The photograph of the black hole, at the centre of galaxy M87, is now a part of human history. We are told that the red-colour is caused by hot gas, matter & radiation around the "edge", the Event Horizon. Given the power of the gravitational forces emanating from black hole, why aren't these three things drawn into the abyss? If light is bent/ drawn into the BH, how does this red image arise? The logic, here, would be that a body, on the Event Horizon, is immune from the gravity--which sounds pretty fatuous?
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$\begingroup$ This is an interesting read on how infalling matter produces light, that then escapes from the vicinity of the black hole: wtamu.edu/~cbaird/sq/mobile/2016/03/29/… $\endgroup$– user226006Commented Apr 11, 2019 at 17:43
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1$\begingroup$ The image was obtained in the radio spectrum. What you see in the photo actually is radio waves with the intensity presented in red colors. Using red was an arbitrary choice of the researches for a dramatic effect (and to confuse 99% of people). They could have used a different color, but then people would ask about green forests or blue oceans on a black hole. $\endgroup$– safesphereCommented Apr 12, 2019 at 6:22
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$\begingroup$ Replace photograph with image $\endgroup$– AlchimistaCommented Apr 12, 2019 at 14:52
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$\begingroup$ Therer already question like this, or at least clearing the issue concomitantly to other aspects. The ring seen is made of that light originating from everywhere having the right position and direction to finally escape towards earth after being bent around the BH. $\endgroup$– AlchimistaCommented Apr 12, 2019 at 15:09
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Given the power of the gravitational forces emanating from black hole, why aren't these three things drawn into the abyss? If light is bent/ drawn into the BH, how does this red image arise?
It's the matter outside the black hole you're seeing. The matter on the inside can't be seen and that's why it's black in the center of the photo.
Now, wait, you say... but I thought black holes sucked everything in. No, they suck in everything within a certain distance, the "event horizon". That's a finite distance. Things outside that distance are still being sucked in, but not the light, so the stuff just outside remains visible.
The "inside" and "outside" are basically defined by this event horizon.
answered Apr 11, 2019 at 18:07