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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

#141

Post by fasteddie31003 »

malfist wrote: post #137
fasteddie31003 wrote: post #40

Earlier quoted context omitted.

Peer reviewed has nothing to do with the scientific method. It is just a layer of scientific bureaucracy. Just give me a calibration image of another celestial body and I'll be happy.

You realize peer review isn't just something you do and they automatically publish you, right? Peer review makes sure your science is sound. But I'm sure you're more of an expert than anybody serving in a peer review board.

Peer review has let plenty of bad science through. Don't burn me at the stake because I speak heresy against the holy theologians of astronomy.

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

#142

Post by system16 »

f1codz wrote: post #130
ISL wrote: post #89

Earlier quoted context omitted.

Gravitational physicist here. Every time we look in a new place and see that GR still works, it is pretty amazing. Part of this is the fact that everyone in the field works very hard to find a crack in GR's armor, and so far it has resisted everyone. The other part is that GR has a romantic beauty to it, both in structure and in predictions. Each time GR matches reality in a new context, the feeling is akin to watchi…

How long does it take to train to fully appreciate this like you do, if that is even possible for someone in a full time job in an unrelated field.

How long is a piece of string? It depends...

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

#144

Post by sailingparrot »

NHQ wrote: post #140

This image came out several years ago or I have seen the future.

third, slightly more plausible, option: What you have seen a few years ago was the image released of the blackhole at the center of the galaxy M87 [1].

Today's announcement is about the blackhole at the center of our own galaxy.

[1]: https://www.nationalgeographic.com/science/article/first-pic...

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

#145

Post by whoopdedo »

KAMSPioneer wrote: post #126
kloch wrote: post #57

Earlier quoted context omitted.

For Interferometry to work the data from different baselines has to be collected at the same time so waiting 6 months does not help. Spacecraft could theoretically be used to extend the baselines but the volume of data to be transferred is prohibitive with current spacecraft comm tech. Even on Earth they resort to shipping cases of hard drives instead of transferring over the Internet. One technique where simply wait…

So I work at one of the participating institutes, and you're very much dead-on about transfer speeds/logistics limiting options here. I'm not an astronomer, so grain of salt, but the data is generated at a bit of an unwieldy pace: there are four collector nodes at each site, each of which generates ~16Gbps of raw data (though read speeds from disk after observation is more like 8Gbps). This, as you say, forces most l…

Where can I read more about how that volume of data is generated? I'm looking at the description of ALMA right now. So is each "node" a cluster of antennas? And each antenna is collecting a high-resolution snapshot across a wide frequency band. And each snapshot has to be timestamped. What's the sampling rate? It says the frequency range is 31GHz to 950GHz but how wide can a single snapshot be? Then to move it around are you using InfiniBand or something even faster?

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

#149

Post by Dave_Rosenthal »

VikingCoder wrote: post #133
kloch wrote: post #41

Earlier quoted context omitted.

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…

Can someone do the math for me? Let's say I'm 6 feet tall... what object would I have to hold out at arm's length, to have the same angular width as the entirety of this image? A bacteria? A virus?

https://www.wolframalpha.com/input?i=50+microarcseconds+*+%2...

The answer is ~200 picometers.

Wolfram lists some helpful comparisons:

1/2 the distance between base pairs in DNA

3x the atomic diameter of helium (the smallest atom)

Suffice to say you'd have a hard time seeing it as it would be 3,000x smaller than the wavelength of visible light.

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