He is an astrophysicist at Harvard
Huh...
Here’s the link to the full episode. The Harvard Astrophysicist part starts
17 minutes and 46 seconds from the end, or at 1:16:58.
It’s the final segment, over an hour into the episode.
https://scifri-episodes.s3.amazonaws.com/scifri20210122-episode.mp3
You can play, pause, slide the marker forward and back and see the time
indicators at this link.
I’ll give it a listen now...
~Easy