6 ms·
A Ring of Controversy Around a Black Hole Photo
- SiempreViernes 7y agoAs far as I can tell from an slightly extended skim of this text, this is a case of people from an adjacent field (theoretical GR) writing a paper that finishes with a remark about their abstract model that does not easily translate to the one used by the EHT. In fact, I find this rather nice summary towards the end of the article: "In particular, EHT’s simulations show all of the effects mentioned above; there’s none of this of which they are unaware. [...] Thus it’s not enough to argue the photo itself is ambiguous; one has to argue that EHT’s more subtle analysis methods are flawed. No one has argued that yet, as far as I am aware." To me this reads very much like "I probably shouldn't have used 'controversy' in the title".
- Causality1 7y agoWhen I first saw the photo with very little explanation attached, I took the ring of light around it to be the accretion disc and found it suspicious that it would be so perfectly perpendicular to earth.
- empath75 7y agoEven if it was the accretion disk, it would look that way no matter how it was facing earth because gravity would bend the light from the far side around.
- subroutine 7y agoDoes the accretion disk emit light, or is the light source coming from somewhere else? (i.e. if the accretion disk is just cosmic dust why would one expect to see the disk?)
- michaelcampbell 7y agoTo all viewers from any viewpoint relative to it? That's the bit I don't understand.
- PaulHoule 7y agoIt might look a bit different if you are looking right down the jet that comes from the pole.
- klodolph 7y agoRemember the black hole from interstellar? Some gravitational simulations were used for the imagery. It was changed for artistic purposes, but you can see the back side of the accretion disc from the front.
- AlbertoGP 7y agoThey explain how they did it in this video: https://www.youtube.com/watch?v=MfGfZwQ_qaY https://www.youtube.com/watch?v=MfGfZwQ_qaY Their advisor, who provided them the relativistic equations they use for the computer graphics simulation is Kip Thorne: https://en.wikipedia.org/wiki/Kip_Thorne https://en.wikipedia.org/wiki/Kip_Thorne
- jvzr 7y agoHe wrote a (good) book about the whole endeavor: The Science of Interstellar
- kaslai 7y agoDerek explains the physics in a reasonably understandable manner in this video on his Youtube channel: https://www.youtube.com/watch?v=zUyH3XhpLTo https://www.youtube.com/watch?v=zUyH3XhpLTo
- wruza 7y agoSo, at 6:38 he says that we would mostly see just a disk, if viewing strictly from the jet vector, yet PaulHoule’s comment fades below and the original empath75’s is intact. For now I assume there is some relativistic effect in action which makes me see them this way.
- jonah 7y agoThis video by Derek Muller (Veritasium) helped me understand this phenomenon. https://www.youtube.com/watch?v=zUyH3XhpLTo https://www.youtube.com/watch?v=zUyH3XhpLTo
- woogiewonka 7y agoThe article states that the photon sphere does not exist, therefore his explanation is incorrect.
- PaulHoule 7y agoThe unit of resolution of that photo is just a little bit smaller than the size of the hole in the middle. Thus you are looking at the inverse convolution function that generates all the in-between pixels as much as you are looking at the black hole. Eyeballing it you can't judge much at all, maybe the central hole is really smaller, maybe the ring is a little thinner, maybe not. It is a Rorschach test as much as anything else.
- jankotek 7y agoImage was made by comparing polarization of photons on each pixel. BH gravity bends space and that changes photon plane. It is all in authors papers.