In Episode 5.7, we journey into the hidden world of particles that shape the sky. We speak with Zoé Brasseur, who studies the rare ice nucleating particles drifting from boreal forests into clouds, and Matthew Boyer, who traces how distant penguin colonies in Antarctica release gases that spark the birth of new aerosol particles, tiny seeds of clouds. Together we travel from forest towers in Finland to the drifting ice of the Arctic and the frozen stations of Antarctica. We hear how these almost invisible specks decide when clouds freeze, rain, or snow, and how life on the ground can ripple upward to influence the climate above. Join us for a conversation that blends fieldwork adventure with discovery, revealing how the smallest of particles can shape the vastness of the atmosphere. Zoé Brasseur is a Scientific Integration and Data Officer at the Svalbard Integrated Arctic Earth Observing System and has a doctorate from Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, Finland Matthew Boyer is a Post-doctoral Researcher at INAR, where he also received his doctoral degree. Read their amazing open access paper here: Penguin guano is an important source of climate-relevant aerosol particles in Antarctica (https://www.nature.com/articles/s43247-025-02312-2) Your hosts for this episode are Sujai Banerji & Touqeer Gill Editing by Touqeer Gill Episode cover by Anubhuti Bhatnagar TSB podcast logo by Tomás Garnier Artínano Jingle by Havelocke: www.thisishavelocke.bandcamp.com Follow The Science Basement: Homepage: www.thesciencebasement.org Facebook: www.facebook.com/ScienceBasement Instagram: @sciencebasement Twitter: @ScienceBasement Email: [email protected]