One of the findings they announced at the press conference is that the spin of the black hole is not aligned with the galactic plane but is tilted "towards us" so that it is viewed face on. How unexpected is that?
Astronomers reveal first image of the black hole at the heart of our galaxy
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Re: Astronomers reveal first image of the black hole at the heart of our galaxy
#322Earlier quoted context omitted.
Thank you for the pointers! By non-quantum I meant that to simulate the motions at that scale (including rotation) it seemed like you could go quite far just by using relativistic physics. But I guess there is not much ordinary about black holes so my mental model is likely quite a ways off.
Ok, I think there are a couple ways of digging out a question to answer from your comment as I understand it. I believe you are asking about how to solve the trajectories of electromagnetic radiation generated just outside these central black holes, since essentially that's what determines the images released to the public today. I'm going to restrict this to the "lens" of the production of hard X-Rays and gammas aro…
Thank you for taking the time for such a didactical and complete answer. It's exchanges like this that take make HN special.
The links are really helpful btw. Where do you get your daily news feed? If you have something like 'hacker news for astronomers', or some very active blog, do let know please.
Re: Astronomers reveal first image of the black hole at the heart of our galaxy
#323Earlier quoted context omitted.
I’m looking forward to reading your scientific paper.
And I am looking forward to have many other different teams reproduce your results independently. I also would like to notice you did not explain why my blue "picture" would be less a "picture" than yours.
A picture of a black hole would be always artificial, for color don't really exist as it's only the brain interpretation of a part of the EM spectrum heavily averaged, that's why we don't see green stars even if there are many stars whose strongest light is green, like our own sun.
Taking a real picture of a black hole like with a cellphone camera would likely be just like a bright white star.
Re: Astronomers reveal first image of the black hole at the heart of our galaxy
#324One of the findings they announced at the press conference is that the spin of the black hole is not aligned with the galactic plane but is tilted "towards us" so that it is viewed face on. How unexpected is that?
Your question stuck in my head and I found this video today which gives a good explanation of the alignment (around 12:45).
Re: Astronomers reveal first image of the black hole at the heart of our galaxy
#325tbh the image isnt inspiring. kinda like a low res computer simulation.
It's an object 26k light years from Earth and emits no light. That they were able to capture an image at all is both a scientific and technological triumph.
i remember the gravitational wave detection. billions of dollars spent for some bleep-bloops.
Re: Astronomers reveal first image of the black hole at the heart of our galaxy
#326Earlier quoted context omitted.
So I have a question about that.. I thought it would only have an accretion disk if it was active. So what gives? I guess I'm wrong? What constitutes "active" if not "stuff is falling in"?
Unexpected question from someone whose nickname starts with "quasar"! :-) Active in the sense of (from https://en.wikipedia.org/wiki/Active_galactic_nucleus >) "much higher than normal ... excess non-stellar emission" from the region very close to the central black hole. Our central parsec is simply dim in practically every wavelength compared to its enclosing central bulge. An active galactic nucleus in our galaxy w…
Thanks for the reply! And yes, given my name I thought I should know more about it. Especially since this was not in line with my previous understanding.
Re: Astronomers reveal first image of the black hole at the heart of our galaxy
#327Very interesting. The previously-released M87 image had just a single "shadow", but this one (of Sag A*) has multiple bright "lumps". Maybe it's in the linked papers which I haven't gotten to yet, but why the difference? Is it due to the observation method or does it reflect a real difference? Or both?
From the announcement presentation, this happened due to this image being an average of many, many different images. Due to it's size, the motion of the accreting material around SgtA* moves much, much faster relative it than the material around M87. While the accreting material around both BHs move at similar speeds, M87 is about 2000x more massive than SgtA . Due to that, the material around M87 takes weeks to orbi…
Great explanation, thanks!
Re: Astronomers reveal first image of the black hole at the heart of our galaxy
#328Earlier quoted context omitted.
I’m looking forward to reading your scientific paper.
And I am looking forward to have many other different teams reproduce your results independently. I also would like to notice you did not explain why my blue "picture" would be less a "picture" than yours.
Re: Astronomers reveal first image of the black hole at the heart of our galaxy
#329Earlier quoted context omitted.
Didn’t I already reply to you weeks ago about a similar comment? Now you can read the actual papers which explain in detail why your comment is incorrect.
I did read them and I'm not satisfied with their methods.
How about this independent analysis:
https://ui.adsabs.harvard.edu/abs/2022arXiv220510267P/abstra...