challenges them?
  • • What is one assumption you could temporarily adopt for the sake of exploration this week, just to see what new ideas or strategies it unlocks?

Episode Summary - Notes by Phoenix

Cosmic Queries - Proving Einstein Right
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