2133: "EHT Black Hole PIcture"

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2133: "EHT Black Hole PIcture"

Postby gmalivuk » Fri Apr 05, 2019 6:26 pm UTC

Image
[five years later] Ok, it seems we were accidentally zoomed in slightly too far. But imagine there's a cool-looking twisted accretion disc just outside this black square!

The now nameless OP who didn't make the comic post correctly wrote:I wondered if this might be imaginary, shame on me! For more, there is this: http://www.astronomy.com/news/2019/04/the-event-horizon-telescope-may-soon-release-first-ever-black-hole-image

Lots of luck to them! You might recall that the original intent of the Keck twin telescopes in Hawaii was to do interferometric imaging over a baseline of some tens of meters, but they gave up because they were unable to obtain the requisite control over spacing. To do interferometry it is necessary to adjust the spacing to within a few tenths of a wavelength (better is better), in visible light that means to ca 0.1 micrometer, 1 ten millionth of a meter.

The reason why they are able to do interferometry using radio telescopes has to do in part with the wavelengths being ca a million times longer, but mostly because they are able to link the sites with RF and synchronize timing to within small parts of a microsecond. That's not technologically possible at light wavelengths at present.

On the other hand, maybe they are exploiting the Hanbry-Twiss effect. That might work, but the immense price paid in terms of SNR will make for some really lousy imagery.

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Re: 2133: EHT Black Hole PIcture

Postby Pfhorrest » Fri Apr 05, 2019 7:11 pm UTC

Good commentary, but you should read viewtopic.php?f=7&t=122637

ETA: Unless the joke was that you couldn't find an image of the comic to include in the post?
Last edited by Pfhorrest on Fri Apr 05, 2019 7:16 pm UTC, edited 1 time in total.
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Re: 2133: EHT Black Hole PIcture

Postby SDK » Fri Apr 05, 2019 7:14 pm UTC

Image
Title text: [five years later] Ok, it seems we were accidentally zoomed in slightly too far. But imagine there's a cool-looking twisted accretion disc just outside this black square!


Jeff's screenshot function was broken too, so he asked me to post the image for him. :wink:
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Re: 2133: EHT Black Hole PIcture

Postby gmalivuk » Fri Apr 05, 2019 10:18 pm UTC

Pfhorrest wrote:
ETA: Unless the joke was that you couldn't find an image of the comic to include in the post?

To correctly execute that joke (i.e. in a way that wouldn't have resulted in me changing the post so it said I made it myself), it would have had to include an off-center and/or out-of-focus smartphone picture of the computer monitor.
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Re: 2133: "EHT Black Hole PIcture"

Postby RogueCynic » Fri Apr 05, 2019 10:21 pm UTC

Someone's trying to get a picture of the center of a black hole? I have one. Here you go.

BlackHole.jpg
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Re: 2133: "EHT Black Hole PIcture"

Postby gcgcgcgc » Sat Apr 06, 2019 12:18 am UTC

^ .... wow. Is that to scale?

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Re: 2133: "EHT Black Hole PIcture"

Postby Old Bruce » Sat Apr 06, 2019 12:52 am UTC

gcgcgcgc wrote:^ .... wow. Is that to scale?

Depends on your monitor's size.

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Re: 2133: "EHT Black Hole PIcture"

Postby Soupspoon » Sat Apr 06, 2019 1:08 am UTC

I think you need to rotate the image, it's not the right way up.

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Re: 2133: "EHT Black Hole PIcture"

Postby Flumble » Sat Apr 06, 2019 3:17 am UTC

So, assuming the image isn't going to be pure black, what will colours/brightness indicate?

Soupspoon wrote:I think you need to rotate the image, it's not the right way up.

It's probably one of those stupid images that has an "orientation" specified in the metadata. Open the image in another viewer and it might be rotated the intended way. :roll:

And to cut the original OP some slack: there's good relevant text in the rest of the message.

