211–220 of 525 posts
Is this what we would see with the naked eye if we were close enough to the black hole? Or would we see nothing, because at this distance we would be dead (or the universe ended all around us)?
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
Ok, wait a second. I liked a lot of this video, but there are some aspects which are kind of ridiculous. He says his reason for his confidence in this prediction is "I think it's going to look like a fuzzy coffee mug stain." He doesn't give an actual reason. He does talk a lot about theory, a lot of it interesting and novel to me, but by the end of the video, most of this theory suggests a different-looking image!
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Yeah, apparently radio interferometry is still very manual and so involves many relatively subjective decisions to produce an image. That's probably why they had several analysers that they then combined into progressively larger teams until they could produce this Consensus-A picture.
There is non-manual ways to do it (called self-calibrating), but those need many more antennas. (What you really need is good coverage of the (u,v) plane AND many more different baselines between pairs of telescopes than the number of individual antennas.) If you do not have that self-calibration fails and leads to horrible image artifact or does not converge at all. They limited the influence of the manual calibrati…
(It is a quasar, simbad says so and that's good enough for this setting!)
Does this confirm or disapprove Steven Hawking Black-hole radiation?
The Hawking radiation for a black hole with this mass would be really small. It actually decreases with added mass. So, this observation does not say anything about Hawking radiation.
So is a black hole 3 dimensional? Is it a sphere? Or does it only work in certain directions? Does everything "fall" the same direction? I ask because even in a brief history of time, the diagrams are very "single plane of space-time, pulled infinitely deep by the black hole"
I am not a physicist, but from my lay understanding, a black hole (and all other forms of matter) exists in a four-dimensional space-time form that we can experience directly, plus a number of higher dimensions that we can only extrapolate, and observe indirectly via experiment (kind of how a picture of a sphere is not a sphere due to a missing dimension, but you can still tell it's a sphere based on other characteristics). The exact number of higher dimensions is the realm of string theory, and could be 10, 11, 26, or something else.
The singularity of the black hole is one-dimensional, I think (I could be wrong, I'm often wrong). The event horizon is... funny. The outside of the event horizon is in four-dimensional space-time and is more or less "spherical". The inside is a land of theory and debate, because by definition we can't directly observe it from our space-time. Do space and time even exist inside the event horizon? I dunno, ask someone who knows what they're talking about. The best I can do is an analogy. Imagine it's the surface of the ocean. Above the surface, you're in air. Below the surface, you're in water.
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Interstellar also turned off the doppler effect, maybe to get a boring symmetric ring instead of an awesome asymmetric one as nature intended it to be!
IIRC, the black hole in Interstellar was also rapidly rotating, which I think was significant to how it looked: https://www.wired.com/2014/10/astrophysics-interstellar-blac... > Nolan's story relied on time dilation: time passing at different rates for different characters. To make this scientifically plausible, Thorne told him, he'd need a massive black hole—in the movie it's called Gargantua—spinning at nearly the…
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It is a letdown. Although I wasn't expecting Jupiter level detail this pic doesn't blow me away because it's just a blurry ring. Jupiter level detail will blow me away.
Consider yourself lucky that a black hole isn't Jupiter level distance from us.
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So amazing that scientists were able to predict what something would look like that we have never seen before.
Einstein predicted the existence of black hole back in early 1915. Pretty amazing.
(As an aside, I have found a whole extra level to nominative determinism since starting to learn German — Schwarzschild = Black shield)
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IIRC, the black hole in Interstellar was also rapidly rotating, which I think was significant to how it looked: https://www.wired.com/2014/10/astrophysics-interstellar-blac... > Nolan's story relied on time dilation: time passing at different rates for different characters. To make this scientifically plausible, Thorne told him, he'd need a massive black hole—in the movie it's called Gargantua—spinning at nearly the…
I'm still wondering why the accretion disk from the released images isn't warped in a way we saw in interstellar. Are we looking at it top-down rather than from its orbital disk? would a differently oriented black hole look more like interstellar? Veritasium also has an explanation and I don't think it has anything to do with its spin.
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There is non-manual ways to do it (called self-calibrating), but those need many more antennas. (What you really need is good coverage of the (u,v) plane AND many more different baselines between pairs of telescopes than the number of individual antennas.) If you do not have that self-calibration fails and leads to horrible image artifact or does not converge at all. They limited the influence of the manual calibrati…
Some quasar other than M87 I suppose :P (It is a quasar, simbad says so and that's good enough for this setting!)