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david_taurus83

Picture of black hole...

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2 hours ago, Rodd said:

But we have to think about individual photons if we are considering a physical orbit due to gravity--the probabilistic nature of the photon cloud would be negated--the photons could only exist in a 2 dimensional space (an orbital line).  No more probability.  And yes--the race track is wide and long--but remember solar system sized matter/energy systems are the contestants--so the density of the accretion disc (energy and mass) would no doubt be very high.  That, after all, is where all the emitted energy comes from--friction between the particles on the racetrack--heated up to gamma ray temperatures-turned into energy--which is where the energy comes form to emit them at relativistic speeds.  they are racing around at relativistic speeds caused by the conservation of angular momentum as they are pulled inward to ever decreasing orbital diameters. creating extreme heat and pressure--so much that the disc cant hold them and they are emitted outward--huge bursts of energy from the friction.

Rodd

But remember Rodd we are not really talking about the accretion disc. The photo sphere would not be anywhere near the density of the accretion disc; anything with mass would not be able to remain in orbit there. So our photons in the photo sphere would be free to go round and round and round and... :) 

Jim  

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2 hours ago, Rodd said:

I still don't think orbiting photons are likely.  The mass of the black hole changes by the microsecond (quicker),

Apologies for the stupid question, but why does the mass of a black hole change any faster / slower than that of any other celestial body?

Paul

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9 minutes ago, saac said:

ut remember Rodd we are not really talking about the accretion disc. The photo sphere would not be anywhere near the density of the accretion disc; anything with mass would not be able to remain in orbit there. So our photons in the photo sphere would be free to go round and round and round and... :) 

Jim  

But thats my point--the photo sphere is close to the event horizon--just where all the stuff is falling in.  I think photons would not be bable to trvale far becuase they would hit the stuff falling in

Rodd

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6 minutes ago, Paul73 said:

Apologies for the stupid question, but why does the mass of a black hole change any faster / slower than that of any other celestial body?

Paul

With every microgram, the orbit of the photon would change--the orbit is a very specific location--like a line 1 photon think.  So if the mass changes-that line changes, even by 1 gram.  But black holes grow in mass because they pull everything in.  A large meteor strikes the earth every 50,000 years? whatever it is.  The black hole we are talking about sucks in matter equivalent to the entire earth every second--or some crazy value like that--its a huge amount.

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I think a lot depends on if you are talking about the imaged black hole or black holes in general. Some black holes seem to be without a accreation disks and my have a quiet environment. 

Regards Andrew 

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6 minutes ago, Paul73 said:

Apologies for the stupid question, but why does the mass of a black hole change any faster / slower than that of any other celestial body?

Paul

Paul, not a stupid question. The black hole gains mass from the matter falling into it from the accretion disc.  The greater rate is a consequence of the proximity of the accretion disc and the size of the gravitational well produced by the black hole - it feeds with a sizeable appetite. 

Jim 

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1 minute ago, andrew s said:

I think a lot depends on if you are talking about the imaged black hole or black holes in general. Some black holes seem to be without a accreation disks and my have a quiet environment. 

Regards Andrew 

I think you are right Andrew, In fact would a black hole without an accretion disc not be entirely hidden from us. 

Jim 

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8 minutes ago, saac said:

I think you are right Andrew, In fact would a black hole without an accretion disc not be entirely hidden from us. 

Jim 

It might be revealed by the lensing of background galaxies etc.

Regards Andrew 

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2 minutes ago, andrew s said:

It might be revealed by the lensing of background galaxies etc.

Regards Andrew 

Indeed, probably the only practicable way of detecting them unless they interact gravitationally with another body causing it to modify its path. Wasn't there a super massive black hole detected like this; it was influencing the paths of stars orbiting it if I recall correctly.

For me one of the pleasing things to come out of this recent image is how well it supports the predictions made by the likes of Kip Thorne.   His interpretation of the massive black hole in the movie Interstellar looks all the more familiar now.  

Jim 

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23 minutes ago, saac said:

Paul, not a stupid question. The black hole gains mass from the matter falling into it from the accretion disc.  The greater rate is a consequence of the proximity of the accretion disc and the size of the gravitational well produced by the black hole - it feeds with a sizeable appetite. 

Jim 

Sounds plausible. Rather like the accretion disc around a young star? Presumably, the clearing of the locality would operate similarly and a temporary equilibrium would be reached.

A massive star collapses to form a black hole. Presumably matter that was orbiting the star would now just be orbiting the black hole instead. The black hole and the star have the same mass, so same gravity? Anything that would have fallen into the star would fall into the black hole, but nothing more. Granted. Things get very interesting the nearer we get to the black hole, but mass changing materially on a second by second basis sounds unlikely. So the photon accretion disc could be possible?? 

My rather clunky understanding of black holes may well have missed the point.

Paul

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Posted (edited)

The video link from Saac is a great description of the physics at play from a visual standpoint. it is a bit mind bending when considering how such gargantuan gravitational forces affect light and, how we ultimately see it, I cant overstate how exciting it is. I have always hoped i'd see both a black hole and Betelgeuse going supernova before I die, check one off the list.

Equally amazing is the story of this young MIT lady who played a crucial role in this image, congrats to her, a modern day hero.

https://www.theguardian.com/science/2019/apr/11/katie-bouman-black-hole-photo

 

 

Edited by Sunshine
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Interesting article from WD, who provided the HDD for this project. Apparently, they used an innovative special helium filled hard drives to image the black hole, due to the harsh conditions some of the observatories are facing.