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Postby BlitzGirl » Sat Apr 06, 2019 6:37 am UTC

I think all press conferences should be properly labeled with PRESS CONFERENCE on the screen.
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Re: 2133: "EHT Black Hole PIcture"

Postby Time Traveler » Sat Apr 06, 2019 5:34 pm UTC

This one struck a chord with me because of how many times I've been frustrated by websites or apps that won't let me save a copy of an image that is already right in front of me on my screen, even breaking core UI functionality to do so. Pinterest is one of the worst offenders in this category, especially because they combine their image-blocking with a slew of other user-hostile features: they hide most of the website behind banners and pop-ups that aggressively push you to create an account (simply to view content, not to interact with it), shrink most images to thumbnail size and provide no way to see the original, and redirect clicks on a post to pages showing a bunch of unrelated posts rather than the thing I clicked on.

I'm glad I know a little about web development, because sometimes the only way to save a copy of an image being displayed on a webpage is to go to Chrome's Developer Console and either find it in the "resources loaded" list or snip the direct URL to the image from the piece of JavaScript that loads it. Whoever decided to prevent users from saving images on these websites evidently didn't understand the fact that in order to display the image on my screen, my browser has to download it, so you can't prevent your precious bits from getting stored on my computer.

BlitzGirl wrote:I think all press conferences should be properly labeled with PRESS CONFERENCE on the screen.


Yes, just like all parties should be labeled with a big hanging banner that says PARTY!
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Re: 2133: "EHT Black Hole PIcture"

Postby 24b4Jeff » Sat Apr 06, 2019 11:38 pm UTC

gmalivuk wrote:Image
[five years later] Ok, it seems we were accidentally zoomed in slightly too far. But imagine there's a cool-looking twisted accretion disc just outside this black square!

The now nameless OP who didn't make the comic post correctly wrote:.


So, why post it yourself?

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Re: 2133: "EHT Black Hole PIcture"

Postby Pfhorrest » Sun Apr 07, 2019 12:32 am UTC

did you not read the link I posted? the answer is in there.
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Re: 2133: "EHT Black Hole PIcture"

Postby gmalivuk » Sun Apr 07, 2019 1:55 am UTC

24b4Jeff wrote:So, why post it yourself?

When you don't post a new comic thread correctly, especially if you get almost everything wrong about how they're supposed to be posted, I change the post so it says I posted it, and I remove the name of the person who did it wrong in the first place.

If you want credit for starting a comic thread, do it right.
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Re: 2133: "EHT Black Hole PIcture"

Postby somitomi » Sun Apr 07, 2019 9:34 am UTC

Time Traveler wrote:I'm glad I know a little about web development, because sometimes the only way to save a copy of an image being displayed on a webpage is to go to Chrome's Developer Console and either find it in the "resources loaded" list or snip the direct URL to the image from the piece of JavaScript that loads it. Whoever decided to prevent users from saving images on these websites evidently didn't understand the fact that in order to display the image on my screen, my browser has to download it, so you can't prevent your precious bits from getting stored on my computer.

I recently giggled a bit over flickr telling me the author doesn't allow me to download a photograph. You try and stop me flickr, I have the power of "Developer Tools". Pinterest does and as a result it's in rather exclusive group of things I utterly despise.
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Re: 2133: "EHT Black Hole PIcture"

Postby speising » Sun Apr 07, 2019 10:31 am UTC

that serves the same function as picket fences: they don't really stop you if you're determined, but they show you that what you're about to do is illegal.

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Re: 2133: "EHT Black Hole PIcture"

Postby fearless_fool » Sun Apr 07, 2019 12:21 pm UTC

The EHT website states that:

The imaging algorithms we developed fill the gaps of data we are missing in order to reconstruct a picture of a black hole.


The mind boggles at the opportunities: what will they fill the gaps with?

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Re: 2133: "EHT Black Hole PIcture"

Postby ijuin » Sun Apr 07, 2019 3:29 pm UTC

Interpolation, perhaps?

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Re: 2133: "EHT Black Hole PIcture"

Postby Drooling Iguana » Mon Apr 08, 2019 10:08 am UTC

fearless_fool wrote:The EHT website states that:

The imaging algorithms we developed fill the gaps of data we are missing in order to reconstruct a picture of a black hole.


The mind boggles at the opportunities: what will they fill the gaps with?

Frog DNA.

