An announcement for beecee

[studiot]

Since beecee has been feting us lately with scientific announcements I thought I would offer the original announcement about the theoretical proposal of black holes.

 

Quote

1783

If there should really exist in nature any bodies whose density is not less than that of the sun, and whose diameters are more than 500 times the diameter of the Sun, since their light could not arrive at us...we could have no information from sight, yet if any other luminiferous bodies should happen to revolve around them we might still perhaps from the motions of these revolving bodies infer the existence of the central ones.

So we can celebrate the latest discoveries nearly 250 years on.

[beecee]

  Actually the "picture of a BH" claim is far better explained in the following video, particularly from the 1m20 sec mark with regards to the shape as close as any image has ever been to the EH, and photon spheres orbitals, which may add confirmation or otherwise for GR. Nice to see you so interested in such a momentous undertaking. If you have a more realistic descriptive language,then be my guest.

https://www.space.com/event-horizon-telescope-is-trying-to-photograph-black-holes.html

or this may help.....1 min 20 sec mark and 2 min 35 sec mark should help in your understanding....

How to Understand the Image of a Black Hole

I hope that helps. It certainly gave me far more insight into the taking a photo of a BH claim.  

ps: I will also post this video in the appropriate thread I started

[studiot]

23 minutes ago, beecee said:

  Actually the "picture of a BH" claim is far better explained in the following video, particularly from the 1m20 sec mark with regards to the shape as close as any image has ever been to the EH, and photon spheres orbitals, which may add confirmation or otherwise for GR. Nice to see you so interested in such a momentous undertaking. If you have a more realistic descriptive language,then be my guest.

 

I hope that helps. It certainly gave me far more insight into the taking a photo of a BH claim.  

ps: I will also post this video in the appropriate thread I started

 

Good because this was off topic here.

 

I thought some might be interested in just how old the original proposal about black holes is.

[beecee]

17 minutes ago, studiot said:

I thought some might be interested in just how old the original proposal about black holes is.

OK, misunderstood. The paragraph quote you offered in the OP, was it from Carl Schwarzchild?

 

Actually the Newtonian version was hypothesised by John Michell, as you probably would be aware, and called a "Dark Star'

[1783] Actually Michell quote then and not Carl.

Edited April 9, 2019 by beecee

[studiot]

The Carl Schwarzchild you mention was born in 1873.

The quote I gave was from a paper read out to the Royal Society by Henry Cavendish in 1783, on behalf of Michell.

[beecee]

2 minutes ago, studiot said:

The Carl Schwarzchild you mention was born in 1873.

The quote I gave was from a paper read out to the Royal Society by Henry Cavendish in 1783, on behalf of Michell.

Yep, I did finally wake up to that fact, eventually! Thanks.

[studiot]

4 minutes ago, beecee said:

Yep, I did finally wake up to that fact, eventually! Thanks.

The other part of my OP was to thank you for all the Science announcements you have alerted us to lately.

 

Edited April 9, 2019 by studiot

[beecee]

22 minutes ago, studiot said:

The other part of my OP was to thank you for all the Science announcements you have alerted us to lately.

 

Thanks. In another forum many many moons ago, I was labeled a "science cheer leader" for that! Actually took it as a compliment although it was not meant to be. 

[madmac]

Michell predicted that if the Sun were 500 times larger in diameter it would be a dark star (ie if mass=500*500*500 solar masses).

He could have added i think that if the Sun were a few km in diameter it would be a mini dark star (if retaining one solar mass).

Neither of these two kinds of dark star need any GR or any singularity.

I wonder if the event horizon team will be able to tell whether M87 is a Michellian dark star or a mini dark star or an Einsteinian blackhole singularity.

[beecee]

40 minutes ago, madmac said:

Michell predicted that if the Sun were 500 times larger in diameter it would be a dark star (ie if mass=500*500*500 solar masses).

He could have added i think that if the Sun were a few km in diameter it would be a mini dark star (if retaining one solar mass).

Neither of these two kinds of dark star need any GR or any singularity.

Thanks for that...interesting.

Quote

I wonder if the event horizon team will be able to tell whether M87 is a Michellian dark star or a mini dark star or an Einsteinian blackhole singularity.

Good question. I think actually, the evidence that rejects the Newtonian variety Dark Star, from the more likely GR variety is in the "dying Pulse Train" effect.

I'm not exactly up with the exact mechanism or theory of this, other then if there was a surface at or just below the EH, [Dark Star Newtonian variety] it would eject pulses of matter/energy, rather then as observed, absorb them [GR variety which tells us that once the Schwarzchild radius is reached, further collapse is compulsory]

http://www.indiana.edu/~geol105/images/gaia_chapter_1/death_spiral.htm

"NASA's Hubble Space Telescope may have, for the first time, provided direct evidence for the existence of black holes by observing the disappearance of matter as it falls beyond the "event horizon."

Joseph F. Dolan, of NASA's Goddard Space Flight Center in Greenbelt, MD, observed pulses of ultraviolet light from clumps of hot gas fade and then disappear as they swirled around a massive, compact object called Cygnus XR-1. This activity is just as would have been expected if the hot gas had fallen into a black hole".

<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>

 

or this.....

https://arxiv.org/ftp/arxiv/papers/1104/1104.3164.pdf

ABSTRACT

Dying pulse trains (DPTs) ñ pulses of radiation with decreasing intensity and decreasing intervals between them ñ are predicted by General Relativity to occur from material spiraling into an event horizon after detaching from the last stable orbit in an accretion disk around a black hole. Two events resembling DPTs were detected in 3 hours observation of Cyg X-1 in the far UV using the High Speed Photometer on the Hubble Space Telescope (Dolan 2001). We observed Cyg X-1, a leading candidate for a black hole, with the proportional counter array on RXTE to seek such events in the low-energy X-ray region. No dying pulse trains with a characteristic timescale between pulses of 1 - 40 ms were detected in 10 hours of observation during Cyg X-1ís high luminosity state, low luminosity state, and transitions between states, although individual pulses are clearly detectable in data with 1 ms temporal resolution. The 2Û upper limit on the rate of DPTís in the X-ray region is less than half the rate reported by Dolan (2001) in the UV. These negative results are consistent with Cyg X-1 being an extreme Kerr black hole with a characteristic timescale between DPT pulses less than 1 ms

Edited April 16, 2019 by beecee

[peterwlocke]

On 4/9/2019 at 3:23 PM, beecee said:

Thanks. In another forum many many moons ago, I was labeled a "science cheer leader" for that! Actually took it as a compliment although it was not meant to be. 

what one

[beecee]

22 minutes ago, peterwlocke said:

what one

One where they entertain religious nuts, IDers of all denominations, woo adherents, anti mainstream science would be's if they could be's, and anything and everything supernatural and paranormal. Oh and of course the conspiracy nutballs...you know the ones...Faked Moon landings, 9/11 being an inside job etc etc. I prefer not to mention it at this time.

[peterwlocke]

was it future science

1 minute ago, beecee said:

One where they entertain religious nuts, IDers of all denominations, woo adherents, anti mainstream science would be's if they could be's, and anything and everything supernatural and paranormal. Oh and of course the conspiracy nutballs...you know the ones...Faked Moon landings, 9/11 being an inside job etc etc. I prefer not to mention it at this time.