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Sagittarius A*

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aetherist:

--- Quote from: TimFox on May 13, 2022, 10:28:27 pm ---Or, as Galileo might have said, "yet, they exist".
(Yes, I know that the original quotation is apocryphal.)

Of course, this is how theories are tested in real physics.
--- End quote ---

John Michell predicted large dark stars (& possibly large dark bodies) in 1783.  Pierre-Simon Laplace predicted large invisible stars (& large invisible bodies)in 1793.  Both used Newtonian gravity to calculate the escape velocity, which needs to be greater than the speed of light.   They used simple ballistics, they didnt need relativity nor any singularity nor super-dense matter.
  https://researchonline.jcu.edu.au/9892/
https://researchonline.jcu.edu.au/9892/1/Microsoft_Word_-_Paper__Black_Hole_Concept_Final_.pdf
Michell said that the Sun would be a dark star if 497 times larger (ie 122,763,473 solar masses). 
Using modern numbers this 497 becomes 485.3.
And we would have a dark star if the same size as Earth & 2156 solar masses. 
This 2156 reduces to 1079 solar masses if  we use Einstein's idea that light slows near mass (c reduces to c'). 
Here we insert the escape velocity into the equation for gamma to get the kmps of the slowed light near such a Michellian dark star. 
This 1079 reduces to 780 solar masses if we assume that the dark star has an atmosphere with n=1.33 (ie like water), ie slowing the escaping light in that proportion (c' reduces to c").
Michellian Dark Stars surely exist, & they are a kind of blackhole. 
I wonder whether the events horizon team can tell the difference tween their singularity kind of impossible blackhole & a  Michellian Dark Star (& Laplacian invisible bodies)?

aetherist:

--- Quote from: raptor1956 on May 12, 2022, 10:42:40 pm ---The image is the work of many instruments scattered around the globe and the way in which they are combined is amazing.  The amount of data and the amount of data processing is at another level.
Why am I not surprised aetherist is a "Sky Scholar" fanboy. Brian 
--- End quote ---
Yesirreee – at another level.
Look at  7:00 on the youtube. 
Their blackhole image is  7416 by 4320 pixels, ie 31,037,120 pixels.
Which is  0.2 micro arcsec per pixel. [according to Robitaille].
They have used data processing to improve their telescope resolutions by a factor of  1250 or more. [according to Robitaille]
That means that their telescopes would provide  20.5 pixels each which is processed to give over 31 million pixels. [according to me]
If this technique were used for hospital MRIs then the MRIs would be able to see down to less than a single human cell. [according to me]

   
Sky Scholar     38K subscribers      Comments    814   
The Black Hole Image - Data Fabrication Masterclass!    25,405 views  Jan 7, 2020  The Event Horizon Telescope Collaboration, First M87 Event Horizon Telescope Results.
Link to Professor Robitaille’s papers on Vixra:  http://vixra.org/author/pierre-marie_...

aetherist:

--- Quote from: eugene on May 12, 2022, 10:14:40 pm ---In any case, thanks for not posting a link to a YT video. Ain't nobody got time to watch YT all day!

--- End quote ---
Here are some more links to Pierre Marie Robitaille youtubes.
Sky Scholar: Lectures, Interviews, and Podcasts by Pierre-marie Robitaille

dietert1:
The massive object has an event horizon. The physics inside the event horizon is unknown and it will remain unknown. Everybody can use their own fantasy. For a scientist a singularity is enough of a model.
Of course the new images don't show the black hole but its cosmic ambient outside of its event horizon. As far as i understand gravitational red shift makes hard x-ray radiation observable as mm waves here on earth.

Regards, Dieter

jpanhalt:

--- Quote from: aetherist on May 13, 2022, 11:56:38 pm ---If this technique were used for hospital MRIs then the MRIs would be able to see down to less than a single human cell.

--- End quote ---
MRI's have gotten a lot better over time.  Today, they can resolve objects that are 100 um across.(https://kottke.org/19/07/the-highest-resolution-mri-scan-of-a-human-brain#:~:text=A%20team%20of%20researchers%20at,small%20as%200.1%20millimeters%20across.)

RBC's are about 8 um.  WBC's are larger.  Megakaryocytes and many tissue cells approach that size.

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