The Absurdity of Detecting Gravitational Waves
Why Hacker News recommends it
HN recommends it as a good layperson explanation of how LIGO's detection works and why it is so hard.
What it is
Veritasium explains in detail how LIGO detects gravitational waves, with a laser interferometer measuring displacements smaller than a proton. The video focuses on the extreme precision and the techniques needed rather than the general discovery story.
Recommended by 3 HN commenters across 2 different months, 2017 to 2019.
What Hacker News said
Strong rec aeleos · 2017-09 · on “Gravitational waves from a binary black hole merger observed by LIGO and Virgo”
There are many good videos on youtube that do a good job explaining what gravitational waves are and how we detect them. Many of these were made in response to the first detection, and they do a pretty good job explaining it in laymans terms. I personally really like veritasiums video here. [this video]
Recommends ehsankia · 2017-06 · on “LIGO Detects Gravitational Waves for Third Time”
Except imagine you're embedded on the string itself and cannot actually sense the string "moving through space". The way you have to measure it is by sensing tiny changes in distance between the left and right side of the string as it wiggles around. The actual detail of the experiment and the precision they reach is quite fascinating. Veratisium has a pretty good video explaining it in more laymen terms [0] [0] [this video]
Recommends netcraft · 2017-06 · on “LIGO Detects Gravitational Waves for Third Time”
Here is a great video with explanations: [this video] Short answer - they use lots of techniques - its super hard.
Cites tqkxzugoaupvwqr · 2017-07 · on “Signatures of extra dimensions in gravitational waves”
From my understanding as a layperson, using other LIGO style detectors to substitute the z-axis won’t work. You need to shoot laser pulses continuously and in sync into two axes from the same detector to be able to detect ripples in spacetime. The sensitivity of two non-connected detectors working together is not high enough. See [1] for how the detection works. [1] [this video]
Cites mysterypie · 2018-08 · on “The Absurdity of Detecting Gravitational Waves (2017) [video]”
I figured that one tube is stretched by the gravitational waves and the perpendicular tube is unaffected, so you're measuring the difference between the two tubes. Simple and easy to understand. However, the video mentioned that both light and the detection apparatus are stretched by the same degree and the physicist says "the light does get stretched and that part doesn't do the measurement for us"[1] -- which makes me think that the simple and easy explanation is not quite right. There's some subtlety that I think I'm missing. [1] [this video] (6min 16sec into the video)
Cites mgalgs · 2019-04 · on “Unveiling the first-ever image of a black hole [video]”
You don't have to watch his channel for very long to learn that he often does (see his video about the recent gravitational wave detection [1], plus a bunch more). [1] [this video]