How fast is the universe expanding? It turns out this important value, the Hubble constant (H0), is under constant debate. The two main teams have numbers that disagree by over 5 standard deviations! Today on a[s]b, we resolve the Hubble tension once and for all, as Cormac and Kiersten square off in the Great H0 Debate. Cormac comes in with feist and facts while Kiersten engages with rebuttal and reason. In the end, there can only be 1 winner, and that’s for you to decide! Vote here for the winner of the debate, what the true value of H0 should be, and what we got wrong in the episode (we tried our best!).
 
Timeline of the Hubble tension: https://miro.medium.com/v2/resize:fit:1400/format:webp/1*oekTYTkZQmw7DxzUaLqDVw.png
 
Astrobites used for this episode: 
https://astrobites.org/2016/04/20/conflicts-between-expansion-history-of-the-local-and-distant-universe/
https://astrobites.org/2020/05/12/magnets-and-hubble/
https://astrobites.org/2021/04/01/south-polarization/
https://astrobites.org/2021/04/27/bursting-the-hubble-trouble-bubble-measuring-h0-with-fast-radio-bursts/
https://astrobites.org/2023/03/29/multi-messenger-constraints-on-the-hubble-constant/
https://astrobites.org/2023/10/04/holy-cow-is-our-journey-through-the-universe-the-reason-for-the-hubble-tension/
https://astrobites.org/2024/04/16/sn_h0pe/
 
Space sound: https://www.system-sounds.com/earth-day/. Credit: SYSTEM Sounds/Matt Russo/Andrew Santaguida
 
Article by Subir Sarkhar: https://inference-review.com/article/heart-of-darkness
 
Cool Wikipedia page Will references: https://en.wikipedia.org/wiki/Numeral_prefix
 
Chart Kiersten references: https://en.wikipedia.org/wiki/Cosmic_distance_ladder#/media/File:Extragalactic_Distance_Ladder_en.svg