Summary
In this episode of Star Talk, Neil deGrasse Tyson and guest co-host Matt Kirsch are joined by Janna Levin, a professor of physics and astronomy at Barnard College of Columbia, to answer questions about black holes, cosmology, and space-time. The hosts address questions from Patreon members, including whether a small object like a ping-pong ball could be carried away by the gravitational waves generated by two orbiting black holes, and what the universe is expanding into. Janna explains that the universe is the whole space, so it is not expanding into anything else. The hosts also discuss the possibility of observing the entire expansion of the universe from an outside platform, which is not possible since any observation requires interaction with particles in the same universe. The episode delves into deep philosophical and scientific questions about the nature of reality and the universe.
The hosts also discuss the effects of gravity and speed on time perception, particularly in the context of black holes. They explain how as one gets closer to a black hole, time and space seem to rotate and fold into each other, leading to time dilation and a loss of time perception relative to other observers. The podcast includes several questions from listeners about the temperature and pressure inside black holes, which the hosts attempt to answer. They also touch on the topic of dark matter and its potential interaction with black holes.
The hosts explain that black holes are not filled with dense matter, but rather are empty spaces created by the sharp curvature of space-time. They mention the phenomenon of Hawking radiation, which causes black holes to emit energy and eventually evaporate. The discussion concludes with an explanation of the theoretical possibility of creating wormholes, which would require negative energy and are not currently feasible with our current understanding of physics.
In the end, the speakers ran out of time but discussed the possibility of a "stoner edition" of their podcast. One of the speakers mentioned having a green card and the other expressed interest in being more involved in the podcast. They thanked their guest, Janet, for her contributions to the podcast and to Pioneer Works. The host, Neil deGrasse Tyson, signed off by encouraging listeners to keep looking up.
