PBS Space Time
3 HN recommenders · recommended in 3 months, 2019–2021
18:05 · 1.1M views · Jan 24, 2019
PBS Space Time explains the Hubble constant tension, in which two precise, independent methods of measuring the universe's expansion rate disagree. It covers why this calls some standard cosmology into question.
Recommended as a clear, layman-friendly explanation of the Hubble tension from a channel regarded well by physicists.
3 comments from Hacker News
Your example of looking at a problem from more than one angle made me think of the problem of finding the Hubble constant that describes the rate of expansion of the universe. There are two recent methods which have different estimates for this rate of expansion. PBS Space time has an excellent video on the topic: this video
The shockwaves are everywhere - you, right now, are in a density node. Inflation wasn’t something that happened from a single point - it happened as a result of vacuum collapse, spontaneously, all over the place. Some of these inflationary zones went much faster than others, and where they intersected, regions of increased density, and therefore matter, occurred. The filamentary nature of the very macroscopic universe reflects these shock intersection zones - they’re full of galaxies. We think that the voids are likely centred around points where inflation occurred. So yeah. You’re the shockwave. Sorry man. Here’s a decent vid from PBS Space Time where they explain some of this nice and clearly - I recommend their channel generally if these topics interest you. this video
I believe they’re referring to the “crisis in cosmology”. I’m purely a layman, but I found some videos useful. I believe at least PBS Space-Time [1] is well regarded in physics circles (for laymen explanations.). I found the other one [2] to be more digestible though. [1] this video [2] [LINK]