Sean Carroll's Mindscape: Science, Society, Philosophy, Culture, Arts, and Ideas

358 | Solo: Vacuum Energy and the Cosmological Constant

The most surprising discovery in fundamental physics during my career as a scientist was undoubtedly the acceleration of the universe [https://en.wikipedia.org/wiki/Accelerating_expansion_of_the_universe], announced in 1998. The most straightforward explanation for these observations is a positive cosmological constant, or vacuum energy. I talk about the origin of the idea with Einstein, how quantum physicists started to think about it and understand the "cosmological constant problem," as well as how its discovery also raised the "coincidence problem." This is the first of two connected solo episodes; the next will be on theories of dark energy that are not the cosmological constant. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2026/06/22/358-solo-vacuum-energy-and-the-cosmological-constant/ [https://www.preposterousuniverse.com/podcast/2026/06/22/358-solo-vacuum-energy-and-the-cosmological-constant/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll].

357 | Jeff Coller on mRNA, Vaccines, and Bespoke Therapeutics

Messenger RNA (mRNA) plays a literally central role in the functioning of life as we know it, shuttling information back and forth between the DNA where it is stored to the ribosome where it is used to produce proteins. RNA may even have been the first molecule to kick-start the origin of life. Today, scientists are learning how to manipulate mRNA to cure and prevent diseases, whether through vaccination or literally editing one's DNA. Jeff Coller explains how it all works and how mRNA is revolutionizing medicine as we know it. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2026/06/15/357-jeff-coller-on-mrna-vaccines-and-bespoke-therapeutics/ [https://www.preposterousuniverse.com/podcast/2026/06/15/357-jeff-coller-on-mrna-vaccines-and-bespoke-therapeutics/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll]. Jeff Coller received his Ph.D. in cell and molecular biology from the University of Wisconsin-Madison. He is currently Bloomberg Distinguished Professor of Biomedical Engineering and Director of the RNA Innovation Center at Johns Hopkins University. He is co-founder of Tevard Biosciences and the Alliance for mRNA Medicines, and leads the REPAIRx consortium. He is a fellow of the American Association for the Advancement of Science. * Web site [http://collerlab.org/] * Johns Hopkins web page [https://www.bme.jhu.edu/people/faculty/jeff-coller/] * Google Scholar publications [https://scholar.google.com/citations?user=wSJc28sAAAAJ&hl=en] * "This May Be the Most Important Medical Story of the Decade," New York Times, April 9, 2026 [https://www.nytimes.com/2026/04/09/opinion/genetic-editing-diseases-health-care.html]

356 | Andrea Wulf on Enlightenment, Nature, Romanticism, and Modernity

All ideas have a history, no matter how inevitable and well-entrenched they may seem to us today. The later Enlightenment was a heady time when people were exploring new conceptions of nature, humanity, and the self. Andrea Wulf is a writer of narrative histories, examining the origins of ideas through the lives of the people who explored them. In this episode we discuss three of her books: The Invention of Nature [https://andreawulf.com/2015/01/15/about-the-invention-of-nature/], about Alexander von Humboldt and environmentalism; Magnificent Rebels [https://andreawulf.com/2022/01/05/about-magnificent-rebels/], about the Jena circle of Romantics including Goethe, Schiller, Schlegel, and others; and most recently The Traveller [https://andreawulf.com/2025/11/19/about-the-traveller/], about George Forster, an early naturalist, ethnographer, and champion of human equality. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2026/06/08/356-andrea-wulf-on-enlightenment-nature-romanticism-and-modernity/ [https://www.preposterousuniverse.com/podcast/2026/06/08/356-andrea-wulf-on-enlightenment-nature-romanticism-and-modernity/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll]. Andrea Wulf was born in India, raised in Germany, and studied design history at the Royal College of Art, London. She is the author of seven books. She is a Miller Scholar at the Santa Fe Institute and a Fellow of the Royal Society of Literature. The Invention of Nature won multiple prizes, including the Royal Society science book prize and the LA Times book prize. * Web site [https://andreawulf.com/] * Amazon author page [https://www.amazon.com/stores/Andrea-Wulf/author/B001HOE9U0?ccs_id=d24d6e84-c228-44fb-90df-a4c95d0ece22] * Wikipedia [https://en.wikipedia.org/wiki/Andrea_Wulf]

AMA | June 2026

Welcome to the June 2026 Ask Me Anything episode of Mindscape! These monthly excursions are funded by Patreon supporters [https://www.patreon.com/seanmcarroll] (who are also the ones asking the questions). We take questions asked by Patreons, whittle them down to a more manageable number -- based primarily on whether I have anything interesting to say about them, not whether the questions themselves are good -- and sometimes group them together if they are about a similar topic. Enjoy! Blog post with AMA questions and transcript: https://www.preposterousuniverse.com/podcast/2026/06/01/ama-june-2026/ [https://www.preposterousuniverse.com/podcast/2026/06/01/ama-june-2026/] New paper I talk about in the beginning of the episode: * S.M. Carroll, N. Diachenko, and S. Dulani, "Toward a Phenomenologically Acceptable Quantum Cyclic Universe." [https://arxiv.org/abs/2605.30405]

355 | Solo: Looking Quantum Mechanics in the Eyeball

One of the major obstacles to understanding quantum mechanics is the difficulty we have in simply accepting what the theory itself is telling us. The problem is that we know what the everyday world looks like -- stuff, arranged in space, evolving through time. So we can't resist the temptation to impose that picture on the quantum description, even if it's not actually there. In this solo episode I talk about what it means to take quantum mechanics at face value, and the difficult work involved in understanding how the everyday world of our experience fits into the picture. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2026/05/25/355-solo-looking-quantum-mechanics-in-the-eyeball/ [https://www.preposterousuniverse.com/podcast/2026/05/25/355-solo-looking-quantum-mechanics-in-the-eyeball/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll]. Here is the survey on physicists' opinions about unsettled big-picture questions: * Afshordi, Halper, Rini, and Schirber, "Big Mysteries Survey: Physicists' Views on Cosmology [https://inspirehep.net/literature/3154769], Black Holes, Quantum Mechanics, and Quantum Gravity [https://arxiv.org/abs/2605.11058]." And here is a short technical overview on the ideas described in this episode: * Carroll, "Reality as a Vector in Hilbert Space. [https://inspirehep.net/literature/1852066]" If you want further papers, look at the papers cited in this one.