Space Nuts
I've already recommended this before, but I'm doing it again here because it remains my favourite. Run by host Andrew Dunkley (#radio host and #author) and Prof. Fred Watson (also author, and astronomer-at-large), #3space nuts dives into many space-related topics around the world and here in australia - ranging from supermassive black holes, to the latest crewed missions, to space telescope projects.
Unexplainable
Hosted by Noam Hassenfeld, Byrd Pinkerton and Brian Resnick (and many more), Unexplainable covers the may #scientific mysteries that riddle our universe. From havana syndrome, to predicting tornados, to resurrecting mammoths, identifying housebug species, this isn't your regular 'mystery' podcast. It dedicates itself to explaining (or 'unexplaining') such mysteries through interviews with the experts involved - and teaching you along the way. Unexplainable is run by the VOX media group.
99% invisible
99 percent invisible is hosted primarily by Roman Mars, with stories presented by the rest of the team - including Chris Berube, Jason De Leon, Emmet FitzGerald, and more. It focuses on topics related to #architecture, Urban planing and #Geograpy While that may sound boring, it strays from what you would consider such a scope would contain, and the stories that 99pi tells are truly fascinating - for example, island sheep adapting to a diet of seaweed, or how lotteries work, all the way to why captions are so terrible.