It seems that traditional HDD seem to fail as air rarifies:

Quote

At high altitude, the lack of air becomes deadly (think of all those who lost their lives climbing the Everest summit) not just for humans, but also for hard drives. The read/write heads inside of a hard drive actually fly over the disk surface on what we call an “air-bearing.” Without enough air, the heads crash into the disk.

Helium is the second lightest and second most abundant element in the observable universe. Being both inert and 1/7th the density of air, filling hard drives with helium and sealing it brought a myriad of advantages, beyond just operating at high altitude.

For example, with less turbulence than air, heads reading and writing data in a helium-sealed drive could operate more precisely so we could squeeze more data tracks onto disks. Due to the thinner environment, we could also use thinner disks to add more of them in a single drive and increase density to deliver new levels of capacities.

I just learned something today!

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I'm using a non-mechanical, circuit-only SSD memory since 2017 and it's 10x faster but maybe head-and-motor drives still have advantages I don't know of.

Edited by Ben the Ignorant
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I guess it must be capacity but I don't know really.  Maybe the cost gets too high for the vast capacities they needed with SSDs.

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48 minutes ago, Gina said:

I guess it must be capacity but I don't know really.  Maybe the cost gets too high for the vast capacities they needed with SSDs.

Given the huge volume of data I think that's a good guess. 

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I've been binge watching Youtube videos about this image. Katy Bouman, the programmer who wrote the algorithms to help fill in the gaps must be feeling very proud, along with the rest of the team involved. An incredible achievement for a young PhD student, or anyone of course!

This is probably also going to give radio astronomy a boost in peoples minds when they think of astronomy. 

 

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1 hour ago, Knight of Clear Skies said:

Given the huge volume of data I think that's a good guess. 

About 5 petabytes  (5*2^50) according to the internet.

Regards Andrew 

Edited by andrew s

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6 hours ago, Lockie said:

I've been binge watching Youtube videos about this image. Katy Bouman, the programmer who wrote the algorithms to help fill in the gaps must be feeling very proud, along with the rest of the team involved. An incredible achievement for a young PhD student, or anyone of course!

This is probably also going to give radio astronomy a boost in peoples minds when they think of astronomy. 

Apparently, this also started a bit of a rather unhealthy discussion on the Internet. The MIT shared the pictures of this PhD student, and they went viral, as you know. Sadly though, she was pushed to the front seat by most medias as the person without which nothing would have happened, at the expense of the other project members (and there were quite a few!). There were some complaints on social networks, saying her work was as important as other people. Apparently, the MIT simply wanted to promote the work of one of their brilliant students, but also because she's a young woman.

It's sad to see that achieving this amazing result also triggers this kind of discussions... Though I can also understand the anonymous project members, who were certainly as worthy as Katie Bouman. But nobody can be blamed because a picture went viral on the Internet.

At least, the positive side is indeed that it may inspire younger people to work for "space stuff". There is so much left to discover, and the recent progress we made in computer science is going to open new doors. The next decades will be fascinating!

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13 hours ago, Space Oddities said:

Apparently, this also started a bit of a rather unhealthy discussion on the Internet. The MIT shared the pictures of this PhD student, and they went viral, as you know. Sadly though, she was pushed to the front seat by most medias as the person without which nothing would have happened, at the expense of the other project members (and there were quite a few!). There were some complaints on social networks, saying her work was as important as other people. Apparently, the MIT simply wanted to promote the work of one of their brilliant students, but also because she's a young woman.

It's sad to see that achieving this amazing result also triggers this kind of discussions... Though I can also understand the anonymous project members, who were certainly as worthy as Katie Bouman. But nobody can be blamed because a picture went viral on the Internet.

At least, the positive side is indeed that it may inspire younger people to work for "space stuff". There is so much left to discover, and the recent progress we made in computer science is going to open new doors. The next decades will be fascinating!

But she's not a student - she was awarded her doctorate in 2017, and has just been appointed as associate professor at Caltech. 

 

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On 14/04/2019 at 20:54, Space Oddities said:

Apparently, this also started a bit of a rather unhealthy discussion on the Internet. The MIT shared the pictures of this PhD student, and they went viral, as you know. Sadly though, she was pushed to the front seat by most medias as the person without which nothing would have happened, at the expense of the other project members (and there were quite a few!). There were some complaints on social networks, saying her work was as important as other people. Apparently, the MIT simply wanted to promote the work of one of their brilliant students, but also because she's a young woman.

It's sad to see that achieving this amazing result also triggers this kind of discussions... Though I can also understand the anonymous project members, who were certainly as worthy as Katie Bouman. But nobody can be blamed because a picture went viral on the Internet.

At least, the positive side is indeed that it may inspire younger people to work for "space stuff". There is so much left to discover, and the recent progress we made in computer science is going to open new doors. The next decades will be fascinating!

Yeah, it's a shame but I can also totally understand it. One person being the face of the discovery when it's a massive multi national effort will always create resentment. This is unfortunately how life goes as we all know. Having said this, I'm satisfied she is a worthy 'face of the project', as she did a lot of PR work leading up to the final image as well as playing a key role writing algorithms etc . 

Here is one of her talks. I'm impressed by anyone who can stand up and explain a complicated subject in an easy to follow way, and with confidence infront of loads of people. I would fall to pieces and be rocking back and fourth in the corner lol:

 

 

Edited by Lockie
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