Unveiling the first-ever image of a black hole [video] • Hacker News Board

Re: Unveiling the first-ever image of a black hole [video]

#111

Post by Ono-Sendai » Wed, Apr 10, 2019, 2:23 PM UTC

nukeop wrote: post #42

acl777 wrote: post #17

There are people that can't believe the Earth is round... I can't imagine what "alternative explanation" will be made to explain a black hole...

There is still zero evidence that there exists such a thing as a black hole with all its fantastic properties. We have a picture of a red-yellow accretion disk and that's it. Black holes remain a mathematical artifact of general relativity and there is as much evidence of their existence as of crystal healing and astral travel. There is at best some evidence of very massive objects at certain points.

I think you're right, that they probably are a mathematical artifact of GR. Regardless, what they are in the real world will share quite a few properties with black holes.

Re: Unveiling the first-ever image of a black hole [video]

#112

Post by SketchySeaBeast » Wed, Apr 10, 2019, 2:23 PM UTC

hacker_9 wrote: post #64

gigatexal wrote: post #29

Any word if Einstein's predictions are correct or refuted? There was word that if the shadow looked a certain way it could mean that relativity is incomplete.

General relativity predicted the event horizon, but it breaks down when trying to predict what is going on in the center, as all equations go to infinity, which is likely to be more a problem with our current understanding than what is actually happening.

I wonder if this is a call for another level of math. Are we just not able to take the derivative of something in respect to space time rather than just time?

Re: Unveiling the first-ever image of a black hole [video]

#113

Post by princekolt » Wed, Apr 10, 2019, 2:24 PM UTC

LoSboccacc wrote: post #88

piker wrote: post #30

Higher resolution official release seems to be: https://www.nsf.gov/news/special_reports/blackholes/download...

the original tiff is 7416x4320 it's still too many pixel, it can be a fifth of that while conveying the same amount of information. I'm puzzled by this, if each of those pixel is actually captured by the lenses, why is it all this much uniform? was it smoothed or does this suggest that it's actually a gigantic uniform cloud of gas? haven't seen the whole video of the release, I'll have to catch up later in the evenin…

There is no lens. This was done using eight radio telescopes (or arrays) around the globe to create a "virtual" radio telescope which is effectively the size of the earth. After that the data of the individual telescopes was processed to produce an image.

There is some more info in the wikipedia article for the Event Horizon Telescope (EHT): https://en.wikipedia.org/wiki/Event_Horizon_Telescope

Re: Unveiling the first-ever image of a black hole [video]

#114

Post by _void » Wed, Apr 10, 2019, 2:24 PM UTC

I don't get the whole "oh it's too blurry and nothing is visible" comments. It's a black hole, what did you expect to see? Interstellar CGI?

Re: Unveiling the first-ever image of a black hole [video]

#115

Post by HenryBemis » Wed, Apr 10, 2019, 2:24 PM UTC

e0m wrote: post #14

"This is like viewing a mustard seed in Washington DC from Brussels"

Pedantic/fun comment: I will assume that one of the presenters said that (I will watch the full video later tonight). One would imagine that that person knows that you cannot see a mustard seed from Brussels because the planet's crust is blocking your line of sight ;) unless the scientist who said that is a flat-earth-believer!

A statement like "it is like viewing a mustard seed X kilometres/miles away would be more appropriate.

And in all seriousness, I have started watching again everything-Star-Trek again (for the 5th time in my life), and news like that make me look up to the sky and think that as a species we do have a chance to move out of here and to a better future.

Re: Unveiling the first-ever image of a black hole [video]

#116

Post by yaseer » Wed, Apr 10, 2019, 2:25 PM UTC

International collaboration on scientific projects (International space station, CERN) always fills me with hope and optimism for humanity.

It's a nice contrast to opening the papers and reading the regular news, dominated by politics, with all the pessimism that creates.

Hooray for science.

Re: Unveiling the first-ever image of a black hole [video]

#117

Post by zaph0d_ » Wed, Apr 10, 2019, 2:27 PM UTC

Are there any papers already out which focus on the technical aspect of reconstructing the image? I heard that they analyzed 3.5 Petabytes of data for this.

Re: Unveiling the first-ever image of a black hole [video]

#118

Post by pcmaffey » Wed, Apr 10, 2019, 2:27 PM UTC

jessriedel wrote: post #53

ragebol wrote: post #25

Earlier quoted context omitted.

Note that the prediction of the light being brighter on one side did come out.

What are you basing that on? (Edit:) From one of the papers released today: > The ring is brighter in the south than the north. This can be explained by a combination of motion in the source and Doppler beaming. As a simple example we consider a luminous, optically thin ring... Then the approaching side of the ring is Doppler boosted, and the receding side is Doppler dimmed...This sense of rotation is consistent with…

Are north and south in astronomy defined relative to Earth’s poles? What about “lateral” directions, since east and west are relative (no poles, ie. no east of earth)?

Re: Unveiling the first-ever image of a black hole [video]

#119

Post by jjeaff » Wed, Apr 10, 2019, 2:27 PM UTC

JumpCrisscross wrote: post #27

Good video that correctly predicted the image and describes why it looks the way it does [1]. TL; DR The dark area is the entire surface of the event horizon, including the side facing away from us, plus some more due to photons missing the event horizon "directly" being drawn in. One side is brighter due to its being Doppler boosted. [1] https://www.youtube.com/watch?v=zUyH3XhpLTo

So amazing that scientists were able to predict what something would look like that we have never seen before.

Re: Unveiling the first-ever image of a black hole [video]

#120

Post by kryptiskt » Wed, Apr 10, 2019, 2:29 PM UTC

patagonia wrote: post #80

legatus wrote: post #52

Earlier quoted context omitted.

Isn't that related to the fact that it has been announced across the world at the same time? In europe it was announced at 3 pm for example. I'm sorry, I don't understand your point

That showmanship counts. I don’t believe HN would argue with me if I said “a strong sales group can make or break a company”. Why is it unfashionable to suggest that, in the marketplace of ideas, with an announcement of this magnitude, this exciting, this “sexy”, the presentation of the announcement would benefit from being delivered in a likewise suitable atmosphere. At night, as an event, in a cool warehouse with c…

Apple always have their unveilings in the morning pacific time.