Unveiling the first-ever image of a black hole [video]

Post by ben_w » Thu, Apr 11, 2019, 7:34 AM UTC

Abishek_Muthian wrote: post #473

JumpCrisscross wrote: post #27

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] https://www.youtube.com/watch?v=zUyH3XhpLTo

In the video he talks about the Schwarzchild radius but doesn't go into details. It is the distance from the center of the black hole to the event horizon. Anything which is not in that radius or not already in a path towards it should be safe from not getting sucked by the black hole. E.g. If our sun becomes a black hole, Schwarzchild radius would be 2.954Km i.e. anything outside ~3Km would be safe. This was explain…

Post by r_c_a_d » Thu, Apr 11, 2019, 7:50 AM UTC

mattfrommars wrote: post #458

JumpCrisscross wrote: post #27

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] https://www.youtube.com/watch?v=zUyH3XhpLTo

If the general theory of relatively was tested again and it proved to provide the next result, what does it say about actually is an black hole? Thus far, from all the experiment and result observed, the theory has been proven to be correct. Hence, it can be said with 99% certainty whatever it predicts must be correct. I hope it does mention about possibility of creating a worm hole.

Post by Cthulhu_ » Thu, Apr 11, 2019, 11:10 AM UTC

exelius wrote: post #468

dredmorbius wrote: post #450

Earlier quoted context omitted.

More distant (longer baseline), not merely additional sensors. Resolving power is proportional to the (virtual) aperture size, not the total sensor area (that gives more signal strength).

So put some telescopes in orbit around the Moon and Mars.

Post by salthound » Thu, Apr 11, 2019, 11:21 AM UTC

SamBam wrote: post #461

jug wrote: post #392

Earlier quoted context omitted.

During the press conference, they said photographing the M87 black hole was like shooting a hibernating bear, and photographing the Sag A* black hole of our galaxy like photographing a quickly moving toddler. Something about the speed making it much harder. It is also much smaller, but that's less of a problem because it's much closer. All in all apparently making it about the same angular size. But it sounds like th…

That's a... weird analogy.

Post by wallace_f » Thu, Apr 11, 2019, 12:44 PM UTC

AnimalMuppet wrote: post #429

Pharmakon wrote: post #416

Earlier quoted context omitted.

It’s not that interesting unfortunately, although I liked your approach. A graviton would be just another boson like a photon, and like a photon would be unable to escape. All of the worldlines of a graviton within the event horizon would lead to a collision with th singularity. It’s just another aspect of “No Hair” on the hole. Remember that this applies everything where r≤1. As far as “flat” worldlines I think you…

But there pretty clearly is a gravitational field at r > 1. If that field is made up of gravitons, and a graviton can't escape from the mass to outside r = 1, then what is the source of the gravitons that compose the field at r > 1? If they don't originate at the mass, then... what?