I remember reading about measuring stars with something other than light.
What would that look like? Knowing all particles between us and your target, and then popping a mass into existence in such a way you get a measurement?
Unveiling the first-ever image of a black hole [video]
391–400 of 525 posts
Re: Unveiling the first-ever image of a black hole [video]
#392Earlier quoted context omitted.
It's actually in a galaxy called Messier 87 which is 55 million lightyears away.
Oh, interesting! Wouldn't it be easier to photograph our own? :-)
During the press conference, they said photographing the M87 black hole was like shooting a hibernating bear, and photographing the Sag A* black hole of our galaxy like photographing a quickly moving toddler. Something about the speed making it much harder. It is also much smaller, but that's less of a problem because it's much closer. All in all apparently making it about the same angular size. But it sounds like they'll get to it, it's just harder.
Re: Unveiling the first-ever image of a black hole [video]
#393Earlier quoted context omitted.
It's actually in a galaxy called Messier 87 which is 55 million lightyears away.
Oh, interesting! Wouldn't it be easier to photograph our own? :-)
Actually not. M87 is a 1000 times farther away than Sgr A* but also a 1000 heavier and thus a 1000 times bigger in diameter. (Diameter/radius scale proportionally with the black hole's mass.) Therefore, the actual angular size on our night sky is the same for both black holes and, from this point of view, both would be equally difficult to observe.
However, as they mention in the press conference, Sgr A* moves a lot faster relative to us than M87, so it's much harder to take a still image. (In the press conference they used the example of trying to take a photo of a toddler with an exposure time of 8 hours.)
Re: Unveiling the first-ever image of a black hole [video]
#394Good 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
It doesn't seem to be that accurate, as expectation was for it to have smoother photo sphere, but it has irregular bulges (5 of them). I think they discussed it briefly in the press conference as well. It would be interesting to see if this would change understanding of general relativity and may be give a hint for a theory of quantum gravity.
Look at the expectation examples in the scientific paper from 2013 that is, from ca. 6 years ago:
https://arxiv.org/abs/1309.3519
It matches quite good, I'd say. Page 4.
Re: Unveiling the first-ever image of a black hole [video]
#395Good 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
> Good video that correctly predicted the image and describes why it looks the way it does This is of course a bummer, since this means that the acquired image does not give us any new clues of where our understanding of physics is wrong.
It's probably a bit too early to say because e.g the magnetic field data that was also collected hasn't even been scrutinized yet. This will also almost for sure lend a better understanding of the relativistic jets, in order to hopefully one day tell why they are this way or another depending on the particular black hole rather than just "they are somehow often there".
It's still very early and like the detection of gravitational waves, I think it feels like more of a symbolic step into a new era of space science. It's easy to forget that yesterday, black holes were a result of mathematics and only indirectly shown that they "ought to exist".
So first, I think we need to cut them some slack! Second, I think that if we at all WANT to shatter the Standard Model, I think we first need to be able to do science at the extremes of it! The LHC is one way, probing into the details of black hole mechanics might end up being another
Re: Unveiling the first-ever image of a black hole [video]
#396Good 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
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Re: Unveiling the first-ever image of a black hole [video]
#397Is black hole a 3D object like a sun?
If so, I assume the light in the event horizon cover the whole object, i mean 3D shaped as well.
How the picture taken from the telescope shown the dark area where the black hole is located?
I mean, shouldn’t the whole black hole covered by the light thus we can’t see the black hole?
Re: Unveiling the first-ever image of a black hole [video]
#398I am not trying to throw cold water on this, but I have some questions. This ted talk has a very basic explanation of how they constructed this image. I was curious if anyone with image interpolation experience could weigh in on the method. https://www.youtube.com/watch?v=P7n2rYt9wfU When she first starts explaining their method around 8:00m in, I was initially very skeptical of this result because she said that they…
Was just wondering this myself. How opinionated is this photo?
Re: Unveiling the first-ever image of a black hole [video]
#399What do you reckon is in the black hole?
Re: Unveiling the first-ever image of a black hole [video]
#400Earlier quoted context omitted.
Smart move by Veritasium, making a video commenting the news just before the news actually happens. Time works in weird ways around black holes. Anyways, it is a good one. So is that channel in general. It is also a good video if you just watched Interstellar, because it also explains why the black hole looks the way it does in the movie. Note that the movie black hole rendering is slightly incorrect for artistic rea…
As far as I know, Veritasium and others occasionally join efforts and coordinate around soon to be published scientific discoveries in a goal to increase exposure. Don’t know if this was the case with the black hole image.
It probably wasn't coordinated, because he got the black hole that was being imaged wrong.
He said we would see a picture of Sagittarius A*, but we actually got the black hole at the center of M87.