Nobel Prize Winner Explains JWST vs The Crisis in Cosmology

The conversation begins with a discussion on the Hubble tension, a discrepancy between the measured expansion rate of the universe from the cosmic microwave background radiation and the rate obtained from nearby measurements. The guest, Dr. Adam Reese, a Nobel laureate, is introduced as an expert in measuring the universe's expansion rate using Cepheid variables. The discussion highlights the importance of double-checking measurements and the potential implications of the Hubble tension, including the possibility of new physics.

Dr. Reese explains the significance of Cepheid variables in measuring long-range distances due to their consistent relationship between pulsation period and luminosity. He describes their characteristics, such as being supergiant stars and having high specificity and luminosity, making them excellent standard candles. The conversation also touches on the challenges of observing these variables and the impact of dust on cosmology.

The discussion delves into the internal mechanism driving the pulsations of Cepheid variables, involving a balance between gravity and thermal pressure. Dr. Reese describes how the opacity of the star's interior, particularly the ionization state of helium, leads to the overshoot and oscillation of the star's expansion and contraction. He also explains the rarity of Cepheid variables and their luminosity, which makes them easily identifiable in distant galaxies.

Dr. Reese discusses the role of the Hubble Space Telescope in measuring the Hubble constant by observing Cepheid variables in distant galaxies. He mentions the success of the Hubble Key Project in achieving 10% precision and the subsequent efforts to further refine the measurement with new instruments. The conversation also highlights the importance of the Hubble Space Telescope in advancing our understanding of the universe's expansion rate.

The discussion addresses the Hubble tension, where different measurements of the Hubble constant yield conflicting results. Dr. Reese explains the efforts to refine the measurements using the Hubble Space Telescope and the significance of these discrepancies. He also talks about the potential implications of the tension, including the possibility of exotic forms of dark energy and the need for new theories to explain the observations.

Dr. Reese discusses the capabilities of the James Webb Space Telescope (JWST) and its impact on resolving the Hubble tension. He explains how JWST's higher resolution and near-infrared capabilities have allowed for more precise measurements of Cepheid variables, reducing the noise in the data and confirming the accuracy of Hubble's measurements. The conversation highlights the potential of JWST in advancing our understanding of the universe's expansion rate.

The discussion turns to the potential for simplifying the distance ladder method with the help of JWST. Dr. Reese suggests that future observations could reduce the number of steps needed to measure distances, potentially eliminating the need for Type 1a supernovae. He also talks about the importance of continued observation and the potential for new discoveries at the limits of JWST's capabilities.

The conversation explores the Hubble tension as a cosmic mystery, with Dr. Reese discussing the implications of the differing measurements of the Hubble constant. He talks about the need for new theories and more measurements, particularly at intermediate times in the universe's history. The discussion also touches on the potential for future missions like the Roman Space Telescope and the European Euclid Observatory to shed light on the tension.

Dr. Reese discusses the potential for future innovations in distance indicators, focusing on the challenges and potential of using quasars and other celestial objects. He emphasizes the importance of understanding the nature of these objects to use them effectively in measuring distances. The conversation also highlights the need for interdisciplinary approaches and the potential for new discoveries in our understanding of dark matter and dark energy.

The discussion concludes with Dr. Reese's thoughts on the need for new instruments to address the Hubble tension. He advocates for building facilities with broad capabilities to tackle a range of problems and emphasizes the importance of optimizing for specific needs. The conversation also touches on the potential for future ground-based telescopes and the possibility of a large-scale space optical UV telescope.

The interview wraps up with reflections on the Hubble tension and the future of astronomy. Dr. Reese expresses excitement about the tools available and the potential for new discoveries. The conversation highlights the community effort behind understanding the universe and the importance of patience and enjoyment in the scientific process. The host also thanks the patrons supporting the discussion and looks forward to future advancements in the field.