Cosmic Queries - Death of a Black Hole
Neil deGrasse Tyson hosts a Cosmic Queries Grab Bag edition, answering listener questions on topics ranging from why eclipses do not happen every month to the evaporation and final moments of black holes. He discusses dark energy and why external gravitational tugs are unlikely to explain it, defends the term "black hole," explores time travel paradoxes and Hawking's chronology protection idea, and explains Jupiter's shielding role in the solar system. The episode also covers entropy and why life on Earth does not violate the second law of thermodynamics, relativistic addition of velocities, the distinction between space and time dimensions, the value of scientific literacy, and what "vacuum" and "nothing" really mean in physics.
Solving the Crisis in Cosmology with Wendy Freedman
Neil deGrasse Tyson and co-host Matt Kirshen interview astronomer Wendy Freedman about measurements of the Hubble constant and the so‑called "crisis" in cosmology. Freedman explains the history of debates over the expansion rate of the universe, the current discrepancy between local distance-ladder measurements and values inferred from the cosmic microwave background, and why she does not yet consider it a true crisis. She describes her team's James Webb Space Telescope program using multiple stellar distance indicators, discusses systematic errors and the distinction between precision and accuracy, and answers audience questions on dark energy, the future evolution of the universe, and whether the universe is finite or infinite.