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Re: 2133: "EHT Black Hole PIcture"

Postby cellocgw » Mon Apr 08, 2019 11:56 am UTC

Drooling Iguana wrote:
fearless_fool wrote:The EHT website states that:

The imaging algorithms we developed fill the gaps of data we are missing in order to reconstruct a picture of a black hole.


The mind boggles at the opportunities: what will they fill the gaps with?

Frog DNA.

Aaaaaaannnd we have a WINNER



Hmmm, what actually happens if you insert Frog DNA into a fertilized bird's egg? Amphibian != dinosaur. Wait, I know: a penguin.
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Re: 2133: "EHT Black Hole PIcture"

Postby jonhaug » Mon Apr 08, 2019 11:58 am UTC

Flumble wrote:So, assuming the image isn't going to be pure black, what will colours/brightness indicate?

Soupspoon wrote:I think you need to rotate the image, it's not the right way up.

It's probably one of those stupid images that has an "orientation" specified in the metadata. Open the image in another viewer and it might be rotated the intended way. :roll:

And to cut the original OP some slack: there's good relevant text in the rest of the message.


Well, this is what I get (ImageMagick):

Code: Select all

  Rendering intent: Perceptual
  Gamma: 0.454545
  Chromaticity:
    red primary: (0.64,0.33)
    green primary: (0.3,0.6)
    blue primary: (0.15,0.06)
    white point: (0.3127,0.329)
  Transparent color: black
  Intensity: Undefined
  Dispose: Undefined
  Orientation: Undefined
  Tainted: False

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Re: 2133: "EHT Black Hole PIcture"

Postby nixiebunny » Mon Apr 08, 2019 12:22 pm UTC

This comic resonates with me, as I am an engineer who has built a bunch of equipment for several of the EHT telescopes. This includes spending a month at the South Pole.

The joke in this comic is that the data reduction happens after all the hard drives with the data are mailed to the correlators at MIT and Max Planck. It's not a real-time observation.

Ask me stuff about the EHT.

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Re: 2133: "EHT Black Hole PIcture"

Postby Quizatzhaderac » Mon Apr 08, 2019 4:48 pm UTC

back in 2017 wrote:Project director: Point all imaging devices at Sagittarius A*!
Targeting tech: Targeting ascension 17h 45m 40.0409s. Declination −29° 0′ 28.118″.
Project director: Activate all imaging devices.
Guy in front of a console with one big button: Activating!
Image of the general galactic core is displayed. A small red box surrounds Sagittarius A*.
Project director: Zoom and enhance!
Targeting tech: Zooming!
Image zooms in a becomes a blur.
Imaging scientist: Enhancing!
Minutes pass
Project director: Well, Johnson!? We're waiting!
Imaging scientist: Umm... you understand that this step will take a few years, right?
Project director: Son of a...!
Unlike CSI, they actually have more pixels, but they obviously don't have the algorithm, otherwise they'd be done long ago.
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Re: 2133: "EHT Black Hole PIcture"

Postby Soupspoon » Mon Apr 08, 2019 5:49 pm UTC

They also can't get 'around' troublesome dust clouds, nebulae, etc...
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(That on a loop shows even more how its pre-production composition broke any semblance of feasible reality. Unless it's based on reconstructive gravitational microlensing so you can see the original feature on both sides of the mirror-edged obstruction at once!)

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Re: 2133: "EHT Black Hole PIcture"

Postby RogueCynic » Mon Apr 08, 2019 10:26 pm UTC

cellocgw wrote:
Drooling Iguana wrote:
fearless_fool wrote:The EHT website states that:

The imaging algorithms we developed fill the gaps of data we are missing in order to reconstruct a picture of a black hole.


The mind boggles at the opportunities: what will they fill the gaps with?

Frog DNA.

Aaaaaaannnd we have a WINNER



Hmmm, what actually happens if you insert Frog DNA into a fertilized bird's egg? Amphibian != dinosaur. Wait, I know: a penguin.


Actually, a basilisk. https://en.wikipedia.org/wiki/Basilisk
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Re: 2133: "EHT Black Hole PIcture"

Postby Mikeski » Tue Apr 09, 2019 2:17 am UTC

RogueCynic wrote:
cellocgw wrote:
Drooling Iguana wrote:
fearless_fool wrote:The EHT website states that:
The imaging algorithms we developed fill the gaps of data we are missing in order to reconstruct a picture of a black hole.

