Jim Rantschler and Randy Morrison discuss physics from elementary particles to cosmological effects at the limits of our theoretical knowledge or have recently emerged.
https://www.podomatic.com/podcasts/physicsfrontiers-rantschler
Bimetric Gravity
Randy introduces Jim to Sabine Hossenfelder's bimetric theory of gravity. In this gravitational theory, there are two types of matter whose only interaction is through gravitation. However, each one reacts to space-time differently, resulting in different metric tensors for each. In low-curvature situations, this creates a kind of anti-gravitation.
Show Notes: http://frontiers.physicsfm.com/47