Astrophysicist Katie Mack discusses Twitter, athletics, mathematics, and the small matter of the fate of the Universe. Katie Mack's website - http://www.astrokatie.com And her Twitter @AstroKatie - https://twitter.com/AstroKatie The End of Everything - Dr Mack's book on Amazon - https://amzn.to/2ZJ2mZh This episode was supported by G-Research, a world-leading quantitative finance research firm, hiring the brightest minds to tackle the biggest questions in finance - learn more at gresearch.co.uk/numberphile/ - https://www.gresearch.co.uk/numberphile/ You can support Numberphile on Patreon - https://www.patreon.com/numberphile With thanks to MSRI - https://www.msri.org PODCAST TRANSCRIPTS: https://www.numberphile.com/podcast-transcripts