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Astronomers reveal first image of the black hole at the heart of our galaxy

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Re: Astronomers reveal first image of the black hole at the heart of our galaxy

#41

Post by kloch »

jrgd wrote: post #32

I find the whole thing amazing and captivating - yet the image is … huh … slightly underwhelming. It looks like some gaussian blurred random image. I wish it could be the kind of crisp image JWST ‘sent’. It’s difficult to force oneself to not romanticise these un-visible things based on artists visualisation we got accustomed to.

It's actually one of the sharpest images ever made - in terms of angular resolution. The Sag.A* ring is about 51 microarcseconds in diameter. The EHT has a theoretical resolution of ~25 micro arcseconds. For comparison NirCam on Webb has a pixel resolution of 70 miliarcseconds (about 2800 times worse resolution than EHT).

The reason it looks blurry is that the black hole features are close to the resolution of EHT so it's only a dozen or so pixels worth of information enlarged to typical image size.

EHT is essentially a radio telescope with a dish the size of the Earth. The only way to get higher angular resolution is to use higher frequencies (which they are working on) or use radio telescopes in space to get longer baselines than the diameter of the Earth.

Re: Astronomers reveal first image of the black hole at the heart of our galaxy

#42

Post by fasteddie31003 »

wumpus wrote: post #34
fasteddie31003 wrote: post #29

I am very skeptical of the Event Horizon Telescope (EHT) images because they are not following a scientific method that results in a true representative image of their target. In my opinion astronomy is jumping the shark with these images by making this a big PR stunt. I've looked at their methods for their earlier images and they seem to be hunting for a circle that looks like a black hole in their data. The EHT's f…

Didn’t I already reply to you weeks ago about a similar comment? Now you can read the actual papers which explain in detail why your comment is incorrect.

I did read them and I'm not satisfied with their methods.

Re: Astronomers reveal first image of the black hole at the heart of our galaxy

#44

Post by nuccy »

jrgd wrote: post #32

I find the whole thing amazing and captivating - yet the image is … huh … slightly underwhelming. It looks like some gaussian blurred random image. I wish it could be the kind of crisp image JWST ‘sent’. It’s difficult to force oneself to not romanticise these un-visible things based on artists visualisation we got accustomed to.

Well, given that JWST has at least 2000 worse resolution that EHT (see my comment below on that topic with some links). Thus the blurriness of this observed object is just a result of enormously small size versus distance to it. Any star observed by JWST is much-much bigger (i.e. has bigger angular size). During the live event [1] they make a lot of size/distance comparisons, like resolving individual bubbles in a beer glass in New York from Munich Biergarten, or a donut on the surface of the Moon resolved from the Earth.

1. https://www.youtube.com/watch?v=rIQLA6lo6R0&t=1930s

Re: Astronomers reveal first image of the black hole at the heart of our galaxy

#45

Post by tzs »

markus_zhang wrote: post #19
adgjlsfhk1 wrote: post #17

Earlier quoted context omitted.

GR and quantum field theory don't work together, so at least one of them is wrong, and it would be good to figure out which and how.

Thanks. Can you please point me to some popular science article that explains why the two do not agree with each other?

Here are a few that might help:

https://gizmodo.com/why-cant-einstein-and-quantum-mechanics-...

https://www.theguardian.com/news/2015/nov/04/relativity-quan...

https://en.wikipedia.org/wiki/Problem_of_time

https://physics.stackexchange.com/questions/387/a-list-of-in...

For a good general source if you want to learn a lot more from a good popular science point of view (but one that takes great care to not accidentally mislead by oversimplification as often happens with popular science) about general relativity and quantum mechanics, try PBS Space Time, especially after Dr. Matt O'Dowd took over as host and main writer.

https://www.youtube.com/c/pbsspacetime

Re: Astronomers reveal first image of the black hole at the heart of our galaxy

#46

Post by [deleted] »

malfist wrote: post #36
fasteddie31003 wrote: post #29

I am very skeptical of the Event Horizon Telescope (EHT) images because they are not following a scientific method that results in a true representative image of their target. In my opinion astronomy is jumping the shark with these images by making this a big PR stunt. I've looked at their methods for their earlier images and they seem to be hunting for a circle that looks like a black hole in their data. The EHT's f…

Why do you think you know more about astronomy than a team of scientists publishing peer reviewed information?

[deleted]

Re: Astronomers reveal first image of the black hole at the heart of our galaxy

#47

Post by wumpus »

fasteddie31003 wrote: post #42
wumpus wrote: post #34

Earlier quoted context omitted.

Didn’t I already reply to you weeks ago about a similar comment? Now you can read the actual papers which explain in detail why your comment is incorrect.

I did read them and I'm not satisfied with their methods.

You read the 10 just published papers? Impressive.

Re: Astronomers reveal first image of the black hole at the heart of our galaxy

#48

Post by mabbo »

markus_zhang wrote: post #11
mabbo wrote: post #5

> “We were stunned by how well the size of the ring agreed with predictions from Einstein’s Theory of General Relativity," And ten thousand physicists sighed disappointingly.

Just curious but why?

Quantum Physics and General Relativity make different predictions in specific circumstances which are beyond our ability to test to figure out which one is wrong. They can't both be perfectly correct. But in every test we can make, both seem to model reality really well.

The best place to look for new data where we might find reality disagreeing with either model is in the extreme parts of the universe, like black holes. If there was even a hint in this photo that General Relativity wasn't perfectly accurate, we might be able to take the discrepancy and build a new model that solves the disagreement.

Whoever does that gets a Nobel Prize and has their name as immortalized as "Einstein".

Re: Astronomers reveal first image of the black hole at the heart of our galaxy

#49

Post by jeremyjh »

adgjlsfhk1 wrote: post #17
markus_zhang wrote: post #11

Earlier quoted context omitted.

Just curious but why?

GR and quantum field theory don't work together, so at least one of them is wrong, and it would be good to figure out which and how.

Why would that matter at this scale ?
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