Comment by photochemsyn | Hacker News Reader

Comment by photochemsyn | Hacker News Reader

Parent Full thread

You mean, this?

https://iopscience.iop.org/article/10.3847/2041-8213/ac6615

>"Since the interferometric measurements are often incomplete in the Fourier domain, the inverse problem of reconstructing an image from the observed data set is usually underdetermined. Consequently, the image reconstruction requires prior information, assumptions, or constraints to derive a reasonable image from the infinite number of possibilities that can explain the measurements."

They seem to have gone to great lengths to address this issue, however. Multiple imaging approaches, synthetic data tests, etc.

https://iopscience.iop.org/article/10.3847/2041-8213/ab0e85/...

Why would looking at something that isn't a supermassive black hole at the center of a galaxy prove that this approach works or doesn't work? You'd have different constraints to apply. See for example VLBI measurements of quasars, which seem to employ the same kind of imaging approach. Theoretical models of quasars aren't the same as theoretical models of black holes. They seem to be using these theoretical models as constraints on data interpretation. Unless the theory is completely wrong, which seems unlikely, this looks like a valid approach.

https://arxiv.org/pdf/1701.04760.pdf

>"Since the interferometric measurements are often incomplete in the Fourier domain, the inverse problem of reconstructing an image from the observed data set is usually underdetermined. Consequently, the image reconstruction requires prior information, assumptions, or constraints to derive a reasonable image from the infinite number of possibilities that can explain the measurements."

If the original commenter has an issue with this, wait 'til they find out about modern CT scans. Or hell even JPEGs.

It's the usual HN physics thread stuff - for some reason physics really brings out the confidently incorrect crowd.

Funny that you mention CT scans.

To quote from a paper[1] on the history of CT scanning:

"Initial images were of inert objects, then specimens from an abattoir, including bullocks brains and pigs bodies"

or

"The prototype was installed at Atkinson Morley’s Hospital in South London where the first patient, a middle aged lady with a suspected frontal lobe tumour, was scanned on 1st October 1971. The surgeon who operated on her shortly afterwards reported that ‘‘it looks exactly like the picture’’"

The default scientific approach to a new imaging algorithm, and especially a new implementation, it to try it on a simple well understood examples first.

[1] Beckmann, E. C. (2006). CT scanning the early days. https://www.birpublications.org/doi/10.1259/bjr/29444122

I cannot get over how many authors that article has.

How is that even possible? Anyone involved in the research in anyway is an author even without contributing to writing the paper with words? Perhaps that’s why.

Right, this. Plus, the paper was probably written by teams, in sections, and giving aggregated feedback.

Rather than attempt to disentangle, large physics collaborations normally have a “You are on all papers we publish while here and X years after you leave”.

Yes, that's basically how it works (kind of like movie credits). On papers with fewer authors, there's a kind of ranking system in the order of the authors: the first author is generally the one who did the experimental work and the actual write-up, the next few may have helped with the write-up and run some of the experiments, the next may have just helped build some of the experimental setup, or otherwise had some material contribution to the research, and the last author is usually their supervisor who reviewed the paper before submission. When the list grows really large like this they usually give up at some point with trying to rank the contributions and just list the rest alphabetically.

> On papers with fewer authors, there's a kind of ranking system in the order of the authors

It depends very much on the field of research and the paper in question. In some fields, it's very common to list the names of the authors alphabetically, no matter the size of their contribution.

Reply on news.ycombinator.com