All Questions
Tagged with event-horizon-telescope black-hole
12
questions
9
votes
2
answers
926
views
Why is the ring in this simulation of Sgr A* off center?
In the recent releases of images of Sgr A*, simulated versions of what they expected were included along side the actual images they were able to get. What confuses me about these simulated images (...
- 3,404
9
votes
1
answer
2k
views
Doubt regarding size and shape of black hole images published by the Event Horizon Telescope (EHT)
The recent publications of the images of black hole shadow by the Event Horizon Telescope collaboration prompts us to study black hole images in more details. According to the no-hair theorem, the ...
- 323
3
votes
1
answer
201
views
How, precisely, do radio astronomers detect (and record) the phases of waves for interferometry?
Interferometry is always in the news, and at radio frequencies it has been for a long time...
The popular press always talks about directly 'interfering' two waves as they come in, but can they tell ...
- 5,307
3
votes
1
answer
280
views
How can light circle a black hole one or more times and then escape again? [duplicate]
The shadow that is cast by a black hole was beautifully captured by the event horizon telescope. A concentration of light in the photon sphere around the hole (adjacent to the event horizon) ...
7
votes
1
answer
143
views
Is there any work underway to push the long baseline capabilities of the Event Horizon Telescope to sub-millimeter wavelengths?
The Max Planck Institute for Radio Astronomy's press release Something is Lurking in the Heart of Quasar 3C 279; First Event Horizon Telescope Images of a Black-Hole Powered Jet shows a stunning ...
- 30.7k
8
votes
2
answers
1k
views
Would Hubble Space Telescope improve black hole image observed by EHT if it joined array of telesopes?
My question is related to black hole image released in April. As far as I understand idea of EHT, it joins observations from multiple locations to work like one telescope with radius that is equal to ...
- 83
2
votes
2
answers
457
views
If a black hole does not emit light, how can one take a picture of the black hole itself?
There's some discussion that the image composed by the Event Horizons Telescope is really just an accretion disk. To "take an image" of something, you need the light reflecting off of the surface of ...
- 282
3
votes
1
answer
403
views
Do the "schwarzschild metric" or the "isotropic metric" fit the Event Horizon telescope data on Messier 87 better?
The "Schwarzschild solution" in "Schwarzschild metric" looks like:
$$\text -c^2d\tau^2=-\left(1-\frac{2GM}{rc^2}\right)c^2dt^2+\left(1-\frac{2GM}{rc^2}\right)^{-1}dr^2+r^2(d\theta^2+\sin^2\theta\,d\...
- 457
3
votes
1
answer
430
views
Is this the best non-radio image of whatever's at the center of M87? How was it taken?
The BBC News article First ever black hole image released shows the instantly-iconic radio image of the (almost certainly) supermassive black hole at the center of the M87 galaxy, just released by the ...
- 30.7k
41
votes
3
answers
9k
views
Why are there uneven bright areas in this photo of black hole?
In the recently released photo of a black hole shown above, which was created by using data from EHT, why is the lower region brighter than the one above? Is it because of the rotation of the ...
- 974
75
votes
5
answers
15k
views
Why not take a picture of a closer black hole?
There are closer galaxies than Messier 87 for sure, even ours! It sparked my curiosity that they went with one 53 million light years away. Is there a reason for this?
- 733
27
votes
2
answers
8k
views
Why didn't the Event Horizon Telescope team mention Sagittarius A*?
At the press conference this morning, the Event Horizon Telescope team didn't say much about Sagittarius A*, which was the target many of us have been waiting for.
Is there any explanation anywhere ...
- 415