Veritasium
8 HN recommenders · recommended in 4 months, 2019–2021
9:19 · 11M views · Apr 9, 2019
Veritasium explains what a black hole should look like, using J.P. Luminet's 1979 work and a cardboard 3D model to show how light bends around it. It was made just as the first black hole image was released.
Recommended for correctly predicting the features of the real black hole image and clearly explaining the lensing physics behind it.
10 comments from Hacker News
Related video, made by Veritasium yesterday, is one of my favorite videos in a long time. He explained how the prediction of this image was made (before the image got released) and the video is great and fun to watch. this video
If the black hole is not spinning, it should look the same from every angle. A spinning black hole is deformed (like the spinning Earth.) Anyway, we are not seeing the black hole (because it looks just like a black circle in front of a black background). The interesting part of the image is a disk of material spinning around it. There is a nice 3d cardboard simulation and clear explanation in a video by Veritasium this video
Good video that correctly predicted the image and describes why it looks the way it does [1]. TL; DR The dark area is the entire surface of the event horizon, including the side facing away from us, plus some more due to photons missing the event horizon "directly" being drawn in. One side is brighter due to its being Doppler boosted. [1] this video
The black hole itself is spherical, but the light we're seeing around it isn't projected by the event horizon; rather, it's light from behind/around the black hole that isn't blocked. This video explains in much more detail: this video
If you mean the brightness asymmetry, it's because the accretion disc is spinning. This video predicts pretty well all of the features we expected to find, and it lines up with the actual image. this video