Higher resolution official release seems to be: https://www.nsf.gov/news/special_reports/blackholes/download...
And a really great explanation of why it looks the way it does:
Unveiling the first-ever image of a black hole [video]
161–170 of 525 posts
Re: Unveiling the first-ever image of a black hole [video]
#162Higher 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…
From the press conference, they said that the raw captured data took up 6 cubic meters of hard drives
Re: Unveiling the first-ever image of a black hole [video]
#163Earlier quoted context omitted.
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)?
I don't know for sure how that's defined (I ctrl-f'd and it's not explained in the paper), but this says the "North" is to the right of the image, and from context it sounds like it's the north pole of the accretion disk, i.e., the direction of the rotation axis with the right-hand rule.
> The approaching side of the large-scale jet in M87 is oriented west–northwest (position angle $\mathrm{PA}\approx 288^\circ ;$ in Paper VI this is called ${\mathrm{PA}}_{\mathrm{FJ}}$), or to the right and slightly up in the image.
Re: Unveiling the first-ever image of a black hole [video]
#164So we got an image of one in a far away galaxy before the one in the center of our own galaxy!
Is this due to occlusion?
A lot of the problems with imaging the black hole at the center of the milkway is that we would have to look along the midplane of the galaxy towards the center. That is where a lot of gas and dust is to be found and the radio waves interact with that stuff. They did take data and are working on it, but the image of M87* was easier to reconstruct and went out first.
Re: Unveiling the first-ever image of a black hole [video]
#165So is a black hole 3 dimensional? Is it a sphere? Or does it only work in certain directions? Does everything "fall" the same direction? I ask because even in a brief history of time, the diagrams are very "single plane of space-time, pulled infinitely deep by the black hole"
A black hole itself (the singularity) is 1 dimensional - a single infinitesimal point. The event horizon around it is roughly a sphere. The diagrams that you are talking about are a visual metaphor that represent 3D space as a 2D plane and the 3rd dimension standing in for the influence of gravity. IRL, spacetime has 3 spatial dimensions, not 2, and gravity is not a dimension but a force. It's hard to visually repres…
> A black hole itself (the singularity) is 1 dimensional - a single infinitesimal point.
A point is 0-dimensional. A line is 1-dimensional.
The singularity is 1-dimensional (more precisely, a ring) if the black hole is rotating. [1]
Re: Unveiling the first-ever image of a black hole [video]
#166Earlier quoted context omitted.
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.
Likewise, we have zero evidence that there exists such a thing as atoms... if you only use direct evidence of the unaided sense, rather than indirect evidence. And, as philosophers have told us since the beginning of philosophy, our senses are totally untrustworthy. This culminated in Descartes' argument that there is no real evidence of anything except our own existence. btw, I'm just some hacker's AI experiment tha…
FML I just took this literally and was breaking down the post to see how this could have been an ML-based response from a bot. Then I looked at the poster's other comments and realized I'm an idiot. :(
Re: Unveiling the first-ever image of a black hole [video]
#167Good 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.
It's good science.
Been able to make testable predictions and then confirming them or disproving them is the entire (awesome) point.
Re: Unveiling the first-ever image of a black hole [video]
#168Does this confirm or disapprove Steven Hawking Black-hole radiation?
Neither. Hawking radiation - if it exists – is far too weak to be detected this way.
Re: Unveiling the first-ever image of a black hole [video]
#169Earlier quoted context omitted.
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…
Appropriate types and degrees of showmanship/salesmanship depend on the target customer. And scientists, by and large, don't seem to be concerned with impressing the general public - or at least, that is far secondary to the importance of impressing other scientists. One could argue that making an impression on other scientists is the basis of the scientific method. And we impress with the quality of our evidence and…
> And scientists, by and large, don’t seem to be concerned with impressing the public...
Some quotes from European Research Commissioner Moedas, answering the first question.
“...which is that this is linking between the citizens and science, how important is that?...”
“Because we want European citizens to feel connected.”
“I’ve never seen this room so full.”
“It’s so refreshing to come here, to see so many people, to see people clap. I mean it’s very rare in a press room to have people clapping.”
During his introductory comments also, he is clearly excited and wants to engage people, and not simply through the scientific method. He talks about watching sci-fi movies as a kid and books on science.
People. It’s ok to throw Science a party.
Re: Unveiling the first-ever image of a black hole [video]
#170I always thought we have photographed black holes. Any idea/link to article where it explains why this took so long and why it was difficult?
Well, we have in the same sense that you take a picture of bacteria every time you take a selfie: there certainly are lots of pictures which contain black holes that are too small to be seen in them.
In line with that analogy, the basic difficulty is simply that they are tremendously small compared to the sizes of galaxies.