The mind boggles at the opportunities: what will they fill the gaps with?

Frog DNA.

Aaaaaaannnd we have a WINNER
Hmmm, what actually happens if you insert Frog DNA into a fertilized bird's egg? Amphibian != dinosaur. Wait, I know: a penguin.

Actually, a basilisk. https://en.wikipedia.org/wiki/Basilisk

Add some beaver DNA, and a few more choice animals, and you might get a platypus.

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Re: 2133: "EHT Black Hole PIcture"

Postby Quizatzhaderac » Tue Apr 09, 2019 9:56 pm UTC

Soupspoon wrote:That on a loop shows even more how its pre-production composition broke any semblance of feasible reality. Unless it's based on reconstructive gravitational microlensing so you can see the original feature on both sides of the mirror-edged obstruction at once!
It took me several time to realize that was supposed to be the same elbow. Why is the image rotated with a lateral transition?
You had to realize you were rotating it to make the image.
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Re: 2133: "EHT Black Hole PIcture"

Postby Keyman » Wed Apr 10, 2019 1:18 pm UTC

Looks like they smoothed out those glitches...
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Re: 2133: "EHT Black Hole PIcture"

Postby Keyman » Wed Apr 10, 2019 1:27 pm UTC

And then, of course, as I'm watching the livestream of the press confeence...the video freezes.
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Re: 2133: "EHT Black Hole PIcture"

Postby Soupspoon » Wed Apr 10, 2019 1:42 pm UTC

Keyman wrote:And then, of course, as I'm watching the livestream of the press confeence...the video freezes.

That's not frozen video, that's extreme time dilation. Who'da thunk that going closer to a black hole to get a better image would have had consequences, eh?

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Re: 2133: "EHT Black Hole PIcture"

Postby SuicideJunkie » Wed Apr 10, 2019 2:32 pm UTC

Time dilation is just an illusion caused by the Mercator projection of spacetime near black poles.

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Re: 2133: "EHT Black Hole PIcture"

Postby Quizatzhaderac » Wed Apr 10, 2019 2:59 pm UTC

Greenland doesn't even really properly exist anymore, it's the time dilation of the Mercator projection.

It's now an archipelago of principally three larger islands, with much of what's labelled "Greenland" is now part of the sea. Currently, greenland is neither "green" nor "land".
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Re: 2133: "EHT Black Hole PIcture"

Postby Pfhorrest » Wed Apr 10, 2019 11:10 pm UTC

SuicideJunkie wrote:black poles.

there is a theory that predicts that for every black pole there is in some other universe a corresponding, usually smaller, white pole.

aside from size, the principle difference is black poles are sucked, while white poles are blown.

and unlike with white poles, once you go to a black pole, you can never go back.
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Re: 2133: "EHT Black Hole PIcture"

Postby Soupspoon » Wed Apr 10, 2019 11:37 pm UTC

If they're white and red, they may not be poles, but russians.

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Re: 2133: "EHT Black Hole PIcture"

Postby 24b4Jeff » Wed Apr 10, 2019 11:57 pm UTC

gmalivuk wrote:
24b4Jeff wrote:So, why post it yourself?

When you don't post a new comic thread correctly, especially if you get almost everything wrong about how they're supposed to be posted, I change the post so it says I posted it, and I remove the name of the person who did it wrong in the first place..


The question was about, (especially if everything about the post is wrong), why you did not do the logical thing, which is simply not allow it to be posted.

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Re: 2133: "EHT Black Hole PIcture"

Postby Soupspoon » Thu Apr 11, 2019 12:11 am UTC

Surely you cared more about the message (that was allowed to be broadcast) than the meaningless bragging rights (that were withheld). Certainly you seem upset at having been found wanting, though it was only your public questioning that made it common knowledge.

Enthusiasm is good, and there was obviously value in your original post, but surely you can see that a compromise had to be made, and this was the most equitable result under the circumstances. Anything else causes more work and/or less value.

Could this be a better discussion for elsewhere, though? (Even in light of the chain of irrelevant whimsy that my last post was part of.)


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